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Old 06-15-2010, 12:57 PM   #7
Larry Brumfield
Senior Member
 
Join Date: Jun 2010
Posts: 351
Default Re: Head Bolt Torque-Hot or Cold?

ALWAYS re-torque aluminum heads when cooled off! Just ask Edelbrock.

The Ford Service Bulletin says "warm" for the reason that I cited in my post above. The theory makes sense, that is, for pistons that may be real close or a little too close in fit. However, like I said I've seen no evidence of this or a problem re-torquing when cooled off.

The reason I tell people to re-torque when cooled off is because the high compression heads, especially those of higher ratios, are not made for the Model A with its only 14 stud and nut clamping power and the head needs all the clamp it can get.

Why would anyone want hot or warm threads expanded against one another? How many of you have seen a torque procedure that says, "Always heat up your fasteners with a torch for maximum torque accuracy." ????

Now if the Model A had 21 or more studs like the early Ford V8 (same size, 7/16"), installation could be a little sloppy and there's still plenty of clamp.

I remember something I witnessed in my youth. A group of younger men were trying to remove a large nut on a shaft that was so tight they couldn't get it to move. So they decided to heat it up with a torch. After they got it good and hot, one of the men said, "Quick... turn the wrench while she's still hot!" They pulled and pulled and the nut wouldn't budge! An older man, who worked at the shop, was witnessing the event and yelled out, "Let that thing cool off ... or better yet, look here." He grabbed a cup of water and poured it all over the nut. A few seconds later he reached down and unscrewed the nut with his fingers!


Larry B.
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