Moe87

My engine is the 350 5.7L L98 and i am looking for more information on the PCV system, specifically on this engine.

Does each side of the engine have it's own PCV exhaust tube or is it one side only? if it has two, do they collect into one tube via a Y or a T connector?

I am looking to add a oil catch can and ideally, i'd delete the pcv from sucking Anything other than the normal intake. To do this i would:

From the crankcase the hose would come out into an oil catch can, which in turn has a breather filter on it. From there the breather would equalize the pressure inside the crankcase with the outside atmosphere. i would then plug the hole in the intake.

NOW, the scientific question: Would equalized pressure for the crankcase always be better than positive / negative pressure between the crankcase and outside? If so is this because under positive pressure, the pistons have to fight the positive outside pressure to intake stroke and with negative pressure, the pistons would have to fight the vacuum to combustion stroke? Are these forces so negligible to the engine i shouldn't worry?

Apeiron

There's a PCV valve on one side to draw fumes out, and a fresh-air hose on the other to let fresh air in.

The effort spent by the pistons to move air within the crankcase is negligible, and remember that every time a piston is moving up or down, there's another one moving in the opposite direction so there's no change in pressure due to piston motion alone. Negative crankcase can be used to promote better ring sealing in some applications.

Moe87

does that fresh air hose have a filter on it for any reason?

if i were to build a oil catch system, would i need to incorporate that intake hose or let it be? (assuming i am just venting to atmosphere)

Apeiron

There's always a filter on anything that can let air inside the engine.

If you're venting to atmosphere, you have no need for an oil catch system.

Moe87

Figured but i've heard the oil mists and then begins coasting various parts of your cars underbelly; hence why i was going to build one.

Another idea someone posted was actually using an oil catch that drips the oil right back into the oil sump. I asume this is a possibility and will not adversely affect my oil (as its already exposed to the crankcase toxins.) Just make sure everything is sealed up fine on the return so no particles pollute the crankcase (any more than normal that is)

am i correct in this assumption?

Apeiron

What is it that you're actually trying to accomplish?

Moe87

not send low octane misty synthetic oil and already expelled crankcase toxins back into my intake.

TTOP350

iTrader: (8)

This is what your needing

http://www.lingenfelter.com/mm5/merc...egory_Code=C54

Apeiron

Oil vapour would actually have a very, very high octane rating, and there aren't many places better than the intake to put the blowby gasses.

How much oil is getting into your intake?

MD83Z

I spliced a clear plastic fuel filter,approx. 1"dia.x 2" into the PVC hose just to monitor how much oil was actually being sucked through my non-baffled valve cover. You can then see how much gets in.

Mr Froman

Very old thread but I figured I'd try here instead of making another. Is there an internal passageway that leads from the crankcase to the valve cover where the PCV valve is?

Apeiron

Yes, the oil drain holes in the lifter valley and heads.

IrocZ'85

iTrader: (9)

I saw this dead thread get revived lol. But I've recently been having a similar issue. My return PCV hose that goes from the Throttle body to the pass-side valve cover has been somehow allowing oil back up through it as well. Should i toss a little fuel filter into this line like MD83Z did, or is there another issue at hand that i should take care of if this is occurring?

my pass side valve cover is also non-baffled. thanks and sorry to post in a dead thread again lol