Supercharged E36 - Oil coming out of fill cap

[zx666r]

Running into a weird issue with my supercharged car.

Background: I had seen a bit of oil burning off at stop lights and assumed based on the location of the leak it was a VCG. I took care of that, went for a drive and it started burning MORE. I had left the coil cover off to check for leaks and the whole top of it was covered in oil, the originating point looking like the oil fill cap. To be sure I zip-tied a few shop towels around the oil cap, cleaned everything up and took it around the block. The shop towels had a good bit of oil on them from just that short loop, confirming my suspicions. I've already tried replacing the cap with a new OEM cap to no avail. Any suggestions?

Only change I made to the car prior to the VCG was changing from a cheap catch can that was recirculated into the intake elbow right behind the supercharger inlet (which caused it to burn all through the exhaust and leave lot of oil in the intake track). I capped the inlet by the supercharger installed and radium can. I mounted it low near where the factory power steering fluid reservoir sits and ran the hose from the valve cover to the can and vented to atmosphere.

Open to ideas, I'm kind of at a loss of what to try. I'm using 1/2" hose from the valve cover with no kinks in the line anywhere. One tight radius bend that I could probably alter if needed.

[andrewgordnier]

Sounds like it could possibly be stuck closed PCV. Make sure the hose is unrestricted and the check valve is working properly.

[zx666r]

Sounds like it could possibly be stuck closed PCV. Make sure the hose is unrestricted and the check valve is working properly.

I checked the connector into the valve cover and it was clear of obstruction. I also removed the baffle under the valve cover to check and make sure nothing was stuck in it. On this car (maybe all early models?) the vent off the valve cover has 2 hoses, the larger of which is going straight to my catch can with no valve, the smaller one does have what looks like a check valve. Would that be the valve in question?

[seagreen323i]

Either way to much blowby and its overwhelming the pcv system or the system itself is clogged. Are you blowing the dipstick out under boost as well? It could possibly be that the seal came off of the oil fill cap.

Sent from my SM-S901U using Tapatalk

[pbonsalb]

I would eliminate the PCV valve in the valve cover and just run a hose from there to the catch can. With no vacuum pull at the new catch can that is vented to atmosphere, you need a bigger hose.

[zx666r]

Either way to much blowby and its overwhelming the pcv system or the system itself is clogged. Are you blowing the dipstick out under boost as well? It could possibly be that the seal came off of the oil fill cap.

Sent from my SM-S901U using Tapatalk

No issue with the dipstick staying seated. The old oil fill cap did have a damaged seal, but a new OEM cap didn't resolve the issue.

I would eliminate the PCV valve in the valve cover and just run a hose from there to the catch can. With no vacuum pull at the new catch can that is vented to atmosphere, you need a bigger hose.

I have a radium VTE can on it now so I could get the RallyRoad 10an fitting for the valve cover and run that to the can if the excess hose volume would help handle the pressure. It's a 1/2" rubber hose right now which I thought would be enough, but maybe not.

[pbonsalb]

Do a test — let the valve cover vent to atmosphere and go for a drive.

[zx666r]

Do a test — let the valve cover vent to atmosphere and go for a drive.

I'll give that a shot and report back. I'm also going to test the check valve on the vent of the radium can. I'm curious if that vent is stuck closed not allowing the pressure to vent off.

We'll see!

[pbonsalb]

You don’t want any check valves on a system vented to atmosphere and likewise no vacuum/boost line.

[eboo]

Try running a hose from from new catch can back to supercharger inlet.
That worked for me

[dbarton62]

^^ this is what I am doing.

I had excessive vacuum in the crankcase due to a failed PCV.
Return line to pre blower in the intake tract.

EDIT: but after MAF.

PCV is eliminated and 1 less point of failure and boost leak.

[pbonsalb]

That is not a vented to atmosphere system. Some do the return to the intake. I don’t since I find oil gets all over the intake tract and manifold.

[dbarton62]

Correct.
Fortunately I have very little if any blow by, confirmed by minimal residue in can at end of each season.

Others results may vary.

[pbonsalb]

If there is an oil film through your intake tube and manifold, that impedes flow slightly.

[zx666r]

You don’t want any check valves on a system vented to atmosphere and likewise no vacuum/boost line.

Pulled the hose off the can, ziptied towels around the cap and went for another drive tonight. VERY minimal signs of oil coming out of the cap, so I think that limits my issues to the can itself, or the hose routing.

