Showerthought: everyone's skipping the torque wrench on aluminum heads

I've seen three warped heads this year from guys just cranking down bolts by feel. The spec on a Ford 5.0 Coyote is 22 ft-lbs for the intake, then 90 degrees, and people are just reefing on them. How many of you actually check the manual for the sequence and final angle?

4 comments

4 Comments

nancy_wood1mo ago

Grab the damn manual and a torque wrench, it's not a suggestion. I watched a buddy turn a simple gasket job into a boat anchor because he thought "good and tight" was a spec. Those aluminum heads don't forgive anything, they just bend. The sequence matters just as much as the final number, skipping steps is how you get leaks and cracks. Spending ten minutes to do it right beats eight hours fixing your mistake later.

paul_ramirez1mo ago

Totally agree with @nancy_wood, that "good and tight" mindset will wreck your engine fast.

gracethomas1mo ago

Been there, done that, got the stripped bolt to prove it. My first time doing valve covers, I cranked them down like I was trying to win a contest. The sound of that aluminum thread giving up still haunts me. A torque wrench felt like overkill until I had to drill out the mess.

betty_perry243d ago

Pull up any LS engine datasheet and you'll see they want you to go in stages, like 22 ft-lbs first, then 22 again after you've done all the bolts, then the final angle. Most people just skip straight to the final number and think that's fine. I've seen guys do the same thing on a 2V Modular motor, cranked the intake bolts to 15 ft-lbs in one shot and wondered why the gasket squirted out the sides. The real hidden problem isn't just the final torque, it's the fact that aluminum expands way faster than cast iron or steel. If you're torquing a cold engine and then it gets hot, that spec changes because the bolt grows and the head grows at different rates. That's why the sequence matters even more on aluminum, you have to let everything settle in stages so the bolt load stays even when the metal decides to move around on you.