I thought I was special, but it looks like I need injectors....

[bowtiguy]

I finally took the plunge on my first C4Z earlier this fall. I brought home #1631, a 1991' Dark Red Metallic/Black interior. Now we have two in the family ( my parents have a 91' Quasar/blue car w/ 19K on the clock).

I wasn't "looking" for a C4Z but have found memories of these cars as I graduated HS in 89'. But I have to say, the Dark Red Metallic is growing on me and it pulls to 7K better than my C6Z did. This was a one family car w/ 9,600 miles. Its spent its entire life here in Colorado.

Prior to purchase, the previous owner had the original selling dealer, "Purifoy Chevrolet" in Fort Lupton, replace both fuel pump assemblies and a bad oil cooler line. Other than that, this car is BONE STOCK even down to its period correct gatorbacks (still has the TPS sensor stickers on the outer rim lips).

Service procedures completed so far

-full oil change including draining the oil cooler/filter
-ZF transmission fluid change
-tighten ALL oil pan gaskets
-replaced power steering fluid
-cleaned coolant overflow tank/topped off.

After securing a set of original ZR-1 A-Molds from my father and getting new PS2's mounted, I've noticed the higher RPM cut out signifying fuel starvation. No vac leaks and secondaries are definitely working.

Combine this with the loss of factory paint on the passenger side plenum & cam cover after the oil line fiasco and it looks like I'm pulling the plenum...

Considering the cars low miles, I'm looking for any recommendations on what to do "while I'm in there" .... before I lite up the CC at Jerrys and Marc's.

After doing a bit of searching and attempting to keep the car as stock as possible in case I decide to go for NCRS or sell it in the future, I've come up with the following list.

- pull plenum/TB/injector housings ( strip & paint these pieces)
- replace ALL top end gaskets
- inspect gas tank( work done by the dealer)
- install new fuel filter
- replace all 16 injectors/gaskets
- replace spark plugs
- TB coolant bypass pipe (vs. plugs)
- test factory coils
- test secondary vac system.
- clean out the engine valley after the residents were evicted
- flush coolant system/install new thermostat
- flush brake all brake fluid
- change rear diff fluid
- stage 1 prom swap from Marc H.
- Bolt on my Borla Cat back.
- drive it!!!

Items on the fence about..

-starter/solenoid
-coil replacement

Any suggestions “while I’m in there”?

[32valvZ]

Hey, just a hello from Canon City Colorado!:cheers:

[owwdee]

That’s a pretty good list.
I would replace the coils, relatively minor cost. Also maybe new plug wires.
I too need to pull my plenum and do a few of the things on your list, especially painting of plenum and cam covers.
Good call on checking the fuel pumps. Factory replacement senders have plastic tube clamps I believe. Seen many things on the forum of the clips breaking and is best to go to stainless clamps.
I’m near DIA. Hope to see your Z around!

[bowtiguy]

Hey, just a hello from Canon City Colorado!:cheers:

right back atcha :wave:

[bowtiguy]

That’s a pretty good list.
I would replace the coils, relatively minor cost. Also maybe new plug wires.
I too need to pull my plenum and do a few of the things on your list, especially painting of plenum and cam covers.
Good call on checking the fuel pumps. Factory replacement senders have plastic tube clamps I believe. Seen many things on the forum of the clips breaking and is best to go to stainless clamps.
I’m near DIA. Hope to see your Z around!

NOTED on the plastic tube clamps. I'll check that out.

Q: Do coils go bad with age or cycles. With 9600 miles on it, its seen less cycles than normal.

And yes, I WILL be driving it. Especially if I get the A/C working.

[owwdee]

NOTED on the plastic tube clamps. I'll check that out.



Q: Do coils go bad with age or cycles. With 9600 miles on it, its seen less cycles than normal.



And yes, I WILL be driving it. Especially if I get the A/C working.



Good question on the coils. Search the forum. I think you can check the resistance to indicate if it’s good or not.

Colorado Auto Air in Northglenn did my A/C this summer. He has R-12. Had a leak in one of the tubes but he was able to repair it very easily and quickly. With your very low miles your compressor might have a significant leak at the shaft. Plenum would need to be off to replace the compressor so that might be an optional item to add to your list.

Very happy to hear you are going to drive it. These cars are too awesome to just be parked.

[Z51JEFF]

I’d replace the coils, one of my new OEM coils died at 8000 miles,replaced with MSDs. Sounds like you pretty much have a game plan set in motion.

