enuttage

I've searched around a bunch here just checking into what might be going on with my car, but didn't get enough specific information to be able to help myself out, so here goes.

I'm very bad at the DIY stuff, so please go easy on me.

I've had PCV issues over the past six months or so, specifically at autocrosses under full boost and hard cornering. At first, I was just blowing my PCV out (discovered by sudden surging in the grid after a hard run). So, I zip-tied it down and moved on. Still blowing out.

I recently had the valve replaced and re-tied (via my mechanic), after cleaning up the oil that had sprayed all over the engine bay.

Well, at the last autocross, my valve never popped out, but I noticed smoking from the intake side of the front of the hood on one of my co-drivers more spirited runs. He thought he smoked my clutch (which he may have ), but the smoke was coming from oil that had sprayed all over the UIM, and down to the intake/turbo side of the car. I'm assuming the smoke was coming off the turbo, but I have no idea. It was brief and only happened twice during runs. A friend, RRR1 from this board, suggested a catch can. I think he's dead on, I just want a second opinion on it.

Either way, I'm curious where it may be coming from, what I may have done wrong in tieing down the PCV so hard, and how I stop it. It isn't a ton of oil, but it is enough to make a mess of the engine bay, worry me, and potentially give me trouble at a roadcourse tech inspection at TWS in a couple of weeks (though I doubt it).

Any thoughts? And if so, any step-by-step "solutions for dummies"?

TIA for any help,

-E

Mahjik

iTrader: (1)

That's about right. Hard cornering on the FD will push oil into the intake track and out your intake (or other leaky areas) and BOV.

You should take a look through this thread:

https://www.rx7club.com/showthread.p...hreadid=226214

enuttage

Thanks Mahjik. Appreciate it.

Okay. Cool. So you're also of the opinion that a catch can will do it. Very good.

Now...the oil on *top* of the UIM? From the PCV, even though it's tied down and hasn't blown out again? Perhaps there's enough pressure there under full boost and high Gs to push it out enough to spring a gusher and then slide back in upon lower pressure strains?

-E

Mahjik

iTrader: (1)

Are you using the stock BOV or do you have an aftermarket one?

Hmmm.... oil on top of the UIM.... Well, I've never seen that happen unless there was a leak from somewhere else and it got sprayed up there.

What all is on the car as far as mods? If you are using the stock twins, I wonder if maybe you have a small leak on the Y-Pipe, causing some oil to spray out from hard cornering.

enuttage

Sorry, I should've mentioned the setup to begin with.

Single turbo RX6 running about 14lbs at full boost. And yes, aftermarket BOV, intake (obviously), etc., etc. (trying to think of anything else of relevance).

CWR dual oil coolers (have no idea how this affects oil pressures).

If I left anything relevant out, lemme know, I'll fill you in.

The only thing I can think of is the PCV coming only part way out because it is tied down now. Dunno. It's the only thing up in that area, and there didn't seem to be any oil on the underside of the hood.

-E

Mahjik

iTrader: (1)

Unfortunately, I can't really help much more without looking around your engine bay.

I know that when I do track events, I do have a fair amount of oil that is spit out of my BOV. My BOV is still in the stock location so it doesn't dirty up much of the rest of the engine bay.

I too have been thinking about the catch can idea.

enuttage

This makes me wonder what it'll be like for me without a catch at TWS. I've never tracked the car, so we'll find out.

You don't have as much violent and sudden shifting of mass (and direction) on track as you do in autoX, but the sustained Gs *have* to be greater on track. Does that sound logical? I wonder if my problem will be better or worse on a road course, is my ultimate question.

That may determine whether I even try to do this before I go.

-E

Mahjik

iTrader: (1)

I would say that the track would produce more of a mess. Your autoX sessions aren't going to last that long. Most normal HPDE have about 4-5 sessions a day at 20-30 minutes a piece. 20-30 throwing yourself around the track will shot some serious oil about!

A buddy "ebb" here on the forum has the stock BOV still with his setup (Pineapple large port, BNR Stage 3's, etc). He had oil almost shooting out the front of the car with the open stock BOV.

I would say the catch can is definitely a good thing to look into for track FD's.

enuttage

Yeah, that's pretty much what I figured.

I'm trying to nudge my father-in-law into helping me out with this one.

Thanks for all the help man. I really appreciate the advice/opinion.

-E

DamonB

All the collected knowledge on FD oil consumption under high g is in the thread Mahjik posted. My car has let out puffs of smoke on occasion from it. The more time the car is spent in hard right corners the worse the problem is.

I plan to add a catch can soon and plumb its drain back into the pan somehow. The catch can keeps the oil out of the intake, but still allows the oil to be "consumed" unless you can drain it on the fly somehow.

wickedrx7

iTrader: (14)

This is very interesting, I had never heard of this before, no wonder I was getting so much oil in my intake track. I thought that my turbos where going. HAHA

Anyways, I have an Idea. Why not add a catch can like described on Triple R's web site, but also add a "Baffle" to the inside of the oil filler neck. You could make a similar one like in this thread: https://www.rx7club.com/showthread.p...hreadid=252344

This would help to slow the oil down from coming up the neck. The only problem that I forsee is it would take longer to fill the motor with oil durring an oil change.

Any thoughts???

Edit: I just read through that thread and notice you had the same idea DamonB. Good minds think alike...

enuttage

How much oil are you losing on course Damon? And where is most of it coming from?

-E

DamonB

For a day of autox I don't normally loose enough to worry about, but I can notice it. The reason oil is consumed is because under hard right turns the oil climbs up the inside of the filler neck. At the top of the filler neck are two hoses; one to the UIM via the PCV valve and another that goes back to the primary turbo inlet. The PCV only shows vac when off the throttle, but the primary turbo inlet always has vac and it will suck up any oil that makes its way into the top of the filler neck. Since the oil enters from the primary it will then go through the entire intake tract before being burnt inside the combustion chamber.

