Serious Concerns Over Parts Availability

[KJL]

After having some issues with trouble codes and researching possible causes, a troubling trend left me somewhat panic stricken. Relatively speaking our cars are not that old but it seems more and more replacement parts are simply no longer available. The few folks who we rely on for such parts are running out of their stock piles. What does this mean for the future of our ZR1's?


I never thought I would consider this but should I just sell them now while they are least running? (I own 2)



When I read one of the possible causes for code 43 is a failed ignition control module and oh BTW they are no longer available or the tail shaft for my transmission is no longer available not to mention the ECM, even the alternator, starter...heck it is even a challenge finding the right wiper blades that fit under the hood.....I am really begin to wonder. Are all the things that make this car so special also be its undoing?



Has anyone compiled a list of parts that are no longer available for our cars?

[Paul Workman]

After having some issues with trouble codes and researching possible causes, a troubling trend left me somewhat panic stricken. Relatively speaking our cars are not that old but it seems more and more replacement parts are simply no longer available. The few folks who we rely on for such parts are running out of their stock piles. What does this mean for the future of our ZR1's?


I never thought I would consider this but should I just sell them now while they are least running? (I own 2)



When I read one of the possible causes for code 43 is a failed ignition control module and oh BTW they are no longer available or the tail shaft for my transmission is no longer available not to mention the ECM, even the alternator, starter...heck it is even a challenge finding the right wiper blades that fit under the hood.....I am really begin to wonder. Are all the things that make this car so special also be its undoing?



Has anyone compiled a list of parts that are no longer available for our cars?

Well, that's what the REGISTRY is for! It's a network of ZR-1 nuts who can help each other with parts, or sources for them. When something gets scarce, many times various individuals (Jerry's Gaskets is but ONE example) come up with new sources. (Jerry is working on and nearly complete with a DIS module...just ONE example.

You're working yourself up needlessly!

[TX '90 ZR1]

Well, that's what the REGISTRY is for! It's a network of ZR-1 nuts who can help each other with parts, or sources for them. When something gets scarce, many times various individuals (Jerry's Gaskets is but ONE example) come up with new sources. (Jerry is working on and nearly complete with a DIS module...just ONE example.

You're working yourself up needlessly!

DITTO!! There's enough firepower here to keep 'em running.
If you have an issue, post it up. Someone here has been there before.

[Demps]

I share your concern. Every time I get in a car, it's something. Today, thankfully, it was only a battery. I'm always tinkering to keep them tip top. Working on something else tomorrow.

My biggest disappointment is GM's abandonment but apparent greed to 'propriety'. It is not right that GM won't support the cars themselves but also won't give an olive branch to the enthusiasts. You can get, for a price, old German car parts. The aftermarket never embraced or lost interest in ZR-1 reproductions--sure it's a business case.

I am extremely thankful for what Jerry is doing. Others too for that matter. Imagine if GM just overtly supported Jerry with DIS specifics.

I'm strongly debating downsizing. Every time I do I seem to just buy another. Everyone is hoping or speculating these cars will take off. I've been doing the same for nearly two decades & 15ish cars. I don't know where they will go but GM's & the industry's abandonment can't help. Maybe it's time to take note.

Ted

[KJL]

While many mechanical parts can be made or modified from other available parts like the transmission tail shaft, my main concern are the electrical components. Are there any after market ignition modules or ECMs that would work for our cars?

[Paul Workman]

When it comes to the Achilles Heel aka the DIS module, we all share your concern; the ECM - not so much as they are available, and just in the past week(s) Marc Haibeck is starting to referbish the ECMs.

Jerry's Gaskets is progressing toward completion of that DIS module, and we all are on the edge of our seats, far as monitoring progress. But, then again, MegaSquirt has developed an ignition system that piggy-backs on the stock GM system (as I understand it).

Note: Fortunately, the DIS module is very robust and NOT a common mode failure item. However, HEAT is always an issue, far as electronics longivity is concerned. One of the advantages of removing the coolant circulating through the TB is the considerable reduction of heat transferred to that DIS module - at least while the motor is running.

I'm reminded of a Ford Model "T" car club I read about. I came across it while reading a post on the CF FORUM (IIRC) which was dealing with this very subject. The OP was concerned about parts for his early C4 and expressing some panic (if that is the right word) over locating parts. The responder with the model T assured him that through his club and the ability of many to fabricate parts otherwise unavailable, that the concern was largely mitigated.

And SO, I believe, it is the case with our cars as well. Far as I know, there aren't many - IF ANY - cars that are parked for lack of parts OR a reasonable solution to work around. And, thank Lotus and Mercury Marine for building such a robust "bullet-proof" motor that doesn't fail often.

[jss06c6]

Like it or not, we've got a fairly complicated engine design with early vintage computer controls. These engines are a testament to reliability from a mechanical perspective, but we still face a death blow from ECM, CDM and Ignition Module failure and obsolescence.

The car is straight forward mechanically, so fairly easy to maintain from that end. Jerry (God Bless Him) and Graham (Him Too) are working on a replacement for the Ignition Module. MSquirt has a partial solution for the ECM. Torqhead has a solution for the LT-1/4 ECM, but not the LT-5. Don't know of anyone that has a CDM replacement under way, but with the number of C4's still out there,we've got some sources of used boxes..

I love working on my ZR-1. It's unique and a conversation starter at the shows. I will be helping others with their ZR-1's at my new shop. I do understand though, that unlike other antique cars that are purely mechanical, the ZR-1 will face extinction some day in the future when electronics are simply not available.

Mercury Marine's SB4 is a good replacement, but again, not built to talk to the CDM..

Let's just enjoy the ride while we've got it...



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[KJL]

Thanks for the responses... I think panic is a good word when thinking about a $30,000 planter :neutral:

Is the DIS the ignition module?

I have the throttle body passages blocked on both cars.

[KJL]

I know where the ECM and ignition modules live but what is the CCM?

[jss06c6]

Thanks for the responses... I think panic is a good word when thinking about a $30,000 planter :neutral:

Is the DIS the ignition module?

I have the throttle body passages blocked on both cars.Yes

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[jss06c6]

I know where the ECM and ignition modules live but what is the CDM?Controls most of your dash functions and systems. The ECM communicates through a serial buss with the CDM...

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[jss06c6]

Oh, and it's literally buried behind the dash!

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[spork2367]

....You're working yourself up needlessly!

I disagree. There are plenty of parts that people casually ignore. Take a relatively pedestrian hit to the rear bumper cover and quarter panel and the insurance company will total your car. I know, I own one that met that very demise. I restored it, but it was at a salvage yard to be parted out. And that was 5 years ago.

Not only that, but people are less and less willing to part with their spares. 5 years ago pretty much anything could be had for a semi reasonable price. Today there are things that are genuinely hard to find.

A member on here waited for several weeks for someone to offer up an ignition module. I eventually did. But I know there are dozens out there. People's generosity with spares may be running out.

A couple years ago fuel pump assemblies were available on rockauto. Now there are like two places with them and not many left.

What happens if you destroy a rear wheel?...There are a pile of parts that I'm not going to list that will be difficult or impossible to find for a reasonable price in the near future.


When it comes to the Achilles Heel aka the DIS module, we all share your concern; the ECM - not so much as they are available, and just in the past week(s) Marc Haibeck is starting to referbish the ECMs.

Jerry's Gaskets is progressing toward completion of that DIS module, and we all are on the edge of our seats, far as monitoring progress. But, then again, MegaSquirt has developed an ignition system that piggy-backs on the stock GM system (as I understand it).

Note: Fortunately, the DIS module is very robust and NOT a common mode failure item. However, HEAT is always an issue, far as electronics longivity is concerned. One of the advantages of removing the coolant circulating through the TB is the considerable reduction of heat transferred to that DIS module - at least while the motor is running.


