The cylinder head saga continues...

If you are definitely using the right scale on the torque wrench and have properly lubricated a set of new bolts and you made sure that the bolts are the correct length for your engine and you made sure there was no junk left at the bottom of the holes and no liquid down them, deep breath after that lot. Then you should be ok to give them that last half a turn to engage the stretch bolt system.

MrCheerful

Deep breath? You're right there - it's an excrutiating moment! I'm giving it a whirl tomorrow morning, then it's light blue touch paper time ;-) Cheers.

Have you replaced the bolts with new ones? The extra turning distance is to stretch the bolts, so if the bolts are old you'll just have to leave it at that.

Errr, that won't work! You have to get the bolt into a sufficient state of tension for apply a downward pressure greater than the combustion forces, otherwise the head/block joint will experience a cyclic load and will rapidly fail. For conventional non-stretch bolts, you would aim to get the bolts tension to about 80% of the yield point. Stretch bolts are taken beyond the yield point, mainly because it's easier to automate the factory assembly process - as the bolt yields to absorb the 'excess' tension, it's no longer necessary to accurately torque the bolt. To re-use the bolt, you would still need to torque it past the yield point - as the bolt is weakened every time this happens, they often fail on re-use as they are designed to be used once only. The OP should use new bolts, the bolts will yield as they are designed to if the tightening procedure is followed. Lots of info in stretch head bolts here:

I understand what you're saying but he's already tightened them past what he thinks is reasonable (hard to judge without being there). Assuming he is using the old bolts (might be new ones after all, he hasn't said) I reckon he can either leave it and hope for the best, or replace the bolts. If he tries the first and it doesn't work it costs him a head gasket and some time, but new bolts are probably quite pricey. I've reused the stretch bolts on a small VW engine without any problems, bearing in mind that there is some margin for error in the specs, but maybe I was just lucky.

Thanks all -

New bolts are £1 each I've found. BTW is there any way to identify "stretch" bolts - there seems to be some discrepancy in the old Haynes as to what type of bolts are used across the model years.

-- Ken Davidson

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AFAIK the bolts are the same, it's just a matter of how they tightened - If the final setting is a specific value on a torque wrench, that means the bolt is conventional - if it's a torque + angle, that would indicate a stretch bolt.

The ones you have to move through an angle after torquing are stretch bolts.

£1 each is all right. Christ, little bolts from Homebase cost nearly that much. I'm sure I read they were £80 a set for my car, that's why I was advocating stinginess.