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[olm]

The bolts are new and the head not be skimmed.

[dave the builder]

did you compare the original bolts with the new ones ?
did you clean out the blind bolt holes in the block before reassembly ?(no oil or coolant)
are you confident of the calibration of the torque wrench ? and know for sure you have set it correctly ?

[Lizzie Zoom]

It is some time since I refitted a cylinder head, and then on 4 pots.

Back in the day the tightening of the bolts was done in sequence, in a cross pattern, from middle to ends. 

As a point of interest, and ready for the day I may have to do it again, but on my V6, what is the prescribed pattern tightening down gradually to full torque?

The tightening pattern(and you loosen in reverse ) hasn't changed. It's like that to prevent distorting the part as the forces are applied. It's why you tighten opposite wheelbolts too. Modern heads have a lot less metal in them, usually aluminium, although the multi-pass approach means that the clamping is built up in stages.

Thanks Nick

I hope I will now never have to do that job again, but who knows!

[Lizzie Zoom]

The bolt tightening sequence, described as a spiral sequence from the middle outwards, can be viewed here.

I would guess that an unskimmed head is 134mm, because that's the spec for X25XE and Y26SE, between the upper and lower planed surfaces. So if it's measurably less then it has been skimmed. If it was skimmed because it was warped then the material removed might be significant.

Good one

[Andy B]

someone one suggested to me, that after the initial torque setting to seat the bolt, to put a spot of paint pen at 12 o'clock on each bolt as an aid to where you're up to when you're then tightening down in 1/4 turns

[Migv6 le Frog Fan]

A sensible tip. 

[dave the builder]

or, if your memory is that bad then don't take your engine apart into 100 bits 

[Migv6 le Frog Fan]

We all make mistakes from time to time. And my memory is that bad these days. 

[dave the builder]

but what if you forget to put the dot on with a marker pen 
it's just adding more to the procedure
but fair enough ,whatever works for who's doing the job 

[Enceladus]

did you compare the original bolts with the new ones ?
did you clean out the blind bolt holes in the block before reassembly ?(no oil or coolant)
are you confident of the calibration of the torque wrench ? and know for sure you have set it correctly ?

It's hard to believe that the bolts are bottoming out unless there's crud or oil in the bolt holes. Surely there must be some allowance.

The GM bolts are described as M11 x 105mm (1.25mm pitch?). So worth checking that the new bolts you're trying to fit are the same.

That said the Victor Reinz 14-32104-02 bolt kits say M11 x 100mm. I don't know why. It might be they're substituting another standard part for a one size fits many approach.

EG. FAI says their bolts are M11 x 105mm.