Oil return line from the drain of the turbo is above the oil level in the sump. Oil return line from an oil seperator/vent to atmosphere catch can should be below the oil level in the sump.

Bob

Oil return line from the turbo is above the oil level in the sump. Oil return line from an oil seperator/catch can should be below the oil level in the sump.

The Mazdaspeed turbo miata has an oil seperator system from the factory it returns the condensed oil below the oil level in the sump as well.

Bob

ok.
looks like i might have to seal off the vent on the lower block then.
losing too much oil
btw, would this have any connection whatsoever to me having knock now? previously I used to run knock free, but of late, been getting knock

i've decided to block off the vent on the lower block. now only connected the crankcase breather outlet from the valve cover to the oil catch tank.

Wondering if I should buy another oil catch for the PCV valve outlet.
hmmm

Has anyone looked into the oil seperator system that BMW uses? It may be possible to impliment onto a Miata for a solution to all of this...

http://www.realoem.com/bmw/diagrams/h/e/54.png

http://i727.photobucket.com/albums/w...5/Photo200.jpg

I’m trying to work out a very similar system Vent crank case at valve cover and side of block. Have an effective separator with a return to the pan via an AN weld bung down low by the drain plug.

I have looked at some of the new heavy diesel technology. Motorized swirl pot separator with a filter element to separate oil return it to the pan and it pulls a vacuum on the crank case as well. Without a throttle body a PCV system just don’t work. Less than 10 years ago the state of the art for big diesel was a large tube from the valve cover pointed at the ground with the end cut at an angle so that air flow could create a slight vacuum. Condensate oil just dripped on the ground.

Bob

My oil separator return line to the pan.

I welded the AN bung on first about the lowest spot on the pan I could find the fit good in the car. I put some water in it and decided it was not low enough to remain submerged with heavy sloshing going on so I added a tube on the inside of the pan to make it pickup all the way in the bottom. Since I welded the bung on first I couldn’t weld it seald so I had to resort to JB-weld to seal the additional tube.

This location should make it so the return line doesn’t spooge oil back up. With with gas pressure pulsations in the crank case.

Bob

Would this work for a "block vent" ?

Put an air filter on the end of your dipstick tube.

I know this sounds ridiculous, but functionally, it would work, right?

bbundy, re: returning the oil separator flow to a point below the sump's oil level -- is the thinking that crankcase pressure spikes are damped out by the oil in the sump?

Correct.

In order for the pressure spike to get out from this port it would have to blow all the oil out of the sump first. Not likely to do that when there are 3 other vents above the sump oil level that will flow gas pressure pulses fairly easily.

Now if I can just figure out a really good separator system for the other 3 vents.

Bob

No it wouldn’t work for a block vent. It is below the oil level in everything but left turns and hard braking.

It would work ok as gravity feed return from an oil separator like the BMW diagram shows I think.

It has shown to not work so good as a turbo oil return because that is pressure fed. Pressure fed wants to return above the sump oil level.

The dipstick also sometimes has issues as a dipstick on the miata especially if you don’t have good crank case ventilation because in some instances like hard left corners the dipstick hole in the pan is above the oil. A good gas pressure pulse when the dipstick hole in the pan is exposed to gas rather than oil will pop the dipstick out as it will try to act like a gas vent.

Bob

OK, I figured it was below the oil line most of the time since it's the -oil dipstick- but I did not know why it blew out- during turns. Thanks for the explanation.

I think numerous people who have flogged the crap out of there cars on the track have experienced the dip stick popping up and a bit of oil spray into the engine compartment by the dip stick. Seen it happen many times.

The owners usually freak out when it happens wondering what they screwed up then they put the dip stick back in and it doesn’t do it again. It is kind of an intermittent thing.

It can also happen very often on a boosted car with a bad PCV valve though and might happen more if you are low on oil.

Bob

i believe I've seen several Evo owners who have the same problem. In the end, they use something similar to the spring found on the hard top latches and tension the dipstick down

Bob,

Have you looked at the Mann Hummel Provent 200?

I have one, it came highly recommended.
Got mine here:
http://www.efiexpress.com/catalog/pr...products_id=52

Won't be on the track with it for several months though. I have the drain plumbed to the oil pan via a one-way check valve (included with kit).

- Will

That looks real interesting. seems wildly expensive for a plastic container with a filter in it though. What sizes are the inlet and outlets?

Bob

The ports are huge. Inlet & outlet (or vent) are 1". Drain at the bottom is 1/2", and the in-line check valve is also 1/2".

