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PCV issues

VB242

VB242

I.M. Weasel
Joined
Sep 21, 2011
Location
Driving the No Malarkey Bus
I recently replaced my catch cans with 2 Chinese knockoff Pro-vent 200's in series like this... I
gbk3vGkkyiCTeIeyJH1knbLl77zbODwJvijgrpH3M3hdF7D0_-9sxAiwqJRczBjl_gGWuUYaXiM76LoDuKvoi6_ZPTtc7-LgDUF6INoXeMmqTRGhD2j_Hm-HxIxWHoNiOtHRnyoOW5I=w500

I also changed the oil and went from 15w40 to 10w30. I'm still getting enough blow by to clog up my ssqv blow off valve. I have the drains from the catch cans tee'd into the turbo drain so they shouldn't be overfilling. I don't see much oil in the 1" tubing, or mostly looks like water vapor but it's definitely oil getting through.

1. Is my problem the knockoff pro- vents? They appear identical in construction.
2. Should I switch back to 15w40 maybe?
3. I've turned the boost down from 24-25psi to 18-20 but haven't had much testing time, I need to clean the pipe with the blowoff valve and see what happens.
4. I don't think it's a broken ring, it idles smoothly, no exhaust smoke.

Thoughts?
 
I'd try some 15-50w oil or 20-50w. You want the flow to be slow enough for the oil to drop out and only the fumes to go into the engine. Looks like it would do that pretty well.
 
That's a lot of boost to cram down your engine's throat if it's old and worn out. The knockoff provents aren't nice, but they should still work okay. Also, you should run 5w40 or 10w40 depending on the weather. You will wreck your engine with 15W or 20W oil. It's too damn viscous for the bearing tolerances on cold starts and does nothing for when the engine is up to temp. Focus more on using good oil rather than bottom shelf Walmart garbage.

Couple questions:

1. Do you have drain checkvalves set up? The drains are supposed to either drain below the oil level or have a checkvalve preventing crankcase pressure from spitting oil vapors back up the intake. As always, RTFM:

https://www.manualslib.com/manual/1965110/MannPlushummel-Provent-Series.html?

2. Have you done a leakdown test?

3. Why are you running two in series? If anything, split them, with one feeding off the intake manifold with a PCV valve, and the other from the intake hose, pre-turbo. This is how I have my single unit set up:


<img src="https://liam821.com/h/242/Oct%202021/PCV_After_001.jpeg" width="1200"</img>
 
Engine probably has less than 2000 miles, no working odometer. I put it together last winter and has only done 2 events a month in autocross season I did gap the rings at the widest spec.

They drain below oil level.

The Amazon description said I could run them in series so I did.

They've really cut the blow by down,

I'll try the 10w40 or 10w50 oil.

I have not done a leak down test, but like I said it doesn't appear to have a broken ring or anything serious.
 
I just looked at the manual link, thanks, I don't think mine have the separator element on top, will verify when I get home.

Edit: after taking a closer look at the Amazon, it looks like I have a fine mesh strainer element but they sell a polyester element that will probably work better. I'll try those too.
 
Last edited:
Just a follow up, the check valves seem to have cured the problem. I left the steel mesh filter in the primary separator and put the poly filter in the secondary. My MBC messed up coincidentally and I thought oil was backing up into the turbo too but it wasn't. Thanks Harlard!
 
VB242 said:
Just a follow up, the check valves seem to have cured the problem. I left the steel mesh filter in the primary separator and put the poly filter in the secondary. My MBC messed up coincidentally and I thought oil was backing up into the turbo too but it wasn't. Thanks Harlard!
Click to expand...

VB242 and Harland: Can you show us what check valves you used?
Thanks, Dave
 
Those have a tiny internal diameter. I would use something like a brake booster check valve out of an BMW E46.
 
Harlard said:
Those have a tiny internal diameter. I would use something like a brake booster check valve out of an BMW E46.
Click to expand...
Is that made out of some kind of metal? If it's plastic, no thanks. Seems to be working regardless of what you call tiny, 1st autocross yesterday and 25psi when possible, no problem.
 
VB242 said:
Is that made out of some kind of metal? If it's plastic, no thanks. Seems to be working regardless of what you call tiny, 1st autocross yesterday and 25psi when possible, no problem.
Click to expand...

There are some made out of aluminum, but I get it the key to look for then is as large of an internal diameter as possible.
Thanks.
 
Guys FWIW..... Healthy engine.... oil gets separated from vapors.... vapors go to a road draft tube that exits aft of the engine. No additional power to be had burning that inert ick. If you MUST burn it due to rules do so.... but a smog test is annual. There are 364 other days in the year.
 
JohnLane said:
Guys FWIW..... Healthy engine.... oil gets separated from vapors.... vapors go to a road draft tube that exits aft of the engine. No additional power to be had burning that inert ick. If you MUST burn it due to rules do so.... but a smog test is annual. There are 364 other days in the year.
Click to expand...

So you're advocating this BELOW.

How many others agree?
 
JohnLane said:
Guys FWIW..... Healthy engine.... oil gets separated from vapors.... vapors go to a road draft tube that exits aft of the engine. No additional power to be had burning that inert ick. If you MUST burn it due to rules do so.... but a smog test is annual. There are 364 other days in the year.
Click to expand...

It's not the 1950's. Use a catch can.
 
Harlard said:
If you are going through the trouble of doing a dual setup, use one catch can for the intake manifold and one for the turbo inlet, and keep the vacuum sources separate.
Click to expand...

Thanks for the feedback, I'll go with the stock to manifold and the turbo to the additional setup on the left then. I take pcv in your drawing is for a pcv valve given I still have to tap my manifold for the bung. Might as well add a pcv valve.
 
Sure thing. Simplifies your plumbing a great deal with the added benefit of a second catch can.
 
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