VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1937-1945 Head Bolt Torque

I need to torque the head bolts on my 1937 216 and found the manual doesn't give a number for foot pounds. Suggestions?

On used head bolts try 50 to 60 pounds.

I would go even farther in that i would use a set of calipers on the head bolts unthreaded shafts and make sure each and every one of them is exactly the same thickness.

Then i would take those same calipers and measure the length of each bolt to make sure they are all the same length.

Reason to do this???? Possibility that somebody got hold of an 18 bar with a socket on the end and reefed on the head bolt , far exceeding recommended torque and actually stretched the bolt, causing a weak area in the bolt. This will now not allow that bolt to be clamped to the proper effective and recommended torque. That weak bolt if installed can lead to a weak spot and might cause a headgasket to blow out because the proper clamping force is not used on the whole surface.

I would run a thread die over all the bolts and then take a BOTTOMING TAP and run it into the block to make sure all the threads are good.

mike lynch

Great recommendation!

The 1941 engine manual states 75-80 pounds on a 216. I can't imagine it'd be any different.

Mike and JD,

That is indeed good advice. And, I recommend it.

(Here's the but)

I personaly wouldn't go to all that much trouble. I'm too impatient to do all that. I would merely inspect by eyeballing the shanks of the bolt and then clean their threads and the treads in the block and stick them in.

I figure that they will torque up or you'll feel the moment of elasticity beginning or they'll break. If they reach elasticity and/or break one you can always take them out and start over again by getting another bolt. Less trouble and less time.

Those bolts are pretty stout and will take a lot more pounds torque than that specified for the installation of a headgasket. I think.

I doubt Gene went to all that much trouble when he was rebuilding engine back at the dealership. Maybe. Maybe not. What say ye Gene?

Charlie

It ain't that easy if the bolt breaks down inside of the block below the surface of the deck.

Here's corroboration on the 75-80 ##:
http://www.1954advance-design.com/Stovebolt-engine/head-bolt.html
and this:
http://olybrake.com/pdf/fel_pro_torque_specs_guide.pdf
and one with tables for variables:
https://www.fillingstation.com/articles/torquespec.htm
Hope this helps.
Kyle

I support cleaning the threads in the block and running a die down the head bolts. If you don't have the correct die then line up the threads on pairs of bolts head to tail. If they all mesh perfectly (100% threads on one bolt fit into the threads on the other) then the bolts are not stretched. Blow out each bolt hole and oil the threads as a minimum. Also tighten in 10 lb increments once within 20-30 lbs of intended max. Also tighten, back off 1/4 turn and tighten again at each step. You will find that you will turn the bolt up to a 1/4 turn past the original position the second time at that torque. Why? you ask? Because the roughness in the threads in the block and bolt are being smoothed out. You will find that necessity of re-torquing is also nearly eliminated.

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EXCELLENT FURTHER ADVICE. !!!!!!!!

MIKE