RV8 Head bolt torque

[AntonyJ]

I see there seems to be different settings for the head bolts on a RV8.
Have seen 70ftlbs stated , but also 15ftlbs followed by an angle rotation sequence.
Is the difference for early or late heads?

[spend]

Early bolts can be reused (65-70), later ones are stretch 35+180degs or something. Get some ARPS & reuse them IMHO.

[AntonyJ]

spend said:

Early bolts can be reused (65-70), later ones are stretch 35+180degs or something. Get some ARPS & reuse them IMHO.

Right, cheers, will have to find out what has been used on this motor.
Guess I can re-use these ones, as thye are new and it hasnt been run.

[Pumaracing]

Any bolt can be reused provided you haven't tightened it past its elastic limit which is how so called 'stretch' bolts are in fact tightened and which is what therefore stops them being reused. I routinely use 'stretch' bolts with a normal torque setting to take them just up to the elastic limit rather than an excessive angle tightening one but of course you need to understand enough about bolt science to be able to calculate that torque setting for a given bolt size and material specification.

'Stretch' bolts are little more than a con to make assembly somewhat more idiot proof and also force you to buy new bolts at every build. No quality fastener like ARP would ever use a tightening sequence which takes the bolt past its elastic limit and which must therefore always weaken the bolt as it's being fitted and reduce the clamping load it could otherwise have produced. In fact their literature warns of the dangers of doing this.

[AntonyJ]

Thinking about it more, isn't it more likely to be the difference between tin and composite gaskets?
i.e different torque settings for different gasket materials?



ETA , sussed it now, stretch bolts have the washer "built" in, earlier bolts have a seperate washer.
Mine have the seperate washer, so they use the higher torque value of 70ftlbs.

Sorry for being thick!

Edited by AntonyJ on Saturday 8th November 06:32

[tr7v8]

Not for the ones adjacent to the exhaust flange, recommendation is to tighten them to around 15lb ft.