I remember that nut being challenging, but I would ** NOT ** have removed that nut to retorque it because we're supposed to do these in 3 stages with a particular sequence.

So maybe the first sequence is each bolt in order to 20 lbs, then each bolt in sequence to 50 lbs, then each bolt in sequence to 70 lbs (I went to 81 because back then ARP wanted you to go to 85, which I thought was crazy high... now they just want 70).

Well, back that nut all of the way out while leaving all of the others means that you went 0 to 20 out of sequence with the other nuts, then you went 20 to 50 out of sequence with those others (because hey, they were all left at 50 lbs, right?!), then you went to 70 on all of the nuts in sequence finally on your 3rd stage (so this part was "correct").

It might work out just fine, but don't kid yourself, that was 2 out of 3 stages out of sequence.

You had between 20 to 50 originally. If it had been me, I would have gone from there to 50. Because that was the last nut in sequence, you would have remained in sequence that way. All 3 stages and sequences would have been by the book that way.



Let's keep in mind why we do "sequence order of bolts" (nuts in this case) and repeat those sequences in (pressure) stages: We want even pressure on the heads, head gasket, and block. So we start at the center and go to 20 foot pounds of pressure as we work around all nuts. That's very light pressure and we cross tighten so that no region goes all of the way down before the others. Then we repeat to 50 ftlbs. Then to 70.

Now, you could IMPROVE on the book way by doing 70 stages instead of just 3. You could tighten the nuts in sequence by just 1 foot pound at a time! Clearly we don't have to be that gentle with our heads, head gaskets, and block, but if we wanted to, that would be the least impact on surfaces and materials.

The sequence spreads the tightening geographically across the whole headgasket surface.

And the stages of footpounds minimizes uneven pressure during each sequence.



Conversely, IMAGINE if you had started that whole job by tightening the last end nut all of the way to 70 foot pounds instead of in stages to 20 foot pounds and on. That would lock down 1 point of the head on top of the head gasket to the block, likely lifting the other side of the head entirely up above the head gasket+block.

Easy to see how that approach would put extreme strain on the aluminum head (bending/warping/cracking), among other undesirable effects.

 

@No Doubt Thanks for posting all of that, it is nice to see it explained clearly.

I went around and around on which way to to go, as I was not happy that the bolt was between 20 and 50, it was at least 20 and possibly over 50 I decided on removal. The rest were at 50.

After doing a lot of research on possible impact, the general consensus was it should be minimal.

I will not know if things are compromised likely for sometime, it was in my mind a roll of the dice either way as the bolt was out of sequence.

 

At least the others were only at 50. If they had all been finished at 70 it would have been worse.

 

@No Doubt Once I realized nothing was going my way I left things alone unit I had a viable solution to get a that one bolt.