Instead of catch can, why not delete PCV?

OldBlue61 · August 21, 2019

Interested to see the outcome as well. Yes, seems like the same general as the road draft tubes many years ago, as Grumpy Bear mentioned.

BigBlueLB756 · August 21, 2019

I try not to think anymore because I have been accused of over-thinking a problem and possible solutions.

Maybe a support group is necessary. Anybody else interested?

Grumpy Bear · August 22, 2019

16 hours ago, BigBlueLB756 said:

I try not to think anymore because I have been accused of over-thinking a problem and possible solutions.

Maybe a support group is necessary. Anybody else interested?

Yes!

j-ten-ner · August 22, 2019

17 hours ago, BigBlueLB756 said:

I try not to think anymore because I have been accused of over-thinking a problem and possible solutions.

Maybe a support group is necessary. Anybody else interested?

I'm in.

so long

j-ten-ner

green02crew · August 23, 2019

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j-ten-ner · August 24, 2019

The manual for my boat says that I should turn on the blower minutes before starting the engine, to get any fumes or gas vapours out of the engine bay to prevent a fire or even an explosion.

The OP mentioned several times "oily air" escaping from the vents.

That would be my concern about the PVC delete.

Just a thought.

so long

j-ten-ner

Edit: And even if the oil-air mixture is not strong enough to ignite, there's still the possibility that the oil can condensate somewhere, build up over time and create a fire hazard.

Edited August 24, 2019 by j-ten-ner

green02crew · August 24, 2019

The manual for my boat says that I should turn on the blower minutes before starting the engine, to get any fumes or gas vapours out of the engine bay to prevent a fire or even an explosion.
The OP mentioned several times "oily air" escaping from the vents.
That would be my concern about the PVC delete.

Just a thought.

so long
j-ten-ner

Edit: And even if the oil-air mixture is not strong enough to ignite, there's still the possibility that the oil can condensate somewhere, build up over time and create a fire hazard.

It’s not that much vapor. And a boat is different, the compartment is more sealed and thus needs venting for gas vapors.

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SierraHD17 · August 24, 2019

It works absolutely fine venting the crankcase. An emissions method is not blowing anything up... same logic that freaks when guys remove catalytic converters. I have the same filtration method on my LS swapped Nova..

SquireSCA · August 25, 2019

So here has what I have done, as a test. I bought a cheap catch-can off of Amazon, and installed it. I will drive the truck as I normally do, for 1,000 miles and then check to see how much oil is in there. If little to nothing, then I will go back to the vent filters and not worry about it. If it catches a good amount of oil, then I will know that using the vent filters would likely have dribbled oil onto the motor and made a bit of a mess.

Either way, it is not using the intake vacuum to draw in the crankcase vapors, giving me the worst case scenario for pulling oil out of there... If it barely pulls any, the filters will be fine. If it's a lot, then the catch can stays. Either way my valves won't be getting any more oil baked onto them, so its a win either way.

RJSmithers · August 25, 2019

14 minutes ago, SquireSCA said:

So here has what I have done, as a test. I bought a cheap catch-can off of Amazon, and installed it. I will drive the truck as I normally do, for 1,000 miles and then check to see how much oil is in there. If little to nothing, then I will go back to the vent filters and not worry about it. If it catches a good amount of oil, then I will know that using the vent filters would likely have dribbled oil onto the motor and made a bit of a mess.

Either way, it is not using the intake vacuum to draw in the crankcase vapors, giving me the worst case scenario for pulling oil out of there... If it barely pulls any, the filters will be fine. If it's a lot, then the catch can stays. Either way my valves won't be getting any more oil baked onto them, so its a win either way.

The only concern I would have is with the current orientation of those filters (horizontal), any vapor that is blocked by the filter, will naturally coalesce on the inside of the filter material and form a small "pool" if not allowed to drain freely (due to gravity) back into the engine. I would simply position them vertically and I wouldn't expect any issues

SquireSCA · August 25, 2019

That occured to me as well, and I will address that if I reinstall them, by finding some short, 90 degree hoses to bridge the filters to the crank vent ports. I want to use the stock quick-disconnect plugs for easy removal, inspection and cleaning from time to time.

SquireSCA · August 25, 2019

So after even 100 miles, there isn't even a drop of oil in the catch can. There isn't even a slightly oil residue in there, which seemed odd.

So I unplugged the hoses from the catch can, started the car and had my wife give it some throttle...

The two plugs coming out of the valve covers... Those are actually drawing a vacuum at idle. There is no pressure coming out of them. As she revved the motor up you could feel some slight pulses in them, but they still seemed to be drawing a slight vacuum, rather than pushing any pressure.

How is that? Where is that vacuum coming from? If that is the case, how would oil make it's way through that hose and into the intake manifold, which also, at 3,000rpm didn't seem to be drawing a vacuum.

Now maybe at high revs it does, and the hoses coming off the valve covers reverse from a vacuum and do push a little pressure that the intake sucks up... But my 100 road miles... I tend to drive with a lead foot. I did the exhaust, intake mod, higher flow filter, Airaid MIT, SuperChips 93 octane performance tune with throttle sensitivity increased by 20%, etc... I have been hard on the gas to redline just to see if it would blow any oil into there, and it hasn't, not in the catch can...

Anyone have any insight on this? Is it possible that the 18 models work differently than others?

SquireSCA · August 25, 2019

I think that we have been looking at this all wrong?

Those two lines coming off of the valve covers, are not the crankcase vents? Those are part of the emissions where the exhaust manifold draws a vacuum and this sucks in fresh filtered air from the intake tube, and inserts it into the exhaust in order to "clean up" emissions. Most of my motorcycles over the years have had suck a thing, called the "PAIR" or "SAI" system... That's not what is putting oil into the intake.

There is a second system down lower, a single line as you can see in this video:

SquireSCA · August 25, 2019

Yeah, I totally had this wrong. What is scary is that nobody reading all this, caught it either! LOL

Anyway, put the valve vent hoses back on the intake tube where they belong. They are drawing air OUT of the intake tube, not depositing hot oily air into it.

The PCV hose is a single, short hose that comes from the top of the case, below the intake tube, and routes to the driver side of the motor, into the side of the intake manifold.

I have pics of the catch can mounted with the hoses, and I marked the hoses with green and red arrows, so you can see the direction the air flows...