Oil Catch Can - PeachParts Mercedes-Benz Forum

300D-91 · #1 09-21-2012, 03:31 PM

While doing the turbo actuator swap I found oil on the intake side of the turbo. With the intake manifold removed it was clear this oil isn't the best thing for my engine. Honestly with over 280 thousand miles, it shouldn't come as a surprise the engine has a little blow-by.

The use of oil catch cans are popular in most forms of auto racing so I adapted that principle and built my own. As with all my projects the goal was keep it simple, clean looking and functional. So here's what my version looks like.

NOTE: The position of the hoses (in & out) in these photos is wrong, they should be reversed.

For those who don't know how an oil catch can works......

The PCV vapors & oil enter the side of the catch can. Inside the can loosely wound stainless steel catches the oil and allows it to drip to the bottom of the can. Meanwhile clean - oil free air is pushed out the top of the can and back into the air intake system at the factory location.

For draining of the collected oil the can can be removed or you can use the petcock valve in the bottom of the can.

The Gears · #2 09-21-2012, 06:31 PM

Nice machining job. Can you post a drawing or sketch.
I have a machine shop and can build one of these. I get oil dripping from under the intake pipe so I guess I have the same problem as you. Also the same miles.

mach4 · #3 09-21-2012, 07:26 PM

Nice. Does yours drain back to the crankcase or do you need to dump it periodically?

Doh, didn't read past the pictures. Sorry.

300D-91 · #4 09-21-2012, 10:02 PM

Quote:

Originally Posted by mach4

Nice. Does yours drain back to the crankcase or do you need to dump it periodically?

Doh, didn't read past the pictures. Sorry.

It would be ideal if it dumped back into the oil pan. Just haven't started looking into my options yet - too many other things on the mods list

300D-91 · #5 09-21-2012, 10:14 PM

Quote:

Originally Posted by The Gears

Nice machining job. Can you post a drawing or sketch.
I have a machine shop and can build one of these. I get oil dripping from under the intake pipe so I guess I have the same problem as you. Also the same miles.

I bought the can from eBay for ~$20 to my door (search for "Billet Aluminum Oil Catch Can Quarter Midget Go Kart")

A local race shop re-threaded it for 3/8" NPT. The straight and 90 degree 3/8" NPT Male x 1/2" Barb fittings came from eTrailer .com

The stainless steel is an unwound Scotch Bright scouring pad thats been stuffed into the can.

The black hose between the PCV valve and can is 1/2" Poly Drip Watering Hose from HomeDepot.

The hose from the can to the intake side of the turbo is the original line trimmed to fit.

Mounting is simply 2 hose clamps bolted to the faux firewall.

That should get you going

Graham · #6 09-22-2012, 10:53 AM

Quote:

Originally Posted by 300D-91

It would be ideal if it dumped back into the oil pan. Just haven't started looking into my options yet - too many other things on the mods list

On the 123 diesels, some had a drain from the air cleaner oil separator (the middle of the air cleaner) back to sump. On my 300D, the block doesn't have that drain, so I just collect oil in the centre of the air cleaner which acts as an oil catch tank. I suck the oil out when I do oil changes on engine.

We also have a diesel smart car. I have not done this yet, but some owners have installed an oil catch to prevent oil from reaching an intercooler that those engines have. What they have done, is tee into the oil dipstick tube and drain the oil back that way.

mach4 · #7 09-22-2012, 11:52 AM

I'd be a little concerned about the efficiency of the catch can the way it is currently configured.

Here is a diagram of the way I believe your setup is.

It would seem that without any significant amount of wool that the fumes need to traverse, or any vortex component to the design, the primary flow would be as the red arrow due to the proximity of the intake and outlet ports.

The internals of a similar external configuration but with internal baffling, is shown in this diagram.

The description of this design is

Quote:

The standard Saikou Michi Design allows fumes/blow-by to enter into the lower chamber and pool, as the first line of defense. The second protective barrier is the layered mesh assembly. Fumes must pass through this filter and become liquid as it hits the thousands of surfaces in the materials. The snorkel has relief holes to prevent "snorkel drowning" in case the occ is not drained often enough.

When I did my catch can I didn't use any internal baffling, but with the ports on opposite ends of the can, fumes need to traverse a good 6 inches of wool to get to the outlet port. Same principal as above, just not nearly as compact, plus I drain to the crankcase so there is no maintenance on the unit. The link to the entire thread is Built a Catch Can

300D-91 · #8 09-25-2012, 03:25 PM

mach4: I reversed the hose locations (in and out) on the can 'after' these pictures were taken. There is no 'extension' or mechanical device forcing air to the cans bottom so it will flow through all of the stainless. After a few days and ~200 miles I checked the can and was able to drain a very small amount of oil.

This coming weekend I want to clean the intake hose and add some clear hose to the out / exhaust side of the can. That will allow me to monitor things and see how it's working. If oil is escaping into the intake then I'll research your idea of adding an extension to the intake port.

panZZer · #9 10-01-2012, 05:27 PM

The stock US w123's got them built into the rattle can air cleaner, I cut mine out when i swapped in the 85 Ca mini semi air cleaner housing--but it seeps oil and the top dosent seal worth a damn-its just a flat piece of plastic lid with two tabs bent over holding the top on. i like this alloy one-- pretty nice part.

sixto · #10 10-01-2012, 05:40 PM

Why is the OE 602/3 PCV hose is shrouded in foam?

Sixto
87 300D