I'm reminded of a Ford Model "T" car club I read about. I came across it while reading a post on the CF FORUM (IIRC) which was dealing with this very subject. The OP was concerned about parts for his early C4 and expressing some panic (if that is the right word) over locating parts. The responder with the model T assured him that through his club and the ability of many to fabricate parts otherwise unavailable, that the concern was largely mitigated.

And SO, I believe, it is the case with our cars as well. Far as I know, there aren't many - IF ANY - cars that are parked for lack of parts OR a reasonable solution to work around. And, thank Lotus and Mercury Marine for building such a robust "bullet-proof" motor that doesn't fail often.

ECM's have been refurbished for years by several different groups with varying success. There are some that simply can't be saved. The megasquirt isn't even released to the public. You can call and order one and it will set you back 2800 bucks. And calling it plug and play is misleading. You can plug it in, and it will likely start your engine and run like crap. I know, I have one. So plan on 3800 minimum to buy one and have your car tuned on a chassis dyno. And lose dash functionality. (hopefully fixed in the future)

Saying there are very few failures of a DIS or ECM is misleading with the huge number of low mileage cars. As people start turning more of these into drivers, there will certainly be more failures. We assume they are robust, but the sample size of high mileage cars is small.

The comparison to the model T is weak at best. The car has like 10 freaking wires and tolerances that could be held with a hand drill and file.

Like it or not, we've got a fairly complicated engine design with early vintage computer controls. These engines are a testament to reliability from a mechanical perspective, but we still face a death blow from ECM, CCM and Ignition Module failure and obsolescence.

Mercury Marine's SB4 is a good replacement, but again, not built to talk to the CCM..

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You could buy another ZR-1 cheaper than the SB4.



It's not just the availability of parts, but the cost. If you have a clean driver with 50k+ miles you have a 20k dollar car. Are you going to spend 25% of the value of the car to repair it more than once?



Fuel injectors: (which will almost all need replaced at some point) 700+

engine rebuild (shouldn't be needed, but happens): non OEM cost, probably 5000 parts and labor, bare minimum. OEM not available. (some used low mileage parts)

DIS: Currently 1500-2500. I am willing to bet Jerry's will be in that neighborhood due to the huge investment and manufacturing cost needed to reproduce it.

ECM: 1500 used. 3800 for a megaquirt to be up and running.


Rear quarter panel bumper cover impact: totaled Probably 4000 out of pocket if it isn't severe.

Catastrophic transmission failure: 2500+ for a used transmission. More for a good rebuild/blueprinting.

Now have any two of those things go wrong...People say "drive it and enjoy it." Sure. But be prepared to have it be worth virtually nothing should something break severely. Most aren't going to spend 5-8k on a 15-20k car. And once you've cobbled half you car back together with non OEM parts, how much value is it really going to retain?

[KJL]

No doubt designed by the same engineer that decided the fuse for the cigarette lighter should be in the hidden fuse block under the passenger side dash.

[TX '90 ZR1]

My Goodness!! Why all the angst (a feeling of deep anxiety or dread, typically an unfocused one)?
One would think that these cars mysteriously appeared from an unknown, other worldly source and are beyond what we mere mortal humans can comprehend.
It's just a freaking car, albeit a special one.
Enjoy your car. If it breaks, I bet someone can figure out how to fix it.
:cheers:

[spork2367]

My Goodness!! Why all the angst (a feeling of deep anxiety or dread, typically an unfocused one)?
One would think that these cars mysteriously appeared from an unknown, other worldly source and are beyond what we mere mortal humans can comprehend.
It's just a freaking car, albeit a special one.
Enjoy your car. If it breaks, I bet someone can figure out how to fix it.
:cheers:

Posts like this are 100% worthless. Sorry, but it's just feel good fluff that doesn't address the OP's concern at all. We all enjoy these cars, that's why we own them. The angst is over the fact that the car is complex, and has difficult to find and/or expensive replacement parts that may someday make the car cost prohibitive to own. There are some parts that will never be remade or have a replacement.

Could you hammer a piece of sheet metal into a rear bumper cover? Sure. Would you want to drive around with it? No.

Could you drop in an LS? Absolutely. Would it still be a special car...no.

Despite what a huge number of people claim, they are hoping to get more out of these cars than they spent. So the angst for them is over the reality that they may not. And the even worse reality that they could end up with a car that is cost prohibitive to fix at all.

[TX '90 ZR1]

I tend to browse and read most of the current posts on this forum. There are some I do not agree with, and others that I do. A large percentage contain some knowledge that is valuable if the particular issue being addressed was encountered.
Each and every post has some value. If not knowledge gained on a technical level, on the level of observing different perspectives about the subject at hand.
:cheers:

[KJL]

I know I mentioned money above but we all know it is more than that. We own these cars because they strike a cord within us. My biggest fear is someday these wonderful cars will go the way other some far less impactful cars have gone way before their time. As a ZR1 community should we not help those few who are trying to find solutions and alternatives to prevent this? I would be the first in line to be help fund R&D and/or product development to this end.

[spork2367]

I know I mentioned money above but we all know it is more than that. We own these cars because they strike a cord within us. My biggest fear is someday these wonderful cars will go the way other some far less impactful cars have gone way before their time. As a ZR1 community should we not help those few who are trying to find solutions and alternatives to prevent this? I would be the first in line to be help fund R&D and/or product development to this end.

Money isn't going to be an issue for everyone. But it will be for some. Whether it's that they can't afford a very expensive replacement part, or whether they can't justify spending 25% of the value of a vehicle to repair it. It's great that a guy like Jerry is willing to use profits from some items to invest into other projects that are less profitable, and or invest his own money. There are things however that will never be replicated unless some incredibly wealthy individual decides he loves ZR-1s and money is no object.

100% concur and a great summary of the issue (actually non issue) :thumbsup:


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Except it is an issue. When an individual on here posted that he needed an ignition module I didn't see you or anyone else pony one up. I sold that individual my one spare unit.

These conversations go the same way every time. Someone posts a musing or question and is seeking facts to support or dispel their musing or answer their question.

The conversation starts with people trying to present the facts as they know them. Then slowly gets jaded by individuals perceptions (the facts through their view of the situation). Then it ultimately declines to pure opinion.

How these threads go:

Question: "Are there going to be enough parts to support these cars into the future?"

Attempt at presenting the facts: "There are definitely some hard to find parts that are only going to get harder to find."

Perception based conjecture and wishful thinking: "There are lots of parts, great people to help, and where there's a will there's a way."

Pure opinion irrelevant to original question: "These cars are the best and we love them no matter what...it's just about smiles per gallon."


There are lots of people whose only perspective on these cars is what they read on this forum and the other forum. Their knowledge of spare parts begins and ends with the for sale section on here and Jerry's gaskets.

On a weekly basis I watch this forum, the other forum, ebay, craigslist, other auction sites, salvage auctions, parts warehouse websites, jerry's, and kurt's.

I doubt there are very many people on here with a better understanding of the parts market than myself. I know I'm not the only one, but there aren't a lot.

If you haven't been watching all those sites, at least once a month, for several years, you really have no idea how the parts market has changed. If your someone who only watches Jerry's site, you'd see him adding items and have the perception that the parts market has gotten better, but you don't see the dozens of items that were commonly available other places that aren't anymore, or the items that have quietly disappeared from his site.

Time will ultimately tell, and maybe people will choose to sell their hoards at some point and the market will be flooded with spare parts. But as it stands now there are parts that will become unavailable in the next couple years that are crucial to these cars.

My view may come across as pessimistic, but unfortunately it's more realistic.

