Elle <honda.lioness@gmail.com> wrote in news:630825e6-6d37-4ea9-a3e5-
0d9ec77dc3b9@e12g2000yqi.googlegroups.com:

> On Sep 11, 7:18*pm, jim beam <m...@privacy.net> wrote:
>> also, do a common-sense blow-by test on the motor. *with the engine at
>> working temp, carefully unscrew the oil filler cap. *if the engine's
>> breathing right, and you don't have a compression/wear problem, you'll
>> get a bit of chuff out of the hole, [and some oil spray]. *if there's
>> something [badly] wrong, either the cap will want to shoot out of your
>> hand as you get close to removal, or you can feel some vacuum if you
>> have your hand over the hole. *what you /should/ feel is a reasonable
>> degree of positive pressure.
>
> Did this test. No shooting of the cap at all, nor any vacuum. With my
> hand on the fill hole, there was a pulsing positive pressure--chuffing
> as you wrote--and oil spraying/slopping onto my hand.
>
> I gather this is not conclusive but a crude test for seriously bad
> compression, right? I expect to get an inexpensive compression tester
> soon and see what this yields.
>



Air jetting from the oil filler cap tells you nothing, I'm afraid. Even a
brand-new engine, freshly broken in and at max oil life will exhibit
/considerable/ jetting from the oil filler cap. From oil filler neck
emissions alone, it's hard to tell the difference between the blowby of a
worn engine and a new one.

You need to have a garage perform wet and dry compression tests. Keep in
mind even these are only analogs for oil ring condition. It is possible to
have good oil rings and poor compression rings, and vice versa.


--
Tegger

The Unofficial Honda/Acura FAQ
www.tegger.com/hondafaq/