DreamerGT

I give this a thread an A+ lots of good info.

69MustangCoupe393cid

So I've been thinking about this more, and I'll just get to the point. What about keeping everything in place, but also running an oil catch can, best of both worlds?

cliffyk

As I said above, in a properly operating PCV system there's nothing to "catch", however if you want to have a "catch can" for visual effect go for it...

69MustangCoupe393cid

Doesn't that valve work based on crank case pressure, the more pressure the more it opens? Also how would it filter out any oil mist and boiled out water and such, isn't it just an open tube that feeds into the engine to burn such things?

The filter would prevent the water and oil from running through the intake and onto the valves and keep the intake and such cleaner no? Not going against what you said, just trying ot better understand how it works because this was more my understanding of it

cliffyk

No, it's operated by manifold vacuum, having a continuous slight bleed at high vacuum, and opening more when vacuum drops so as to allow a metered flow of crankcase vapours into the intake to be burned.

See above, it doesn't "filter" anything, and what flows through are vapours. Combustion by-products, including water vapour, and in whatever slight amount of engine oil and/or it's additives are boiled off.

A catch can is not a filter, it's a device that provides a place for any liquid components of the PCV flow, and any gases in the flow that might condense in the can, to collect.

On a forced induction or very high compression engine, with the higher blow-by created by much higher combustion chamber pressures, a catch can may be desirable to capture the this greater flow of crud from the crankcase.

However on an n/a DD disabling the PCV system and installing a catch-can is not needed, and I would argue detrimental to engine life.

Placing one in the PCV line won't do any harm, however the only thing it will collect is stuff condensed from crankcase gases, because of the heat sink presented by the catch can's existence.