[Shop-talk] Head studs
Wayne
wmc_st at xxiii.com
Mon May 5 22:08:41 MDT 2008
> I would have read the responses to be use anti-seize compound on the
> threads, not necessarily on the smooth shaft. BTW, ARP says that loctite is
I should have gotten on this earlier... but wanted to mention lubed vs
dry threads can make a HUGE difference in torque specs. I read one
article that suggested de-rating the torque spec as much as 80% for an
oiled thread, if the original spec was dry!
I would consider the manufacturer's specs first; seems like older
domestic engines I've read about say the spec is oiled. I don't see any
point in anti-seize or Loctite. But my serious engine tweaking is
limited to Nissan SR20s (though I'm damn good at it!)
The best thing is angular tightening, which has become quite common on
modern engines from what I pick up. This is the equivalent of the
dial-gauge rod bolt tightening (stretch measurement) but into a blind
thread. For example, on the Nissan engine, they approximately spec:
Tighten to 30 ft/lbs
Tighten to 60 ft/lbs
Loosen all bolts
Tighten to 30 ft/lbs
Turn all bolts 90 degrees
Turn all bolts another 90 degrees
This produced very consistent tightening (bolt stretch) independent of
thread friction.
-Wayne
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