Final torque spec for factory head bolts?
Thread Starter
TECH Veteran
Joined: Aug 2002
Posts: 4,055
Likes: 1
From: Hartsdale, NY
Final torque spec for factory head bolts? I used stock bolts for my H/C swap. I sprayed the bolts with silicone before installation and then realized i could not mark them with a felt tip pen for purposes of torking them to GM specs.
So I just titghted the bolts 40lbs, 50lbs, 60lbs, 70lbs and finally 75lbs. I used an inside out sequence - just like the old days....
My heads have been on for 3 years with no issues.
I was always curious about the final recommended factory tork spec for GM head bolts. I assume 75lbs with silicone is about right.
Should I be loosing any sleep?
So I just titghted the bolts 40lbs, 50lbs, 60lbs, 70lbs and finally 75lbs. I used an inside out sequence - just like the old days....
My heads have been on for 3 years with no issues.
I was always curious about the final recommended factory tork spec for GM head bolts. I assume 75lbs with silicone is about right.
Should I be loosing any sleep?
Thread Starter
TECH Veteran
Joined: Aug 2002
Posts: 4,055
Likes: 1
From: Hartsdale, NY
So I could conclude that 75lbs is approximately correct Vs. the tighten all bolts to 370 Newton inch pounds and then turn each 140 degrees and jump up and down three times with your tongue out - method?
Step One..All 11mm bolts 22 ft. pounds
Step Two..All 11mm bolts turn an additional 90 degrees
Step Three..11mm bolts (1-8) turn an additional 90 degrees
11mm bolts (9 and 10) turn an additional 50 degrees
Step Four.. All 8 mm bolts 22 ft. pounds.
Hope this helps you out.
Step Two..All 11mm bolts turn an additional 90 degrees
Step Three..11mm bolts (1-8) turn an additional 90 degrees
11mm bolts (9 and 10) turn an additional 50 degrees
Step Four.. All 8 mm bolts 22 ft. pounds.
Hope this helps you out.
Torquing the factory bolts to a static torque measurement is not going to be accurate, but obviously will still hold the heads on. By going to a static 75 lb. ft. you're probably not nearly tight enough compared to doing it properly, but if you have a relatively weak combo it probably didn't hurt you. Wouldn't try nitrous or forced induction though 
Torquing by angle DOES NOT directly relate to static torque. As the fastener stretches, you may not see a large change in the amount of torque required to turn the fastener. So you could ultimately either be much too loose, or much too tight (and lead to a fastener failure).
Torquing by angle DOES NOT directly relate to static torque. As the fastener stretches, you may not see a large change in the amount of torque required to turn the fastener. So you could ultimately either be much too loose, or much too tight (and lead to a fastener failure).
