Help headbolts!

[Al Eyre]

gone to put my head on today all the bolts are torqued up and theres about 1mm of play(seperation) from the head im sing a z20let head gasket and got a coscast head using early type bolts :/ do i need washers as none came with the bolts set

[EY]

Yep I'm sorry to say that early bolts use washers.

[Al Eyre]

bloody hell lol ok ill get some washers from autovaux soon as its open wednesday :s

[EY]

You can reuse the washers from the previous bolts, if you still have them?

[Al Eyre]

no never came with any bolts :/ reckon i could get some 3 mm washers to fit my headbolst from a bolt supllier?

[Topbuzz]

Strange as the washers usually come/are bolt of the bolt. Where did you get the head bolts from? Anyway, now you've used the head bolts you've got to get some more again. Both early or late head bolts will fit, one of them is slightly longer in length and the one is trox male and the other is torx female head bolt. But either way both types will fit.

[Gordo]

Gen' Gm ones would be best, if they don't have them, HARDENED steel washers from a fastener specialist would work IF the outside diameter doesn't cause issues.

[Al Eyre]

i see think ive sourced some anyway... i got them from autovaux GM ones and ive been through 2 pairs and non came with headbolts..i bought one set and had the probably that the threads on the block must of been dirty so after hours of trying to find a TAP and die kit for the 11 mm bolts that nobody does i had to go buy another set to make my own tap (cut grooves into the bolt) to clear out the threads which worked fine i then when to torque up the current bolts and didnt work lol... just to confirm anyway the are the head torquee settings 25nm 60 60 60 there the forums ones ive found but the ones in the book i have say 25nm 90 90 90?

[Topbuzz]

I just followed what was mentioned in the Haynes book. However if the head bolts came with its own torque settings then use those.
The GM Calibra workshop manual I have says 25nm + 90 + 90 + 90

[Al Eyre]

yes same as my manual but a few people on here was sayign that GM changed them to 60 60 60 because people were cracking there heads :/ ..

[dag]

in the haynes for early type head bolts it says 25nm then angle tighten 65 degrees,65 degrees,65 degrees then 30 to 45 degrees when engines up to normal operating temperature ,the later type head bolts were 25nm+90+90+90,ive done quiet a few heads on these and missed out the 45 degrees when warm stage with no problems at all,the 3 stages of 90degrees is very scary when it comes to headbolts snapping

[Al Eyre]

yes thats what i thought i mean im a big lad but putting 3 90s on especially the last 90 feels like im gunna crack the head just doing that :s

[dag]

yeh the 3 90s are for the later style dis pack/coilpack head that uses later style bolts,ive used the 3 90s successfully but damn scared of snaping a bolt or pulling the thread out of the block

[Al Eyre]

well ive done them 25 nm there aboust lol and 3 averagly accurate 60s hahah but ive done them alot worse before on my old let and was fine like

[dag]

should be fine if you've used a fresh set of bolts as these are stretch bolts and should only be used once

[Al Eyre]

yes been through 2 sets lol the second set have been hand tightened in then back out but hardly reckon they will have stretched as i never torqued them in

[moejoe]

Can I just point out that if u have tryd to torque the head up without the washers on the bolts then I would advise u check ur block over to make sure u haven't put any cracks by the holes! As u have probably been trying to screw the bolts deeper than the thread in the block rather than applying downwards pressure on the head. hence the gap between the block and head.
Good luck with the build!

[Gordo]

Good point, it would be similar to hydraulicing when oil in a hole can develop enough pressure when a bolt is screwed down, to actually split the block material!
TBH, though, I would be horrified if the chap really lacked the nous to stop when they started to get more than finger tight when there was still a gap between the head and the block surface.

[vectra640]

I've torqued mine down to 80lbs per bolt, now that's scary, 80lbs is tons more than 25Nm 3 times but that's what was specified on my ZLET gasket which was on my CLET, at 80lbs it's close to going bang

[Al Eyre]

hi yes i never torqued them full without the washers just hand tight so dont think ive cracked the block ...well i hope not the bottom end on that block is worth about 3 k alone lol

[Gordo]

Unless you're green and answer to 'Hulk', you should be fine