[Dynomite]

My Goodness!! Why all the angst (a feeling of deep anxiety or dread, typically an unfocused one)?
One would think that these cars mysteriously appeared from an unknown, other worldly source and are beyond what we mere mortal humans can comprehend.
It's just a freaking car, albeit a special one.
Enjoy your car. If it breaks, I bet someone can figure out how to fix it.
:cheers:

Concur 100% as before...…….. and after the dissertation :D

Oh.....and guys and gals.....get yourself a NEW Hood Support Gas Cylinder as the Stock Hood Support Gas Cylinder looses gas pressure in its old age. A New Hood Support Gas Cylinder will actually lift the hood back to the top if you lower the hood 6 inches.
Ecklers Corvette Hood Support with New Outer Sleeve (http://www.ecklerscorvette.com/corvette-hood-support-1985late-1996.html)

[TX '90 ZR1]

Dynomite:
Per your statement: Oh.....and guys and gals.....get yourself a NEW Hood Support as the Stock Hood Supports loose gas pressure in their old age.

Well? There's something else for me to add to the "must have" list!
I went and ordered my self 2, yes TWO, can condoms after all the hoopla about them!!
Oh well, if it's fun and feels good, go for it !!!!!
:dancing

[DRM500RUBYZR-1]

Concur 100% as before...…….. and after the dissertation :D

Oh.....and guys and gals.....get yourself a NEW Hood Support as the Stock Hood Supports loose gas pressure in their old age. A New Hood Support will actually lift the hood back to the top if you lower the hood 6 inches.
Ecklers Corvette Hood Support with New Outer Sleeve (http://www.ecklerscorvette.com/corvette-hood-support-1985late-1996.html)



Agree strongly with the first;
and even more strongly with the second.


I am amazed at pristine C-4's that come here, and I watch the owner struggle with the hood as if it were normal.
They replace unbroken things for no reason other than "preventative", yet
miss these seemingly obvious and important things.
Replace the aged support, and splurge on one of Carter's safety pieces when it is open as an added and useful precaution.
Marty

[spork2367]

Concur 100% as before...…….. and after the dissertation :D

Oh.....and guys and gals.....get yourself a NEW Hood Support as the Stock Hood Supports loose gas pressure in their old age. A New Hood Support will actually lift the hood back to the top if you lower the hood 6 inches.
Ecklers Corvette Hood Support with New Outer Sleeve (http://www.ecklerscorvette.com/corvette-hood-support-1985late-1996.html)


Edited for correctness...


How these threads go:

Question: "Are there going to be enough parts to support these cars into the future?"

Attempt at presenting the facts: "There are definitely some hard to find parts that are only going to get harder to find."

Perception based conjecture and wishful thinking: "There are lots of parts, great people to help, and where there's a will there's a way."

Pure opinion irrelevant to original question: "These cars are the best and we love them no matter what...it's just about smiles per gallon."

Present solution to non-issue, unrelated to original question: "Hey, here's a non-critical part that's already being reproduced...go buy one."

[32valvZ]

Quick, everyone go to your garage and light your ZR-1 on fire,,,, then set yourself on fire too.. as you and your ZR-1 get older, parts of you will wear out!! Put an end to both of you before it happens!

[spork2367]

Quick, everyone go to your garage and light your ZR-1 on fire,,,, then set yourself on fire too.. as you and your ZR-1 get older, parts of you will wear out!! Put an end to both of you before it happens!

I can't set the garage on fire, that's where I'm hoarding all my spare parts!

The decision that owners will eventually need to make:


Keep moderate to low mileage to not risk value of car hoping that it eventually climbs.

Drive car, enjoy, maintain as best you can, be willing to accept that it will lose value and may one day not be worth repairing.

[KJL]

I think as a ZR1 community we all should be aware of this issue and actively try to assist those few individuals that are trying to keep these cars alive and also try to help ourselves as well by getting involved with assisting after marked companies to develop aftermarket solutions and locating salvage ZR1s and pooling our resources to generate a parts bank for those hard to find parts. Perhaps creating a forum just to support this effort. I guess unlike some, I am not satisfied sitting back allowing others to deal with this problem.


This whole thing really struck me when I did some clutch work on my car, after putting it all back together I have an oil leak out of the transmission slip yoke seal which had been replaced. the oil was dripping onto the exhaust which passes directly under it so I had to be fixed. After determining the issue was excessive play due to spline wear, which is very odd for a car with just 24,000 miles on it, I decided to order another one. No-can-do. One of those parts that slowly disappeared from the shelves. With the help of Bill Boudreau (ZFdoc) we found a yoke with the same spline count but was a 1330 so I had to use a 1310/1330 conversion Spicer joint which are also hard to find plus he had to do some machining to the yoke by shortening 30mm so it would fit. Re-sleeving is another option.

My point is I post all the things that I do to the car (mostly on the Corvette forum because is is easier to post pictures) but this wealth of knowledge all goes away in the technical forum at some point. Why can't we have a rant free forum that strictly deals with solutions to known issues that don't have a shelf life?



In the mean time I will be keeping an eye out for parts.


Also, why is it so difficult to build aftermarket electronics for these cars? This may be a stupid question but why doesn't GM sell the specs for these devices so they can be reproduced?

[We Gone]

I'll just drive mine until It can't be fixed anymore than sell it for parts and move on! I'm sure I'll be long gone before that happens..

[lfalzarano]

You can alway stuff a big block in there and still enjoy driving a Vette!


Lou

[DRM500RUBYZR-1]

Lou,
Scary.
I was thinking the same thing.


I then mused about an LS9 or maybe even the new LT5, just to keep it in the family.
:cheers:Marty

[KJL]

I am sure my 72 will still be on road long after my ZR1s are sold for parts. We gone, let me know when that happens, I will be happy to take one off ur hands ! Just keep driving it a lot so I don’t have to wait too long.;)

[spork2367]

This whole thing really struck me when I did some clutch work on my car, after putting it all back together I have an oil leak out of the transmission slip yoke seal which had been replaced. the oil was dripping onto the exhaust which passes directly under it so I had to be fixed. After determining the issue was excessive play due to spline wear, which is very odd for a car with just 24,000 miles on it, I decided to order another one. No-can-do. One of those parts that slowly disappeared from the shelves. With the help of Bill Boudreau (ZFdoc) we found a yoke with the same spline count but was a 1330 so I had to use a 1310/1330 conversion Spicer joint which are also hard to find plus he had to do some machining to the yoke by shortening 30mm so it would fit. Re-sleeving is another option.

Also, why is it so difficult to build aftermarket electronics for these cars? This may be a stupid question but why doesn't GM sell the specs for these devices so they can be reproduced?

Part of the reason these discussions drift to opinion is because there are a lot of owners who are blissfully unaware of actual parts shortages and or what it would cost to have those parts remade.


95% of the transmission is identical between ZR-1s and non, but if you break that 5% part, you're screwed.


Lose one liner due to a piston or ring issue on a 93-95 car and if you can't track down a good used one, you are spending well over 3k for pistons and liners without labor.

No matter what anyone wants to say, there are parts shortages, and some of the repairs would be considered cost prohibitive based on what the cars are worth. If you have a higher mileage driver, that may be worth 12-15k, you really have to love it to spend 4-5k on an engine rebuild. Worse yet, someone hits you from the rear at a red light and the insurance company totals the car. There are used bumper covers around, some take off quarter panels, a few trim pieces. Good luck finding the bumper cover supports that go between the aluminum and the bumper cover. They are ZR-1 specific.


I'll just drive mine until It can't be fixed anymore than sell it for parts and move on! I'm sure I'll be long gone before that happens..

Probably the best way to look at C4s in general!

[A26B]

Re: OE Sleeves & Liners


I have at least 36 NOS Sleeves, more likely closer to 75.
For good used, I have a LOT. Most are 8 cyl sets of low miles take-out sleeve/rod/piston/ring/pin during 368+ engine builds by Doug Rippie & Lingenfelter. I don't really know how many of 90~92 & 93~95, but probably add up to 20+ engine sets. Corey Henderson, Mark Haibeck & Aaron Scott probably have that many more at least, plus more in the hands of individuals.

As far a condition of those take-outs, I would venture 99% are within GM spec. The set from my 60K 94 were within spec.