[Paul Workman]

Welcome to the family of the BEAST! There are several ZR-1 owners in CO and they all like to drive um from what I've seen. (I used to live in Bailey and Franktown too [just east of Castle Rock]).

There is a recent post RE injectors, and although you want to keep it stock, you'd want to draw the line @ injectors! It's the alcohol and the water attracts that is the issue for all ZR-1s from 90-92 (water being less of a problem where you live perhaps than in other climates). In 93 the switch was made to alcohol tolerant injectors which ended the alcohol related problems.

Particularly popular for the stock and ported 5.7L LT5 are the stainless steel, alcohol tolerant injectors by RC Injectors, Accel (150821s from Summit Racing = my personal choice), and the SS injectors available from FIC.

Note: Stock injectors are rated at 21# at 43# psi. ALL of these injectors (mentioned) are apparently good choices for our 5.7L LT5s making up to 510 chp. And, there may be others too, as long as they're alcohol tolerant and not prone to rusting (i.e., stainless steel construction).

[efnfast]

Correct me if I'm wrong, but if you buy stock, OEM injectors from Chevy, they will be the same as what you have, I.E. still not ethanol tolerant.

[A26B]

Correct me if I'm wrong, but if you buy stock, OEM injectors from Chevy, they will be the same as what you have, I.E. still not ethanol tolerant.

Steve & all,

I think this could be a mixed bag. Although not likely, if a dealer still had some very old stock, circa 90~92, the injectors could be original replacement for the 90~92 ZR-1 and NOT Ethanol tolerant. The PN's for these would be:
17069647-(Primary)
17069648-(Secondary)

More likely, any dealer with inventory, would be for the 93~95 injectors which ARE ethanol tolerant. The PN's for these would be:
17109952-(Primary)
17109953-(Secondary)

OEM Injectors
All models, 90~95 both PRIMARY & SECONDARY are the same flow rate.

Injectors O-ring Seals
90~92 PRIMARY & SECONDARY, Upper/Top Seal is the same, PN 17112222
90~92 SECONDARY, Lower/Bottom Seal ONLY, is a larger o-ring seal, PN 10067600, which is located inside the injector housing and seals on the injector o.d. body.

90~95 PRIMARY & SECONDARY use the same o-ring seal, both TOP & BOTTOM, PN 17112222.

OEM Applications & Crossover
93~95 OEM injectors are direct replacements for 90~92 with the following parameters;
PRIMARY; Remove/Do not install, the lower o-ring seal that comes with the injector. The larger, Lower o-ring seal, PN 10067600 will be required. It is not necessary to grind/remove the lower flange from the PRIMARY injector nozzle.
SECONDARY; Requires no change for 90~92 application

OEM Visual Difference
90~92 PRIMARY (original): the absence of any o-ring seal or seal flange on the bottom of the injector nozzle.
SECONDARY: no difference.

BIG DIFFERENCE IS COST: Dealers will charge at least double the cost of aftermarket injectors.

[efnfast]

Thanks Jerry, great info.
Does Jerry's sell injectors?

[A26B]

Thanks Jerry, great info.
Does Jerry's sell injectors?

Thanks for asking Steve.

Yes we do, FIC. Jon Banner, the owner of FIC has always provided outstanding customer service. It's always nice to be able to reach a supplier & get answers from someone in the know.

[Z51JEFF]

Thanks for asking Steve.

Yes we do, FIC. Jon Banner, the owner of FIC has always provided outstanding customer service. It's always nice to be able to reach a supplier & get answers from someone in the know.

Yes,Jon is #1 as far as I’m concerned. The guy does business the way people used to do it.

[efnfast]

Thanks Jerry, that always makes it easy.
You don't have to explain to Jerry what that weird engine is, just ping Jerry and the parts are on the way.
O.P., certainly if these are the original injectors, they should be done while you are in there.

[XfireZ51]

Thanks for asking Steve.

Yes we do, FIC. Jon Banner, the owner of FIC has always provided outstanding customer service. It's always nice to be able to reach a supplier & get answers from someone in the know.

Jerry,

Have u ever asked Jon if he could provide the Injector Bias v BAT V compensation values for his injectors?

[bowtiguy]

Good question on the coils. Search the forum. I think you can check the resistance to indicate if it’s good or not.

Colorado Auto Air in Northglenn did my A/C this summer. He has R-12. Had a leak in one of the tubes but he was able to repair it very easily and quickly. With your very low miles your compressor might have a significant leak at the shaft. Plenum would need to be off to replace the compressor so that might be an optional item to add to your list.

