In a message dated 6/7/2007 4:00:40 P.M. Mountain Daylight Time,
karhu@california.com writes:
I kinda wonder if the seals which are in trannies and diffs are gonna
like half an atmosphere of pressure on the outside pushin' in....
Benn
Hi Benn
You're the guy I pictured with your lips sucked in! Kidding.
The only reason I knew about it is the SB2.2 engine I have has a port on the
front face of the block. It's tapped into the chamber in the block that
houses the mechanical fuel pump push rod and pump actuator lever. I couldn't
figure why it was there so I asked a Nascar engine builder. He said they plumb
in
the rear end breather line to it to keep the rear seals from blowing gear oil
out on the track, there by getting black flagged and posing a safety hazard.
He didn't mention the trans breather line like I did and my Nascar
"clutchless" tranny had a 1/2" rubber hose leading from the breather vent line
up the
back of the trans, terminating at the back of the bellhousing, next to the
distributor. It was capped, rather unceremoniously, with what looks like a
hunk
of green scotchbrite and a plastic wire tie. The trans must have come from a
Busch or Craftsman truck team! LOL
The trans in a Nascar application may not have gear oil slinging problems
like the read ends do. The rears have the problem of centrifugal force trying
to gush the oil out the right seal where the trans just sits there mindlessly
and spins. They may not vent the trans to the engine vacuum to maximize the
suck to the rear. Disclaimer, I'm not talking dirty, that's your mind working!
LOL
I can't answer your question on how much suck a seal can take before it does
get it's lips sucked in but, I guess if the Nascar guys do it and don't suck
in their seals, it probably takes more than a half an atmosphere. I bet a
quick surf to a seal site would reveal how much suck, would a seal suck, suck
if a seal suck could suck seal.
Otto
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