crankcase ventilation

[zaq123]

Well, first, I think this is a really creative solution, and very well done. Honestly, there is very little information online or on forums about this specific application.

I was originally going to use a catch can with the inlet coming from the valve cover, but I couldn't figure out exactly where the outlet should go. The bitch tube and the dipstick tube both go to the crankcase, which is great - there will be a slight vacuum there. Others have said to connect the outlet line to the RHD vacuum block - but all of those ports/nipples already go to other places. And I was worried about oil vapor contaminating those vacuum lines.

This brings me to your solution. It's great because M20 dipstick tubes are cheap, and the risk is low. Your pictures are great, but there are a few things that I can't see.

Questions:

1. Do you need an oil separator if the line is going directly from the valve cover to the dipstick?
2. I am not running a plenum, just open trumpets, so i don't have an airbox. What would you recommend?
3. I assume you got the 5/8 thin-wall aluminum tube on McMaster, but did you just sleeve it over the dipstick tube - then flare them together? I've never used a flaring tool, but now I will go buy one.
4. I assume you just removed the length of the dipstick tube that is now occupied by the AN Tee fitting?

I think that's it for now, and thanks again.

and to answer your questions:

1. yes and the one that vents outside because you will basically seal the system and that line will be a smaller version go the bitch tube. Again as I mentioned above, You may create an issue with draining collected moisture into your oil because you can and its lines will act as a sort of crank vapour cooler. Can create lots of moisture too.
2. Id recommend to run an airbox to really get any advantage from your ITBs..
3.I think I got it on amazon. It's not sealing anything, flare does. It's there as a spacer of sort. It keeps AN fitting's cap more centred over the dipstick. Dipstick is a little thin walled for the tubing that AN fitting was designed for. Bit it's just a spacer so not critical at all.
4. Yes, once set and done, new dipstick needs to be exactly long as before. So you need to minus AN height and plus how much flare will take away from the tube. I have a piece I cut out somewhere if you want me to measure it. I also recommend buying a spare M20 dipstick on eBay or whatever so you are not out of dipstick while you are doing it or if you mess up. They are cheap and plenty

[zaq123]

Well, first, I think this is a really creative solution, and very well done. Honestly, there is very little information online or on forums about this specific application.

I was originally going to use a catch can with the inlet coming from the valve cover, but I couldn't figure out exactly where the outlet should go. The bitch tube and the dipstick tube both go to the crankcase, which is great - there will be a slight vacuum there. Others have said to connect the outlet line to the RHD vacuum block - but all of those ports/nipples already go to other places. And I was worried about oil vapor contaminating those vacuum lines.

This brings me to your solution. It's great because M20 dipstick tubes are cheap, and the risk is low. Your pictures are great, but there are a few things that I can't see.

Questions:

1. Do you need an oil separator if the line is going directly from the valve cover to the dipstick?
2. I am not running a plenum, just open trumpets, so i don't have an airbox. What would you recommend?
3. I assume you got the 5/8 thin-wall aluminum tube on McMaster, but did you just sleeve it over the dipstick tube - then flare them together? I've never used a flaring tool, but now I will go buy one.
4. I assume you just removed the length of the dipstick tube that is now occupied by the AN Tee fitting?

I think that's it for now, and thanks again.

definitely do not connect return to the vacuum block of ITBs. It will create a giant vacuum leak you don't want. There is not much vacuum in the crankcase of any ITB engine as far as I know. Most OEM ITB setups vent the crankcase into ITB plenum which is obviously has almost no vacuum with a very minimal vacuum under WOT (if your airbox totally sealed etc.
How much blow by does your engine have? Is it oil you see for sure or just some oily moisture? M20 has a little more restrictive built it baffle than S14, by a little but still more restrictive. As you know, OEM M20 design vents directly to the intake manifold . So if your engine doesn't have excessive blow by, M20 cover plus oil separator similar to S14 will do the job on the healthy engine. So far I have almost 3k km on this setup and no signs of oil in the airbox at all.
I did vent to the atmosphere while figuring this setup and it was mostly oily moisture that I saw. Most catch cans and their tubing aren't positioned in the engine bay areas where 80C+ temperatures hence the moisture does not get burned off. I set my separator routing and separator itself similar to what OEM design does: close to the block and right above the block so it keeps any moisture away to create any milkshake.
BTW, that hose bending din't work too well so I ended up making a line out of pieces of hose with brass elbow to go to the separator, very short line. I can take a few pictures of the setup if you'd like. Let me know.

