View Full Version : Steel IH Gaskets & Primary Port is 38mm
Update: Finally got injector housings off and discovered why I had an oil leak at the IH to head gasket, it appears a steel gasket was used...see pictures. Not sure why? I also discovered that the IH primary ports have been opened up to just shy of 38mm. The steel gaskets are also 38mm but the head was not matched to the gasket or IH. Question: why was a steel gasket used and should I proceed with opening up the primary port on the heads to 38mm to match the IH? I will have to trim some material off the new gasket as well.
GOLDCYLON
10-01-2013, 09:52 AM
Steel? Never seen those before. Haibeck sells a steel Cometic Headgasket like the LSX motors use but ive never seen steel IH gaskets before. GC
WVZR-1
10-01-2013, 10:10 AM
Update: Finally got injector housings off and discovered why I had an oil leak at the IH to head gasket, it appears a steel gasket was used...see pictures. Not sure why? I also discovered that the IH primary ports have been opened up to just shy of 38mm. The steel gaskets are also 38mm but the head was not matched to the gasket or IH. Question: why was a steel gasket used and should I proceed with opening up the primary port on the heads to 38mm to match the IH? I will have to trim some material off the new gasket as well.
Steel? Are you sure? Maybe "aluminum" or there's "copper" choices I believe also.
I just pulled one off the head, i believe it is aluminum, it looked like stainless but it is soft. Aluminum would make more sense.
The gasket also appears to be coated with a clear material..... permatex shellac?
Either way, this is a relatively low clamp pressure application, unless the surfaces are perfect, using any type of metal gasket is risky as my leaks demonstrate.
I think I will just match the head to Jerry's gasket instead of the IH which is a tad bigger.
The gaskets have a "ring" and weight of steel however. Could be a soft stainless?
GOLDCYLON
10-01-2013, 11:36 AM
The gaskets have a "ring" and weight of steel however. Could be a soft stainless?
Got a magnet handy ?
Low carbon stainless wont be magnetic either... not a reliable test. I guess material doesn't mater in the long run, I was just curious as to why someone would chose this over a conventional gasket...heat transfer? Warmer IH better?
GOLDCYLON
10-01-2013, 12:03 PM
Low carbon stainless wont be magnetic either... not a reliable test. I guess material doesn't mater in the long run, I was just curious as to why someone would chose this over a conventional gasket...heat transfer? Warmer IH better?
Stainless was not mentioned in post number #1 just steel. If thats the case yep I concur. Like stated earlier never seen a stainless steel IH gasket before only the newer steel head gaskets.
Paul Workman
10-01-2013, 08:10 PM
I think I will just match the head to Jerry's gasket instead of the IH which is a tad bigger.
Well, that would be up to you. [-X BUT! You ARE going to have some pulse reversion, and laminar flow will actually be less than if the IH's were the same size as the opening into the heads!** At the very least, you might want to spend a little time and open up the runner cross-section to match the IH and taper down into the heads at least a couple cm, if you're keeping them (danged secondaries)! It will will be worth the effort!
Flyin Ryan does some pretty good runner engineering. He mentioned to me that 4% change in diameter for length is about as much as you can get w/o running into (restriction). And, since then, I've run across some reinforcement for that recommendation. Just sayin... After all, it is well within the realm of possibility to touch 400 rwhp with just a top end and headers, if everything is done correctly. IF. (And, it isn't that much effort if you have the IH's off already!!)
Strongly recommend matching the IH ports and tapering into the heads. You'll reap some cheap horses in the process.
P.
carter200
10-01-2013, 09:04 PM
Listen to Paul. He knows what he is talking about. What number is your 95? Mine is 392 of the 448 made. Good luck and when you are ready to make her sparkle under the hood and on the wheels give mne a shout. :cheers:
Paul-
You mention the secondaries, they do match quite well with the IH so I will be leaving them alone. The primaries are the ports that are mismatched. I guess I will match them the best I can. Jerry said to also be careful near the coolant passage. Need enough "meat" in between to get a good seal, but of course the IH is already done so.... it is what it is. The blue line in the pic below represents the size of the IH port. I am ready to go!!