I should have said it's a rollover valve, not a check valve. It's this valve: http://www.radiumauto.com/Roll-Over-...arb-P1983.aspx

I have it mounted to the top of this can: http://www.radiumauto.com/VTE-Compet...-Can-P289.aspx

And I have the hose from the valve cover plumbed into the side port of the can, since the rollover valve noted it should be mounted vertically. I might try to route the hose differently in case it was getting restricted, but other than that I'm unsure what issues that can may be causing.

EDIT: In reading this description more, I may need the VTA can? Looks like they intend the VTE can to be routed back to the engine which may explain some of the issues. I'm not sure why the VTE can COULDN'T be vented to atmosphere, but they're the engineers, not me.

[pbonsalb]

Try dbarton’s version — no check valve in the hose from the valve cover to the catch can and then a return to the intake after the HFM. Since you have a catch can designed for recirculating trying that makes sense.

A rollover valve actuated only if upside down. That has a different function than a PCV check valve.

[zx666r]

Try dbarton’s version — no check valve in the hose from the valve cover to the catch can and then a return to the intake after the HFM. Since you have a catch can designed for recirculating trying that makes sense.

A rollover valve actuated only if upside down. That has a different function than a PCV check valve.

Yeah, that was my understanding of the valve. I'm just not sure how the baffling of the VTE can may be hampering the pressure venting even though that filter is properly mounted. I'll have to pick up another 10an fitting and see if rerouting it at least lessens the oil in the intake. The idea was to eliminate it from in the intake all together.

[Sio2crew]

Radium sells these orb fittings. They are low profile to -an. Worked a treat for me. The other thing i have is a vw tdi oil sepation cap. So im running 4 lines to my catch can. I never see a drop in my can, but my car is built, je 9 to 1 pistons. Eagle rods. Correct ring gap. Cut ring. Ect ect.20230305_225935.jpg

https://www.fcpeuro.com/products/vw-...-vag-06a103465

https://www.summitracing.com/parts/rdm-20-1000-1010

I used a catch can with 4 -10an inlets. Two filters , under my maf. ( Overkill? probably. )

Only question i have, are you missing the intake cam plastic cover under your valve cover ?

This black piece? Should see it under your cap if your v.c. is plastic. If its missing you can get your symptoms.

Screenshot_20230710_230839_Chrome.jpg

On my turbo m54, i ran 3 -10an straits off the m56 cover like this..... used vibrant bulk head orb to an fittings nutted inside with thin nuts. I only put a few thousand miles on the zhp m54b30 (mls/spacer/raceware studs) it just stits as a back up now. Less than 30,000 original miles. It never had much blow by. (Stock ring gap/ 3582)


If i was going to recirculate the air, after the maf. (I wouldent tho. ) if i was going to recirculate the oil in the catch can, i would send it to the inlet on the oil dip stick where the old ccv drained into.

[Sio2crew]

Screenshot_20230710_233010_Chrome.jpg

Says125% more filtration, and you clean it.... a.k.a. media to clog up.... a drain from the petcock to your dip stick tube may help keep it cleaner?

Seems more like a oil seperator than a catch can. If i was to upgade/next build.. might be to this one.

https://youtu.be/mp81Hzan5Fk


The other option is an exhaust venturi. Creates vacum from exhaust flow. Sucks the vapor into the exhaust to burn in you cat? (Not sure if thats good or bad) it does not flow a lot of volume. Ive made borosilicate venturi sets fior scientific labs. They never flow much for their size.

"Does the crank case vent to sealed can to your intake create enough vacum to seal piston rings when you drive off boost? "

I have seen it implyed, but I dont know if its true?

https://www.google.com/search?q=exha...obile&ie=UTF-8

Side note.... sense o.p.was asking for ideas..

Ive also seen a vacum pump on a turbo e46. I dont think It was crank case pressure related. It was used for roll racing tho? I think somethin somethin hooked to the booster, vacum for brakes /brake boosting? (Was a long time ago)

Not sure what it would flow, or if it would be of any real benifit on a ccv system looking for vac. ( I digress.)

https://www.maxpeedingrodsus.com/col...ns/vacuum-pump

[GazM3]

I found a similar issue with the M60 and vortech, even with a catch can venting to atmosphere. I now run a closed system with the "vent" from the catch can installed in full venturi (the pipe blended into the intake in the direction of the airflow) back to the low pressure intake pre supercharger, so the momentum of the intake air creates a vacuum which seems to also reduce excess blow by creating less vapour in the engine for the vent to deal with. Its nice to have no smelly mist discharge also. There is minimal oil residue in the intake tract, and now on a stand-alone ecu I don't have any maf sensors to worry about.

[PartsCargo]

You should check the catch can installation: Ensure that the catch can is installed correctly and tightly sealed. Make sure all connections and fittings are secure and free from any leaks.