I was torquing head bolts wrong for years until a guy in Phoenix showed me his trick

I was doing a head gasket on a 6.7 Powerstroke last month, and a mechanic from another shop was watching. He saw me torque the bolts in the order from the manual, then just walk away. He said, 'You're not doing the final quarter-turn angle torque? The manual says to, but a lot of guys skip it.' I had been skipping that step on every single job for about five years, thinking it was just for factory assembly. I went back and did it, and the feel was totally different. Has anyone else found a step in the book they were just ignoring?

3 comments

3 Comments

anna_roberts25d ago

Wait, isn't that final turn to get the bolt into its stretch range? Honestly, skipping it seems like you're just clamping with the bolt threads, not the bolt itself. That's a huge difference in clamping force.

the_linda24d ago

Consider how much heat cycles and vibration could loosen that bolt over time without proper stretch.

chen.jade24d ago

Funny, I used to think that final turn was overkill too. But @anna_roberts is right about the clamping force, it really does make a difference.