However, NEW piston rings are essentially extinct, leaving only used ones for repairs. For old school guys like me, rings were never re-used & cylinders re-honed so new rings would "seat" properly. Modern materials & manufacturing such as used in the LT5, have made reuse of "in-spec" rings feasible.

I think it's important to note that most ZR-1 will likely never need to replace sleeves, rods, pistons, rings. Most of what we have sold to customers were for engines damages by catalyst dust backflow (rare & restricted to mostly 1990 models), damage from SPT screws, broken or improperly timed cams and Tensioners not properly re-set.

With normal maintenance, LT5's with 200K+ are known & 125K+ is common. So how many ZR-1 LT5's will ever see that?

It just doesn't take a lot of deep, internal parts to keep these engines in use. Removal of the plenum provides access to the vast majority of LT5 maintenance items.

Quote:
Originally Posted by We Gone View Post
I'll just drive mine until It can't be fixed anymore than sell it for parts and move on! I'm sure I'll be long gone before that happens..

Probably the best way to look at C4s in general!

A very feasible means to take care of the fleet of ZR-1's. It's not going to require a large number of them to do it.

[Dynomite]

With normal maintenance, LT5's with 200K+ are known & 125K+ is common. So how many ZR-1 LT5's will ever see that?


One Maintenance item I think about is the Chain Guides wear (and only the two chain guides pushed by the Tensioners). There have been a couple instances (only 2 that I am aware of) of timing chain failure or chain guide failure (still have no clue on what caused the Timing Chain Failures).

Jerry.....what is now your best estimate on Timing Chain guide longevity and replacement?
(I know it depends on Engine Oil and Engine Oil Maintenance for example) :cheers:

[phrogs]

Good luck finding the bumper cover supports that go between the aluminum and the bumper cover. They are ZR-1 specific.



I have two of them more than happy to sell these unobtainim parts for less than a DIS module.

[A26B]

One Maintenance item I think about is the Chain Guides wear (and only the two chain guides pushed by the Tensioners). There have been a couple instances (only 2 that I am aware of) of timing chain failure or chain guide failure (still have no clue on what caused the Timing Chain Failures).

Jerry.....what is now your best estimate on Timing Chain guide longevity and replacement?
(I know it depends on Engine Oil and Engine Oil Maintenance for example) :cheers:

We need to differentiate between the guide & guide facing. Guides, for all practical purpose, don't wear out or break. Insofar as the guide facings, I have enough facings to last another 395 years, based on sales average over the last 5 years. Or, I have 1,975 sets in stock & you can do you own math. :dancing

FWIW, I have a good inventory of both new & used guides & there are always used guides available, due primarily to the lack of need.

Guide Facing Longevity: Hard question to answer with so little sales volume to work from. Considering 23+ years of age on less than 7000 ZR-1's, I would say a very long time. I would guess most of my sales are because of the "while I'm in there" syndrome, which I endorse. I've heard of a couple of broken pivot guide facings over the years. However, if guide facings follow the trend of other parts, once they begin to fail in ernest, the frequency of failure will increase, like the fuel pressure regulator.

Timing Chain Failure Causes: A couple that I know of failed due to other parts failing & ultimately damaging the chain; cam cover chain guide screws coming loose (didn't remove before powder coating) This is another part that is done "while I'm in there." I don't get to see a lot of sprockets to judge wear, but only rarely do I ever sell any of the chain sprockets. Worn sprockets usually accompany worn chains.

IWIS manufactures Secondary Timing Chains for us now. I have no concern that they will not be available for the forseeable future. IWIS is a major supplier for cam chains for European automobiles. IWIS chains are pre-stressed to seat the links & pins, just like the OE chains are. They have a slightly heavier side bar and still fit the OEM sprockets perfectly. We have had them installed in 2 3 exotic LT5 racing engines, turning upwards of 8500 rpm. in racing events.

[spork2367]

I have two of them more than happy to sell these unobtainim parts for less than a DIS module.

They aren't unobtanium, they are just extremely difficult to find. I have one spare set I picked up not too long ago.

But for someone it will be about knowing where to find one when they really need it. We know a lot of these parts are out there. As long as there is a forum like this, we have a good medium to locate a lot of them.

Hopefully the DIS craze goes away when Jerry gets his released.

[rkreigh]

I'm confused why everyone wants to rip out the lt5 when it's some of the electronics that are rare. Jerry is working on the DIS and as soon as some one needs one let me know.


I'll sell you mine and use the money for putting a megasquirt on it. coil on plug is WAY better than coil packs and the megasquirt offers a very affordable option to the unobtanium DIS parts. keep in mind there are 7000 of these made and they rarely fail. by the time they do Jerry is likely to have completed a solution. GM isn't going to share tech data guys, they won't even give out dyno sheets for goodness sake so that's not going to happen. And as Jerry will attest, reverse engineering is very hard work.


Overall the lt5 is an anvil, I just put 106k on mine, and if I hadn't lost a hose and run the car hot so often (ac), the head gasket would not have failed.

these are 200k plus engines, just not that many people run them enough to find that out

I used to worry about the hard parts like main bearings, and the stock rings are not to be found. But if you want to keep the lt5 stock, the take out parts are available from folks that updated to 4 inch liners. those stock parts are pretty good and I think we are too quick to discard them.


I had the stock crank, bearings, and rotating assembly with liners and matched pistons and basically couldn't give it away a few years back. Look at how long the liners and pistons stayed at auction because the bid didn't meet reserve at the NCM!!!

yes, there are many parts that can be tough to get, but gents like Jerry and many talented folks step up to address that. In the age of 3d printing and modern electronics, with a bit of work, the old gal can be updated to use the new stuff. racers do it all the time and it's really not as hard as some would think.


we have the technology to keep the beast alive despite the challenges as long as there is a desire and some $ to do so.

[Hog]

From a performance perspective: The advantages of Coil Near Plug (CNP) over a single coil system as used on the GEN-II LT1/4 can be marked. The advantages over a multicoil system such as is used on the 90-95 DOHC LT5 are much less, the plug wires are a lot shorter.

Much of anything fun comes down to money. Sometimes it takes more than average to overcome the will of some to hold onto "rare" components. I'd love to see how many SLP T-Rams are actually installed on cars compared to the number that are hid away somewhere for bragging rights alone.
I was disgusted to see Ferrari V-12 cam blanks for some disgustingly low price. The guy had hundreds of them. Different story for our LT5s, though the custom ones that are available are pure engine porn.

[rkreigh]

no doubt the factory ignition works great until it doesn't the DIS is going for stooopid money just like thermostat housings and other odds and ends


I've set myself out to wear out as many of these parts as possible rather than worry about getting them.


I haven't had any serious worries and always able to work around the issue at hand


I'd worry more about not using the car


life is too short not to

[KJL]

Are the ECMs, DIS and CDMs interchangeable between model years? That would be helpful info to have. What would happen if I plugged my 95 ECM into my 92? Or are they split between 90-93 and 93-95?

[spork2367]

I'm confused why everyone wants to rip out the lt5 when it's some of the electronics that are rare. Jerry is working on the DIS and as soon as some one needs one let me know.

There were a couple tongue in cheek comments about it, but I don't think anyone is advocating ripping out LT5s...

I'll sell you mine and use the money for putting a megasquirt on it. coil on plug is WAY better than coil packs and the megasquirt offers a very affordable option to the unobtanium DIS parts. keep in mind there are 7000 of these made and they rarely fail. by the time they do Jerry is likely to have completed a solution. GM isn't going to share tech data guys, they won't even give out dyno sheets for goodness sake so that's not going to happen. And as Jerry will attest, reverse engineering is very hard work.

Even with megaquirt, COP wouldn't be a plug and play affair. Just getting the megasquirt running well with a stock engine and DIS is not for the layman. I am setting one up now on a 1991.

We don't have a lot of high mileage engines to say exactly how often they fail. They are electronic and in a high heat area. Eventually they will fail.

