Re: One valve down, the final episode.

[steveb@newkla.kla.com (Steven Buchholz)]

Hmmmmm.

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*Anyway, as of this morning we know that the valve was bent
*because "something got into the cylinder". The cylinder head has
*some scratches all over it. The "thing", after it danced around, it went 
*through the exhaust valve, got caught there and the valve bent.
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The valve gets pushed down by the lobes on the camshaft and is returned 
by the spring.  There are only two ways that the valve could get bent:

1) the tension of the spring pulling up on the valve with something stuck 
   in it,
2) the crown of the piston came into contact with the valve due to the 
   cam belt breaking with the valve in the open position.

I confirmed that there will be interference between the valves and the 
piston on an '86 5000T (by calling the service people at Carlsen in Palo 
Alto).  I'd be very surprised if the problem was due to #1.  For something 
to "get into" the cylinder it would have to go through one of the the 
valves or somehow get by the rings.  If the car has been serviced recently 
there is one other possibility ... the spark plug hole.  Since the engine 
is tilted to the side there is a nice surface for stuff to collect around 
the spark plug hole.  Could something have fallen in?  Could the ground 
electrode have broken off the spark plug?  Did they find anything lodged 
in the exhaust valve when they pulled the head off?

After I bought my TQC I found that the impeller on the compressor side was 
damaged due to something that went through the intake system.  As far as I 
know it never made it to the intake, but may be stuck in the intercooler.  
I thought it might have been a nut that holds the airflow sensor box 
together.  I would recommend that that you have the turbo looked at 
if you think the thing came in through the intake tract (I don't think 
the 5000T has an intercooler).  Another source of bits from the intake 
system could be the screws that hold the throttle plate on or something 
else hooked up to the intake plenum.  That screw would probably fall right 
down the throat of Cyl #1's intake runner (if it didn't drop back into the 
turbo!).

You've got the thing apart ... it's best to make sure all the damage is
repaired now.  It shouldn't cost too much to have the hose taken off the 
turbo to check it out.  

Good luck!
Steve Buchholz