Very happy to hear you are going to drive it. These cars are too awesome to just be parked.

Thanks for the hook up on a local A/C shop. I’ll be giving them a call for sure. The compressor seal is new to me ( can’t search ALL the threads) and a good item to add to the list.

[bowtiguy]

Thanks for the great injector info Jerry. I,m planning a different ZR1 build in the future using a fully ported/polished ( inside & out) top end LT5 I have. For now, I plan on using suitable aftermarket replacements on this car. I’m not going to go annal on the original parts & Ill keep whatever comes off it just in case the market wakes up, value increases, I can no longer drive & decide to sell it in the future.😂

And,as soon as I get my car done, I’ll be placing more orders to resurrect my dads 91, quasar Z. Then we’ll start dipping into the classics. Looking forward to retirement.

[A26B]

Jerry,

Have u ever asked Jon if he could provide the Injector Bias v BAT V compensation values for his injectors?

Hi Dominique,

No, I have not. It's out of my knowledge & experience range! You know more about that than I will ever have occasion to use. He will be happy to discuss it with you though.

[XfireZ51]

I asked some time ago for that info and was told they either didn’t have it or it wasn’t necessary. For an injector shop it should be easy enough to determine what those values are. As a vendor, I thought u might have more influence for the request.
Accel and Bosch data is readily available, not sure about RCs. Altho the info on the Accels for the LT-5 has been hard to come by until recently.

[owwdee]

Thanks for the hook up on a local A/C shop. I’ll be giving them a call for sure. The compressor seal is new to me ( can’t search ALL the threads) and a good item to add to the list.



My understanding is that if the compressor has not seen much use, the seals can dry out and leak. My 40k mile 91 spent most of its life in Florida so I would assume it had frequent AC use which is maybe why I didn’t have any leaks on the original compressor.

[bowtiguy]

A/C update. Hooked the system up to a proper R12 Vac pump. Seams the pintel <sp?> valves wouldn't hold Vac. Once you the caps were installed, it was good!

Looks like the A/C compressor seals are still good. Placed an amazon order for the parts (all $16 of them). plan to swap out the valves and jump the compressor at the low limit switch to make sure it isn't locked up. From there, will do a long term Vac test and fill her up with R12.

[bowtiguy]

FINALLY, got my 68' C10 resto mod out of the garage so I could use my lift and open up the LT5.

- got everything removed down to the block valley
- leveled & removed mickeys old house
- steam cleaned everything w/ my new toy.
- coils tested perfect (primaries & secondaries)
- plug wires tested w/in spec too.
- starter cleaned, bearings lubed, solenoid contacts cleaned

I pulled the seats (along with all 4 Bose Gold speaker assemblies to replace capacitors) so I could treat them before stranding the car on the bend pac lift.

PCV and secondary system tested good.

I'd like to keep everything as stock as possible. The coolant hoses are stock complete w/ GM part #'s/ They are not cracked but are definitely on the stiff side.

I found Dayton brand replacements online but they cost almost as much as a full samco kit. Does anyone reproduce these?

[Ccmano]

I believe Marc Haibeck sells a complete OEM style replacement hose kit.
http://www.zr1specialist.com/HAT%20Web/products/hoses.htm

Are you leaving the secondaries in or removing them. Now is a good time to make that decision.
H
:cheers:

[bowtiguy]

I believe Marc Haibeck sells a complete OEM style replacement hose kit.
http://www.zr1specialist.com/HAT%20Web/products/hoses.htm

Are you leaving the secondaries in or removing them. Now is a good time to make that decision.
H
:cheers:

Thanks for pointing that out! I looked through Gerrys Site but didn't think to check Marc's.

Personally, I like the samco hoses. They will go on my late fathers 91' Quazar car before my brother gets it. The plan for my dark Red metallic car is to keep it as stock as possible including the secondaries. The only visible upgrade will be the set of original A-molds I put on it and maybe a catch can!

[bowtiguy]

well....THAT escalated quickly!

[Z51JEFF]

well....THAT escalated quickly!

It always does,you might want to do yourself a favor and completely wrap those brake fluid reservoirs,while they’re loose,in anything to keep it from getting anywhere. Where ever I deal with break fluid I want to know exactly where it is at all times.

[bowtiguy]

It always does,you might want to do yourself a favor and completely wrap those brake fluid reservoirs,while they’re loose,in anything to keep it from getting anywhere. Where ever I deal with break fluid I want to know exactly where it is at all times.

