msilvia

Reading earlier threads I got the impression that the factory crankcase vent system (the two ports in the filler neck) can, in addition to the problem of oil pushing up the filler neck and into the intake track, actually leak oil externally, especially at the track. Am I understanding that correctly? From where does the system actually leak? The downward nipple to the intake? The dipstick? The filler pedestal base?

I had to cut a track day short recently because I noticed a significant amount of oil on the driver's side of the engine, concentrated around the oil filler area and seemingly dripping down from there. Also noticed the underside on the throttle body/intake elbow was a bit oily. I drove the car home and didnt notice any additional leaking, so it seems like this was only happening under high pressure or high-g scenarios on track. Could this have been caused by high crankcase pressure pushing the oil out somewhere?

izanami

I'm not sure where it would leak from. First time I went to the track I noticed it spraying out of my BOV. Everything in front of it was covered, as well as the rest of the intake tract. Maybe if you have a small leak at the bottom between the elbow and throttle body it will force any oil that pools there out. That said, the drivers side of my engine is kinda grimy anyways so may not have noticed it as much.

If your going to keep going to the track i would set up a catch can and be done with it.

ptrhahn

iTrader: (9)

The crankcase pressure probably blew the dipstick out enough to blow oil all over.

Barry_Beef

Could be leaking out of the filter base. A possibility, I had an aftermarket filter in there awhile ago and I noticed after hard driving it leaked from there. Genuine has never leaked for me

cib24

The FD is no stranger to blowby and excess crankcase pressure when driven hard. Under track conditions the blowby is significantly worse, in particular when you take a high g-force right turn and accelerate out of that turn on boost. The crankcase pressure pushes a bunch of oil up the filler neck and through the factory PCV (if you have one) and the other pipe that leads to the elbow connected to the front of the primary turbo.

As a result, oil flows through the primary turbo and coats your intercooler, intake elbow, manifold and everything with oil. This excess oil often gets pushed out at the connection of the intake elbow and the throttle body because I suppose the seal isn't that great there. It will shoot out in all directions as it has happened to me numerous times. If crank case pressure is too great then the oil shoots out of the dipstick under right turns.

This is why most people that run on track whom are running twins or are not able to vent both sides of the oil pan do the following:

1. Run 1/4-1/3 full on the dipstick on track days to reduce oil blowby up the filler neck.

2. Disconnect the PCV and other oil line down to the primary turbo inlet elbow.

3. Run a fuel hose from the filler neck to a vented catch can, a can as large as you can fit. Empty caught oil after each 15-20 minute track stint and top up the oil.

I did this but it still wasn't enough so I bought the IR Performance stainless steel baffled filler neck which attempts to prevent oil from flying up the filler neck on right hand turns under boost, but in the instance that oil still makes it up to the filler neck the IR Performance baffled filler neck has an AN10 (5/8") hose connector which I run to a vented catch can. Increasing the hose size (factory filler neck size is about 3/8" or 9mm) slows the oil down that makes it up that far and relieves a lot of pressure out of the vented can so I get much less blowby than I used to and no longer have the oiliest intake and intercooler system in the world.

msilvia

Thanks all. IRP filler neck to vented catch can is probably going to be my solution to knock this out.

I'm a little confused about oil coming out the intake elbow at the o-ring. If the oil can get out I'd think you'd have a serious boost problem as the compressed air would get out even more easily.

cib24

I haven't figured out why the intake elbow to throttle body connection allows oil to leak past the o-ring either but perhaps it is just a less than ideal mating surface of metal on plastic (factory elbow).

You should still run your oil below 1/2 at the very least to reduce blowby even after the IR Performance filler neck is installed. And note that clearance is a royal pain in the *** with a strut brace because the IRP neck AN10 fitting is pointing towards the strut brace and nose of the car instead of more smartly to the passenger side like the factory filler neck. I had to buy numerous fittings and spacers to make a 5/8" hose fit and run to my catch can.

TomU

iTrader: (11)

First priority should be the catch can. This will capture your blow by. The IRP neck would then limit the amount of blow by. Just had my first track day with the IRP neck. Didn't have nearly as much oil in my catch can, but then again it was a wet day and I wasn't flogging it nearly as hard.

If you're TB o-ring is leaking, I would get a new one and make sure the TB is torqued to spec.

Also, I would be hesitant filling your oil less than 1/2. Yes, you'll have less blow by, but you may also have less oil in your engine. I'd rather empty my catch can than have my engine fail. Best solution is a baffled oil pan.

msilvia

Funny you say that, as it was only in the third session, after I increased my oil levels past the halfway point on the dipstick, that I started having this issue. I'll see how full I can run it next year with a better ventilation system in place. Like you, I was nervous running it low.

Where were you on track? I was just at Summit Main last Friday. Surprisingly, I was one of two FDs on track that day. Maybe we'll run into each other some time.

cib24

Which is why people that track the car regularly fill up to 1/2 way at max. RX-8 guys do the same thing and they don't even have boost creating a lot of excess crankcase pressure to worry about.

Your motor will be fine at less than half way on the dip stick.

Smokey The Talon

iTrader: (33)

I use a baffled oil pan and IR fill neck and still have to empty the damn catch can after every session. It's annoying as crap and drives me crazy.

To the OP, this is still a better solution than having oil go thru your intake and making a big mess.

silverTRD

iTrader: (37)

What is your catch can setup Smokey? Vented or Non?

Also, on stock twins I'm assuming?

cib24

Yup. I am thinking about a baffled pan as well but it's a big job and it seems I would need it to be custom-made to baffle exactly at the oil filler neck area. I will do it when I install my engine mounts.

