Originally Posted by
Leo109
Hi All,
Daphne Discovery has blotted her copy book again. The only 60,000 km old Turner Performance AMC head blew the gasket last week - very disappointing.
My friendly local head machiner (yes, I know your not supposed to, but I can't justify another new head) who says he's spent 20+ years building race engines, gave me the following tips:
* He says new bolts will always stretch slightly after repeated heat cycling and not maintain the required clamping force unless released and re- tightened after being in service for some time.
* Reuse the old bolts (that were new with the AMC head), as they've already had lots of thermal cycling.
* Thoroughly clean the block threads (and everything else too),
* Use proper engine bolt assembly lube, not just oil
* Follow the torque plus two/three stages of 'degree' tightening sequence, then
* Loosen all the bolts off and repeat the entire tightening sequence again, then
* yet again loosen all the bolts of and repeat the entire tightening sequence a third time!
He says I will be amazed how much further the bolts will turn between the first and third cycle.
So, esteemed spanner-wielding gurus - what do you think of this approach please?
All help much appreciated.
I can see this turning into a looooooooonnnnng thread
JayTee
Nullus Anxietus
Getting involved in discussions is the best way to learn.
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