New Crankcase Breather Scrubber System

[Herr-Kuhn]

I'm about to go in and get some more of my new crankcase breather scrubbers made and I'm only posting here to determine interest in the units as a stand alone item.

The 928's breather system is very weak from the factory and adding any kind of boost to the engine only makes matters work. The best place to breathe from the crankcase is out of the center of the block, where the system is designed to breathe. The only problem is, on a 928 the crankcase opening sits just above the crankshaft. Any blow-by which passes the opening gets exposed to the oil which is being slung by the crankshaft. If nothing is done to eliminate the oil from this cloud, it will continue right up and out the breather port...which on the stock filler cover is waaaay too small. Here is what I do on the Twin Turbo:

Install scrubber box in the opening (trust me, no louver will better the performance of the scrubber box...been there, done that)

Port out the back side of the stock filler cover and plug the two factory ports

Drill for a 1" fitting in the oil filler cover (under the filler lid)...this requires covering the opening duting oil fill, but not that big a deal.

Install two breather ports in each valve cover

Breathe high pressure air into the non-cupped side of the valve covers

Combine the two remaining breather ports into the one inch line out of the center breather...the idea here is any blow-by in the valve train is given a path by which it can also escape with the main blow by gasses

The three outlets are T'd together and then I run them into a Provent air oil unit.

Here are a few pics of the scrubber box:






It's a prototype and I didn't have a small stainless rod that day, so production units would be better looking.

It's a 3 level approach...oil must first get past the louvers, then past a screen and finally past a copper scrubber inside the box.

I'm currently running this on my Twin Turbo and the outlet of my Provent is completely clean and dry...even after the car sits for days there is no oil on the ground (my crankcase goes out to atmosphere). The reason I use copper instead of stainless is because it is much softer.

If you are interested in one of the scrubber boxes, please let me know and I will get a batch made up on my next production run. Scrubber Box will be $100.00

[rhjames]

for most of us, any improvement in oil breather control is a plus. even if you don't go to Pro-Vent, this should help a bunch. I've always said the factory really screwed up when they left the huge hole exposing the crank to the breather system---Pretty dumb mistake.

count me in--

--Russ

[Red Baron]

We're on the build this week, so keep me in mind. I'll be giving you a call this week also.

[Louie928]

Finally! The right way to do it. I'll take one.

[Herr-Kuhn]

Sounds good guys...I'll have an extra ten made up in addition to the ones for my systems.

[Herr-Kuhn]

If you look closely in this picture you can see the 1" breather hose just below the oil fill lid.

[Fabio421]

Originally Posted by Louie928

Finally! The right way to do it. I'll take one.

Thats a hell of an endorsement right there. :thumbup:

[Barbapapa]

That's a great design. You can build several dozen and they won't sit there for long. If you stock some I'll buy one for my next wet sump engine.

[Alan in AZ]

John - I'll take one also. Just getting ready to do a Provent install and want to vent fresh air into the cam covers and breathe it all out through the main filler port so will need something like this for pre-separation.

Alan

[Normy]

John count me in.

You will provide a diagram so that I can hook up the hoses correctly yes?

N

[Alan in AZ]

John what are you sealing it with? the stock gasket above & below the plate or otherwise?

Normy - I think the routing is up to you depending on whether you install a Provent or not. As I see it you could just install this seperator/scrubber and it would significantly reduce oil ingestion alone - with no other hose routing changes.

But if you install the provent you have to decide how to connect its intake to the oil filler and how to vent it - while to get the blowby/entrained oil to avoid the intake you pretty much have to cap off the stock vacuum ports to the filler neck

From there you can either vent the provent to air, airpump intake, vac source into the exhaust or back into the intake vac.

That leaves exactly how you vent the cam covers: most obvious options are to T' them into the provent intake (per DR), or just fed them fresh air (perhaps also with cam cover-cam cover balancer like on the GTS) from the airbox bottom as Louie does.

Lots of options - no single best way for all engines/conditions.

Alan

[icemang17]

John
Great product......put me down for one too!!!!! send an email to icemang17@aol.com with your billing-paypal info!

[Louie928]

Originally Posted by Alan in AZ

John what are you sealing it with? the stock gasket above & below the plate or otherwise?

Normy - I think the routing is up to you depending on whether you install a Provent or not. As I see it you could just install this seperator/scrubber and it would significantly reduce oil ingestion alone - with no other hose routing changes.

No. Without a way for crankcase pressure to escape out through an approx 1" minimum hose, the crankcase pressure will simply blow up the oil drain holes in the heads and out the cam cover vents bypassing the louvered separator.

