[Healeys] Archimedes and his screw

[insptwo at msn.com]

Gary: If I'm reading this right, that means we are getting screwed every time
we stop!

Bill

BJ7
 >
> In a message dated 10/14/09 11:46:33 AM, healeys-request at autox.team.net
> writes:
>
>
> > I attribute this to the scroll seal and'slinger' working well as long as
> > you're driving fast and steady, but not so well at slow speeds with lots
of
> > stops.
> >
> We should call it by its right name: Reverse Archimedes Screw... (look it
> up if you wonder how a Greek could have invented something that has become
> iconic British).
>
> You lose the oil when you shut off the engine, because the negative
> pressure in the crankcase, which is helping pull the oil off the screw and
back
> into the crankcase briefly becomes positive pressure, which pushes whatever
oil
> was on and around the screw back into the bell housing.
>
> That oil in turn dribbles out of the little hole at the bottom of the bell
> housing, which should have a split pin (cotter pin to the Chevy mechanic)
> hanging out of it. The split pin is there to keep that hole clear of dirt
and
> debris, so that the oil can actually drain out (and on to your garage floor)
> rather than collecting and eventually "oiling" the clutch plate.
>
> So, as long as the car is running, it isn't leaking oil. When it stops, it
> leaks -- as it is designed to do. The more times you stop (and the greater
> the worn tolerances between your engine block and the Archimedes screw) the
> more oil you'll leak.
>
> Cheers
> gary