pressure plate/flywheel bolts

[inisross]

I was once told the only "dumb" question, is one not asked, so here goes.

My husband is doing a 700r4 to t5 swap in our 1988 2.8L RS camaro. The t5 and hydraulic clutch is from a 1985 camaro. Anything that can go wrong, so far has. The following is my question.

Purchased pressure plate kit and had the flywheel resurfaced. When torquing the pressure plate to flywheel the bolts kept snapping. So I went to the parts store and purchased new bolts, thinking the old were just bad. The new GM were a different size. Apparently the old bolts are only an 8mm. These 8mm can not be torqued to 30#'s, (only 14-21) which is what the manual calls for. My husband even went out and purchased 8mm 12.9's and they snapped. So, can the torque be set at only 20? The 8mm seem to be the only thread that fits. HELP!

[Mr. Luos]

If they call for 30 ft/pounds...then they need to be 30 ft/pounds.
Trust me.

On the LS1...the flywheel to crank bolts are even more pressure than that. 74 ft/pounds if I remember right. Even then...without some loctite...they can come loose.
Pressure plate to flywheel are torque to 52 ft/pounds for the LS1.

Maybe try going in a pattern and torquing down 15 ft/pounds...then same order torquing down 23 ft/pounds...then 30 ft/pounds

1..4
3.....6
5..2


If you have problems with breaking the bolts...see if maybe ARP makes some bolts that work for your application.

[inisross]

Sorry, new to this site.............ARP?

[CamaroRS92]

Looking at a metric bolt chart - an 8mm grade 12.9 torque specifications are only 29 (ft-lb.) or 40 (n-m).

Possibilities-
1) check to be sure you are interpreting the manual recommendations correctly (ie; is it calling for newton meters and you mistook it for foot pounds?)

2) are these import bolts or were they made in the US? - Import bolts (especially from mexico) have EXTREMELY POOR QUALITY and in my experience dont even come close to the strength ratings of american made bolts. I have seen mexican made grade 8 bolts that were less strong than a grade 2.
If you determine these are imports or still having problems with torque, i would suggest going to a reputable bolt supplier & tell them your requirements and that you want american made. You will get the correct ones that way for sure.

3) Mis-calibrated torque wrench?? (maybe not, but how many times has it been dropped- it happens)

[Mr. Luos]

Originally Posted by inisross

Sorry, new to this site.............ARP?

ARP is a manufacturer of high strength fasteners/bolts.

[inisross]

We do not have a manual for this vehicle. I had gleaned the info from another forum. Does anyone know what torque the manual says?

[inisross]

First I wish to thank everyone for their time and effort in answering my newbie questions.

On another site the answer I received was what I needed. If the question should ever again arise:

The bolts are actually 5/16 (which my husband had already retapped and purchased bolts) and are to be torqued to 20#. If they had been the 3/8 bolt it would have been 25#.

Again, thank you.