mj1pate

I checked the Crank end-play on my 86.5 and it came in well in spec. Now I would like to reassemble and torque the lower engine inspection plate bolts and the exhaust pipe to manifold bolts. I can not find the explicit torque rating on these bolts in the FWSM, and suspect that these bolts fall within the general torque spec of :

M6 bolts = 8 + 2
M8 bolts = 20 + 2
M10 bolts = 40 + 5

I do not see any such markings on the inspec plate bolts or the exhaust pipe bolts. Doies anyone know the torque spec for these bolts and how to identify which size a bolt is?

Thanks, I would like to get this car back together

Mike

Mike Frye

Mike,

By the lower inspection plate, do you mean the lower bell housing?

The lower bell housing is not a critical torque spec as I've read that some people leave the rear ones out or just cut them off and use them as a locator pin for future removal without having to remove the exhaust.

I would go with your gut on these as well as for the exhaust flange bolts. I was surprised with the torque spec on the exhaust bolts and tightened them a little tighter by hand after they were torqued.

When Adam and I did his a few weeks ago he was able to find torque specs for them, and I seem to think the exhaust bolts were like 16 ft-lbs, which seemed too light.

Good luck.

mj1pate

Right you are, Mike....silly me. The old "good and tight" method applies to the exhaust pipe parts and "good and snug" applies to non-fluid sealing aluminum parts.

Mike

Mike Frye

Mike,

When I said 'go with your gut', I meant by using the 'default' torque values you listed in your original e-mail.

I'm just as paranoid as the next guy about torque values (unless the next guy is Adam G.) especially in aluminum, but in this case I think the +/- is less critical and the potential for damage is minimal if you err on the side of under-torquing it.

Ad0911

I actually had 2 missing exhaust manifold studs (broken) total on my 1978 engine which has never been dismantled and one stud was half broken. It broke when I put the spanner on. Could this be due to overtightening at the factory?

Should I remove all other studs as well and put in new ones?

Imo000

I've seen this on a local '79. and since the exhaust wasn;t leaking, we came to a conclusion to leave it alone. I would suggest this to you too. If the broken stud is not causing aleak, then don't touch it. Depanding on the location of hte broken stud (his was at the very back) getting to to fix it with the head on the engine might not be possible.

As for using default values for certain diameter bolt. Well just make 100% sure that the bolt you are refering to is the correct size. There were cases where people used the socket size as a bolt size. What I mean by this is a bolt woudl fit a 10mm socket and they woudl think it's a 10mm bolt when infact, most bolts that have a 10mm head are only 6mm. So this person woudl look up the value for a 10mm torque spec and use that to tighten the 6mm bolt. As no suprise to anyone, this much torque woudl snap a 6mm in an instant.


So jsut make sure if you MUST use a torque wrench, use a good one and the correct value. BUT as suggested above. I woudl use my hand and feel to torque these non torque esential bolts down.


I hope this helps!