The GM issue has already been address in this thread. We know they are zero help.

yes, there are many parts that can be tough to get, but gents like Jerry and many talented folks step up to address that. In the age of 3d printing and modern electronics, with a bit of work, the old gal can be updated to use the new stuff. racers do it all the time and it's really not as hard as some would think.

Racers also spend 10-15k putting modern sensors and new controllers on engines. They spend money that can't be justified on weekend cars, or even daily drivers. Not only that, but they aren't worried about compatibility with other systems on the car, creature comforts, etc.

we have the technology to keep the beast alive despite the challenges as long as there is a desire and some $ to do so.

Not "some" money, lots of money. I would be curious what Jerry has invested in development work alone, let alone inventory. At some point, there won't be enough other parts to share costs with. There are parts that would be cost prohibitive for even Jerry to justify. Not saying there won't be work arounds, but then you get back to the issue of originality and collectability.


Much of anything fun comes down to money. Sometimes it takes more than average to overcome the will of some to hold onto "rare" components. I'd love to see how many SLP T-Rams are actually installed on cars compared to the number that are hid away somewhere for bragging rights alone.
I was disgusted to see Ferrari V-12 cam blanks for some disgustingly low price. The guy had hundreds of them. Different story for our LT5s, though the custom ones that are available are pure engine porn.

The majority of spare parts for these cars remain unused. But like you said, people letting go of them is a different story. It does seem to go in waves though.

no doubt the factory ignition works great until it doesn't the DIS is going for stooopid money just like thermostat housings and other odds and ends

Jerry's new unit should curb that. NOS units will still bring a premium for those wanting originality.

Are the ECMs, DIS and CDMs interchangeable between model years? That would be helpful info to have. What would happen if I plugged my 95 ECM into my 92? Or are they split between 90-93 and 93-95?

DIS swaps across all years. ECMs swap across all years as long as you swap the chip. Can't speak to the other modules.



The big picture here is this: Despite their perceived and or real reliability, as a whole, the population is only accruing miles. As that mileage increases, statistical probability dictates that parts of the system will fail. I do both statistical process control and statistical reliability engineering for the engines our company produces.

Every mechanical system fails given enough time and/or cycles. We've already seen failure modes in these engines and as the mileage goes up, the probability of failure does as well. It also goes up for many parts as a function of age alone and not necessarily use (capacitors, seals, o-rings, etc.)

There are a lot of cars that are just now breaking out of the low mileage barrier as more and more are turned from collectors into drivers. In the next 5-10 years we will see more failures than ever. That is just a mathematical fact. The only thing that would prevent that is if every single owner stopped driving them tomorrow and never drove them again.

[rkreigh]

I'd like to see more development done on the Megasquirt. the hardware and software for that solution looks solid, and I'd love to run the coil on plug to eliminate the DIS as the megasquirt will drive the coils just fine.


I realize that was easier to do with the "plug and play" wiring approach, I just don't want to go that direction. the ecotec Saturn sky coils seem to be a potential fit and I remember a gent posting about boat coils being adapted.


It's not that the DIS doesn't work, it's that COP works well and allows the DIS to be used by those that need it to help offset the cost of the upgrade.


Just the MSPro is around 1200 which is fairly cheap considering the functionality it provides. Much faster processing, and better overall engine management and fail safe capabilities.



I don't care about the mileage or security system, what else do I lose with the lack of ccm interfaces?


seems like if you splice into the factory wiring rather than eliminate the factory ecm it could potentiall work better. Like to hear more thoughts on this.


That's the approach the c5 guys do that with the dominator and haltec computers, seems like it might also be feasible on the ZR-1.


good thread, graham and Gerry thanks for the "plan A" approach which looks like it's coming to fruition and is clearly simple and works~!


for the hot rodders, the megasquirt solution doesn't sound cost prohibitive in comparison to the DIS replacement.

[spork2367]

I'd like to see more development done on the Megasquirt. the hardware and software for that solution looks solid, and I'd love to run the coil on plug to eliminate the DIS as the megasquirt will drive the coils just fine.


I realize that was easier to do with the "plug and play" wiring approach, I just don't want to go that direction. the ecotec Saturn sky coils seem to be a potential fit and I remember a gent posting about boat coils being adapted.


It's not that the DIS doesn't work, it's that COP works well and allows the DIS to be used by those that need it to help offset the cost of the upgrade.

The cost of even a NOS DIS until today is hundreds cheaper than just the megasquirt ECU with no custom dyno tuning for your car.

Just the MSPro is around 1200 which is fairly cheap considering the functionality it provides. Much faster processing, and better overall engine management and fail safe capabilities.

The DIYAutotune unit is an MS3Pro unit with the proper internal wiring, external plugs and case dimensions to fit our cars. That being said, that unit will run you 2700-2800. Simply doing it yourself with a generic MS kit would require a knowledge of these engines electrical systems and sensors, as well as a knowledge of the megasquirt system WELL beyond the capability of 99% of ZR1 owners.

A person has to decide if driving the car is the hobby, or reinventing the wheel is the hobby.

I don't care about the mileage or security system, what else do I lose with the lack of ccm interfaces?

I believe fuel mileage/trip calculator is the only thing lost with the current unit. And that system has been cracked, so when DIYAutotune decides, they should be able to figure it out.

seems like if you splice into the factory wiring rather than eliminate the factory ecm it could potentiall work better. Like to hear more thoughts on this.

Not sure what you're asking here. The advantage of the plug and play DIYAutotune unit is that it uses the standard plugs, so should you choose to find a factory ECM in the future you could return it to stock. You also eliminate the possible failure point of bad connections in splices. If you mean retain the factory ECM to control some things and use the megasquirt to control other things, I'm sure that could be done, but it would be messy.

That's the approach the c5 guys do that with the dominator and haltec computers, seems like it might also be feasible on the ZR-1.

They have complete stand alone computers and harnesses for LS engines, so I'm not sure what they aren't doing specifically with the dominator or haltech computers.

good thread, graham and Gerry thanks for the "plan A" approach which looks like it's coming to fruition and is clearly simple and works~!


for the hot rodders, the megasquirt solution doesn't sound cost prohibitive in comparison to the DIS replacement.

For a stock motor, it is cost prohibitive, by a large margin. You could buy a used ECM and DIS combined for hundreds less than the cost of the DIYAutotune MS unit.



The info I have.

[KJL]

Speaking of hard to find parts.....anyone know a cheap source for the spare tire? Mine are old and beginning to dry rot and can't hold pressure for very long. I found the tire online but it costs a small fortune and then I need to have it mounted....

[spork2367]

Speaking of hard to find parts.....anyone know a cheap source for the spare tire? Mine are old and beginning to dry rot and can't hold pressure for very long. I found the tire online but it costs a small fortune and then I need to have it mounted....

https://www.ebay.com/i/142899741296?chn=ps

[Mystic ZR-1]

Spare tire on EBay:
Not a bad price and condition!
But it doesn't have ZR-1 and the date written
on it in yellow tire crayon from the factory...
WWNCRSD?

[TX '90 ZR1]

Spare tire on EBay:
Not a bad price and condition!
But it doesn't have ZR-1 and the date written
on it in yellow tire crayon from the factory...
WWNCRSD?

OH MY!!!
If the yellow tire crayon markings are missing might as well put it in the trash heap!
WWNCRSD? Answer: SH*T A BRICK!!!
[-X

[Mystic ZR-1]

OH MY!!!
If the yellow tire crayon markings are missing might as well put it in the trash heap!
WWNCRSD? Answer: SH*T A BRICK!!!
[-X

😋

[precast1]

Agree strongly with the first;
and even more strongly with the second.