Without a catch can and on race tires I can easily inhale a quart of oil over the course of a few sessions. I don't mind too much that the engine ingests the oil, but I do mind loosing that much oil from the system.

enuttage

Well, street tire grip will help me a little this time, but out of curiosity, what do you mean by a few sessions?

Whether I use a catch can or not, I'm still trying to guage when I'm going to need to get off course and potentially top off the oil. A quart lost is a quart lost, which is a lot.

I just don't want to go in unprepared.

I really appreciate the feedback guys. I've learned a lot here.

-E

rceron

I've had all those issues as well. Recently I installed a catch can, removed the PCV valve, capped the upper side vents on the oiler filler tube and placed a single outlet on top of the oil filler tube on the cap itself. I went further and did the "williams sonoma turkey baster" modification and I STILL ran into major problems.

It now seems that I may have a problem with the o-ring in the oil filler tube itself. If that's not the problem then I'm doomed. I have oil spraying all over the place during HPDE events.

So check your oil filler tube for cracks or issues with the o-ring.

R

PS Crispy has a great write up on the problem and his solution. I've basically followed his lead on this.

Scrub

iTrader: (25)

When going single can't you block that line that goes back into the intake from the oil filler neck? I have the one blocked that went to the UIM.

DamonB

A few 20-30 minute sessions on a roadcourse. The more long right hand turns, the worse the problem is.

DamonB

Actually you could block all of them at the filler neck and just run a breather filter on it (although it's not emissions legal!); that's something else I'm considering. I think I could easily make a new filler tube out of steel pipe and just put a breather on top of it. I could easily swap it back to stock if need be for inspection.

wickedrx7

iTrader: (14)

I had probelms with my oring, actually lack of o-ring. I am in the process of doing a rebuild and plan to silicone my oil tube down, and not even mess with the o-ring.

Scrub

iTrader: (25)

Where could I get a breather filter that size?

enuttage

Well...I may as well block 'em all then. I want to make sure I don't screw something up though. I believe I'll be posting pictures soon here.

Emissions, at this point, is a lost cause. I have zero emissions devices installed and have removed everything restricting flow (or pulley resistance).

Thanks Damon and Scrub.

-E

wickedrx7

iTrader: (14)

After doing some thinking, it might be better to us the stock location for the vent line to the catch can. Here is my reasoning; when taking hard right corners the oil is being pushed up the left side of the oil filler neck until it reaches the top and then it would just go out the vent line. If you use the stock location (on the right side of the tube), the oil would have to fill up the oil tube in order to go out the vent line. Does this make sense? Anyone tried the stock location for the vent line to the catch can?

I am thinking that this might “reduce” the amount of oil that is being vented out. Just a thought.

One more thought for the day, a better baffling idea. I think this might really help to reduce oil from coming up the neck. See pic below

DamonB

wickedrx7, read through the link I posted earlier. All this has been tried and tested by lots of people who spend lots of time on the track. It's not as simple as you might think.

enuttage

An update on this for anyone that may ever experience the same problems I had:

It looks highly likely that the oil was not from high G-loads causing a push into the oil filler neck. More likely it was oil pressure loads that were giving me too much pressure in the crankcase.

This is all very unscientific, of course, but I kept the PCV line in place (my dumb *** finally put two and two together and realized the PCV was working just fine if it was blowing out. One way check valve in action!), and just vented the oil filler cap with a fabricated setup that involved a nice stainless steel parmesan cheese shaker, some lawn mower filter material, much dremeling, sawing and drilling, and a repositioning of the strut brace.

I'll post pics as soon as I stop being lazy and feel like it.

Anyway, I figured this would give me a quick idea of how much oil might be spilling up past the filler neck. Turns out...none. Zip. I did freakin' donuts in a cul-de-sac and nothing.

Meanwhile, the dude I consult on *anything* mechanical in town, Patrick, suggested that my oil pan leak, my PCV blowouts, my BOV leaks, etc., might all be linked to overpressurization.

Well, sure enough, after I vented the filler neck, oil pressures (on the stock guage - I know, I know it sucks, but it gave me reference points) dropped by about 20-30psi (or ms - whatever the guage reads) at WOT.

So, long story longer, I headed out to TWS a week and a half ago, and presto! No oil leakage. No oil spillage. Nada. Good, clean, runs with no oil problems and the engine purring with no higher than 91C water temps. Beautiful. I think the car is finally sorted. Now I have to sell it later this year...

Thanks for all the help guys, and hopefully my little endeavor will help someone else out down the road.

KevinK2

I don't think level gets that high, unless crankcase was severly overfilled.

Normally level is below the bottom of the fill neck, and blow by gases can exit through the neck cleanly. On a long, hard right, the level tilts (45 deg at 1g corner). existing baffle slows the tilt down, so only long high speed rights are a problem.

Once level tilts enough to cover bottom entry to filler neck, blowby gas builds pressure and starts pushing oil up neck until main level drops and allows gasses to boil/bubble up through the column of oil in the neck, atomizing the oil and allowing it to enter the venting hose.

running 1/2 down on oil level helps. I suggest losing the pcv to manifold line, as was done in later models. I use a couple 90's to run pvc hose from oem neck fitting to a catch tank that hangs off the cross brace bracket, then run return hose back to the hose that goes to the turbo inlet.

made my tank from a modified plastic fuel filter with side ports. normally empty, but catches about an oz or 2 at summit points 90 mph turn 10, during a 20 minute session. never any oil in the intake/IC anymore.

a small "jaz" catch tank would work. I'd lose the filter, and add some flat filter gauze from pep-boys, to sorta divide the tank.