oups59

It is almost time for the head gaskets job . Looking for parts that I need to buy.

And I have a question about the cylinder-head bolts, Should I replace all of them with new ones or I can re-use the existing ones?

Thanks

blown 87

General mechanics rule of thumb is that if a bolt is a torque plus angle on torque that is USUALLY a Torque to yield bolt.

I replaced mine, but I have heard that they do not have to be and that they should always be.

Not much of a answer, but I would replace them.

Imo000

The early 32Vs have studs and re also torque to yield. If you need to replace the torque to yield bolts, what are you supposed to do with the studs?

the flyin' scotsman

For peace of mind I'd replace the bolts Luc but I haven't priced them.

69gaugeman

If I am not mistaken, they are not torque to yield but torque to some value before yield. At yield the strength of the bolt diminishes. They want to take up almost all the elastic deformation but not tread into yield.

Spent a LOT of time in engine plants up till three years ago and was involved in gauging in all facets.

The reason they changed from strict torque measurements is the statistical variation is much larger than torque plus angle. The friction becomes a larger and larger factor as torque increases, to the point where any contamination (oil or not) on the threads made for huge variations in final torque

I would have no issue with reusing once, but a second time might be pushing it.

69gaugeman

Oh also, when they machine the crank bores they put in bolts and do the same thing. They then remove the bolts at assembly and put in new ones. They reuse the old ones for the machining cycle over and over.