I am amazed at pristine C-4's that come here, and I watch the owner struggle with the hood as if it were normal.
They replace unbroken things for no reason other than "preventative", yet
miss these seemingly obvious and important things.
Replace the aged support, and splurge on one of Carter's safety pieces when it is open as an added and useful precaution.
MartyCarters the man I have mine don't have to worry about the hood crashing down and maybe break the windshield. Plus Carter can make a bunch of parts.

Sent from my SM-G950U using ZR-1 Net Registry mobile app (http://r.tapatalk.com/byo?rid=90383)

[KJL]

Update: I still have not found a solution to the code 43 (Knock sensor). I just started to actively put the issue to bed. The sensor harness volts checked out OK and the resistance to block is also OK. Marc H. has been nice enough to assist with trouble shooting this. One possibility is after the car reaches running temp and is moving, the ECM runs a self diagnostic by generating a knock to check the knock sensor is functioning. It is possible this knock is not being picked up be the sensor and the fault code results. The code is generated when the coolant reaches about 200F like clock work. I have an ALDLdroid data scanner and it confirmed there was no increase in knock count when the code was generated but the engine was retarded by 7 degrees once the check engine light appears sooooo…… I have a knock sensor on order from Jerry and Marc is researching the issue to see if there are any programable options.

[secondchance]

Update: I still have not found a solution to the code 43 (Knock sensor). I just started to actively put the issue to bed. The sensor harness volts checked out OK and the resistance to block is also OK. Marc H. has been nice enough to assist with trouble shooting this. One possibility is after the car reaches running temp and is moving, the ECM runs a self diagnostic by generating a knock to check the knock sensor is functioning. It is possible this knock is not being picked up be the sensor and the fault code results. The code is generated when the coolant reaches about 200F like clock work. I have an ALDLdroid data scanner and it confirmed there was no increase in knock count when the code was generated but the engine was retarded by 7 degrees once the check engine light appears sooooo…… I have a knock sensor on order from Jerry and Marc is researching the issue to see if there are any programable options.
Torque spec for knock sensor I believe is 14 lb-ft. Check the manual to be sure.

[Subfixer]

Update: I still have not found a solution to the code 43 (Knock sensor). I just started to actively put the issue to bed. The sensor harness volts checked out OK and the resistance to block is also OK. Marc H. has been nice enough to assist with trouble shooting this. One possibility is after the car reaches running temp and is moving, the ECM runs a self diagnostic by generating a knock to check the knock sensor is functioning. It is possible this knock is not being picked up be the sensor and the fault code results. The code is generated when the coolant reaches about 200F like clock work. I have an ALDLdroid data scanner and it confirmed there was no increase in knock count when the code was generated but the engine was retarded by 7 degrees once the check engine light appears sooooo…… I have a knock sensor on order from Jerry and Marc is researching the issue to see if there are any programable options.



I have the exact same problem in my 92. Running out of parts to throw at it. Knock sensor already replaced. Same results with voltage and resistance readings. All connections to the ECU have been checked for continuity to each sensor. Same symptoms and readings on ALDLdroid. The 7 degree retard is the ECU going into safe mode. The only parts I haven't replaced are the O2 sensors, as one is intermittent 0.0 volts (with no code set), MEMCAL chip (although I removed Mark's piggyback and used the stock chip with no change in symptoms) and the ECU.

[Z51JEFF]

In general GM only supports replacement parts for 8 years then the parts are no longer made. It’s pretty sad when you can’t get a part for an 8 year old GM product but you can to a V.W. dealer and buy new bumper brackets for a 30 year old bug.

[KJL]

Update:
After some additional testing it was determined that the knock sensor circuit located in the memcal chip was not detecting knocks at all. Repeat attempts at using a steel rod and hammer could not produce a recorded knock even with the new knock sensor. I sent the chip to Mark and he confirmed my ALDLdroid readings as being correct. He replaced the knock circuit and verified correct function and returned the chip to me. No more code 43. I have not yet verified with the ALDLdroid knocks are being received using a rod and hammer on the driver side exhaust flange but chances are good all is well as it would not be passing the self knock system diagnostic otherwise. Lesson learned here is to collect as much data as possible to assist the experts like Mark diagnose the problem.


Also, the knock sensor does not penetrate the water jacket so no need to worry about losing coolant.

[davidijaxson]

I have been shopping for a ZR-1 and am getting ready to head out of state to look at one and pull the trigger if all is as expected. The car is in great shape, a 1990 with 28k. However being 30 years old I realize that things can break at any time. Given this thread I am having concerns that maybe making the purchase is not the best decision to make. I am sure most of you have had your car for some time. Would you purchase a ZR-1 now giving what you know about parts availability and probably a myriad of other things I am not aware of. I appreciate any input.

[Dynomite]

I have been shopping for a ZR-1 and am getting ready to head out of state to look at one and pull the trigger if all is as expected. The car is in great shape, a 1990 with 28k. However being 30 years old I realize that things can break at any time. Given this thread I am having concerns that maybe making the purchase is not the best decision to make. I am sure most of you have had your car for some time. Would you purchase a ZR-1 now giving what you know about parts availability and probably a myriad of other things I am not aware of. I appreciate any input.

Parts are readily available........there is NO Myriad of other things....
I do a standard top end restoration (see signature) and replace all fluids with the best (SAME FOR ALL ZR-1s)....:thumbsup:

The LT5 is the most fun, most reliable and most unique engine around. :cheers:

https://cimg7.ibsrv.net/gimg/www.corvetteforum.com-vbulletin/800x600-1/80-353a8770_2463_4a3d_bd53_860920b2b618_1__215baaf45f a8310b57b69078bd80040f5003d62d.jpg

[lfalzarano]

I’ve had mine for 20 years. I keep it stock and I expect things will fail over time. Batteries and tires are the big expense. Parts are available from many reputable sources. There are many experts in this group and some offer rebuilding parts as a service. They are great and not expensive. Most of the ZR-1 is basic C4. The engine obviously not.

So if the care looks in great shape and the engine is clean, you could pull the trigger. If you provide the location, maybe a member could drop by and look it over with you.




Sent from my iPhone using ZR-1 Net Registry (http://r.tapatalk.com/byo?rid=90383)

[lfalzarano]

BTW - take it for a test ride. Nail it and once you hit redline if you are not smiling from ear to ear, look for another car. JMHO.


Sent from my iPhone using ZR-1 Net Registry (http://r.tapatalk.com/byo?rid=90383)

[spork2367]

I have been shopping for a ZR-1 and am getting ready to head out of state to look at one and pull the trigger if all is as expected. The car is in great shape, a 1990 with 28k. However being 30 years old I realize that things can break at any time. Given this thread I am having concerns that maybe making the purchase is not the best decision to make. I am sure most of you have had your car for some time. Would you purchase a ZR-1 now giving what you know about parts availability and probably a myriad of other things I am not aware of. I appreciate any input.

Now the more pragmatic response (maybe a bit cynical). If you want a fantastic driver's car, are willing to live with slightly higher maintenance costs, and aren't overly concerned about originality. Go for it.

If originality is important, that will be hard to maintain on a driver's car as there are some replacement parts that no longer have OEM replacements. When it comes to engine parts, Jerry's is really the only reliable source. When people say "many sources" that really only applies to the non-zr1 specific parts.

There are a very small number of parts that can be very difficult and expensive to replace/fix. DIS modules come and go on ebay, but they aren't always out there. There have been few failures, but the average mileage for the entire population of zr1's is probably in the 20-30k neighborhood, so not really failure point yet. Don't know where Jerry is at on his replacement.

Transmissions are also expensive, zr-1 specific, and tough to find. Most are repairable.

Body panels from the doors back are specific and getting harder to find. I know no one buys a car planning on wrecking it, but accidents happen (often by other drivers).

You could have 80-90% as much fun in a modified non-zr1 C4 or lightly modified C5 for a fraction of the cost (of buying and maintaining), but the zr-1 has an allure to it that is hard to resist.