Yes, seems to know about as much about these cars as any person could know. Very impressive. How do I figure out what number my car is? Is it part of the VIN? Attached are pictures of the car.
carter200
10-01-2013, 10:21 PM
Yes, seems to know about as much about these cars as any person could know. Very impressive. How do I figure out what number my car is? Is it part of the VIN? Attached are pictures of the car.
The last four of your vin. Good luck on the porting............
carter200
10-02-2013, 12:34 AM
Now add it to your signature and you'll have it for all to see. Have fun porting and err on the side of caution.......:)
Follow up- Just about done opening up the primary ports. It was easy and quick. The burrs I received from Eastwoods really worked well. I will post a couple of pics today. After thinking about something Jerry had mentioned regarding the width of the "land" between the primary port and the coolant passage as being the area that may be prone to problems of it is too narrow...perhaps that is why they selected an aluminum gasket instead of paper.... maybe because the primaries were "over" ported. I am planing on using permatex high tack gasket sealer on the gaskets just to make sure.
I couldn't use the 90 degree die grinder shown in pic, too much vibration. I had to swap to my in-line grinder, worked 100% better.
We Gone
10-04-2013, 11:45 AM
Nice.. Hope we get an opportunity to meet up one day. Are you going to SGC in Nov?
http://www.zr1.net/forum/showthread.php?t=21276
I would love to but I may be out of state for work. Looks like a Friday and Saturday Nov 22/23. I may get lucky and be home in time.
Here is a new pic, the primary port now transitions very nicely into the head. When compare to the original there is a big difference. Now my primary ports are about 37.5 or so mm in diameter.
I am going back to do a little clean up on the driver side. Still a bit more needs to come off. I am leaving a little extra meat between the port and coolant passage just to be safe and ensure a good gasket seal....I hope. After I apply the flapper wheel, I am putting a tiny chamfer around the perimeter of each port with a de-burring tool.
I would love to stab in a Pete's cam while I have it all apart. I read an article on Marc's web site, most of it seems doable, I have most of the tools, would need to track down some temp cam retainer caps, most other tools look like they can be built. The two issues that would be show stoppers for me are the need to remove the brake booster and the chain tensioners. I hate working under dash and the procedure for compressing a tensioner looks quite complex. I wonder what is involved with pulling the engine. I have all the equipment to do it, and have done it several times on my 72.
Paul Workman
10-05-2013, 09:42 AM
Mark told me he phased a set of cams with the motor in place, using a CD camera, etc. But, felt the effort was greater than pulling the motor, FWIW.
Pulling an LT5 isn't difficult, but compared to pulling my wife's motor from her '69 C3, it takes me about twice as long to do the LT5. And, as always, the first time is the most time consuming - learning as you go.
The LT5 has "a few" more connectors than you 72 C3: 55 electrical connectors associated with pulling the motor, which includes the O2s and the VSS on the trans; ± 8 connectors, depending on if you remove none, one, or both ends of plug wires (optional, depending on the purpose of pulling the motor), and sundry vacuum lines too.
The trans, and in particular the C-beam (to me) is almost as much hassle as the motor - primarily due to it's size and re-alignment quirks - especially if you don't have a lift and do it off jack stands as I am relegated to doing. (Suggestion: I learned long ago that Bill Boudreau's C-beam plates are worth every cent (to me) in easing the whole C-beam fiasco...if nothing else!) And, on a C4 you don't have to remove the hood. So, there's that in our favor too.
But, all-in-all, having done it only a few times now, my impression of pulling the LT5 is pretty straight forward and not difficult. There's more "stuff" to disconnect and reconnect and some minor tail shaft housing alignment considerations, compared to your 72, but if you're comfortable and have the tools, pulling the LT5 is not a bad job. Access to a lift...would almost make it fun! NO lift...not so much.;)
Lotsa experts here that can guide you with every step; including e.g., some cam phasing options that are important, especially if changing cams is in the mix.
Have fun!
I guess if one has a lift and all the tools etc. pulling the motor would be such a big deal.
I read Marc's article regarding the cam work. If someone could tell me that the work could be done without pulling the brake booster I would give it more serious consideration.... I have done that on my 72 and damn near broke my neck trying to contort my body up into the under dash space. no thank you... I am to old and inflexible for that kind of work anymore, maybe 10 years ago when I did it the first time. May I will email Marc and ask him if it is possible.
