Snowy_Astra

I got some headbolts today so i can get the engine sorted finally, and i done 25NM then round the sequence 90 degrees twice.

25NM
90
90

But the bolts say it should be

25nm
90
90
90

But they seem ever so tight, not like all the others i've done in the past. Is there a differn't proceedure with steel gaskets? Its 0.4mm larger than the standard one (1.6mm)

Another thing i noticed, when i done 25NM torque down on all bolts, when i done the first 90 degree turn on the first two bolts, all the rest went loose. Doesn't that defeat the object of doing the 25nm in the first place?

Any comforting information much appreciated.

p.s This is a late C20XE vauxhall block, with late 105mm bolts (Chip, i'm looking in your direction I just get so scared with headbolts )

Anonymous

Cant comment on the number of times to do it, put its perfectly normal for the others to loosen as you tighten the next series first bolt or two down.

Thats why you MUST tighten them in the right order! (start from the center and work out)

Snowy_Astra

Yep, done all that

Just wondered if it was differn't with a steel gasket

Anonymous

I always just install the steel ones the same way, i normally round up slightly on the torqueing though, but im not sure if thats acutally right or not, its just what i have got into the habbit of doing and its worked for me so far.

Snowy_Astra

Well i rebuilt the top end of the omega's ecotec, and its the same system

25nm
90
90
90

But i done:
25nm
90
90
45

Just to be sure cos i wasn't prepared to strip it all down again to get a snapped bolt.

I'll do the final turn when the engine is in the car, there's no way in hell i can do it whilst its balancing on a yellow pages

Cheers Chip

Anonymous

I cant stand head bolts, i always use studs instead.

Snowy_Astra

Can't afford them Bolts will have to suffice for now