[DRM500RUBYZR-1]

"Would you purchase a ZR-1 now giving what you know about parts availability and probably a myriad of other things I am not aware of. I appreciate any input."

David, this is not directed at you.

I have heard these same words for over 25 years now.
Yet I know of very few, if any, sidelined cars over a lack of parts.
Perhaps a lack of proper diagnosis at the moment, but not lack of parts.
Reminds me of a movie......................

https://www.youtube.com/watch?v=VUBFCaWiQ28


:cheers:
Marty

[Ccmano]

"Would you purchase a ZR-1 now giving what you know about parts availability and probably a myriad of other things I am not aware of. I appreciate any input."

David, this is not directed at you.

I have heard these same words for over 25 years now.
Yet I know of very few, if any, sidelined cars over a lack of parts.
Perhaps a lack of proper diagnosis at the moment, but not lack of parts.
Reminds me of a movie......................

https://www.youtube.com/watch?v=VUBFCaWiQ28


:cheers:
Marty

I agree Marty, finding qualified somewhat local service and maintenance is probably the bigger issue. Look at LA, in that large car oriented market there is literally no one of any standing. In my opinion this, more that anything, is what keeps prices relatively low.
H
:cheers:

[davidijaxson]

Thanks for the replies. I am taking a friend with me to look at the car and he is a pretty good mechanic, has a previous career doing Corvette bodywork and has owned several Corvettes although no C4s. Assuming it is as advertised and we strike a deal I will pull the trigger.

Thanks again. I will share picks if it happens.

[secondchance]

Would you purchase a ZR-1 now giving what you know about parts availability and probably a myriad of other things I am not aware of. I appreciate any input.

Having owned and pretty much driven as daily driver since 91, answer is a resounding “yes”!
So far, knock on fiberglass, my 94 was never sidelined due to lack of parts.
Fact that I live in the Wazooland made it possible since 2009. Even before, only headache I had turned out to be injector failure.

[EvanZR1]

I have been shopping for a ZR-1 and am getting ready to head out of state to look at one and pull the trigger if all is as expected. The car is in great shape, a 1990 with 28k. However being 30 years old I realize that things can break at any time. Given this thread I am having concerns that maybe making the purchase is not the best decision to make. I am sure most of you have had your car for some time. Would you purchase a ZR-1 now giving what you know about parts availability and probably a myriad of other things I am not aware of. I appreciate any input.

I'd absolutely buy another ZR-1 in a heartbeat. Between the last owner and myself, my entire car has basically been fully restored/rebuilt (full paint job, interior replacement, engine rebuild/upgrade, suspension rebuild/upgrade, AC system rebuild/service, etc). Through all of that there was never any point where the work was delayed waiting on parts.

Get the ZR-1, drive the ZR-1, and enjoy the heck out of the car!

[KJL]

David-
I started this thread and am surprised at how many responses it has gotten. My first question to you is why a ZR1? Knowing this I will be able to formulate a better response to you. I currently own 2 low mileage ZR1's. I love them both but probably would not have purchased the 92 knowing what I know now about expertise and parts availability. There are precious few individuals who really know these cars. Every year that goes by less and less parts become available. There are people who endlessly search the web to purchase as many of the theses soon to be extinct parts to either keep for their own cars or resell at crazy prices. I recently have had to deal with faulty tire pressure sensors (Which are no longer available) and a bad knock sensor circuit on the my 95's memcal chip which was replace by Marc Haibeck but not after considerable trouble shooting by me using a data logger and preforming many system tests and replacing the knock sensor. Anyway....as I have seen in some responses to your post, how willing are you to learn about the car yourself and work on it yourself and are there trusted service entities in your area that are willing to work on the car when needed? I just got turned away from a Chevy dealership when I brought my 96 Corvette LT4 to have the AC looked at, probably a bad compressor (I replaced the compressor clutch) and got turned away. They said because of parts unavailability they no longer work of C4s. There is another place here that just works on corvettes but it will be a month before they can schedule me an appointment. Also, if anything happens to your AC system, it will need to be converted to the new refrigerant. There are opinions regarding this and the parts to do the conversion correctly may not be available. When you check out the car, make sure everything works especially the secondary throttle system. Learn how to pull codes from the dash and AC unit to check for problems. Many codes can be turned off and take some time to re-appear. Make sure you take the car on an extended test drive. The headlights and Bose speaker amps are prone to problems. I replaced all the gears in my head lights myself and all the dried out capacitors on the Bose speak circuit boards myself. Make sure all the seat adjustments work and give the engine bay a good look over, make sure you know what a stock engine bay should look like to spot any modifications. I could go on but I think you get the picture.

To elaborate on why I asked why a ZR1.... if you are looking at buying a corvette just because you want an affordable second fun car and have no interests in the mechanics of the car or working on cars or learning everything about the car, searching for parts (which can be challenging at times but its not like you are looking for parts for a model T) etc.... I would recommend looking at a Z06 C5 which gets you a lot of bang for the buck or maybe a 1996 C4 Collectors Edition or Grand Sport which are OBD II cars and also have new refrigerant so AC system can serviced. If you really want a ZR1, I would look for 93-95 model years for a variety of reasons.

[Dynomite]

Are the ECMs, DIS and CDMs interchangeable between model years? That would be helpful info to have. What would happen if I plugged my 95 ECM into my 92? Or are they split between 90-93 and 93-95?

Short answer.......all interchangeable :cheers:

ECM Interchangeability (http://www.zr1specialist.com/HAT%20Web/Tech%20Info/ecm%20interchange.htm)

DIS Interchangeability (http://www.zr1.net/forum/showthread.php?t=30974&highlight=DIS)

CDM Interchangeability (http://www.zr1.net/forum/showthread.php?t=29660&highlight=CDM)

Oh.....and guys and gals.....I suggested "get yourself a NEW Hood Support Gas Cylinder as the Stock Hood Support looses gas pressure in its old age. A New Hood Support Gas Cylinder will actually lift the hood back to the top if you lower the hood 6 inches.
Ecklers Corvette Hood Support with New Outer Sleeve (http://www.ecklerscorvette.com/corvette-hood-support-1985late-1996.html)"

This also applies to the rear Hatchback Lift Gas Cylinders.......except different but available Gas Cylinders ........With the new Gas Cylinders..... you pop the Hatchback Open Button and up it goes by itself.

[XfireZ51]

Most of the work to be done on a ZR is pretty straightforward and can be done DIY. The only work I have someone like Pete do has to do w the cams/cylinder heads and block. Brakes, clutch, driveline, tuning, suspension etc is all stuff I can do on my own with good parts availability. Some of this I’ve also upgraded, like tires, wheels and brakes to newer generation components, ie C6Z.
My main concern is the DIS which so far has proven incredibly resilient.

[davidijaxson]

Thanks to all for responding to my question and an apology for taking the thread off topic. I should have started a new thread.

Left Dallas early Saturday morning and drove to check out the car I am interested in. To make a log story short we struck a deal and I will go pick the car up in two weeks. Car has been immaculately maintained so I am confident that it is in as good a mechanical condition as possible given the age of the vehicle.

I look forward to learning more about the ZR-1 and learning from you all.

Best,

[EvanZR1]

Congrats! Let me know once you have it back to DFW, we should meet up.

[tnova]

Always good to reread posts for those "ah-ha" moments. At 160k miles my LT5 was going through oil and it would usually not respond to the secondary's kicking in most of time. Passing smog (I lived in SoCal until end of 2017) was a bear. After disassembling the engine found the liner wear out of spec, unusual for an LT5.


When rereading this thread I saw Jerry's post about catalytic converter dust back flow wearing out the pistons, rings, and liners. The "ah-ha" moment was that I found the catalysts had structurally collapsed, sounding like a can of gravel when the exhaust manifold were handled. So there's the tie to my lack of performance when accelerating (blocked exhaust path at cats) and the wear on the liners (cat dust backflow).


I'm one of those that had to replace all liners and rings. Headers are now in place so exhaust flow not issue.