I guess perception is everything! I actually thought it was cheap in comparison to most catch-cans (Moroso, Canton, etc). Full disclosure: EFI Express is local to me, and I've met the owner a few times. He is good friends with a friend of mine. That said, I only found out that they carried the Provent 200 after I did some research and decided to buy one.

I went to EFI's shop and saw a few installs. Seems these are very popular with turbo Audi/VW cars, especially the TDIs.

FWIW, other places I've found sell the Provent for a lot more $$$$. I was prepared to spend about $100 before I found the item on EFI's website.

Here's another source:
http://www.cfpfilters.com/store/provent200.html

Here are the tech specs of the Provent 200 and a few other models in that lineup:
http://www.mann-hummel.com/group/upl...BCHACUaaBi.pdf

Main Provent 200 page on Mann-Hummel's site:
http://www.mann-hummel.com/company/i...=35&rec_no=192

Mann-Hummel is an OEM provider of air & liquid filtration systems, and they seem to have a specialty in crank case ventilation systems. I wouldn't be surprised if they make the BMW system posted above ^^^^.

Interesting the Mann-Hummel installation diagram shows the check valve on the return is only used for when the return is above the oil level. I think my return has that one covered. pretty much exaclty the type of system I was planning on installing. just hadnt worked out the details of the oil separator.

Bob

I don't see alot of track time and am not getting any blow by on the driver port into the intake. I am getting a little bit through the pcv and was going to tap the pcv port 3/8npt to -10an and route to atm.

I was planning on doing the same to driver side but am not sure if I can tap 3/8npt on that side it looks kinda small. What size are you all using to tap the valve cover?

I never see any issues until I take it to the track and flog the hell out of it on sticky tires with High G-loading. Then oil wants to come out every crank case ventilation orifice it can find fresh well working engine or not.

Bob

So, for my setup would I be ok to ditch the pcv and route only that side to a can VATM and leave the driver side the way it is?

I just don't want to keep blowing oil into the intake manifold. I removed it the other day to clean and paint and had alot of gunky oil build up.

Instead of a catch can, I plan to add scrubbers in the cam cover:
https://www.miataturbo.net/engine-performance-56/cam-cover-blowby-flow-crankcase-pressure-tiny-hole-modification-54742/

I also plan to enlrage the tiny 1/4" valve cover hole in the baffling, through which all the blowby gases are forced to flow.

Been there done that. Works fine on the street. Full cornering grip on a winged car and full throttle track abuse and it still doesn’t work. Turn 5 and I think 6 specifically up the hill at Laguna loads up oil in the right back corner of the head I think and spooges it into the baffle a heavy amount.

Bob

I didn't really think that setup would be good enough for you.

I will say it looks like the VVT cam cover looks as though it is set up a little better. I’m using a 94-97 valve cover on a 99 head and the opening for the baffle in the cover is further in the back corner and it is just above the raised hole in the head to the lower portion of the block designed as the main path for blow by gas to get from the lower to the upper crank case. My theory is in a hard right left turn with a lot of acceleration the oil in the top of the head all goes to that corner and blowby gas ends up pushing liquid oil into the baffle rather than just vaporized oil particles.

Bob

So for AN fitting attachments, what sizing is the best.. -10 or -8. I imagine that the holes in the cover aren`t even close to the size of -10.

drill it out.
your going to move the same volume of air... do you want high or low velocity to move that volume?


go -12 if you CAN.

I used -8 for the valve cover -10 for everything els. total guess on my part.

Bob

I bored my breather out to 1/4" NPT, and used 1/2" hose:
https://www.miataturbo.net/showpost....3&postcount=20

-8 is 1/2" hose. 1/4" NPT has a smaller hole in it than my -8 AN weld bungs though I believe.

Bob

I measured the i.d. of my fittings, and they were about 0.38" ~ 0.40". Ditto for typical 1/2" barbs. The enlarged hole inside my valve cover is 0.40".

Where is that $150 "racing" catch can system?
I can't find the post for the life of me......

Ahh bbundy posted it in another thread:
http://www.mann-hummel.com/industria...BVFLGOcGNM.pdf

THIS is what my car has (hopefully) and not a bad engine.
Now I only need to fix it's 2nd issue too: 6500rpm flat spot.

Btw venting to exhaust is working great

But

Despite no smoke clouds you will get a greasey rear bumper after a month or so.

Mine was sucking oil out the catch can and making huge clouds of smoke the first time I tried it on the track. A combination of some on off throttle, high G left turn, with hard acceleration off a left hand corner puked lots of liquid oil into the catch can faster than it would drain back.