[tarkE30]

Well, first, I think this is a really creative solution, and very well done. Honestly, there is very little information online or on forums about this specific application.

I was originally going to use a catch can with the inlet coming from the valve cover, but I couldn't figure out exactly where the outlet should go. The bitch tube and the dipstick tube both go to the crankcase, which is great - there will be a slight vacuum there. Others have said to connect the outlet line to the RHD vacuum block - but all of those ports/nipples already go to other places. And I was worried about oil vapor contaminating those vacuum lines.

This brings me to your solution. It's great because M20 dipstick tubes are cheap, and the risk is low. Your pictures are great, but there are a few things that I can't see.

Questions:

1. Do you need an oil separator if the line is going directly from the valve cover to the dipstick?
2. I am not running a plenum, just open trumpets, so i don't have an airbox. What would you recommend?
3. I assume you got the 5/8 thin-wall aluminum tube on McMaster, but did you just sleeve it over the dipstick tube - then flare them together? I've never used a flaring tool, but now I will go buy one.
4. I assume you just removed the length of the dipstick tube that is now occupied by the AN Tee fitting?

I think that's it for now, and thanks again.

[zaq123]

zaq123 i sent you a DM earlier. I have a similar setup (2.9L stroker w/ RHD ITB's) and want to know more about your crankcase venting solution and if it's working out. TIA!

yes it works great. I have some details about it in my post above. What details/specifics would you like to know?

[tarkE30]

zaq123 i sent you a DM earlier. I have a similar setup (2.9L stroker w/ RHD ITB's) and want to know more about your crankcase venting solution and if it's working out. TIA!

[zaq123]

here is what I came up with. I didn't want to braze the oil return line on the dipstick tube as it would require painting the whole thing. Also Didn't want to separate the dipstick tube 325iX style with rubber hose and clamps as I wanted more rigid setup. -10AN 37' flared fitting did the job plus it lets change the angle of the dipstick tube as one needs it to be.
Had to bend 3/4 ID Gates hose (p/n 28478) with a steam and spring mandrel for a kink free routing around fuel rail, inj. harness and all those things. Basically hot steam through the hose with subsequent cooling in the bucket of cold water.
Also OEM dipstick tube is not exactly 5/8 to fit snuggly in the flaring tool so a couple of thin wall (0.016" wall) pieces of 5/8 aluminium tubing did the trick as it fits nice and snug around e30 dipstick tube for true 5/8 diameter.

Here is the result. Still need to get 90 degree AN to hose barb adaptor for the drain hose but you get an idea. Oil separator will be attached to the back of the airbox between runners 3 and 4 via grommet. 21mm ID x 2.5mm groove grommet works perfect with S62 oil separator and the aluminium Airbox backplate.

[zaq123]

Im in the process of rigging up the oil separator from S62 p/n 11151406789. Basically want to make similar arrangement to S14 oil separator where its going to vent into the back of ITB airbox and drain into the dipstick tube. That oil separator will be plugged in to the airbox via grommet to minimize on running vent lines, similar how S62 has it mounted. Just need to hot steam shape the hose from the valve cover. Just want to make somewhat maintenance free system where one doesn't have to keep an eye on the catch can

[digger]

there is should be only a very small amount of vacuum as it is pre throttle body so just whatever the upstream system creates which is very small.

[zaq123]

any comments on this? There is no vacuum in the crankcase on M20 because it wants before throttle plate? Am I correct?

