[Land-speed] Crankcase breathers

[Tom Bryant]

I have been having problems with oil aeration which causes a drop in oil
pressure in toward the end of a run, especially since replacing my dry sump
pump. When we were doing the dyno work this in April, John suggested that I
was pulling too much air into the crankcase. I had a breather on each valve
cover. We taped off on valve cover and picked up about 10 psi at the upper
rpm, which verified his suggestion.

A few years ago, I was discussing crankcase breathing with my previous
engine guru and he said since it was good to have a vacuum in the crankcase,
the conventional wisdom was to use a closed system with a pressure relief.

Does anyone know where I can buy a closed breather with a built in pressure
relief. So far I have been unable to locate one on the net.

Tom

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