C2 Flywheel & Pressure Plate Torque Specs

[James W.]

Does someone have a '63-'65 shop manual handy and could tell me what the recommended torque specs are for the flywheel and pessure plate bolts on a 1965, 327/365 engine?

Thank you!

James West

[John H.]

Re: C2 Flywheel & Pressure Plate Torque Specs

James -

Flywheel is 60, pressure plate is 35.

[John H.]

Re: C2 Flywheel & Pressure Plate Torque Specs

James -

Flywheel is 60, pressure plate is 35.

[James W.]

Re: C2 Flywheel & Pressure Plate Torque Specs

John,

Thanks for the quick response. Is it recommended to use any loc-tite on the flywheel or pressure plate bolt threads at installation?

Thanks,

James West

[James W.]

Re: C2 Flywheel & Pressure Plate Torque Specs

John,

Thanks for the quick response. Is it recommended to use any loc-tite on the flywheel or pressure plate bolt threads at installation?

Thanks,

James West

[Mike McKown]

Re: C2 Flywheel & Pressure Plate Torque Specs

Use a progressive sequence on the pressure plate bolts. Run each bolt down about a quarter of the way, then half, two thirds and then full torque.

No Loc-tite. Just lock washers.

[Mike McKown]

Re: C2 Flywheel & Pressure Plate Torque Specs

Use a progressive sequence on the pressure plate bolts. Run each bolt down about a quarter of the way, then half, two thirds and then full torque.

No Loc-tite. Just lock washers.

[Joe L.]

Re: C2 Flywheel & Pressure Plate Torque Specs

Mike and James-----

Pressure plate bolts are special 3/8-16 bolts of GM-280M material (SAE grade 5)with a captured split lockwasher. What's special about them is that they have a non-threaded shank which, for a bolt of their short length, is a special feature. These bolts are generally used as-is with no threadlocking compound. As I've said many times before, split lockwashers offer VERY litle, if any, actual "locking" to the fastening system. I really don't understand why the factory ever originally used them. But, they're ok for this application.

The flywheel bolts are another matter. These bolts use an external tooth star washer for "locking". Actually, an external tooth star washer is a better thread locking agent than a split lock washer, but not by much. The big problem with this as I see it is that external tooth star washers are a very low strength, non-hardened sort of piece. The flywheel bolts, on the other hand, are of GM 300M material (SAE grade . No chain is stronger than its weakest link. So, in my opinion, when an ungraded, soft star washer is used in this fastening system, the whole system is degraded. If the star washer should break or further compress, all tension on the bolt will be lost and the bolt will be useless. Worse, it may easily work its way out and cause other problems.

Yes, I realize that GM has made millions of engines with this same flywheel retention fastening system and it's been very trouble-free. Notwithstanding that, you won't find this system on any car that I've gotten into. What do I recommend and use? I use ARP flywheel bolts. These are VERY high quality fastners and they are to be used without washers of any kind. If it makes you feel better you can use Lock-Tite 242 on the threads, but you don't have to. Torqued to the ARP spec, they'll stay right where they are for as long as they need to.

I use ARP pressure plate bolts, too. Neither the flywheel or pressure plate bolts, as high a quality as the ARP pieces are, are really all that expensive.

[Joe L.]

Re: C2 Flywheel & Pressure Plate Torque Specs

Mike and James-----

Pressure plate bolts are special 3/8-16 bolts of GM-280M material (SAE grade 5)with a captured split lockwasher. What's special about them is that they have a non-threaded shank which, for a bolt of their short length, is a special feature. These bolts are generally used as-is with no threadlocking compound. As I've said many times before, split lockwashers offer VERY litle, if any, actual "locking" to the fastening system. I really don't understand why the factory ever originally used them. But, they're ok for this application.

The flywheel bolts are another matter. These bolts use an external tooth star washer for "locking". Actually, an external tooth star washer is a better thread locking agent than a split lock washer, but not by much. The big problem with this as I see it is that external tooth star washers are a very low strength, non-hardened sort of piece. The flywheel bolts, on the other hand, are of GM 300M material (SAE grade . No chain is stronger than its weakest link. So, in my opinion, when an ungraded, soft star washer is used in this fastening system, the whole system is degraded. If the star washer should break or further compress, all tension on the bolt will be lost and the bolt will be useless. Worse, it may easily work its way out and cause other problems.

Yes, I realize that GM has made millions of engines with this same flywheel retention fastening system and it's been very trouble-free. Notwithstanding that, you won't find this system on any car that I've gotten into. What do I recommend and use? I use ARP flywheel bolts. These are VERY high quality fastners and they are to be used without washers of any kind. If it makes you feel better you can use Lock-Tite 242 on the threads, but you don't have to. Torqued to the ARP spec, they'll stay right where they are for as long as they need to.

I use ARP pressure plate bolts, too. Neither the flywheel or pressure plate bolts, as high a quality as the ARP pieces are, are really all that expensive.

[Mike McKown]

Re: C2 Flywheel & Pressure Plate Torque Specs

Joe:

I wouldn't debate that every application that uses a split lock washer is effectively locked by the washer. I would say that anytime you pull a fastener apart and you can see a shard of metal being lifted by the reverse rotation of the nut, bolt, screw, etc., you definitely made use of the split feature of the washer.

[Mike McKown]

Re: C2 Flywheel & Pressure Plate Torque Specs

Joe:

I wouldn't debate that every application that uses a split lock washer is effectively locked by the washer. I would say that anytime you pull a fastener apart and you can see a shard of metal being lifted by the reverse rotation of the nut, bolt, screw, etc., you definitely made use of the split feature of the washer.