:thumbsup:I drained both brake fluid rez's right after taking this pic!

After dropping the knee bolster, steering column and pulling the brake booster, I managed to get the cam covers pulled.....not a single stuck bolt on the entire car at 9,600 miles!

Then I spent 8 hrs blasting the top end parts down to metal.( very fine crushed glass media). Today is clean parts/wash & prep for primer /paint day on friday.

THEN, I can do what I set out to do, swap the injectors & O-rings and get this thing back together.

[bowtiguy]

Long time no update. The car is up and running and has made it to a couple of car shows locally. Its everything I remember, such a blast to drive.

Like most things, I just couldn't do things 1/2 ***. SO...I spent 8 hrs blasting everything down to bare metal using my buddies blast cabinet in an unheated metal garage during a Colorado cold snap in the teens.

It took 5 boxs of crushed glass media from Tractor town. I'm sure the process would have gone faster if I had the correct media, but I didnt want to use anything too aggressive. steps I took to protect everything.

1) tape off all mating surfaces with gorilla tape.
2) used cardboard on the bottom of the blast cabinet to prtect the 28 year old aluminum parts.


Sorry, I have very few pictures of the final product after blasting. It was cold, I was in a hurry and my mother was in town visiting.

[bowtiguy]

Next step was to clean everything thoroughly.

1) First step was to blow as much media out with compressed air.
2) Next, I filled a clean garbage can with warm water and simple green and proceeded to dip, soak, and use a variety of brushes to clean out all the passages.
3) then I repeated the process with warm water and Dawn.
4) I let air dry and only handled parts with disposable gloves to avoid any oils form my hands to come in contact with the parts.
5) the next step involved wiping every soon to be painted surface down with acetone
6) then the masking began. I found that 3M blue painters tape and a couple sharp flat razor blades worked well....I actually enjoyed this part.
7) one final wipe with acetone before primer application.

Once again, lacking in "in process" pics. It gets better

[bowtiguy]

My next major step was to convert my office break room into a Paint booth as I had a good indirect heat source and could position an exhaust fanat the back exit door to pull air through from the front of the office......in Febuary...in Colorado.

Ultimately, I used (2) coats of Upol brand acid etch epoxy primer on everything but the bottom side of the plenum with about 30 minutes flash time between coats.

Then, I proceeded to use Jerrys paint starting with a 20 minute flash time and growing to over 35 minutes as the coats added up to a total of 4.

I was pretty happy with how things were turning out but would later be VERY happy once a small misfortune turned into a couple of additional coats.

First attempt turned out so...

[bowtiguy]

Now onto what I hope is the single thing I can contribute to refinishing the top end on our LT5's.....painting in the letters/numbers in the Plenum cam covers.

PAINTING BY CAPILLARY ACTION!!

I thought about masking things off, but I've read mixed results. After attempting to hand paint with the smallest brushs I could find, I ended up just making a mess. The high temp gloss paint I was using was interacting with the paint from Jerrys and creating a wrinkle finish.

Knowing that I would have to sand down the plenum somewhat prior to doing a couple more top coats I started to experiment. The parts had been curing for over two weeks so I knew that wasn't the issue.

What I ended up settling on was hand scrapping Jerrys paint out of the bottom of each letter/number in the castings to expose either primer or the aluminum casting. I work on it for 30 minuted at a time, once my fingers got fatigued.... I'd take a break.

At one point I slipped pretty bad. (Remember that earlier reference to being VERY happy with the paint later?) That slip ended up requiring a light sanding of the plenum and 3 more coats of Jerrys paint. I'm glad I did. It smoothed out the roughness in the plenum casting to better match the factory surface of the cam covers.

Once the final coats had cured I started back into it again. I lightly masked off up to the letters/numbers with blue tape and paper. Cleaned the grooves. Then I used nothing more than a red plastic extension tip off a can of brake clean.

1) sprayed high temp rattle can paint into a small clear glass bowl
2) placed the end of the plastic straw into the paint
3) it would suck up about 12-3/4 of an inch.
4) carefully place the wet tip of the straw into the letters and pull ( NOT push) the tip away until the paint stopping filling in the groove...thats it, it was the perfect paint applicator!!!

Turned out so...

[bowtiguy]

Lessons I learned...

