Re:Re: Cooked Coolant(??) and Kissed Pistons

[Jason Ball <madmac@domain.elided>]

Eric H. wrote:
<snip> The kissed piston issue is a matter for some debate. Most
people will tell you that an Alfa 6 can't survive that sort
of contact. I feel that it has more to do with WHEN the
contact happened. <snip>

- ------
I'm not really sure when the collision happened.   I bought the donor car and
drove it home from Dallas to Austin.  The trip home involved a few pulls to
the redline. The car did have what i thought was a noisy valvetrain but I
wrote it off just needing a valve adjustment.    I  gave the car a few more
"test runs" when I was home so that I could get a feel for what parts were
worth keeping, and again I pulled it to the redline.  Then I checked the
compression which was 190-195PSI on the mistimed cam side, and commenced with
the tear down.   
- -----

Eric H. wrote:
<snip> My belief is this: the valves are only seriously damaged if
the collision happens when the engine is running or somehow
turning at high RPM's. Judging from the condition of that
Milano's timing belt, I think that low RPM collision simply
stops the cam from turning and makes the timing belt ratchet
over the stationary pulley. Valve stems aren't butter,
they're designed to absorb quite a bit of force. <snip>

- ------
I'm guessing that the motor was hot and running when when the collisions
happened because the contact point on the pistons were "cleaned' of carbon and
the faces of the valves were also free of carbon all the way around.  All
three pistons and valves looked this way. Again the cam was a notch or two
advanced, Max.

To me, all this suggests that the motor was indeed running after the timing
slippage/ piston kiss happened. 

My theory is that the contact happened under high RPM where either the valves
are floating or the rods were stretching a tad.   

- --- I guess my big concern is the pistons.  The pistons really don't look
"damaged", but I'm really quite new to all this.  I'm not sure what the
consequences of even "light valve to piston contact might have on Alfa
pistons--    

Can anyone comment on this? 

Thanks for your help and advice Eric!

Jason Ball 
Austin, Texas
87 Milano Silver 170k (waiting for the donor motor or a rebuild)
87 Milano Gold 101k (donor car w/ now questionable motor)
85 Subaru 4wd wagon (just keeps going and going.....)

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