Bill Ball

Louie, you're not stepping on any sacred cows here. I appreciate your comments. They confirm my interpretation of the problem. I am doing a revised filler based on Tony's. I just bought a bunch of 1" copper plumbings pieces at Home Depot last night! That will about quadruple the filler and breather cross-section from Andy's design. A couple of 90 degree elbows and I will clear the water bridge. For an internal separator, I'm just planning a simple baffle - a roof under the plate with some drip points in the middle that will possibly allow dripping away from of the highest speed part of the air stream. I have to think some more about that, but whatever it is is it's not going to be elaborate.

Anyway, I'm the one to apologize here for stepping all over Andrew's thread, although it all started with the oil filler!

Louie928

Hi Andy,
Yes, but the crank is directly under that large opening so you need a functional unit that fits down into the hole and blocks oil thrown by the crank while catching and allowing the caught oil to drainback. At the same time not impeding the blowby gasses.

I made a "box" that fit the shape of the void. The bottom of the box was near the bottom of the hole. That put it not far from the crank. The sides of the box were made from unidirectional steel mesh like is used for oilwindage tray in the bottom of an oil sump. I bought mine from Canton Racing Products, http://www.cantonracingproducts.com/...age_trays.html. The same stuff is probably available elsewhere. The bottom of the box has strips of steel about 1/2" or 3/4" wide and 1/8" thick angled like louvers to deflect oil thrown in the direction of crank rotation.
I have a horizontal partition also made from the windage tray mesh about halfway up where one side's angle changes to more vertical. Both chambers are filled with copper Brillo pad material. The top isn't a flat plate, but is a raised chamber to get as much volume inside as I could. I used two 3/4" dia tubes in one corner for the outlets. Not that going out the corner was necessarily better, but it allowed me to use the vertical distance for a volume increasing box rather than 90 deg angle fitting. Also two 3/4" outlets was easier for me to locate hose rather than a single larger tube/hose. The area of two 3/4" is about 13% more than a single 1" I may have a baffle in front of the outlets, but I can't remember right now. The inside of the outlets should project into the chamber a half inch or so so that any oil clinging to the walls of the chamber can't easily find it's way into the outlets. The whole thing was brazed together. The outlet tubes go to another oil separator rectangular box with a maze like chamber/baffle arrangement inside with an outlet for gasses on the top and another outlet for oil on the bottom. It's also filled with copper Brillo pad. The drainback line feeds into the side of the oil sump above the oil level. Not too difficult when the engine is out and sump off. I'll try to post some pics of the box under the oil filler plate, but Tony's is similar to mine so maybe his pics will suffice to illustrate what I'm trying to describe.

I'm not saying that this is the only way to attack the problem, but you do need to use every bit of space/volume available to slow down the velocity of the escaping blowby and try to separate the entrained oil and provide a way for it to get back to the engine above the level of oil in the sump. Some of that task can be accomplished inside the engine before the blowby escapes. The rest has to be done outside.

Flott Leben

I read and understood your post. Having the oil return after engine shutdown does us little good. If you run long enough at high throttle (Bill's case) you will fill, and maybe overflow to waste, the catch can. If you need to wait for shutdown to return the oil to crankcase you run the risk of running low on oil on extended runs - like Open Road Races - where you need the largest possible oil volume and pressure.

Louie928

Yes, If you must return the oil below the level in the sump, use an electric scavange pump. You are not dealing wth a large instantaneous volume.

AO

Louis:

Thanks for that description. It's going into my archives. I'm going to go with DR's setup (for now), but If I have any other issues, I work with DR to enhance the design for everyone.

I was talking to Tim Murphy last night about this as well. He's got a huge separator/ctach can, and he's thinking about putting in a float switch with a little pump that will run for a pre-specified amount of time. This would be the only way of ensuring that the oil gets returned to the sump in a timely manner. Don't know where he's at in development, but since the Mad Scientist is in his backyard, I would think he could prototype it in a weekend.

