[Vwdiesel] Analyzing compression numbers - oil in injector hole?

[Val Christian]

Sometimes there's a dribbling injector which leaves oil collecting 
and polymerizing in the prechamber / heatshield area.  

Also the 400 compression is low...are you getting vibration when 
the engine is colder, at initial startup, or white smoke for the
first few seconds of operation?

I would be less concerned with the compression, and more concerned with
the fuel delivery at this point.  The compression is usually what it
is, and takes allot of work to change.

Compression is not just rings.  How is your cylinder head?  After 150 
to 200k miles, I normally have to replace guides and seals.

Also, at about that point, or sooner, head gaskets seem to start 
failing, depending upon how many cycles the engine has gone through.


> 
> Ooops forgot to ponder on the rest of the posting
> Oil in the prechamber... Are you sure it was oil and not dirty diesel?
> If oil was leaking through a crack then it would be defying the higher 
> pressure of the chamber, I guess it could get past a ring with a duff oil 
> scraper. Coolant oil being historic seems viable. The low pressure in one 
> cylinder is a little out of spec...
> Mark
> ----- Original Message ----- 
> From: "Will Taygan" <william at taygan.com>
> To: <vwdiesel at vwfans.com>
> Sent: Friday, November 16, 2007 11:47 PM
> Subject: [Vwdiesel] Analyzing compression numbers - oil in injector hole?
> 
> 
> >I compression tested the 91 ecodiesel a month ago and got
> > 450-480-450-400.  (the 94 TD was 450-500 on all 4!)
> >
> > It starts well when cold, starts well when hot, but there's a zone when
> > it's just warm and the glow plugs don't come on that it cranks for a few
> > seconds before it catches.  Engine? Pump? Glow Sensor?  The afterglow is
> > 7 seconds, so I just double-glow the 7 second period (no light, just
> > current) and things usually improve.
> >
> > I found a good teaspoon of oil in the #4 injector hole (lowest
> > compression cylinder) when I pulled it.  I've never seen that before.
> >
> > There is some trace oil in the coolant overflow.  Looks like it had a
> > blown headgasket that someone repaired and now there's just a film on
> > the plastic.  Maybe a few pencil-dot sized specks of oil floating in
> > there.
> >
> > I'm not too worried about it, just curious.  Ideas? Theories?
> >
> > Will.
> >
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