CrispyRX7

iTrader: (139)

Maybe some of you road racing guys might have some ideas. In the FD model (maybe others I dunno but it's just the FD's I've seen with this problem) there is a propensity for oil pickup in the filler neck during hard long left hander corners. During hard cornering oil gets "sloshed" up into the filler neck. This oil gets either sucked up into the PCV line to the UIM or is routed back to the turbo inlet. The result is oil pooling everywhere inthe intake tract. The PCV line and turbo line are typically just a means of venting oil pan/crankcase pressure from "combustion blowby." Ok now add a race suspension and sticky tires and it's not just gas being vented but oil too!

But to the point. I added a vented catch can to catch the oil being pushed out of the oil filler neck and yet still relieve "crankcase" pressure. Trouble is on tracks run clockwise the catch can fills in a hurry and thus simply begins to oil down the side of the car **AND THE REAR TIRES!** This makes for quite and exciting ride.

So I'm soliciting suggestions from anyone racing an FD on how they have remedied this problem.
For details on what I've tried you can go here (but none of which has worked to my satisfaction):
http://reganrotaryracing.tripod.com/catch.htm

TIA
Crispy

DomFD3S

Have you tried an oil pan baffle plate? This would prevent the oil from being "sloshed" up too much. (FYI: Racing Beat has them).

BTW, has anyone tried the Moroso oil pan??????
http://www.optauto.com/webstore/prod...k=yes&dept=878

CrispyRX7

iTrader: (139)

Thanks. I'll take a look at what they have. The stock FD pan is pretty well baffled but hey you never know.
Thanks
Crispy

maxpesce

Has anyone tried adding a drain line from the catch can back to the Pan? So the catch can would be self draining. Maybe using the oil level switch fitting location on the pan? You might also need a check valve in the return to prevent oil traveling up the line and into the catch can. It is just something I have been thinking about.

DomFD3S

Interesting idea, Max. Never thought of that. Hmm...

DamonB

You could make it simpler than that, just send it back down the oil filler tube.

I have not yet modified my fill tube, but I have a few ideas. One of which is from the old days of just inserting a tube into the nipples of the oil filler. Since the nipples are flush with the insides of the oil fill tube, any oil traveling up the walls of the tube automatically finds its way out the nipples. If you put a tube through the nipple that actually extended into the middle of the oil filler tube, any oil sloshing up the walls would not be able to get into the nipple. For oil to come in it would have to actually be lofted all the way into the air and find itself at the entry to the tube. I think this alone would dramatically reduce the amount of oil ingested.

CrispyRX7

iTrader: (139)

Great ideas guys and all which I have considered also.

Regarding draining it back to the pan you would still need a check valve of sorts as you wouldn't want any "crankcase" pressure actually pushing oil up the drain tube and into the catch can. But yes it's an idea.

Draining the oil back to the fill tube is also another great idea. The problem, in my case, with using one of the existing nipples is that the drain of my catch can is below the level of the nipple so it wouldn't drain all the way. I have considered tapping the fill tube itself and inserting a fitting with hose extending to the center of the fill tube for draining oil back as you noted.

So is anyone going to try this or am I to be the guinea pig

Thanks for the insights,
Crispy
- glad not to be alone with this problem

DamonB

Is there any pressure? The oil pan on a rotary is not exposed to combustion pressures and if there were crankcase pressure my dipstick and fill tube would leak like a seive


Yeah, I figure you just get a big brass nipple from the hardware store and tap the tube near the bottom. A one way valve is a good idea, but it would have to be very "soft". It must open under the mere weight of the oil.

CrispyRX7

iTrader: (139)

yes there is some pressure. That's why we have a PCV valve designed as part of the system. And insn't there soem "blowby" pst the side seals that can pressurize the oil pan? Doesn't oil once it's past the eshaft bearings simply gravitty feed back to the pan? I dunno but that PCV is there to vent something...no?


my thoughts exactly. Or at least tap it lower than the bottom fitting on the catch can.

And herein lays the problem. Then again if done this way is a check valve even necesary? Any pressure is going to feed out the top of the filler tube, the upper line, into the top fiting of the catch can (which should be a void space at atmospheric pressure) rather than trying to push oil up the drain tube from the bottom of the catch can. Thoughts?