Louie928

Hi Andy,
Yup, probably work. I knew I shouldn't have entered this discussion because it is exactly like those on this topic preceeding it. The dicussions always come down to doing extraordinary things to deal with the symptoms rather than solving the problem of very inadequate crankcase venting which is the cause. I've got a video showing the inside of the cam cover and what happens in there when oil froth is blown up from the crankcase. Some people accept that as ok, but I can't, so I go in a different direction. I really can't help further.

PorKen

I'm thinking about putting water cooled tubes inside the crankcase hole...



...pulling only from the crank hole, the cam cover ports would be for filtered air inlets.

(Louie's work has made me rethink the cam covers as an outlet.)

Louie928

Hi Ken,
What function would the water cooled tubes have? You want water and combustion byproduct vapors to escape from the motor so you wouldn't want them to condense on anything.

Allright! One convert to see the cam cover ports as fresh air inlets! I feel like a JW house caller after a succesful hit.

Flott Leben

Louie, I agree completely. If we could vent adequately and prevent oil vaporization, frothing and windage - we would all be better off. We are all just brainstorming here on different ideas. Obviously, you have given these problems much more thought than all of us combined and we do appreciate your input.

PorKen

Louie,

I don't think the tubes could drop the temp very much with water, given the possible size of the coil(s), and the location, so I don't think there would be much condensation. However, even a small decrease in temp might help slow down the speed of the vapors through the Brillo™ pack.

Like a large muffler which cools the exhaust, thus slowing the sound waves.

It might have to be combined with a vacuum pump, to keep a constant flow of air through the crankcase. Any condensing water would then increase the effectiveness of the cooler, too?

Ketchmi

Hmmm, I have been using the cam covers as air inlets for a couple of years now with a small custom air/oil separator between the oil fill and the air pump intake. It drains the oil back into the oilpan constantly via the supercharger drain system. I use a venturi on the air pump intake to provide vacuum and had to restrict it so I didn't pull oil straight out of the separator into the air pump. Do a search, it's been working fine for a long time. I even had the chance to view it on a dyno this week, barely any vapor coming out of the cam cover vents during a 545rwhp dyno run (12.5psi). I have small K&N style filters on the cam covers and they stay pink for about a year, must not be getting much oil out of them. I have also installed air/oil separators in the cam covers, my idea being that if there is excessive blowby during the 2% of time that this thing is actually at maximum boost it can vent out of the cam covers. So far it hasn't really had to, I have no residue on the cam covers. No catch can, no pumps, no mess, no problems. This car is daily driven and on boost a large percentage of the time, it is not raced (on a track anyway) and not even I am crazy enough to hold it at maximum boost for any amount of time.

I have not installed an air/oil separator in the oil filler but do think it's a good idea. It would clean up the front of the engine area which is already pretty crowded on this CS car.

Someone has made it work...and it would be even easier on twin screwed cars.

blown 87

Dave, what do you mean by the air pump intake? Are you talking about the A.I.R. pump?

blown 87

I know the drag racers will not put any thing on there car that take HP away.
My Snap-On tool guy runs a bracket car (rear engine rail) of about 650 cubic inches on alky and runs a belt drive pump for the crankcase.

PorKen

Might have to install the crank seals backwards? I think it was the DEVEK people that said the 928 seals aren't good for much vacuum.

Ketchmi

I am talking about the emission system air pump located directly above the A/C compressor. On a factory S4, the inlet is routed to the filter on the top of the fan shroud. I customized the inlet hose to pull through another K&N filter with a venturi inline between the filter and the air pump. It could also be serviced by an exhaust venturi, I believe PorKen has done some work in this area. Getting the amount of vaccum correct was the hardest part as to maximize vaccum while still allowing oil to drain back into the dipstick tube. I did have a bit too much vaccum a couple of times before I got it right and that just pumps oil directly into the exhaust. Great for killing mosquitos but not very attractive.