[alfa] Re:Help - stripped cam bearing stud

[Jon Pike <jhpike@xxxxxxx>]

> Assembling the head on my 2000GTV engine and the last of the 12 cam bearing
> > nuts that I torqued (to a lousy 14lbft) stripped the thread out of the hole.
What's with the last stud thing?  I had exactly the same thing happen to me.


> Look at the "2L engine rebuild" page, and you'll see that Mike had the same 
> trouble on a pair of cam bearing studs, but used a product called a 
> "timesert", rather than a helicoil.  Not sure what the differences are, but 
> if anyone knows which is better, it would be Mike.
I did some research on various thread repair things..  Keenserts were 
well thought of,  but you need to drill nearly a 1/2" hole for the cam 
stud size.. they are pretty thick.

The Timesert is different than a Helicoil in that it's a solid sleeve 
(with a interlapped inner and outer thread so it can be very thin) as 
opposed to a coiled piece of square wire approximating the thread.
They seem to be considered better than Helicoils..  though most of what 
I've heard of as Helicoil problems (areas of high heat, like exhaust 
studs) wouldn't be a big deal in a low stress low temp area like the cam 
bearing.

Tips I got for doing it,  were that the threads do guide your drilling, 
if you're careful,   and the key thing is that the cam bearing isn't 
located by the threaded hole,  but by the sleeve that fits into the 
head.  If you don't get too far off,  the sleeve will preserve the 
alignment of the bearing,  which of course is pretty critical.  The 
other tip was if you have a junk cam bearing cap,  you could use it as a 
drilling guide.  The guy who did  my machine work for the rebuild (Dick 
at EMS) even sent me one in the mail so I would have one. 
I was going to do the drilling myself..  but ended up asking around and 
found a guy who'd do it for $25... and let him as I was having a bit of 
trouble getting the stud free.  That seemed to be less than what buying 
the kit with the tap,  and a special drill bit, and probably a stud 
puller would have cost me.  Worked great,  though I felt a bit guilty 
after Dick went to the trouble of sending me the cam cap.

Hope it helps..

Jon
77 Spider  (who recently discovered it's better to put on the bell 
housing to block shim  BEFORE you put the flywheel and clutch on the 
motor!!)
Irvine, CA
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