Thanks to the Net and people with experience and dedication to keeping the LT5 alive.


Tony (Tnova)

[XfireZ51]

Where did u find liners and rings? Was it recent?

[tnova]

Jerry’s of course. About two years ago. Liners were no problem but I think I bought the last complete set of rings that he had. At the time I was rebuilding the engine with passing CA smog in mind. I no longer live in SoCal so I should have gone with the kit he now sells that use aftermarket pistons, rings, and rods. Heads, IP, IH, and TB are ported by GVD.


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[gtcollins@maxnet.co.nz]

That's what happened to my LT5 left hand catalytic converter collapsed and destroyed the liners cat material was all the way over on the right hand side no damage to the liners on the thought but the left were totally worn away my car is 1990 0308 with 24000 miles on it some said it was early 1990s that have that problem a friend has just just brought 1990 0549 the catalytic converters were checked before he purchased the ZR-1 all ok my ZR-1 always had white streaks or a grayish appearance in the left exhaust were the other side was always black when the catalytic converter failed the exhaust was totally white so maybe if you so now knowing about the catalytic converter problem if I see a ZR-1 with the same symptoms it's not a big job to remove the 02 sensors and check the catalytic converter material it should be white looking and flat across the surface with no pitting

Glen


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[KJL]

Just out of curiosity did you do the engine work yourself? I know it takes some special tools and know-how to to work on these things.
Did you put new converters on or just delete them?

[A26B]

Here is what catalytic dust does to the LT5 oil control ring.

https://www.jerrysgaskets.com/catalytic-converter-dust-damage-to-rings/

The damage to the Oil Control Ring occurs AFTER the catalytic dust has gone past both compression rings.

[KJL]

Here is what catalytic dust does to the LT5 oil control ring.

https://www.jerrysgaskets.com/catalytic-converter-dust-damage-to-rings/

The damage to the Oil Control Ring occurs AFTER the catalytic dust has gone past both compression rings.

What is the solution? I have a 1992 with original cats with only 25000 miles on it. My 95 has new aftermarket cats and headers.

[EvanZR1]

What is the solution?
Long tubes with no cats? ;)

[A26B]

Exhaust design change in 93 incorporated moving the catalytic converters further away towards the rear, along with making the converter separate instead of integral with the exhaust header.

FOR THE MOST ORIGINAL APPEARING MODIFICATION
There are several different things that can be done. I would recommend removing the manifold/cat assembly and gut the cats. Then if necessary, install a metallic substrate catalytic converter behind the original.

[gtcollins@maxnet.co.nz]

What is the solution? I have a 1992 with original cats with only 25000 miles on it. My 95 has new aftermarket cats and headers.This is my solution and I got a second engine for my ZR-1 and will be rebuilding the original I bought tools and will make some as well

Glen Collins 11147

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[tnova]

I did the rebuild myself. I've rebuilt several engines transmissions over the years and didn't find the LT5 that unique conceptually to work on. The FMS engine manual and Net have oodles of information on procedures and tips to work specifically on the LT5. As for special tools I have a hodge-podge of self made, adapted, and purchased from others (Phil) except for the cam retainers which I borrowed. Now Marc has drawings of the cam retainers to have machined and even easier, Jerry sells complete sets. Jerry also has drawings of simple tools on his site. Only problem i had was the tool to set the pilot bearing depth but adapted and measured for that. Discovered that the crankshaft turning socket used during assembly is very close to one on the self at local autoparts store for a Chrysler.

Regarding cats, I had an initial plan since I still lived in SoCal to replace the manifolds with cats with a low mileage set I bought from Marc which are still on a shelf in my home shop. Once I moved I put on a set of headers and was going go install them with a set of C6 cats. But now I have no smog requirement so the headers go directly into an X-pipe that replaced the first sound damper (muffler? resonator?). I'm holding onto the C6 cats incase I ever have to get it smogged again and will have them integrated in the header to X-pipe tubing.

If you must have the original exhaust manifolds in your state, I'd gut the cats if they're failing and run it that way. I'm in support of reasonable requirements to reduce pollution, especially since more efficient engines with little pollution are really just engines ringing out HP and torque as never before. Modern engines with computer controls and high flow intakes and exhausts, including cats, really make better performance that our smogged choked engines of the 70's, 80's, and 90's. Happy to move my LT5 forward a decade or so.

[EvanZR1]

I think probably almost every state except Comi-fornia, I mean California, has an antique or classic exemption for cars older than 1996 at this point, which exempts them from emissions testing and safety inspection. In TX it's super simple, walk in with your filled out form, walk out with your plate. They don't even physically look at the vehicle.

[Corvettes White]

I think probably almost every state except Comi-fornia, I mean California, has an antique or classic exemption for cars older than 1996 at this point, which exempts them from emissions testing and safety inspection. In TX it's super simple, walk in with your filled out form, walk out with your plate. They don't even physically look at the vehicle.

Why so many Californians are moving to Texas!😄

[KJL]

My 92 is exempt here in GA so I can do anything I want. Regarding the 92, I would like to keep that car close to stock but if I am going to go through the trouble of removing the manifolds/cats, I will just go ahead and install headers and delete the cats all together. I have already performed a top end porting of the plenum and IH's which really woke her up. Headers would just improve upon that.

Is it possible to remove the manifolds and install headers with the engine still in the car? I have tightened the header bolts on my 95 so I know how hard it is to access.

[KJL]

Cool! Those engines are not cheap either. So is you plan to rebuild using parts from the one you just purchased?

I am also considering upgrading the engine on my 95. The IHs and plenum have been ported but I am considering an upgrade package from one of the well respected experts we all know. It already puts 400hp to the rear wheels with the current upgrades. I would like to track the car at HPDI events.

Any recommendations?

My dilemma is do I dump thousands into an upgrade on a car that is not easy to fix if it breaks or just buy a newer car that most parts can still be purchased at NAPA.

[We Gone]

Yes headers can be installed without removal of the engine,I would bet 75%+ are done in this manner. A lift is a big plus.

[KJL]

Hey Steve! it has been awhile. I hope you are doing well. Thanks again for helping me out when I purchased the 92. She runs great with the port job. It really was amazing how much HP it picked op. It took about a year to do it. I have a thread in the other forum that tracks my progress through the whole project. I also locked the secondary throttles blades open and had the chip modified. I think that helps the low end power seat of the pants feel. I think I am going to do the same for the 95. Plus it pulls all those plastic waiting to fail vacuum lines and actuators out from under the plenum.

My Kingdome for lift! I am getting to old to work on my back but to poor to afford a lift.

Thanks for the info, I will need to see what headers are out there for these things.

You planning on going to the Gathering this your? I went last year and my wife had to pull me off of the track! That was quite fun.

I see you sold off some of your inventory. I am considering selling the 92 and my 96 LT4.

[KJL]

Thanks Jerry! Do you sell Stainless headers by any chance?

[A26B]

Thanks Jerry! Do you sell Stainless headers by any chance?

No, leave that up to others. I try to concentrate on making parts available for the LT5 that are essential for operation. There are ample sources for performance mods.

Thanks for checking!

[KJL]

No, leave that up to others. I try to concentrate on making parts available for the LT5 that are essential for operation. There are ample sources for performance mods.

Thanks for checking!

Just keep doing what you are doing! I wish there were some way I could help the effort to keep our cars on the road. Thanks again for all you do!

[Corvette95]

How can you tell if your converters are going bad in a 90? No codes, no reason to believe they are bad? Would gutting them be something to do to get ahead of the problem? 33K miles.

[spork2367]

How can you tell if your converters are going bad in a 90? No codes, no reason to believe they are bad? Would gutting them be something to do to get ahead of the problem? 33K miles.

Gutting your cats for no reason will negatively affect the value of the car. You’re better off putting headers on and redoing the exhaust.

[BigJohn]

What part are y’all looking for?