-----Original Message-----
From: owner-triumphs@autox.team.net
[mailto:owner-triumphs@autox.team.net] On Behalf Of Randall
Sent: Monday, August 15, 2005 3:50 PM
To: 'triumphs'
Subject: RE: Compression test how to
> I have found that it is best to take all the plugs out before starting
> the compression check.
In fact, most course manuals say to do it that way.
> If the engine has set for any length of time a
> squirt of oil into each cylinder will help achieve correct settings.
That I disagree with ! Squirting oil into the cylinders will mask
leaking
rings ... in fact this is exactly how one tests whether it is rings or
valves that are leaking.
Randall
Of course you do! Don't you always? Notice I said to do it if the
engine has set for any length of time. If the engine has been running,
it should already have a coating of oil on the cylinder walls. But if
the walls are dry, the oil will set the cylinders to a condition that
simulates an engine that has been running. While it might mask leaking
rings, not doing it will provide readings that are not under operating
conditions and therefore questionable. If you want be sure of the
readings, repeat them several times and see if the readings go down over
the range of test cycles. If they do go down, that would indicate that
the rings are not properly sealing. But they might go down and still be
within operating tolerances.
Joe
|