Bill Ball

I guess I could try the separator and drain it back to the pan. I'm not too thrilled about the external plumbing and drain back. I'd rather have the oil stay in the the block. Andy's oil filler is just a plate. It has a rather small inlet (becomes an outlet), I suppose in an attempt to reduce oil ejection, but all that does is make oil filling painfully slow. So, some modification of that inlet, ala Tony's baffling, making sure the pot scrubber is secure from going where it should not be, sounds like a worthy project.

AO

On DR's SC kit, he includes the Provent separator which works great. Any oil that is captured is then fed back to the pan via a modified dip stick tube that has a Y with a check valve in it. I'll see if I can find a picture.

Bill Ball

Thanks, Andrew. It sounds like the simplest way to go.

AO

I don't have the pic on this pc... I'll post it tomorrow. G'night!

pmotts

Bill,

I added the extra breather line out of the drivers side cam cover and have never had an oil issue. One hard track day and many high RPM runs and I have never had oil in my 'catch can'. I am not saying this is the cure but I have been happy with it on two different superchared motors.

Imo000

I’ve been working on an early 90’s Nissan NX2000, 2.0L 16V DOHC (SR20D) engine. These engines come from the factory with an external oil separator that looks to be simple enough to install on a boosted 928. The oil separator is about the size of a coffee mug and has a high inlet and a low outlet. Because of this small size, this could work really well on a 928. I already have an custom catch can but perhaps anyone that is thinking of installing a self draining catch can might want to look into pulling one off at the wreckers.

BrianG

Can you post up a picture of the thing??

AO

Well I thought I had a picture... but I guess I don't. I'll be working on the car tonight and I'll see if I can get a decent picture for you, but there's a lot of crap in the way...

Imo000

Here is a link to one. http://www.serca.org/regions/texas/i...e/MVC-019S.JPG It's the black rectangular box, next to the boost tube.

bd0nalds0n

I think if you took off the plate and added some kind of 90-degree tube (like what you did on your manifold outlet to the bypass valve), you might be able to avoid this problem--that's what I had Greg do to my car. The crank whips up too much oil, and it's just a straight shot up the oil filler neck, and into the breather line.

Bill Ball

Brian:

Yes, it appears a lot of oil is getting thrown up and blown out the oil filler inlet. So, either an elbow or a plate on spacers on the bottom of the filler plate that the oil will hit and hopefully just drop off of, seems like a plan. Then I could increase the filler inlet size to allow faster oil changes. I literally have to drip the oil in now or it backs up. In fact, that may contribute to the oil blow out since it doesn't take much oil to seal the opening and then the air flow blows it out. So, a wider opening might, perhaps counterintuitively, promote less oil ejection.

BrianG

Bill, I used Andy's breather lines, except that I excluded the oil filler, plus I put the brillo-pad in the vertical line that rises from the oil-filler housing cover-plate, hoping that condensate will fall back down to the engine right there.

I am using the forward PCV vent hole (that has the OEM plastic plug in it) on the left cam cover for oil replenisment. I removed the cir-clip from the inside groove of the plug, and just replaced the old O-ring with a new one. The fit of the plug is firm. It remains to be seen if it will stay in place when the engine is run (hard). I figure that if it get's blown out, I can fit a second o-ring to where the circlip was, as well.

Louie928

Whatever route you take to reduce oil getting into the intake, remember that the 928 is woefully inadequate in lower crankcase breathing capacity. The two 12mm hoses on the original oil filler unit are not enough to be useful, and one is plugged by a valve. What actual breathing capacity exists is on the right side cam covers. The worst possible choice. First do whatever you can to increase the size of the breather out of the bottom of the crankcase. I thought I had pictures of my oil separator/breather that fits into the place where the oil filler used to go. I guess I don't have those pictures. Maybe Tony does. He took several at Wichita 2 yrs ago. If you want to make a separator to fit there, it's a metal can that fits into the big rectangular hole with a flange around the top to bolt to the block. I used heavy unidirectional screen like is found on the crankcase windage trays for the sides. Tony used aluminum sheet. I have a horizontal partition about halfway up with copper brillo pad material inside the upper part. The partition is there to separate the brillo pad material from the bottom part where it could get beat by the oil and maybe come apart and go out. The opening in the bottom has louvers with the openings facing away from the direction oil would be thrown by the crank. The louver openings are about 3/8" wide between louvers. Use whatever connector you need on top to connect to your filler hose. Keep the diameter as large as possible and I'd assume this would lead out to another oil separator and vent. The engine will generate anywhere from 5 to 8 cu ft/min of blowby depending on condition and boost. This all has to go somewhere and you need to insure the velocity stays low enough so a lot of oil isn't carried with it. Some do like the GTS and add breathers to the left side cam cover. That's ok. While the blowby still has to go up the oil drainback holes in the head, with the extra vents on the left side it helps a lot plus the left side cam cover is a better vent side than the right side.

Bill Ball

That's why I think I'm losing so much oil out the filler. Andy used a tiny filler. I intend to make it much larger and probably just put a plate below it that the air will smack into and have to go around, but with enough space so the air flow is very free.

Louie928

The 32v engines have a set of louvers right where the top of the hole into the crankcase is. That's enough to keep oil out of the breather I have in the cap of my S4. I should think a plate like tehstock one with louvers, or something similar, should be ok.