Exhaust Manifold Bolts Torque

[Christopher R.]

1. What's the recommended torque values for '62-'65 2 1/2 exhaust manifolds?

1a. Anti-seize compound will be used.

2. I know the factory didn't, but is it a good practice to retorque them after a few heat cycles?

BTW, from the bolt head in, it's bolt head, french lock, shielding bracket, spacer, manifold.

[Joe L.]

Re: Exhaust Manifold Bolts Torque

Chris----

The GM spec on the end bolts (the 2 on either end) is 20 lb/ft. The inside bolts (the 2 in the middle) are 30 lb/ft.

[John H.]

Re: Exhaust Manifold Bolts Torque

Chris -

'63 Shop Manual sez 25-35 lb-ft. for the center bolts, 15-20 lb-ft. for the end pairs with the french locks. No need to re-torque (no gaskets to compress).

[Al C.]

Re: Exhaust Manifold Bolts Torque

I'm planning to install the shielding on my '58 soon. Should I expect to find the manifold bolts to be rusted in place? Practically everything I've worked on in this car has been rusted in place after almost 30 years of storage. It appears that it would be very difficult to get PB Blaster into the threads of these long bolts; I'm afraid that a broken bolt will mean pulling the engine to get to it.
... Al '58 #378 245hp (soon...) NCRS SACC

[Carl R.]

Re: Exhaust Manifold Bolts Torque

Hi Mr. Cellier,

Funny how this sparks (painful) memories of ten years ago...I ran into that very situation on the passenger side manifold on my 1967 car (bolt head rounded off when trying to remove).

Took a round grinding attachment (about 3/4") on a drill and about 1-2 hours to grind the head of the bolt to where I chisel the head off. Then, after removing the manifold, the remaining stud unscrewed with my fingers. Sometimes you get lucky. Did mark the manifold some but I was changing for correct # anyhow. I don't know of any good way to get penetrating oil into these threads, but if one sticks (and you're both handy & brave) you could try gently heating the bolt head with a torch (have removed many a stubborn bolt that way). If all else fails & the bolt breaks off a good machine shop could probably remove/helicoil threads as necessary.

Good luck (at least better than mine)!

Carl

P.S. If you want to use gaskets when replacing get the Fel-Pro composition steel, trim to match the manifold contours, and paint the same color as manifold. Difficult to discern once in situ.