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I’ve been told two different things about tightening head bolts. One is that you should only tighten each bolt a couple of turns before moving to the next in the sequence, repeating over and over and over until you’ve finally got everything torqued to spec.
The other is that it’s OK to tighten bolt 1 fully to stage 1 torque before touching bolt 2, and so on. Repeat for stages 2 and 3.
Which is correct? I’d be doing it on a Jeep 4.0L (so a cast iron head and block).
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Yipes, while on some engines you might get away with torquing the bolts in any old way, there has to be a reason they give a preferred tightening order and method in the factory manuals!
I would go with the factory manual procedure. it’s no harder to do it the right way, and the downside is pretty dreadful.
If you don’t have a shop manual, in general you want to work from the middle to the outer bolts, maybe 30% at a time. Three passes should do it. Maybe a fourth pass just to be sure the gasket has settled down.
[quote=”grg8888″ post=92377]
I would go with the factory manual procedure. it’s no harder to do it the right way, and the downside is pretty dreadful[/quote]Sorry, I must have not explained myself very well. I wasn’t questioning the tightening sequence (which is fully laid out in the FSM), I was talking about how you actually tighten each bolt.
Eric’s video shows that he fully tightens each bolt to its stage 1 torque before moving to the next. Then again for stages 2 and 3. My question actually was (before I saw the video), is it OK to do that, or should each bolt only be tightened a couple of turns before moving on to the next? Meaning it could take many passes over each bolt just to get them all to stage 1 torque?
The fact that Eric is shown doing it on an aluminium head pretty much confirms that it’s going to be fine to do that with a cast-iron head 🙂
Tight all bolts by hand. Get the torque wrench, set it for the force needed for step one. Do all bolts in the specified sequence with the force required for step one. When done, set the wrench for the force needed for step two. Again do all bolts in the same order, then step 3. That’s the only right way to do it. Exactly as shown in the video. Aluminum, cast iron – doesn’t matter, same procedure.
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