Anthony,
Only some pistons had marks in them? Some pistons have valve recessions in
the tops of them, and I've seen people replacing only 1 or 2 'bad' pistons
during a rebuild. Maybe the engine has been re-ringed at some stage and one
or more damaged or worn pistons were replaced with new ones that have valve
recessions on them?
I would suggest that valves hitting pistons would cause lots of damage, so
perhaps this isn't what happened
Did the machinist have to replace any of the valves due to damage, or did
they notice any of them were damaged before they reground them?
- Tom
----- Original Message -----
From: "Anthony" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Wednesday, February 28, 2001 1:51 PM
Subject: Re: A87 Head & Machining
> I just spent $120 getting my head machined and the valves recut which I'm
told it needed and was a good thing to do to it.
>
> The thing that has me slightly worried is that after decoking the pistons
I found a few small marks in them in the shape or an arc (the size a 1/4 of
a 5 cent piece would make), only on or two and on the raised lip around the
edge of the piston but I also noticed that the head had been machined before
as the "NISSAN JAPAN A87" marking was less than a millimetre from the
bottom edge.
>
> Would these marks on the pistons be from the valves hitting the pistons?
and after have the head machined will they hit even more? And finally is
this a problem? Something tells me it is ....
>
> A worried
> Anthony
>
>
> [EMAIL PROTECTED] wrote:
> >
> > Anthony,
> >
> > Tom has covered most of your question - the A87 head was used standard
on
> > most of the Japanese and Aussie L18 engines, open chamber heads were
used in
> > other markets (USA etc) probably to satisfy anti polly laws (only
guessing)
> > but open chambers sure weren't used for performance reasons.
> >
> > regards
> > Terry
> >
> > -----Original Message-----
> > From: [EMAIL PROTECTED]
> > [mailto:[EMAIL PROTECTED]]On Behalf Of Anthony
> > Sent: Tuesday, 27 February 2001 11:56
> > To: [EMAIL PROTECTED]
> > Subject: A87 Head
> >
> >
> > Sorry to ask this again but I'd really like to know ...
> >
> > What makes the A87 head so good? or is it the standard L18 head?
> > What type of performance increase is gained by having one over the
standard?
> >
> > Anthony
> > __________________________________________________________________
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