[Vwdiesel] Compression check with Hyd lifters and Alum head

[Val Christian]

>From my experience, it's a function of your battery/starter, as to how
much impact there is doing the check with the cylinders closed vs open.
I just always do it with them open.  

On a wild guess, you might see 25 psi improvement if you open up the 
other cylinders.  That's just a guess.  Years ago I played with it,
but I don't remember the specifics.

My take is that the real purpose of a compression check is to let you
know if you have a glaring problem.  Like a bad cylinder.  The second
purpose is to let you track general condition of the cylinder.  Yes,
350 is less than 400, but I've had 1.5 engines which did 325 max 350 range
and lasted another 100Kmiles.  

So if you really want numbers, you can try it again, and see what you get.
Personally, I wouldn't bother.  I'd keep driving it, and monitoring cold
start performance, oil consumption and fuel economy.

The right answer, which I've avoided thusfar, is to read Bentley, and 
see what their proceedure calls for.

Val



> 
> I'm curious since I just did a compression test on my '89 1.6 na hydraulic 
> if pulling all the injectors is to just make it easier on the 
> starter/battery or if it also affects the reading? Of course when I did it 
> I did it the opposite way buy pulling one injector at a time and replacing 
> it before going to the next. I did let it crank each time until until there 
> was no more gain on the gauge (8-10 revs). Are my results skewed because of 
> the way I did it?  My numbers all came in low at 350-385 and now I wonder 
> if I should redo it.
> 
> thanks,
> 
> Bart
> 
> 
> 
> >I agree with Loren.  Also have a battery charger on hand and top the
> >battery off prior to compression testing.
> >
> >I test compression on gassers and diesels, with all plugs/injectors pulled.
> >
> >Since the injectors and plugs already are slobbered with neversieze,
> >all my compression checkers have neversieze throughout.  It's probably worked
> >into each of the gauges.
> >
> >Speaking of compression gauges...I have a K-D diesel compression gauge.
> >It has a quick disconnect, and came with MB, VW and GM adapters.
> >Now I'm looking for a TDI adapter.  Any suggestions?
> >
> >Val
> >
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