I have phased cams before and cameras are relatively cheap, heck I am sure there is an ap for that!
You didn't mention header removal in you post. That cant be fun either.
Update:10-5-13
Finished cleaning up all the aluminum flecks everywhere. Even with masking and plastic, that stuff finds its way around. Removing the oil soaked paper towels I stuffed into to primary ports went as well as could be expected. I cleaned them out best I could with vacuum and small diameter hose, then gently lifted them out with pliers and using the vacuum to catch any fliers, then cleaned the bores with brake cleaner soaked paper towels. I am sure a few flecks of aluminum made there way into a couple of ports that happened to have a open valve.... I assume (hope) they should either vaporize or get blown out of the system. I think it would be a good idea to use to layers of protection. I found that because of the swirling of the aluminum bits, they found their way deep into the paper towel crevices and could not be all vacuumed out. Paper towel may not have been the best choice. Going to clean out the valley, re-torque crank case vent cover bolts, check secondary vacuum actuators, checked them individually using vacuum tester and they checked out OK. I am also going to test them via the on-board vacuum pump and solenoid actuation.
mike100
10-05-2013, 10:40 PM
I'm sure I had a couple of flecks blow thru when i did mine. None got on the valve seat- that was all I was concerned about. Did mine with piston at TDC in each cylinder.
I definitely makes a mess. prep and cleaning is 30% of the job. The actual grinding was maybe 4-5 hours on mine if I recall.
I am going to make one more pass and make sure the bores are as clean as possible. I never would have considered doing this if the heads had been iron. I cant imagine a few tiny flakes of aluminum could harm the valve seats or cylinder bores in any way...
Update:
Just finished cleaning the engine and prepping the gasket surfaces. Used an engine degreaser and simply green with water bottle sprayer and a steam cleaning machine (not necessary). Looks good. Wasn't bad to start with unlike my 96 LT4, damn, there was so much gunk on the front of that engine.... there are 4 penetrations through that front cover, water pump shaft, opti spark, crank and crack pos sensor, all leaked and all were replaced. Took a week of cleaning. tight as a drum now.
Next up, replacing all the o-rings in the fuel lines, injector housings and injectors plus the two PVC tubes that plug into the valve covers. Using kit from Jerry. I believe I am using the Viton kit. Trimming the IH and plenum housing gaskets to fit my ports. I will us the old metal IH gaskets as a template for trimming the new gaskets. I will use a high tack gasket sealant around any port that comes in contact with engine fluids. As part of the work, Jerry recommended to remove the crank case vent cover bolts one at a time, apply some 234 loctite (blue) and torque to correct spec. He suggested this should be adequate and replacement of that gasket is likely not necessary. He also recommended using oil as an o-ring assembly lubricant.
Paul Workman
10-10-2013, 11:44 AM
When I did my first "R&R" under the plenum, I found several bolts on the IH's, plenum, etc. to be less than recommended torque. Since then I've always used the blue Loctite on ALL such hold-down bolts** and have not had any problems with gasket leaks due to torque issues.
**RED Loctite used on the Fidanza FW and pressure plate bolts, however.
Just sayin...
P.
Same here. Some of the bolts were just slightly more than hand tight. Going Blue on all plenum and IH bolts including the starter.
I cant believe it has been sense October when I started this. My travel for work has been non stop but I finally got her back together and cranked her over yesterday. She started right up and ran very smoothly. I think air was also being pulled through the IH gasket as well. Anyway, just need to finish battery relocation. I also relocated the intake temperature sensor while i was at it.
Finished reassembly and it starts and runs great. No more leak either. That said, while i had it apart i removed the alternator and had it checked out because I had some battery issues and NAPA said it was good. Not good. Lights pulsate just a tiny bit. Most noticeable at idle. Unplug alternator and pulsating stops...bad voltage reg.... great. Looks like another plenum removal exercise, i don't understand how this could have passed... The guy checking it didn't seem like he know was he was doing.... should have taken it elsewhere. I haven't put Marcs chip in yet, need to get the car registered and through ridiculous emissions test. I need to get some miles on the car before I bring it. Feel like I am talking to myslf here but I can't stand it when threads are started but not really completed. After I get the car registered and the new chip installed, I am going to dyno the car with both chips and see if all the porting work and Marc's chip provided any additional HP.