1) Marcs quote for refinishing the LT5 top end is Reasonable
2) Marcs quote for R&R AND refinishing the top end is a FREAKING bargain!
3) crushed glass a a media works, I think a true bead media would be faster
4) Masking tape is your friend!!
5) Painting by "The Capillary Method" is the ONLY way to go on painted top ends. Those who have powder coat done can get away with the paint/wipe method.
6) if you decide to use paint. I did SEVERAL ( 7+) heat cycles where I started the car and brought it up to operating temp for 10 minutes then let it cool back down. There was plenty of degassing going on. it smelled less and less with each heat cycle.

All in all, I think I have about $500 in materials( paint NOT gaskets). Labor...I lost count. I learned A LOT about the LT5 in the process and was able to clean every surface I could reach along with replace every gasket/o-ring from the long block up!

--> I ended up using (4) cans of Jerrys paint and applying an average of 5 coats. The hazmat shipping is $$$ so buy them all at once.


I'm currently going through the NCRS manual to check all the boxs. My plan is to get the car judged in August, then finally roll that odometer into 5 digits!

[billschroeder5842]

Great job- you attention to detail will pay off in the end!

[WARP TEN]

Marc's painter has recently been able to produce an exact duplicate of the original factory finish. When I had mine done, wanting to look close to stock, the best he could do was called "Fine Silver" that is beautiful but a little more silvery than stock. The finish he showed me in the shop the other day looked absolutely stock. --Bob

[rush91]

Looking great!!

[bowtiguy]

Great job- you attention to detail will pay off in the end!

Thanks, I spent so much time cleaning it I dont want to drive it until after it gets judged. :o

Marc's painter has recently been able to produce an exact duplicate of the original factory finish. When I had mine done, wanting to look close to stock, the best he could do was called "Fine Silver" that is beautiful but a little more silvery than stock. The finish he showed me in the shop the other day looked absolutely stock. --Bob

Its good to hear he has a factory finish option now.

Looking great!!

Thank you. I grew up in a household of blue corvettes but this Dark Red metallic is growing on me!

[A26B]

......I grew up in a household of blue corvettes but this Dark Red metallic is growing on me!

:thumbsup:The dark red metallic is actually my favorite color of all the unique ones, aqua, steel blue, polo green, yellow, etc.

Your engine paint work looks outstanding!!

As far as the original LT5 engine color(s), there is not just 1 color for all year models. I've seen original color ranging from a silvery gray to a darker, drab gray and different shades in between.

[bowtiguy]

:thumbsup:The dark red metallic is actually my favorite color of all the unique ones, aqua, steel blue, polo green, yellow, etc.

Your engine paint work looks outstanding!! .

Thanks Jerry! high praise coming from you. I would also like to take this opportunity to thank you for doing what you do to keep these awesome engines/cars on the road. I cant imagine how many of these beasts would just sit and rot without your great products! Every time I see someone bash reliability or question parts availability, they get links to your site and Marcs.

BTW, my late fathers ( now my younger brothers) 91' Quasar Blue ZR-1 is next. Just 19K on the clock but all the same problems suffered by 91's. Thats two more you've helped save! :worship:

[chadmcghee]

:thumbsup:I drained both brake fluid rez's right after taking this pic!

After dropping the knee bolster, steering column and pulling the brake booster, I managed to get the cam covers pulled.....not a single stuck bolt on the entire car at 9,600 miles!

Then I spent 8 hrs blasting the top end parts down to metal.( very fine crushed glass media). Today is clean parts/wash & prep for primer /paint day on friday.

THEN, I can do what I set out to do, swap the injectors & O-rings and get this thing back together.


I'm preparing to do this job to my recently acquired one-owner 1992. Was removing the the brake booster necessary to remove the cam cover?

[Z51JEFF]

The paint came out very nice,I honestly don’t see how the NCRS can focus on only one shade/sheen of the engine paint when there are several different factory shades. I’m not a fan of red but I do like that red metallic, score I bought my 91 I was looking at a 90 in this color.

[Ccmano]

I'm preparing to do this job to my recently acquired one-owner 1992. Was removing the the brake booster necessary to remove the cam cover?

While it can be done, it’s remains must easier to simply remove the booster. You also get chance to look at the back end of the master cylinder and inspect for leaking.
H
:cheers:

[Dynomite]

I'm preparing to do this job to my recently acquired one-owner 1992. Was removing the the brake booster necessary to remove the cam cover?

See...........Post 67 - Removing Cam Covers (Engine In Car) for Inspections of Camshafts (http://forums.corvetteforum.com/c4-zr-1-discussion/3005470-tech-info-lt5-modifications-rebuild-tricks-500-hp-4.html#post1581665190)