Crispy
- trying hard not to overcomplicate what should be a simple problem to fix

DamonB

But wouldn't the blow by also have to blow by the coolant passages to get into the oil pan? Or blow by at the sides of the rotors that made its way into the rotor bearings would merely intermix with the oil. These combustion gases would then be present, but not pressurizing the oil pan. The PCV is a mandated devices to consume these gases inside the motor. The pan itself cannot possibly be pressurised?


I think you are correct but having the one way valve would be "more perfect" so to speak. I don't think it would be an issue without it.

gfelber

Crispy,

Your oil return line will work from the JAZ catch can if you plumb into one of the turbo oil return tubes (front is probably the best). I'm doing that on my single. Obviously more difficult if you still have stock twins, but you could probably make a custom fitting that would work.

Gene

CrispyRX7

iTrader: (139)

I really want to agree with you. But I can tell you that once my catch can was full, a quick squirt of WOT followed by a lift and I'd get a puff of oil mist out of the catch can breather filter and out of the hood vent so something is going on?


Agree.


Gene,


I've heard of this done. My only reservation is running the line from the drivers side all the way over to the pax (turbo) side of the car. It would have to go under the engine, no? And seeing as I still have the stock twins for me, yes, it would be more difficult. Something to explore though for sure.
Thanks.

Anymore suggestions

Crispy

John Magnuson

BIGGER CATCH CAN

Ugh

Go to a dry sump system?

CrispyRX7

iTrader: (139)

John,
The thought had crossed my mind but
1) Bigger catch can still doesn't address the dwindling oil level in the oil pan after a few laps.
and
2)got an extra $1000 laying around

Crispy

John Magnuson

Sure I do Crispy. I like your website a lot so don't worry about paying me back. What's your paypal?

PaulyDee

$1000? You better triple that number if you want to go dry sump.

PMD

artowar

iTrader: (1)

I think that you need the check valve to keep oil from being pushed into the catch can via the drain tube. Without it, you've effectively lowered the level that oil needs to *slosh* to get out of the oil filler tube.

If this works, then catch can becomes a buffer or accumulator, and we need enough capacity to hold whatever spills over during the worst case, high-G, right turn.

So, who's going to volunteer for skidpad testing?

CrispyRX7

iTrader: (139)

FWIW I already have some contraption/gauge rigged to measure filler neck (crankcase) "pressure" to 1) see if there really is any pressure or if it's entirely oil slosh and 2) to see if at any time there is an atmospheric condition or marginal vacuum (although I don't know when) to allow drainback of oil into the filler neck from the catch can. I also plan to do a quick and dirty bench top test to see if oil will gravity feed through a PCV valve that I might consider using for a return line check valve.
Will report back later..unless someone beats me to it
Crispy

PS Pauly...$1000 was tongue in cheek as I have no idea what a dry sump would run... You on the other hand am sure know

DamonB

Part # 0000-01-9312 Dry sump front cover $2423.40

CrispyRX7

iTrader: (139)

You got that John? $2423.00.
Please paypal funds to.....

But this is interesting. Has anyone, or know anyone who has dry sumped and FD

Crispy

DamonB

Not an FD, but 13B's; yes.

RX-Midget

The blow-by will pressurize the pan. Once it passes the side seals on the rotor and enters the bearing area, the only place for it to go is to the pan. I'm sure it is worse under boost because now you have positive pressure during the entire combustion cycle as opposed to only the compression, igintion and exhaust cycle.

Works just like worn rings on a piston motor.....

Let us know what kind of pressure you see at the filler tube. I run the same Jaz catch can on a NA under high G cornering and have never had to drain a drop out of it. I also have a RB sump baffle and additional internal baffling added to the pan.

gfelber

I think you cuold use the original metal vacuum line that ran from the oil neck to the primary turbo inlet. This crosses over the top of the motor and, with the rubber hose removed or re-routed, should be low enough to mate to the bottom of you JAZ (not positive, though). Have to work out the plumbing from the outlet (i.e., near the primary turbo) to the turbo oil drain. Shoudn't be an issue with pressure either since the can is vented and the the pan is non-pressurized.

What do you think?

Gene

CrispyRX7

iTrader: (139)

Gene,
Definitely an option. I still think that hard line is a bit too high but I'll take a look.
Some say there is pressure in the pan some say not.
As for whether I see pressure in the pan or not, I'll have to test and see
BTW the pan baffle is not available for the FD
Crispy

bradrx7

Crispy, I have a pan baffle plate designed for an FD. Email me offline for details. As you know, my Jaz system works perfectly on any diorection track I run. Brad