Re: exhaust manifold nuts 1928 526 6 cyl

Posted by Tim Cole On 2014/12/25 10:47:27

The parts book lists a flat washer, lock washer and nut.

As for torque, the recommended hand wrench is 6 inches long so not a lot of torque is required.

The ASTM specification for 5/16 - 24 grade 2 is only 13 ft lbs. If you use anti-seize on the nuts the clamping force will be increased significantly.

This is contingent on a planed manifold surface. Those manifolds are very sturdy, however too much torque will distort the block. The exhaust system pressure is around 7 psi.

This topic makes me wonder is some of these cracked blocks are the result of too much stress from those manifolds.

Here in Detroit they have all sorts of ways to determine torque values and they still come up with some totally crazy stuff that snaps bolts during testing.