[Diy_efi] Venturi effect crankcase breather - crankcase vacuum

[arnie]

----- Original Message ----- 
From: "Adam Wade" <espresso_doppio at yahoo.com>
To: "List for general do-it-yourself EFI talk" <diy_efi at diy-efi.org>
Sent: Wednesday, July 09, 2003 7:44 PM
Subject: RE: [Diy_efi] Venturi effect crankcase breather


> --- Jack Vines <jackv at ambassadorprograms.org> wrote:
> 
> > Can you help me better understand what specific
> > factors involved in pulling a vacuum in the
> > crankcase cause the dramatic drop in engine life
> > and which parts wear faster and why?  Are we talking
> > ring wear, bearing wear, piston skirt wear?
> 
> As I was led to understand by the Harley engineer (who
> is also a race engineer for several AMA Formula Xtreme
> teams, I should also add), there was significant
> additional ring wear once you got past a certain level
> of depression in the crankcase.  He didn't go into too
> many details, but I suspect there may be bending of
> the ring with fairly low pressures that cause the wear
> to be concentrated on the upper edge of the ring face
> (although this is merely supposition on my part).
> 
> Adam Wade       

Is that where you are coming from?  It was not stated, having
too much vacuum WON'T adversly affect engine life.  That is 
not to say having the correct amount is better for ring seal without
having ANY adverse longevity effect.  A person can drown from 
drinking too much water.  It should not be assumed the correct 
amount is harmful as well.  That is why I inquired as to the amount 
of vacuum being used in your (engineer) example.  Details?  It IS
about the details.  :)  It really is of little concern what happens to 
the ring with too much vacuum, I'm more concerned at what level 
this condition occurs.  As stated in an earlier post, 12-15 in. Hg. is 
used successfully for track use.  I have not seen evidence as that 
being too much.        

GAS       


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