In a message dated 5/20/2005 12:25:18 AM Central Standard Time,
AMfoto1@aol.com writes:
> I've replaced that original breather tube with a TR4A plug (like yours)
> that's been modified with a 1/2" pipe, which will in turn have a hose
> attached
> leading to a catch tank/breather. A similar hose will provide ventilation
> for the
> cast alloy valve cover. There won't be a PCV valve or anything like that.
> Just
> an open breathing circuit with a small filter on the catch tank, serving
> both
> the valve cover and the crankcase.
>
I am under the impression that the shape and position of the "draft" tube is
an important part of the crankcase breathing system. The velocity of the air
passing under the car past the tube will create a slight depression (vacuum)
at the tube. This is a typical Pitot tube arrangement. This slight depression
will draw blowby gas laden air from the crankcase which will be replaced with
fresh air passing through the breather cap on the valve cover.
Redirecting the tube to a catch basin eliminates the purging effect and the
only thing emanating from the tube will be there excess gasses that slip past
the rings. Although racers do this all the time they also change their oil
after every race.
I recommend two courses of action:
1) do nothing but change the oil more frequently or
2) Retrofit a TR4A style PVC system which will restore the crankcase purging
action without depositing excess oil on the streets.
Dave Massey
57 TR3
71 TR6
80 TR8
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