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Aluminum Head Saga-@#$%^!

To: MG Listserver <>
Subject: Aluminum Head Saga-@#$%^!
From: Chris Attias <>
Date: Thu, 12 Aug 1999 08:57:13 -0700
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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