GOLDCYLON
07-16-2014, 07:08 PM
Finished reassembly and it starts and runs great. No more leak either. That said, while i had it apart i removed the alternator and had it checked out because I had some battery issues and NAPA said it was good. Not good. Lights pulsate just a tiny bit. Most noticeable at idle. Unplug alternator and pulsating stops...bad voltage reg.... great. Looks like another plenum removal exercise, i don't understand how this could have passed... The guy checking it didn't seem like he know was he was doing.... should have taken it elsewhere. I haven't put Marcs chip in yet, need to get the car registered and through ridiculous emissions test. I need to get some miles on the car before I bring it. Feel like I am talking to myslf here but I can't stand it when threads are started but not really completed. After I get the car registered and the new chip installed, I am going to dyno the car with both chips and see if all the porting work and Marc's chip provided any additional HP.
Pull the air horn and the throttle body only you do not need to pull the plenum to remove the alternator
KILLSHOTS
07-16-2014, 08:47 PM
Finished reassembly and it starts and runs great. No more leak either. That said, while i had it apart i removed the alternator and had it checked out because I had some battery issues and NAPA said it was good. Not good. Lights pulsate just a tiny bit. Most noticeable at idle. Unplug alternator and pulsating stops...bad voltage reg.... great. Looks like another plenum removal exercise, i don't understand how this could have passed... The guy checking it didn't seem like he know was he was doing.... should have taken it elsewhere. I haven't put Marcs chip in yet, need to get the car registered and through ridiculous emissions test. I need to get some miles on the car before I bring it. Feel like I am talking to myslf here but I can't stand it when threads are started but not really completed. After I get the car registered and the new chip installed, I am going to dyno the car with both chips and see if all the porting work and Marc's chip provided any additional HP.
Marc suggests to run the car through emissions with the stock chip, if possible. Also, make sure you run the test with the power key OFF or you will not like the result. When I had my 15K mile Z with brand new injectors and plugs tested, I didn't know that...ran it in full power mode and it failed MISERABLY! (BTW, the car was 100% stock at that time, except for those new injectors)
Thanks, that is a relief! The three attach pictures show the battery relocation, intake temp sensor relocation and a nice clean under plenum area.
The dyno numbers are in. Brief overview, discovered leak between injector housing and head. Removed intake and injector housing and discovered what appeared to be an aluminum gasket. Also discovered a mismatch between the injector housing ports and heads. Using a die grinder, I matched the ports to the heads, replaced gasket with one that actually seals and replaced the performance chip that was installed with the car when I purchased with a Haibeck chip.
The numbers from an older dyno run from previous owner:
Max rwhp: 392 Max rwtq: 357
Yesterday's runs:
http://i1295.photobucket.com/albums/b628/klavallee/Corvette/KLAVALLEEZR1HPTQ_zps33791be7.png (http://s1295.photobucket.com/user/klavallee/media/Corvette/KLAVALLEEZR1HPTQ_zps33791be7.png.html)
http://i1295.photobucket.com/albums/b628/klavallee/Corvette/KLAVALLEEZR1AFR_zps40159d34.png (http://s1295.photobucket.com/user/klavallee/media/Corvette/KLAVALLEEZR1AFR_zps40159d34.png.html)
Basically no gains from the extra port work matching the injector housings to the heads. The car is also running a bit lean. Marc is going to adjust the chip for me which should be good for a couple of extra ponies.
I hope someone finds this thread helpful. The dyno chart below represents the last run after Marc adjusted the a/f ratio numbers on my chip. The only performance mods on this engine are port work to injector housing, port matched heads to injector housing (While on car), intake and throttle body, headers, high flow cats and injectors. Also removed the typical emissions stuff and coolant bypass. I still have the secondary throttle blades in place and functional. Also relocated the battery and swapped to a light weight Odyssey AGM battery and relocated the intake air temp sensor to in front of radiator. The car passes GA emissions. It would be interesting to see if the blades could be forced open if the car would pass. If so, I would remove all that crap as well.
http://i1295.photobucket.com/albums/b628/klavallee/DynoRun8-27-14_zpsbe4ede04.png (http://s1295.photobucket.com/user/klavallee/media/DynoRun8-27-14_zpsbe4ede04.png.html)
phrogs
08-29-2014, 08:04 PM
Well I also find that they leak even when you use the right gaskets, Torque them correctly and it still leaks, every LT5 I have had leaked around the IH and I just learned to deal with it.
