Crankcase Ventilation 3.5 RV8

[Belle427]

A friend has a 3.5 RV8 in his kit car that was originally removed from a Rover P6 which I believe had twin SU carbs.
It now has an Edelbrock 4 barrel carb, and some Edelbrock Chevy valve covers.
Currently the passenger side valve cover is connected to the carb pcv port via a pcv valve, and the drivers side has a push in vent which is connected to the air cleaner base.
There is also a crankcase vent pipe at the back of the block which is currently fitted with a small filter.
Could anyone tell me the correct way to pipe this system?
I’ve read that if it’s piped as above then the crankcase vent pipe should be plugged to let the pcv system function correctly.
On the P6 I believe it was both valve covers to carbs via flame traps and the rear crankcase block pipe was connected to the air cleaner somewhere via a fuel style filter to draw in the fresh air.
Any input is much appreciated.

[GreenV8S]

Belle427 said:

Currently the passenger side valve cover is connected to the carb pcv port via a pcv valve, and the drivers side has a push in vent which is connected to the air cleaner base.
There is also a crankcase vent pipe at the back of the block which is currently fitted with a small filter.

That seems reasonable to me.

There should be a path from the crank case via a PCV check valve to the vacuum side of the throttle body. This applies positive ventilation when there is depression in the inlet manifold.

There should be a path from the crank case to the fresh air side of the throttle body. This feeds the blow-by into the intake when there is no manifold depression. Often both these feeds are taken from a single outlet on one rocker cover which contains an oil separator.

There should be a path for filtered air to be drawn into the crank case so that the crank case doesn't see too much vacuum when there is positive ventilation. Often this is connected to the opposite rocker cover to the PCV outlet so that fresh air is drawn across the whole engine.

Alternatively, throw all that in the bin and connect a catch tank.

[Belle427]

Ok thanks.
Would you just pipe everything to the catch tank minus the carb vacuum?

[GreenV8S]

If you're going for the catch tank approach, I'd fit an oil separator into each rocker cover and route them both to the catch tank. For a low spec engine you could probably get away with just one; the other cover would be used for the oil filler.

With the catch tank fitteed there would be no crankcase air vent and the carb PCV inlet would be blocked off. Some people do also leave the air vent in place (with the little air filter) just to fill the hole - it doesn't do any harm but isn't needed, and will probably block up pretty quickly if the engine blows out any oil.

[Belle427]

Thanks.

[HealeyV8]

On mine I have similar setup but with rear blanked and a oil separator can plumbed in between carb vac port and PCV to stop the heavier crud going into the carb.