Clutch Pressure Plate Bolts

Hi Jerry,

Once again you are a wealth of information and are always looking out for others. After wrestling with my bellhousing due to previous owner putting permanent loctite on it; I could not bust some of the bolts with impact either so on my back with foot holding beaker bar, I needed two arms to bust the bolts.

Anyway, getting back to the pressure plate bolts and your information it appears I need the LT1/LT4 bolts. Any part numbers available? If not, I should be able to call the dealer with the year, make, model to get it.

I am replacing the stock dual mass (what a heavy SOB) with Fidanza aluminum (bought from a fellow ZR-1 owner) that came with the ARP bolts it appears, but did not come with the oversized ground washers that SRP sells. It would not matter as it won't work for the Fidanza 3.2 clutch set up that I bought that came with the thinner pressure place as shown.


Valeo pressure plate that came with Fidanza 3.2 clutch kit. Stock bolt compared with longer ARP (minus washer)


Stock pressure plate with stock bolt compared with ARP (minus washer)

The Fidanza flywheel that I bought from fellow member was installed it appears, but not used and the bolt holes are tapped out and it came with a tap and I can tread them in quite deep but the bolts are still way too long. I guess worst case scenario is to use the stock pressure plate.

What are the effects of going with the thinner pressure plates?


Thanks again for the info.

[A26B]

Craig,
The "ARP" bolts (ones on the right) you are showing are not correct either. The shank should not extend any further below the pressure plate that the stock bolts (shown on the left of the bottom photo)

If you cannot get the proper bolt with longer thread engagement, then use the stock ones with the original pressure plate. Just be sure to clean the threads with something like brake cleaner, use blue loctite and do not over-torque.

Stock bolts should also be available for the thinner Valeo replacement pressure plate.

Originally Posted by A26B

Craig,
The "ARP" bolts (ones on the right) you are showing are not correct either. The shank should not extend any further below the pressure plate that the stock bolts (shown on the left of the bottom photo)

If you cannot get the proper bolt with longer thread engagement, then use the stock ones with the original pressure plate. Just be sure to clean the threads with something like brake cleaner, use blue loctite and do not over-torque.

Stock bolts should also be available for the thinner Valeo replacement pressure plate.

Jerry,

Thanks for the info and I should have noticed that. If I use the stock pressure plate I'll get a set from SRP. I'll check out the local dealer to see what the LT1/LT4 bolts look like.

What are the concerns if any using the new Valeo pressure plate if I can find the correct bolts? Since it appears to be over 1/4" lower, does the clutch system compensate for the difference in the pedal and engagement location, etc. I would imagine so, but not sure looking at the clutch slave.

Thanks again,

[XfireZ51]

Originally Posted by Jeffvette

Jerry it is of concern, but even after telling people, they just don't pay attention or care. The proper thing to do is to call up your local dealership and order the bolts for the LT1/4 pressure plate. It's 6 bolts!

The use of the fidanza flywheel however is a different issue. You going into alum rather than steel. What Randy/Ron is trying to do is get more thread engagement into the alum. With that being said, I'm running the factory bolts with my fidanza and have no issues and I beat my car.

Jeff,

Marc H. has stated the same. He uses stock bolts with the Fidanza.
I went with the SRP bolts using my stock PP/Fidanza FW.

Originally Posted by HAWAIIZR-1

Jerry,

Thanks for the info and I should have noticed that. If I use the stock pressure plate I'll get a set from SRP. I'll check out the local dealer to see what the LT1/LT4 bolts look like.

What are the concerns if any using the new Valeo pressure plate if I can find the correct bolts? Since it appears to be over 1/4" lower, does the clutch system compensate for the difference in the pedal and engagement location, etc. I would imagine so, but not sure looking at the clutch slave.

Thanks again,

Craig I have some bolts I can sen you with the key. Just let me know when you want everything and if there are any other parts.

Originally Posted by Jeffvette

Craig I have some bolts I can sen you with the key. Just let me know when you want everything and if there are any other parts.

Jeff,

Thanks for the offer. Let me get the motor out this weekend I'll get back to you once I find out what else went wrong. I believe I need some other parts; do you have the new bolts for the cams or only Marc? Anyway I'll make the list since the clutch will be last; I just was in between the other stuff and wanted to figure out what issues with the clutch as I pulled it.

Aloha!!

I found the L98/LT1/LT4 GM part number 10079898 just in case someone needs it. This is from a post of the ZF Doc via internet search.

[jpgolf14]

Back from the dead.

Hi guys, I'm new to the forum and do not own a ZR1 Vette. However you guys do have the best info on this LT1 pressure plate bolt fiasco.

I am putting an LT1 T56 trans into my '87 IROC. And I finally found a place that seems to have the correct bolts. McLeod part number 1502.

However my problem is my nice new SPEC steel flywheel does not have the counterbores in it. So does anyone know the diameter of the counterbores in the stock flywheel? Is it just 3/8"? I am going to take the flywheel to a machine shop to have the counterbores drilled.

Thanks,

John

[FU]

Consult Jerry (A26B) he may be able to help you out.

[A26B]

Originally Posted by jpgolf14

Back from the dead.

Hi guys, I'm new to the forum and do not own a ZR1 Vette. However you guys do have the best info on this LT1 pressure plate bolt fiasco.

I am putting an LT1 T56 trans into my '87 IROC. And I finally found a place that seems to have the correct bolts. McLeod part number 1502.

However my problem is my nice new SPEC steel flywheel does not have the counterbores in it. So does anyone know the diameter of the counterbores in the stock flywheel? Is it just 3/8"? I am going to take the flywheel to a machine shop to have the counterbores drilled.

Thanks,

John

Please refer to post #4 above foor the bolt dia. Counterbore size would be as close to 0.376" as you can reasonably get. The tighter the "slip" fit, the better.