[zaq123]

Also related question regarding How crankcase ventilation is designed on M20. Ok so there is a drain tube between the head and the crankcase as well as oil drain holes near cam rockers in the head. Valve cover has only one line routed right before a throttle plate. Correct me if I misunderstand the design:
1. Unlike in typical PCV design, the crankcase is not under vacuum (typically a vac. line from somewhere after TB) and it has no fresh air intake (typically the air box)
2. Crankcase venting is sealed to the engine and valve cover vent is just vent fumes
3. There is no vacuum in the system. There reason why folks report idle changes when removing oil fill cap because any air inlet created after stock AFM affects AFM door opening? For example if one plugs TB valve cover vent port and drops the hose from the valve cover vent to open air, no more idle changes on stock m20?

[zaq123]

Moving the vent won’t do anything.

I would add some additional separation capability such as catch can as I don’t think the baffled valve cover is adequate and there are better products these days. Otherwise you will get oily mess

I might try routing to a oe separator and adding a tee in the dipstick tube

do you catch a lot of oil? Also return to dipstick could be a simple solution to keep it maintenance free. One can do BMW OEM design to achieve that, they way they designed a dipstick on Z1 Roadster or 325xi :)
Just cut the dipstick and use hose/hose clamps, BMW design after all :)

[digger]

ok resurecting this because I still figuring this out. Right now, my lave cover vents into ITB manifold/airbox back plate, right between cylinder 5 and 6 trumpets. I guess it was most direct route from the valve cover over the fuel rail and into the airbag backplate.
I got me thinking about the intake temperatures with ITBs. My setup most likely warms up air for cylinder 5 and 6, not sure how bad, or how significant. S14, S50 ITB engines vent into the bottom of the intake manifold stock but in the center between cylinder 3 and 4. If you think about, M20 crankcase venting setup is somewhat similar to lets say S50, but all baffling / oil draining happens inside the valve cover unlike at the external plastic oil separator on S14, S50.

Do you think I should move this vent line between cylinder 3 and 4 or keep my current setup? I don't think catch can is really needed because the course is post the valve cover baffle which basically is a catch can except it drains oil back into the head.
How much oil do you guys collect in those monthly anyway? If anything, wouldn't catch can be more of a mess because of the condensation in all those long lines in cold climates? Self created condensation coil?

Moving the vent won’t do anything.

I would add some additional separation capability such as catch can as I don’t think the baffled valve cover is adequate and there are better products these days. Otherwise you will get oily mess

I might try routing to a oe separator and adding a tee in the dipstick tube

[Rtalatief]

ok resurecting this because I still figuring this out.

Use a catch can, otherwise you will clean gunk on your intake runner regularly.

[zaq123]

ok resurecting this because I still figuring this out. Right now, my lave cover vents into ITB manifold/airbox back plate, right between cylinder 5 and 6 trumpets. I guess it was most direct route from the valve cover over the fuel rail and into the airbag backplate.
I got me thinking about the intake temperatures with ITBs. My setup most likely warms up air for cylinder 5 and 6, not sure how bad, or how significant. S14, S50 ITB engines vent into the bottom of the intake manifold stock but in the center between cylinder 3 and 4. If you think about, M20 crankcase venting setup is somewhat similar to lets say S50, but all baffling / oil draining happens inside the valve cover unlike at the external plastic oil separator on S14, S50.

Do you think I should move this vent line between cylinder 3 and 4 or keep my current setup? I don't think catch can is really needed because the course is post the valve cover baffle which basically is a catch can except it drains oil back into the head.
How much oil do you guys collect in those monthly anyway? If anything, wouldn't catch can be more of a mess because of the condensation in all those long lines in cold climates? Self created condensation coil?

[digger]

Do you run this setup with ITB? Got any pictures? I'm looking for proper crankcase vent setup once I go ITB.

I don't but there are plenty of pics I've seen around. It's just a hose connected to a canister with a filter on the end