[Vwdiesel] low compression

[Bryan Belman]

I am no expert.  Just years of vw diesel stuff.
that is way low and I would guess either broken rings, but that would eat oil, 
or valve sealing issue is more likely.
Intake or exhaust valve not seating, crudded up, something.
580 is way on the high side, 520 is nice, 480's are good too.

Is this a mechanical head?  If yes, get out the feeler guages.  Do a valve / 
lifter adjustment on the head with the shims.
That could be part of the low compression issue, rather easy to do I guess.

If it runs ok, no over heating, no oil consumption, no bubbles, would I drive it 
another 1,000 miles, YES.

With the 1.6na motor, you can pull the head off, drop the pan and then take off 
the rod caps and pull the pistons, all in the van.

You will find the issue at that point.

 Bryan Belman, Pt. Pleasant, NJ
04 Jetta Wagon TDI PD, 100hp, 5sp -- running :<)
92 Jetta 1.6 Eco-Turbo Diesel, 5sp -- running :<)
82 Diesel Westy 1.9NA -- running :<)
70 Type 1 stock Beetle -- Not running :<( 




________________________________
From: Chris Geiser <cfgeiser at gmail.com>
To: vwdiesel at vwfans.com
Sent: Wed, August 11, 2010 1:40:03 PM
Subject: [Vwdiesel] low compression

Second post to the list in 2 days - not a good week!!

I've got an '82 Vanagon diesel - not a main vehicle anymore (put collectors
plates on it last year).

Parked it over last winter; might have been a bit low on power last year?
Started it a few times over winter to warm it up and keep engine lubed /
fuel circulated, but didn't want to drive it around in the salt anymore.
Driving this spring / summer now, it's noticeably low on power (even for a
vanagon diesel!!), smokes and misses a bit after startup, smokes on the
highway, but not an unusual amount.  Injection pump rebuild last year.
Tested the injectors last week and they were fine.  While I had the
injectors out, I did a starter driven cold compression test:

Compression readings from the timing belt back in order:
1:  580
2:  480
3:  180
4:  480

Squirted a bit of oil in #3 and redid test - went up to 220ish.  Over the
past few months I did not notice any oil in the coolant, or compression /
bubbles in the cooling system, so I'm not too suspicious of the head.  This
engine is not the original - I bought this van in '99, at that time the van
had about 130k miles on it but had a Canadian (green block) rebuild put in
about 100K.  Assuming that is accurate info from the original owner, the van
now has about 260K miles on it, with this engine now having about 160K
miles.  Uses very little if any oil, and doesn't lose coolant.

I have two requests:

First; diagnostic thoughts (broken ring(s) on 3?  broken valve? or just
tired worn engine?). Anything valve-wise that can be checked by pulling the
valve cover other than basic adjustment?

Secondly - what do you think is the natural course of this engine from here
if I keep driving it - will it at somepoint lose enough compression that it
won't start, or do you think there's a good chance that #3 will
catastrophically fail and send a rod through the block?

I'd ideally like to use it for about 1000 miles yet this summer, then pull
the head and have a look over winter, but I'd rather not lose the block in
the process.

Thanks for any advice... there's some great thinkers on this list and I
appreciate all of your shared ideas!!

Chris
(in Wisconsin)
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