I think that old rascal, Bernoulli is at work here. In a dynamic situation
such as an engine running at high rpm, the engine is pulling the maximum
volume of air through the inlet tract. In that the cross-sectional area of
the valve passages is constant, the greater the volume of air, the greater
the velocity. As this high velocity slug of air enters the combustion
chamber on the intake stroke, it will expand, creating a low pressure (per
Bernoulli's principal) within the combustion chamber until the piston starts
the compression stroke. I would think that this would be sufficient to
really suck the oil through the worn valve guides.
-----Original Message-----
From: owner-triumphs@autox.team.net
[mailto:owner-triumphs@autox.team.net]On Behalf Of R. Ashford Little II
Sent: Monday, November 18, 2002 4:23 PM
To: 'Randall Young'
Cc: 6-Pack; Triumphs@autox. Net
Subject: RE: Blue smoke and good compression
OK, first of all thank you for your opinions. BUT, I need to pose
another question so I can get's me a little "edumaction." Basically, I
have a question as to whether the blue smoke is being caused by a
worn/bad oil ring in number 2 or as most have said by worn valve guides.
The question is this: since I get more smoke at upper rpm's, but the
manifold vacuum pressure is less at upper rpm's than at idle, then why
doesn't it smoke more at idle than at those elevated rpm's?
If we are using manifold pressure as the source to pull oil down the
guides then it would appear that it would smoke at low to mid rpm's more
than at high rpm's.
I truly hope I'm missing something basic here since head's are cheaper
than engine rebuilds.
Thx,
R. Ashford Little II
www.geocities.com/ralittle2
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