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Re: Oil Leaking

Subject: Re: Oil Leaking
From: Bob Howard <>
Date: Tue, 5 Oct 2004 13:22:17 -0400
   Agreed that the charcoal cannister cannot cause the engine to be
pressurised. Didn't intend to imply that it would.    Charcoal cannister
is the air intake for the system.  Even if the cannister is completely
blocked, the suction on the carburettors should result in negative
pressure within the engine.  That is, of course, unless there is
considerable blow-by, but that would not seem to be the situation if the
new rings are properly seated.  While some vapor pressure develops from
the heating and pumping around of hot oil, intake suction should be more
than able to handle that vapor without an increase of internal engine
pressure, and the suction should pull the vapors out of the engine as
long as a source of intake air exists.

On Tue, 5 Oct 2004 08:31:51 -0700 "Frank Marrone"
<> writes:
> Bob,
> The engine has recently been disassembled and cleaned.  New rings 
> and bearings were installed but the cylinders were not bored.  A flex 
> hone was used to prep the bore surfaces.
> I agree with the statement that a clogged charcoal canister would 
> prevent air from being drawn through the engine.  My point is that if
> is blowby then it will be drawn out of the engine through the carbs 
> despite a clogged canister (assuming the vacuum connection to the
engine is 
> good).
> The ventilation path is now past the rings and into the carbs.  I 
> still must maintain that a clogged charcoal canister itself can not
cause the 
> crankcase to be over pressurized by blowby.  Under-pressurized maybe,
> could be bad to, but not over pressurized by blowby.  
> Do you see my point?  Do you concur?
> Frank
> '73 GT 
> > through it.  The vacuum in the engine would be whatever the 
> > carbs could pull against the resistance of the cannister's 
> > filter. If it's clogged completely, then no air could pass 
> > through at all and there would be no ventilation through the 
> > engine.  If partially clogged, there would be partial flow. 
> >    You could have intermittent clogs at the connections.  We 
> > don't know the maintenance history of the engine, so it is 
> > possible that there are
> > bits of gooey crud in the hoses and other places.   
> > Bob

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