Michael,
I agree. If you consider the fact that the air pressure at the intake of
the carb drops in pressure until it reaches the cylinder then it is
compressed by the piston, the highest pressure in the engine is in the
cylinder. While in between the compression stroke of the piston there is
generated a momentary low pressure, a pressure lower than atmospheric
pressure to draw the fuel air mixture into the engine.
The momentary low pressure draws the fuel air mixture in and the momentary
high pressure will force the exhaust gases out. The high pressure is still
in the cylinder and is seeking the lower pressure in the exhaust pipe.
There is a few degrees of crankshaft rotation that the intake and exhaust
valves are open at the same time. It is at that moment that the momentum of
the exhaust gases will help draw more of the fuel air mixture into the
cylinder. This action in effect increases the volumetric efficiency of the
engine and gives the engine more power. That's why clean open and straight
exhaust system increase horsepower.
So, how can you have this cause oil consumption at high RPM's? The tighter
the engine winds the faster the exhaust gases leave the cylinder and move
down the exhaust pipe. Creating greater momentum and pulling harder on the
area right at the exhaust valve guide, drawing enough oil into the tailpipe
to be seen at those higher revs.
Or, maybe I'm just guessing and pulling this out of thin air (or other areas
of my anatomy) and I have no idea what I'm talking about. ;-)
It's your valve guides, man. Get them checked.
Jeff Howard
Rayne LA
USA
'69 GT6+
'80 Spit
----- Original Message -----
From: "Michael Marr" <mmarr@nexant.com>
To: "Jeffery Howard" <nhoward442@charter.net>; "R. Ashford Little II"
<ralittle2@mindspring.com>; "'Randall Young'" <ryoung@navcomtech.com>
Cc: "6-Pack" <6pack@autox.team.net>; "Triumphs@autox. Net"
<Triumphs@autox.team.net>
Sent: Monday, November 18, 2002 8:57 PM
Subject: RE: Blue smoke and good compression
> Actually, the pressure anywhere in the exhaust tract must be above
> atmospheric, or it would not go out the tale pipe. The pressure
> differential is provided by the HIGH pressure of the burning gases in the
> combustion chamber plus the compressive action of the exhaust stroke.
>
> -----Original Message-----
> From: owner-triumphs@autox.team.net
> [mailto:owner-triumphs@autox.team.net]On Behalf Of Jeffery Howard
> Sent: Monday, November 18, 2002 8:16 PM
> To: R. Ashford Little II; 'Randall Young'
> Cc: 6-Pack; Triumphs@autox. Net
> Subject: Re: Blue smoke and good compression
>
>
> The exhaust side is a low pressure side. If it were not the exhaust would
> not go out the tail pipe.
>
> Jeff Howard
> Rayne LA
> USA
> '69 GT6+
> '80 Spit
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