But if you install the provent you have to decide how to connect its intake to the oil filler and how to vent it - while to get the blowby/entrained oil to avoid the intake you pretty much have to cap off the stock vacuum ports to the filler neck

Correct.

From there you can either vent the provent to air, airpump intake, vac source into the exhaust or back into the intake vac.

That leaves exactly how you vent the cam covers: most obvious options are to T' them into the provent intake (per DR), or just fed them fresh air (perhaps also with cam cover-cam cover balancer like on the GTS) from the airbox bottom as Louie does.

Lots of options - no single best way for all engines/conditions.

The common required charactistic is to vent the crankcase with a large hose. However you can do that, do it.

[Herman K]

John please put me on the list for one of those as well.

Thx

[Herr-Kuhn]

Credit should go to Louie for being the guy who figured out the best way to do it. I've seen a lot of the louvers and have used one on my 4.5 twin turbo, but I really think this style box does a much better job.

I seal it with a 16V style gasket under the scrubber and then the factory 32V O-ring on the top side. I also used some high temp silicone on the underside because this is just sheet metal and the plastic cover isn't all that rigid. Key is keeping the heat really low on the TIG to avoid any distortion.

I have to perfect the laser cut files to aid in manufacturability...the first one was a PIG to bend and took about 2 hours to assemble. My laser cutter is quoting me 10 right now...I hope to be able to hold the price I listed here, but the box is 304SS and stainless is through the bloody roof right now on prices...but who wants combustion byproduct in a rusty goo inside the engine crankcase?...it had to be corrosion free.

I had my intake off so I installed it that way...I can't guarantee it will go under the intake and past a removed water bridge, but it may.

Louie is spot on...the breather ports over the stock crankcase opening are very small and don't really do much of anything except force more blow by up the oil drain back ports in the heads...keep in mind the oil is trying to come down and the blow by trying to force its way up...sort of like urinating into the wind. You have to port out the cover, remove the baffle totally and cut out the walls...basically just open it all up and then simply plug the outlets and forget about those factory hoses under the intake...they are USELESS.

Louie doesn't port the other breathers into the outlet. My reasoning for that was to allow any blow by that got past my valve guides and seals (turbo runs some exhaust back pressure) to have a way out without having to go back through the sump. As always it's a trial and error process with this stuff.

There's a lot of dynamics at work here...but I think the key is to breathe out the center and smack out all the oil you can at that point. I'm certain some oil is still getting to the Provent, but it seems to be doing a fine job at cleaning the final shot up before I vent off...it's clean enough that it could go right back into the intake side if I really wanted to...but I like my MAF completely oil free (don't start with the K&N MAF failure arguement...besides, my K&Ns are like 6 feet and 2 intercoolers away from the MAF...lots of time to drop out any oil)

[Alan in AZ]

Originally Posted by Louie928

No. Without a way for crankcase pressure to escape out through an approx 1" minimum hose, the crankcase pressure will simply blow up the oil drain holes in the heads and out the cam cover vents bypassing the louvered separator.

Yes I suppose you'd have to change the plumbing to the cam covers else thats the path the oil will go - but It seems fresh air venting the cam covers and switching the big "Y" throttle body connector over to the filler neck could be a minimal system.

I think John answered the other part - early perimeter gasket underneath + RTV/Slicone and the 32V stock O-ring seal above.

The venting I assumed to be via a Provent - with the big 3/4" - 1" feed (like DR's extreme system). I posted on rennlist about the overall system I envisage (on the DR 'sharkvent' thread). I see this oil scrubber and a Provent as a great combo system. I do think with these two in series the provent output vent can be scavenged by all the existing 3 vac lines back into the intake (should be pretty clean), would need to replicate the restriction to the intake vac and a check valve for the big "Y" port. Then I'd go with fresh air only venting into all 4 cam ports (e.g. add one DS) fed from the filter box - for unidir drain flow.

I am feeling like I finally have the right plan for this...

Alan

[Herr-Kuhn]

Make no mistake...this one area is the biggest achillies heel of the 928's engine design. It's been years to get to this spot and at least 3 or 4 hard brains on it for that same time period in a few different parts of the country. Now there should be no more secrets as to what works and what does not!

[atb928]

Hey John,
Put me on the list.

-Adam

[BrendanC]

At one time, was the idea not to use all four Cam cover breathers as INTAKES and have good vacuum coming out from the main front area over the oil filler?

I'm still not properly picturing what is being done with the four breathers on the cam covers and which way they are plumbed. The ideal is to have none of this plumbed into the intake, correct? Especially for boosted motors.

[BrendanC]

I'm in for one of the production ones as well.