Re: [alfa] Piston Slap

[bearbvd@xxxxxxxxxxxxxx (Greg Hermann)]

At 10:16 PM 9/29/03, Steve Moresi wrote:
>I can't remember at the moment, but I believe our pistons have the pin bore
>offset to one side of the engine to keep piston slap from happening  => at
>TDC the force on the piston keeps it cocked one way in the bore, keeping it
>from rattling back and forth.  If you put it in backwards it rattles like
>hell.

And ALSO makes more horsepower. I don't THINK any (stock) Alfa pistons have
offset pins, though.

Reversing the pin offset on Chevy motors (with stock pistons0 was a common
Smokey Yunick trick to make more power.

Greg
>
>Steve
>
>At 02:28 PM 9/28/2003 -0700, you wrote:
>>Fellow and esteemed Digesti-
>>
>>I have a '87 Spider Veloce which has been diagnosed as having piston slap in
>>the #1 cylinder. The engine has only about 25,000 mi., It uses almost no
>>oil, has normal power but makes a tapping noise which goes away when the #1
>>plug is removed. My opinion is that the liner is abnormally worn, but I have
>>no idea why as the engine has never overheated nor run with low oil (Mobil 1
>>15W50). Oil pressure is over 60psi at 2500rpm and registers even when hot at
>>idle (does not read zero, but actual value is hard to tell from the gage).
>>Also, there is no smoke at all from the exhaust.  My question is this: Is
>>there any potential for catastrophic failure if I just go ahead and drive it
>>and ignore the noise? Also, has any one ever heard of a problem like this on
>>such a low milage engine?
>>
>>--
>>John Cecil
>><jcecil@domain.elided>
>><jcecil66@domain.elided>
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