Pascal,

  Leakdown maximum allowable spread is 10%.  So, take 180; 10% = 18 psi.
The largest difference allowable between the highest cylinder's psi reading
and the lowest cylinder's psi reading can't exceed 18 psi of difference.
  Your highest is 180 and your lowest is 165, so the difference is 15 psi;
you're well within allowable limits.  No rebuild is required at this time.
  If one cylinder is excessively low, you listen to the three places to
determine where it's leaking from.  If it's a valve, you'll hear it at the
air intake manifold or exhaust (tailpipe), depending on which valve is
leaking.  Attempt to remedy by 'staking' the valve (rap it with a mallet).
If there's a bit of carbon on the seat holding it open, this will fix it.
If it's rings, you'll hear it leaking at the crankcase breather.  Attempt to
remedy by turning over a few times, and adding few drops of oil through the
sparkplug hole and then turning it over again.  If this greatly improves the
reading, your cylinder was a little dry. But, if it has a tendency to start
leaking down excessively again as the oil scrapes away after multiple
readings, it's time for rings.
  BTW, those are really good numbers, nice and high all around, and pretty
good balance overall.

HTH,

 Mike B.

----- Original Message -----
From: "Giasson, Pascal (DNR/MRN)" <Pascal.Giasson@GNB.CA>
To: <vanagon@GERRY.VANAGON.COM>
Sent: Saturday, April 14, 2007 10:39 PM
Subject: Leakdown and compression test results

Well I finally tested my home made leakdown tester today.  Here are my
results:
cylinder # 1 - 7.5% leakdown  (compression 165)
cylinder # 2 - 6.25% leakdown (compression 180)
cylinder # 3 - 17.5% leakdown (compression 170)
cylinder # 4 - 13.72% leakdown (compression 175)

Motor is a 1.9l with 134K miles.

Now I have to figure what all that data means.  If anyone has any thought
please let me know.  I might try it again tomorow to double check.

Pascal
'84 Westy