Re: M20 Piston slap

[Kyle <kyle_5r@xxxxxxxxx>]

It would seem to me that *if* this noise is indeed
piston slap that it would worsen as the engine gets
warmer - the metal would expand and contact would
worsen.  The result of piston slap is bent valves
and/or valves that eventually fail to seat properly. 
The solution would be to take the head off (inspect
while you are there) and install two head gaskets.  If
a bearing is loose, a more probable reasoning, it
seems that heat could expand the metal around it and
possibly curtail the knock noise at operating temp. 
These are just my observations, YMMV.  

- -Kyle     

> Date: Tue, 18 Apr 2000 13:45:39 +0200
> From: "Apfelthaler, Horst"
> <Horst.Apfelthaler@domain.elided>
> Subject: M20 piston slap
> 
> Hello,
> 
> I have a very bad (kind of knocking) noise on my
> project car's m20/b27
> engine.
> It seems that its piston slap because in the
> meantime I swapped a lot of
> components
> like head, oil pump, water pump, conrod bearings...
> for different reasons.
> 
> The noise is still there after a cold start. 
> You cannot hear it at idle, but when you accelerate
> it sounds like a diesel.
> There is no noise when driving for >5min, or when
> the engine has reached its
> operating temperature.
> I currently run Castrol TXT 5W40 oil.
> 
> Questions:
> Is there a cheap method to minimize the slap - or is
> it time to build a new
> engine?
> Is piston slap harmful to the engine (life) or is it
> just an annoying noise?
> 
=== message truncated ===

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