I don't mind a bit of oil in the intake but by running a vented can I don't have that issue anymore. However, my issue is the same as yours needing to empty after every session. I wish I could fit an even larger catch can because then I could stay out on the track longer.

Have you ever watched your oil pressure when coming out of right hand turns on boost? From 6-7 bar down to less than 2.0 bar (my normal idle pressure) for a split second! The baffled filler neck has helped that slightly but it is still a bit concerning! I only noticed it after watching back my sessions from my GoPro and looking at my gauges.

Smokey The Talon

iTrader: (33)

Stock simplified twins at 13psi. I run the bacon sports (Winchester) oil pan which has nice baffles and more capacity. Also run the IR fill neck with a -10 line to a JAZ one quart vented catch can. I tried running a vent line to the (still functioning) secondary turbo oil drain but that did not help.

I can run it low enough to have oil stop coming out but it basically doesn't register on the dipstick at that point and I'm not comfortable with that...so I do the dance and empty the catch can and put more oil in after every session.

I think next I'm going to try going back to the stock oil neck and drilling it for the -10 fitting. I'm running out if ideas though and still highly annoyed.

silverTRD

iTrader: (37)

I'd like to hear more about the line to the 2nd turbo drain. I always thought that this would be the fix for the twin turbo cars but you're making think otherwise.

cib24

Yeah, single turbo guys usually run a vented catch can that is attached to the filler neck and the secondary turbo drain line which basically ensures crankcase pressure is vented on both sides under both right and left hand boosted turns. The twins people typically don't do it because it is a royal pain in the *** to remove the twins and fabricate a custom secondary turbo oil drain line that also vents to a catch can.

The other option is to tap the front cover to make a AN10 line to the catch can for the passenger side (USA) / driver's side (Japan/UK/AUS) of the motor but you would only ever do that when you are rebuilding your motor so very few people have ever done that.

At the end of the day, twins seem to create excessive crankcase pressure on track and the best compromised solution so far is to run less than half full on the dip stick (just like the N/A RX-8 guys do, and which we can get away with as the oil pan is a bit deeper than say the RX-8 one), use a baffled oil pan and/or filler neck, run a AN10 fitting or even larger from the filler neck to a huge catch can that is vented to the atmosphere. Empty the catch can at the end of each 15-20 minute session, add oil and repeat. At least your car will always be using fresh oil this way when on track ;-P

Also, our motors could just have a lot of blowby due to worn side seals or whatever which exacerbates the issue but last time I compression tested my motor it was all 8.0 on the front rotor and about 7.7 on the rear rotor so I'm not so sure that is my issue.

Who knows.

ptrhahn

iTrader: (9)

Not everyone has had great success with the turbo drain line. I recall Crispy tried it (write up on his site), and it puked more oil into the can. Theoretically I get how/why it would work, but in practice maybe not—but it also could have been other factors like the sizes of the lines used.

The old thinking was to restrict flow to keep the oil in... they newer thinking is to un-restrict flow so the air escapes with less pressure and oil squirtage.

I've heard of people tapping the front cover, and that's supposed to really help, but it's a lot of work. The -10 off the filler neck seems to be the ticket. At some point I'll try that in conjunction with the single turbo side line to see if there's any benefit.

Smokey The Talon

iTrader: (33)

Yeah, I tried the restrict method and it didn't pan out at least not to the level I wanted. It was functioning, but I had to drain/fill after every session. I'm going to try the un-restrict method and see if it's any different. Sometimes having a FD track car is like a giant science experiment!

Silver TRD, I had a spare secondary turbo drain line that I had a -6AN fitting welded to. Then I ran a -6 line from the turbo drain over the trans, behind the motor, and to my catch can in addition to the -10 coming from the IR oil neck. Didn't seem to make it any worse, but no better either. In addition I kept having trouble with oil oozing from the AN fitting on the drain line, so I took it off and capped off that fitting on the catch can. I'm not sure if the oil draining from the turbo wouldn't allow enough venting on that side, or what the issue was, but either way it didn't work for me.

rajeevx7

iTrader: (11)

https://www.rx7club.com/3rd-generation-specific-1993-2002-16/oil-filler-neck-leak-overflow-turkeybaster-699876/


I think 99% of my leaks were from my dipstick being blown out.

neit_jnf

iTrader: (17)

how about having a catch can with a drain line going down to the front cover so that the oil drains itself?

Monkman33

iTrader: (28)

There is yet another project to add to the ever growing list.

Valkyrie

Returning blowby to the oil pan sounds like a terrible idea.

OTOH, I'm glad to see people are having similar problems as me.

I have a catch can and still get oil all over the place when I drive on the track. Still not sure where it's coming from.

I think installing a spring to hold the dipstick down might be a good idea...

It would also be a good idea to keep the dipstick's grommet clean so you can see if oil is getting blown out of it.

Smokey The Talon

iTrader: (33)

try buying a new dipstick. They can get worn/loose over time. You shouldn't have to hold it down to keep it in.

TomU

iTrader: (11)

If your dipstick is getting pushed up, I don't think your crankcase ventilation is adequate. Is your catch can vented or non-vented?

I also wouldn't return the oil. Mine usually looks like crap.

For me, draining the catch can, adding meth, adding OMP oil, adding pre-mix, and all the other quirks goes hand and hand with having an engine that rotates. Kind of like having a magneto that needs to be manually advanced and a carb that needs to be manually choked.

IRPerformance

iTrader: (41)

If you have my oil neck run a -10 line to a vented catch can. Eliminate the stock pcv. It doesn't work well. You can also have another issue like the turbos pushing oil because the stock system dumps oil into the primary turbo inlet, so its not uncommon to find it all over you intake piping.