Do we really need the oil separators? - PeachParts Mercedes-Benz Forum

rwthomas1 · #1 11-24-2004, 12:32 AM

Since I am in the middle of a little headgasket work I am spending much time looking at my MB shop manual (CD). Many of the pictures in the manual show the Euro engine setup with no oil separator. That little flat spot right before the turbo inlet on the U-pipe from the air cleaner to turbo is shown with a simple fitting and the vent tube from the valve cover is directed right into it. My guess is the oil separator unit was added to please US emissions standards? Seems perfectly reasonable to just run like this and do away with the factory oil separator. None of my other diesels have an oil separator and they all run fine. Why not? RT

pawoSD · #2 11-24-2004, 02:11 AM

I have wondered this as well....as I am interested in getting rid of the OEM airbox/bend, and just putting a chrome pipe with a K&N washable filter on the end or something, thus I would have to run a line right from the valve cover right into the turbo intake pipe. I'd assume this would be ok to do...at some point I'm going to get too sick of paying for, and dealing with replacing, those little rubber mounts that love to break.....a month ago I had ALL of them break!!

The whole air thing came off and was laying off to the side, and it messed up that bend tube too, that was not fun.

Its fine right now as it has all new mounts as of then, but someday I'd like to just do away with it completely.

kmaysob · #3 11-24-2004, 05:41 AM

you would consume lots of oil if you dont have the seperator. and the intake would be pretty slimy

vwbuge · #4 11-24-2004, 05:54 AM

I do just fine with my setup. I have a K & N style filter mounted on a straight intake tube from the turbo inlet. The hose from the valve cover runs directly to this tube and all the gases are inhaled by the turbo and then burnt.
The car doesn't smoke much at all and I use less than a 1/2 quart between changes.

engatwork · #5 11-24-2004, 06:57 AM

If you look at a pre '80 or so 300SD it does not have a separator. On the '79 I just went through I watched oil consumption real close with this set up and did not see excessive consumption.

boneheaddoctor · #6 11-24-2004, 07:56 AM

Quote:

Originally Posted by kmaysob

you would consume lots of oil if you dont have the seperator. and the intake would be pretty slimy

My 300SD has no oil seperator, never came with one either. Valve cover to the "U" pipe directly from the factory, Used about a quart every 2,000 miles roughly. Had my intake off because I put a block heater in it where none existed before and did it from above. My intake had no crud buildup. Thats the EGR that gunks them up.

Fredmburgess · #7 11-24-2004, 12:09 PM

Thanks for posting the question, RW. I'm sick of looking at those big stupid aircleaner housings but have been avoiding dealing with it until I figured out how to make an oil separator. I'll just skip it for now and see how it works.
Sold the '84 300D with WVO conversion on Ebay last week. Tons of hits - the WVO thing really drew some interest. Making new tanks for these two "new" cars now.

fmb

dieseldiehard · #8 11-24-2004, 01:45 PM

I found the separator from a 240D was helpful in reducing oil consumption. Made a long (2000 mile) trip without it and wish I had something all the way.
I was venting the cam cover and had some blowby under the car that also attracted attention when I went to the airport to pick someone up, the security cop tried to tell me there was smoke coming from my engine and I told her not to worry, blah blah.
picture of the K&N setup on the '85 engine, the 240D separator is just visible to the rear, and note the hose from it to a Tee I placed in the front of the K&N for suction:

boneheaddoctor · #9 11-24-2004, 01:47 PM

Quote:

Originally Posted by dieseldiehard

I found the separator from a 240D was helpful in reducing oil consumption. Made a long (2000 mile) trip without it and wish I had something all the way.
I was venting the cam cover and had some blowby under the car that also attracted attention when I went to the airport to pick someone up, the security cop tried to tell me there was smoke coming from my engine and I told her not to worry, blah blah.
picture of the K&N setup on the '85 engine, the 240D separator is just visible to the rear, and note the hose from it to a Tee I placed in the front of the K&N for suction:

Does your have the factory Golf tee that helpts the egr work great?

I wish I had the drain to the upper pan yours has......I would have to put it where the dipstick goes.

Fredmburgess · #10 11-24-2004, 03:03 PM

Dieseldiehard,is the 240D separator a self contained unit? I've only had the 300's with the separator built into the air cleaner housing.

Nice setup. How much boost are you running and have you adjusted the ALDA as well?

fmb

dieseldiehard · #11 11-24-2004, 06:43 PM

Hi Fredmburgess,
The separator is a self contained External unit used only in later (84?) 240D's. It was a bit tricky making the mounting angles to hold it over the existing oil drain tube that was used wiht the big AF cannister, but it worked out nicely with ssoome aluminum stock. If anyone ever attemps to make the brackets like I did, I recommend using only nylock nuts to hold them together. Regular lockwashers and nuts come apart bcause there is so much vibration there even with a perfectly running engine.
I have since removed the air regulator in the turbo boost line (the red circle you see in the photo adjacent to the turbo) - it didn't add any overall acceleration after I swapped a new turbo into that engine. The first turbo was losing its bearings and the extra boost seemed to help it after it spooled up, giving a neck snapping when it shifted.
I turned the ALDA CCW about 2 turns. It was a newly rebuilt IP too, the rebuilder left off the snap-in cover over the ALDA adjustment.I think it was set too conservative by the rebuilder, they assured me that I would start belching black smoke if I went too far but I never got that far, just enough to lose a little fuel economy but it really gives the car a lot more acceleration (before the turbo builds pressure)
Copme to think of it, I just have accumulated 15K miles on the rebuilt engine in that picture I better plan on a valve lashing sometime soon.
BTW, someone cut away the stock AF housing to remove the separator, using a cold chisel or something. Not something I would want to do, if you can find the 240D separator its a nice self contained unit in a thick rubber molded case. Dealer price was $69 (w/ discount) but someone on the Shopforum was buying one at a wrecking yard for $15 - search for 240Dog or someone named Ed in San Jose (where's that old Email when I need it?)

dieseldiehard · #12 11-24-2004, 06:48 PM

Well, under the EGR is a thin stainless steel plate across the whole opening that helps keep pressure where it belongs.

boneheaddoctor · #13 11-24-2004, 07:07 PM

Quote:

Originally Posted by dieseldiehard

Well, under the EGR is a thin stainless steel plate across the whole opening that helps keep pressure where it belongs.

AHHH, the revised update to the golf tee.................

Q45Denver · #14 11-24-2004, 07:40 PM

I just got this brand new WWII Surplus Oil Separator off eBay. The instructions state that it is cyclonic and was for an old airplane. Haven't installed it yet but looks like it will work OK. I noticed that the seller had several for sale at the time. The one I have from a 240D? is leaking from the top and doesn't appear to be of real high quality or have a very high flow rate.

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&rd=1&item=2493390905&ssPageName=STRK:MEWN:IT

boneheaddoctor · #15 11-24-2004, 09:16 PM

Quote:

Originally Posted by q45denver

I just got this brand new WWII Surplus Oil Separator off eBay. The instructions state that it is cyclonic and was for an old airplane. Haven't installed it yet but looks like it will work OK. I noticed that the seller had several for sale at the time. The one I have from a 240D? is leaking from the top and doesn't appear to be of real high quality or have a very high flow rate.

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&rd=1&item=2493390905&ssPageName=STRK:MEWN:IT

Cool............shame he's out of them....that inlet and outlet is beefy though, 1 inch.

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