Mine were all 1990's as well.
Well I also find that they leak even when you use the right gaskets, Torque them correctly and it still leaks, every LT5 I have had leaked around the IH and I just learned to deal with it.
Mine were all 1990's as well.
This was beyond just a leak, the valleys that exist just below the injector housings would fill with PCV oily liquid. The metal gaskets were far from sealing. Tight as a drum....for now.
Harvie
08-30-2014, 11:10 PM
Try using Permatex 3H item 80019, it will seal the gasket.
The dyno numbers are in. Brief overview, discovered leak between injector housing and head. Removed intake and injector housing and discovered what appeared to be an aluminum gasket. Also discovered a mismatch between the injector housing ports and heads. Using a die grinder, I matched the ports to the heads, replaced gasket with one that actually seals and replaced the performance chip that was installed with the car when I purchased with a Haibeck chip.
The numbers from an older dyno run from previous owner:
Max rwhp: 392 Max rwtq: 357
Yesterday's runs:
http://i1295.photobucket.com/albums/b628/klavallee/Corvette/KLAVALLEEZR1HPTQ_zps33791be7.png (http://s1295.photobucket.com/user/klavallee/media/Corvette/KLAVALLEEZR1HPTQ_zps33791be7.png.html)
http://i1295.photobucket.com/albums/b628/klavallee/Corvette/KLAVALLEEZR1AFR_zps40159d34.png (http://s1295.photobucket.com/user/klavallee/media/Corvette/KLAVALLEEZR1AFR_zps40159d34.png.html)
Basically no gains from the extra port work matching the injector housings to the heads. The car is also running a bit lean. Marc is going to adjust the chip for me which should be good for a couple of extra ponies.
Unfortunately typical results from gasket matching/port matching. Most flow occurs in the middle of a port, not along the sides.
I used to port/gasket match all my junk, and your dyno results prove why I shouldnt anymore.
thanks for sharing, you have a strong running engine there, guessing approx 480hp at the crank. Cheers!
Harvie
08-31-2014, 03:04 PM
Bigger/larger is not always better, higher rate of flow is what is needed to make more power.
I have ruined 5K heads opening them up to where they had to be welded back up to have the material restored then the ports recountoured to get the propper rate of flow.
The use of a flow bench is the best way to accomplish it. The cheapest way (in the long run) is to pay a expirenced person with a flow bench do it and you clean up/polish after them.
To increase overall air flow you have to do all the passage ways both into the engine and back out of the engine. to maximize the flow and pattern. Opening up just the middle actualy reduces the flow and creates bubble/bottle necks that lose power.
I have cleaned up behind the very best Batton Superflow Mondello Brad Anderson Ladds Sonny Barton etc all have the same charastics, maniflods, headders, exhaust that flow the air in a uniform manner thru simular size openings with minimal redirection/obstruction of the air patterens. That is how more power is created. The Air pump that flow more air makes more power...
Bigger/larger is not always better, higher rate of flow is what is needed to make more power.
I have ruined 5K heads opening them up to where they had to be welded back up to have the material restored then the ports recountoured to get the propper rate of flow.
The use of a flow bench is the best way to accomplish it. The cheapest way (in the long run) is to pay a expirenced person with a flow bench do it and you clean up/polish after them.
To increase overall air flow you have to do all the passage ways both into the engine and back out of the engine. to maximize the flow and pattern. Opening up just the middle actualy reduces the flow and creates bubble/bottle necks that lose power.
I have cleaned up behind the very best Batton Superflow Mondello Brad Anderson Ladds Sonny Barton etc all have the same charastics, maniflods, headders, exhaust that flow the air in a uniform manner thru simular size openings with minimal redirection/obstruction of the air patterens. That is how more power is created. The Air pump that flow more air makes more power...
