How to add a catch can setup to OBD1 motor?

[butters]

I would like to not have oil pooling in my intake manifold if I can help keep my rebuilt S50 clean.

I am looking into the factory OBD2 cyclone separators but it seems the hoses connect in a much different manner.

An alternative would be to run a simple catch can, but I imagine that it would go on the smaller vacuum line and most cans I see are set up for the 3/4" tube. The OBD1 system also has 2 tubes splitting right from the valve cover, and the catch can would also ideally need to go between it and the intake elbow (non-vacuum). So I'm unsure how to go about merging these tubes to incorporate a can.

Anyone tackle this issue? A bunch of indirect discussion in the archives and not much concrete information.

[butters]

Is there a catch can that could simply go in-line on the small diameter vacuum line between the "valve" and the ICV connection?

[butters]

Does the OBD2 cyclone separator not run on vacuum? Looks like it has 3 ports - oil drain, feed from valve cover, and feed to intake elbow (before throttle).

[dsobering47]

The stock cyclone seperator sucks. I replaced mine with a catch can, but I'm pulling vacuum from the exhaust via an unused o2 sensor bung. The stock seperator pulls vacuum from the intake manifold and from the intake boot...so it constantly pulls vac regardless of throttle position. The bottom connection is for the drain into the oil pan (moisture-ridden oil, which is dumb).

My setup goes from the valve cover, to the catch can, then to the exhaust (for vac). Right now my setup pulls too much vacuum, so I'll need to add a restrictor somewhere, but other than that its solid.

[dsobering47]

I was trying to find comparable setups from the e36 track/race guys but nothing really turned up. I hate the stock setup for all its plastic (and drain into the oil pan) so this is a better solution for me (in my opinion)

[butters]

I'd agree. I came across a specialist - Saikou Michi - via BFc with a beautiful product and seems like a reasonable price. I haven't contacted yet but I was thinking that they could potentially build a dual-reservoir system made for the two hoses that come from the OBD1 "valve," keeping one under vacuum (small dia.) and the other going to the intake elbow (large dia.). Is that larger OBD1 hose really open to atmosphere?

[dsobering47]

None of the hoses should be open to atmosphere. All youre doing is providing a canister for moisture-ridden oil vapors to collect, and it should be under vacuum, coming off the valve cover. Where you source your vacuum supply is up to you (intake, manifold, exhaust). I chose exhaust so zero oil vapor would be put into the intake manifold/valves.

All that saikou guy did was make a nice canister....they all do the same thing (better or worse than each other), they just collect and slow the oil vapor. After a while, if you dont have a built in drain, then you will have to empty your canister.

[butters]

None of the hoses should be open to atmosphere. All youre doing is providing a canister for moisture-ridden oil vapors to collect, and it should be under vacuum, coming off the valve cover. Where you source your vacuum supply is up to you (intake, manifold, exhaust). I chose exhaust so zero oil vapor would be put into the intake manifold/valves.

All that saikou guy did was make a nice canister....they all do the same thing (better or worse than each other), they just collect and slow the oil vapor. After a while, if you dont have a built in drain, then you will have to empty your canister.

From the factory, the OBD1 motors have the "PCV" on the valve cover which attaches to 2 hoses. The larger hose connects to the intake elbow. The intake elbow, correct me if I'm wrong, is upstream of the throttle body and thus open to atmosphere. This is where my confusion lies.

The saikou guy would be able to custom make the canister so that I can retain the dual hose setup, and yea the canisters are a solid design and well made. True it's the same basic concept as any other canister.

[Wanganstyle]

[LEFT]use e39 m5 cyclone item if its desired to remove oil from the vapor and return it to the oil pan.

Or run the OEM bmw s52b32 intake; its actually quite efficient and the cyclone item does its job well. Quite good on track for corner exits; the smaller runners do the intended function.

otherwise just run the OEM OBD1 setup without cyclone and add a little oil once a while; a small amount of oil doesn't hurt anything and; the vacuum from the engine pulling from the crankcase aids in rings sealing.

A built 0 mile head with a block with rings that are within 3% leakdown will only consume 1/3-1/2 quart of oil every 3-3.5 hours of non-stop endurance racing using the OEM BMW OBD1 vent from valve cover to throttle body. I think that's reasonably efficient for 110% use of the engine over a decent amount of time (180-210 minutes wide open throttle attack). We add about 1/3 quart every driver change/fuel/pit

if one desires to clean the intake tract; buy some seafoam; use frequently if desired

[dsobering47]

1/2 qt of oil per 4 hours of driving is too much for my taste. And I've cleaned enough valves to be fed up. Hose in the intake, behind maf, but in front of throttle, would be vacuum...not "open" at all. Worst case scenario with my setup is oil is burned in exhaust and has no affect on engine performance, buildup, or internal consumption (at least through intake/head).

Just sharing what I did with my vehicle...when I find an obviously superior system, then I'll argue

[butters]

[quote=Wanganstyle;3903533A built 0 mile head with a block with rings that are within 3% leakdown will only consume 1/3-1/2 quart of oil every 3-3.5 hours of non-stop endurance racing using the OEM BMW OBD1 vent from valve cover to throttle body. I think that's reasonably efficient for 110% use of the engine over a decent amount of time (180-210 minutes wide open throttle attack). We add about 1/3 quart every driver change/fuel/pit[/quote]

I actually don't have any measurable consumption issue. I'm just looking to keep everything clean, in a non-race application.

Hose in the intake, behind maf, but in front of throttle, would be vacuum...not "open" at all.

I see. I suppose it's a differing vacuum level, hence the function of the ICV which pulls from the adjacent connection on the elbow.

[dsobering47]

I think they have multiple hoses to the valve (before/after throttle) so there is always a vacuum source. But I could be wrong, wouldnt be the first time

[Wanganstyle]

IACV receives metered air post AFM before throttle body from the Oem throttle body boot.

Valve cover vent tube goes to throttle boot also. The oil from the vapor lubricates the IACV as well.

The oil vapor doesn't hurt anything; if confused about it just keep the obd2 intake manifold with cyclone oil vapor separator valve. The obd2 intake manifold is in practice more effective than the old obd1 piece.




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[dirtbag30]

would running it like this work?



or what these guys did and route it back to the intake port? thoughts?

see link

http://www.technicalgarage.com/articles/e36/catchcan/

[butters]

^that's OBD2, I'd stick with the improved factory design or perhaps put the occ between the cyclone separator and the intake manifold if you're dead set on seeing if it does anything for you.