good comments, dardal

[Joe Bachan <jbachan@xxxxxxxxxxxxxxxxxx>]

 I'm sorry but I have to disagree with the quoted
statment below. A compression test can tell a great
deal more that just the condition of the top
compression ring of a weak cylinder. For example first
if you have two weak cylinder side by side this is a
good indicator of a blown head gasked 'tween the
cylinders, 2. if a weak cylinder compresion has the
same low dry compression as wet (a few squits of oil
down the spark plug hole to seal any weak rings)
you're probally looking at burnt valves. and third if
the compression increased after putting the oil down
the spark plug hole (wet compression reading) your
probally looking at rings. Further more rings tend to
wear evenly unless on breaks if the oil ring failed
the second compression ring would remove the oil. Yes 
in time it would build up carbon and break but this
two would cause weak compression and you would see
signs as oil consumpsion or fowled plugs. I'm soory I
have to disaggree with the old service guy on this
one.
Joe
76NYB
 ...
> Compression test?  As the old line Chrysler service
> mangager pointed out to me years ago, all the
> compression test will check is the top (compression)
> ring.  It can still hold good compression and the
> oil rings can still have enough wear and age
> (including loss of tension) to not effectively
> scrape the oil from the cylinder wall.  The other
> thing on a compression test is to use it as a point
> of reference, one cylinder to another cylinder, not
> looking for hard and fast numbers per se, but how
> they all relate to each other.
>  
>