[TECH] Detecting bad rings

[jdbubb at verizon.net (Dan Bubb)]

Do a compression test. Keep your battery charged, use a consistent 
procedure. Number of revs, throttle position, clutch in or out....
Then redo the test except squirt several squirts of oil into the cylinder 
before you test each cylinder. Markedly better numbers indicate a ring 
problem since the oil will tend  to seal the rings.
You could also do a cylinder leak down test. This test pressurizes the 
cylinder so you can hear where it's leaking from. Adding oil also works on 
this test.
Lastly if the engine is burning it and not just leaking it, you can 
genereally tell how it's getting into the cylinder by when it burns it. 
Valve guide seals leak best when intake manifold vacuum is high, so the car 
will puke blue smoke when you let off the gas from high engine speed. 
They'll also leak at idle, but you may need to idle for a minute or so 
before the oil will make it the combustion chamber and start smoking. 
Revving it after idling for a while will also produce a nice big cloud as 
all the oil collected in the ports is sucked into the engine at once.
Rings will allow oil past most of the time, most visibly when the oil is 
really getting thrown around inside. High revs, high power smoking is 
generally rings. Not much vacuum in the ports to suck oil past the valve 
guide seals then!
Last, you could just have massive blowby. This will just pump oil mist into 
the air filter box and coat everything downstream with oil. A light coating 
is normal. Drops of oil here and there with a coated air filter is probably 
a problem.
Dan

From: "Jason F. Snow" <jasonfsnow@rcn.com>
Sent: Wednesday, February 08, 2006 4:16 PM

> What is a sure fire way of finding out if you have a head problem or a 
> block
> problem?
>
>
>
> I'm burning 1 quart of oil every 200-250 miles and I want to know if my
> rings are bad or if it is something in the head. I'm guessing bad rings.
>
>
>
> Let me know,
>
>
>
> Jason
>
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