I have finally mounted my spiffy new aluminum (siamese type) head on
the block, but the project is not over. I was having some problem
getting it down on the head studs, and couldn't figure out why. I
examined the studs. Some of them were a little pitted, and possibly
distorted, so I went ahead and bought a set of ARP high strength ones
from APT. It seemed like a good idea, since there is some
differential expansion of the two metals, and good studs might ensure
that when it is torqued down properly it stays that way. And the
black twelve-point nuts look cool...
I put on the new studs and looked down the holes in the head.
Everything seemed to be lining up With the aid of a flashlight, I
noticed that an exhaust stud was drilled through the casting, into
the stud hole. It was acting like a set screw. @#$%*.
Backed off on the stud until I had the head torqued down. So far so
good. Put the manifolds on and started to torque them to 15 lb.-ft.
Two studs started to pull out. @#$%^*&! I realize that the head I'm
installing is "slightly used" (4 hours) acost me substantially less
than a new one, so I'm not ready to call the manufacturer yet.
I looked in Carroll Smith's fastener book for alternatives. He
states that any assembly in alloy that needs to be taken apart more
than once ought to have thread inserts. OK by me. I am now looking
to install Helicoils in the offending holes, unless I can find a
better product. Any ideas?
As an aside, Smith also states that any fastener in a (race) car
should be put together with some sort of locking nut. He makes
exception in cases where someone uses a torque wrench properly. In
race prep he seems to be a belt and suspenders kind of guy.
Chris Attias
'64 MGB
'84 Alfa Romeo GTV-6
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