A little late on this reply, to your comment regarding just opening up the middle, The car has headers with high flow cats through high flow mufflers, the injector housings, intake plenum, throttle body were all professionally "significantly" ported, previous pics earlier in post show this. This is the main reason why I decided to do it. It made no sense to open up every passage in the system but then restrict it at the head. I contoured the openings based on advice from forum members and articles. If there was only a mild mismatch, I would have left the head alone but it was significant. Port/gasket matching is not rocket science.....that said, I would never consider attempting anything other than port/gasket matching. My guess is it did help the flow and that is why she was running a bit lean, after Marks adjustment, I picked up a few more HP. I could safely say the port matching likely gained about 5 HP.....was it worth it? I love working on cars, if I didn't do it, I would always be wondering.
5 ft lbs of torque is a nice pick up :cheers:
I hope someone finds this thread helpful. The dyno chart below represents the last run after Marc adjusted the a/f ratio numbers on my chip. The only performance mods on this engine are port work to injector housing, port matched heads to injector housing (While on car), intake and throttle body, headers, high flow cats and injectors. Also removed the typical emissions stuff and coolant bypass. I still have the secondary throttle blades in place and functional. Also relocated the battery and swapped to a light weight Odyssey AGM battery and relocated the intake air temp sensor to in front of radiator. The car passes GA emissions. It would be interesting to see if the blades could be forced open if the car would pass. If so, I would remove all that crap as well.
http://i1295.photobucket.com/albums/b628/klavallee/DynoRun8-27-14_zpsbe4ede04.png (http://s1295.photobucket.com/user/klavallee/media/DynoRun8-27-14_zpsbe4ede04.png.html)
Nice numbers for whats done to the car. Is this the '92 or the '95?
The 95. Surprising increase for port work, headers, exhaust and chip. I would like to keep the 92 as stock looking as possible. My plan for that car is top end porting, and may just remove the resonators and install a cross pipe in place of it. I read on Marc's site that these are a major flow restriction in the stock exhaust system in the 90 through 92 Z's and install a chip.
5ABI VT
11-26-2014, 03:33 AM
Great thread :) Im going to sit and read through it all from the start to see if I missed anything =D>
I too have been debating on going at the heads to match the port work but Im not brave enough to get in there.. yet.
Im about to install mine tomorrow I spent the entire day cleaning gasket surfaces and just finished cleaning and replacing my o rings as well. If I may ask did you use any gasket sealant or high temp rtv etc on the gaskets ? I was wondering if maybe I should line them up with a tiny bit just to be sure they seal.
Great numbers btw !! :cheers:
Great thread :) Im going to sit and read through it all from the start to see if I missed anything =D>
I too have been debating on going at the heads to match the port work but Im not brave enough to get in there.. yet.
Im about to install mine tomorrow I spent the entire day cleaning gasket surfaces and just finished cleaning and replacing my o rings as well. If I may ask did you use any gasket sealant or high temp rtv etc on the gaskets ? I was wondering if maybe I should line them up with a tiny bit just to be sure they seal.
Great numbers btw !! :cheers:
Unless you have a significant mismatch, you may want to leave it alone. I learned from some observant forum members that my injector housings were not 95's. Upon further investigation I learned they were swapped because the original owner didn't want to port the originals (I wish he kept them...). My issue was likely due to that and and some core shift, the mismatch was not symmetrical. They lined up perfectly on the inboard side (closest to secondary bore).
When it comes to sealant everybody has an opinion. Because the injector housing to head gasket is leak prone, I used a high tack Permatex product around the coolant and PCV passages. Item # 765-1221. Kinda messy, use thin coats. I have also seen #80019 recommended. The first one is made for NAPA, I believe they both are similar in function and application.
I used "dabs" of it for the intake to locate the gaskets because my gaskets had to be hand trimmed to fit and they needed to be exactly located, no room for error. If you don't need to use it for the plenum, I wouldn't use it. If you still have coolant passages in the plenum, you may wan to use around those only. Take special care torquing all bolts. Use a torque wrench and clean all bolts and bolt holes the best that you can. I use a an ultrasonic jewelery cleaner with paint thinner or Simply Green. I used medium strength blue thread locker on bolts. Jerry's gaskets has a great "thicker" Loctite product that worked very well. Also, keep a spare set of gaskets handy, never know when you may need to pull the plenum again.
vBulletin® v3.8.11, Copyright ©2000-2025, vBulletin Solutions Inc.