Alfa Valve Shim

[AlfaNeely@xxxxxxx]

       I rented my 1984 Alfa Spider SCCA ITB race car two weeks ago.  When I 
started it up to put it in the trailer, I noticed a loud click and a misfire.
       I ran the compression and had none on cylinder #2.  I pulled the valve 
cover and found #2 intake was not closing.  I suspected a bent valve from 
over reving or a broken valve spring.
       I pulled the head yesterday.  Had to weld a nut to the cam follower to 
get it pulled out.  It appears the valve adjusting shim broke.  The shim is a 
flat cup that fits on the end of the valve stem and comes in various 
thicknesses for valve adjustment.  The cam pushes directly on the cam 
follower which pushes the shim which pushes on the end of the valve stem.  
Normally very trouble free arrangement with minimal weight and little to go 
wrong.
       When I got the cam follower out, I found the top of the valve retainer 
had been beat and pounded mercilessly.  It appears the valve shim broke and 
the parts stayed on top of the retainer for a considerable period during 
which they were pulverized.  There is no evidence of the shim itself other 
than the damage and a bit of powder around the spring.
       The bore around the valve spring where the cam follower slides up and 
down is badly scored.  All the shrapnel was what was holding the valve open.  
I am not sure if the head can be cleaned up enough to save or not.  I thought 
about counter boring the valve pocket and making an aluminum sleeve, but it 
is probably simpler just to grab a head from one of my parts cars.
       The local Alfa mechanic came out to get some parts from my parts cars. 
 He looked at the head and said he has never seen a valve shim come apart 
before.

       Not sure if I will make the next race on May 18 or not.  I have to 
build a cylinder head plus the transmission and I want to put in my new fuel 
cell and panhard bar rear suspension.  Plus turn the rotors and rebuild the 
brakes.

Ciao,
Russ Neely
Oklahoma City
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