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I know the factory did NOT use Loctite...................but the engine builders during this time definitely did. Agree the OEM bolts were a slim hex head.
I know for a fact that the factory flywheel bolts for my 390 AMX were torque prevailing from the factory, and I did not know what they were initially. Later got into discussions with JohnZ and I believe a factory guy (bolting technologist) who either designed or recommended the use of these bolts for OEM flywheel use. Maybe just AMC 390 engine used them, but I don't think so. It was a special made engine during this time with forged components and a different assembly line. I thought these TP bolts went across factory lines back in this time.
Larry
Last edited by Powershift; 06-18-2019 at 12:17 PM.
The bolts from Corvette Central with external star washers look correct to me. OEM ('50's/'60's didn't use torque prevailing or Loc-Tite.
The head of the bolt was a hex, about half normal height to clear the clutch disc springs.
The CC flywheel bolts are all threaded and do not have a shoulder. Correct flywheel and PP bolts should have the shoulder at the top. You can see this shoulder on the ARP bolts I referenced above.
Larry
Last edited by Powershift; 06-18-2019 at 01:15 PM.
Ok, should get all the parts by Monday and will begin install. Thanks for all the help. I ended up going with Sachs clutch kit from Rock Auto and all the fasteners from a few vendors. Once I get everything and compare with the current setup making sure it all matches will then proceed. Any other items to check. The fork cam be relubed? I s there some kind of felt washer to install, I don't see one.
I have two manuals that state 65lbs for the flywheel, but I can't find a spec for the pressure plate. I'm planning on installing it tomorrow (with Chevy bolts)
Bolts have to stretch a little to remain tight. 11-18 won't stretch a grade 5, 3/8" bolt. Loc-Tite or no Loc-Tite.
That is the book torque spec. Not all bolts are torqued close to yield stretch to assure the needed clamping force for friction resistance like head and crankshaft bolts.
11-18 ft-lbs??? There's no way I'd leave them that loose. I'm using Chevy shop manual and Motor Manual specs for everything else, but they don't list the PP bolts. (Lars doesn't mention it in his video either) If I can't find a real spec, I was planning to go 40-50 ft-lbs.
Thanks Mike. I have original Chevy shoulder bolts but I'm adding grade 8 lock washers. I also have NOS flywheel bolts. When I took the engine apart, all the flywheel bolts had their heads shaved down. The ******** who last changed the clutch obviously put the disk in backwards!
Just a reminder to tighten the PP bolts about 1/4 turn at a time using the "star" pattern for tightening. PP needs to come down to flywheel slowly and evenly to avoid problems later. This may be basic stuff for you, but perhaps not for others. Since the PP bolts are the same as Fxxd you can check the Fxxd websites for their PP bolt torque setting. Or RAM or Hays websites.
But your final number sounds about right.
Larry
EDIT: A quick check for Brand X shows 25-35 ft-lbs for pressure plate to flywheel.
Last edited by Powershift; 06-19-2019 at 09:20 PM.
A reason for the lower torque values on the PP bolts to the flywheel is that the spring action of the PP is actually loading the bolts in tension. The threads torque is only one component and the PP spring action is the other component. According to some websites, the spring component is a few tons force.........spread across the 5 or 6 PP bolts.
The only thing I'd add is two have the flywheel balanced by itself and then have the clutch blanced to the flywheel. Good source of possible vibration.
YES. Balance the flywheel by itself, then again with just the clutch bolted on. Leave the disc out. Have an “x” stamped on the flywheel and the clutch for future reference/orientation.
if you skip this step, you will suffer shifter buzz.
A reason for the lower torque values on the PP bolts to the flywheel is that the spring action of the PP is actually loading the bolts in tension. The threads torque is only one component and the PP spring action is the other component. According to some websites, the spring component is a few tons force.........spread across the 5 or 6 PP bolts.
Good morning gents, I have the bolts. Are these correct bolts? Are the star washers to be installed on the flywheel or not? I have conflicting info within the posts so far, someone said no, no washer and others yes. What was the original setup? Also in the photo attached you can see the hairline cracks in the flywheel, can those be removed with resurfacing? Thanks
I think the bolts are good with washers but I'll leave that to the others to verify. Only way to know if the heat cracks will machine out is to have it surfaced. There are different opinions on a flywheel exhibiting some heat cracking. Some feel on a standard engine that's not seeing hard use, that they are not a problem. Others who just prefer not to take a chance will replace it regardless of if they machine out. Definitely if you have a healthy engine and plan on some competition or hard driving it's time to get a SFI rated billet steel or aluminum flywheel. Cast flywheels are definitely not explosion proof (resistant???).
If you do buy a new flywheel do not assume it is good out of the box. They need to checked for run out and that they are flat across the face. Some bad ones have turned up and I was one of the unfortunate few.
Last edited by DansYellow66; 06-21-2019 at 08:53 AM.
06-18-2019, 10:35 AM
you can check the Fxxd websites for their PP bolt torque setting. Or RAM or Hays websites.