Solution: eliminated the vent on the intake side that was the stock PCV port and problem dissapeard. I’m just using the valve cover vent that comes out on the exhaust side which is baffled to the center of the valve cover. I also have a vent hose going into the side of the block by the alternator same location as some 1.6l blocks have a capped off port. I also found a PCV valve that fit perfectly to work as a check valve in my return hose to the very bottom of the pan.

What I learned is the baffleing for the PCV port in the valve cover dosn't work. oil must pool up in the back right corner of the valve train where the stock baffling has its inlet on that side.

Bob

so basically the catch can is not necessary? I'm still a little unclear on how you have the return line. basically just a line with a check valve between alternator port on the block and a port you made in the pan?

yup you vent the alt4ernator VTA

and

the catch can to the power steering pump

Quick stupid question. I'm still out of a job and I need to fix my blow-by issues, can I get away with blocking off the IM port and placing a filter on the hole in the intake side of the valve cover?

I doubt it. When I ran with the intake side blocked I was puking out oil from the driver side. You should just vent both sides to a catch can like setup.

Or just put a filter on both sides

Yea that's what I meant. Block port in IM and have filters on both valve cover holes. I currently have only one hole with a filter and the other with the stock pcv system.

I thought most people capped the passenger side and run the driver side to a catch can.

Some people do and it works decently, when I ran like that I was puking out 7 ounces of oil every 100 miles or so.

I am currently waiting on my next VC to get finished. I am putting 3 -10an bungs on it and am planning on running them to 2 separate catch cans. I will post pictures as soon as I get it back from the shop who is doing the welding.

In for results

I saw a car the other day at the track that had the valve cover lines go to a re-purposed canister previously used for the AC, so that the oil had a place to go when pulling g's. the canister would drain the oil back to the oil pan. a linethen connected to a catch can for the vapors. the canisters are almost free at a parts yard so this might be a good, cheaper option instead of running two catch cans. the car was an extremely well developed audi 5cly with a very large turbo.

$50 BMW M5 separator sliced open:

https://www.miataturbo.net/attachmen...ine=1340121952

How cyclone separators work:
https://www.miataturbo.net/attachmen...ine=1340121952

From briefly driving the car around it seemed to have worked. If you check my build thread you can see finished pictures. Unfortunately I no longer have oil pressure so that I can not actually get some time on the setup currently.

interesting. seems like a good simple solution.

I recently tried to modify a $10 ebay catch can to make it work properly but I ran out of time and had some issues making my copied design work so I decided to buy a new one from a local speed shop with built in baffles to get the job done. I'm thinking about modifying it to delete the air filter and feeding the intake line pressure but I'm not sure if this is worthwhile. thoughts?

Hi bob, just to clarify, you haven't got a line going from the inlet manifold to the valve cover - you've just capped both?

I'm guessing the vent line from the block and exhaust side valve cover both go to a catch can which is vented to atmosphere?

Cheers

Bring this thread back as I'm in the process of building my motor now. It has been discussed about how to vent the gasses from the block under boost. I was looking at the vent hole that is raised and located at the back on the passenger side. It appears that port and the one ahead of it connect together along the side of the block right where the BP lettering is and then goes down to a very large casting hole, you can see it when you look inside the block. Has anybody drilled a block vent hole there? It's high enough in the block that G-forces on the oil wouldn't be a factor there. 3/8" NPT with a 90 pointing up would ensure any stray oil would drain back. Has anybody else thought of this? Downside?

https://www.miataturbo.net/attachmen...ine=1351734671
https://www.miataturbo.net/attachmen...ine=1351734671
https://www.miataturbo.net/attachmen...ine=1351734671
https://www.miataturbo.net/attachmen...ine=1351734671

So on the track at what WHP level and boost/turbo size is everyone seeing these issue's? 250whp? 300? 350? Im not going for crazy power on my build, 250 to 275whp tops. Im just not trying to over build with some over the top case breather, pan return,... setup. Also its a fresh 84mm 9:1 2554 for now later either 2860 or 2871. Also yes track use with the sticky shoe's!

I'm at 260rwhp or something and do need the catch can

Just VTA your breather and drill out and VTA your PCV. Done

This blow-by is probably normal with forged pistons and cold engine, right?


I don't know what they are putting to E85 bioethanol here. That 0.5 liters in catch can is how much I get in there in one week. It’s some kind of alcohol / water / oil mix. It burns with blue flame

How do you have the lines to your catch can run? Are they stock sized lines?

No. 12mm ID both sides of the valve cover

Could you running a little too rich? Unburnt fuel in the crankcase? Stuck Injector?

AFR's are in 12:1 range. Although it’s an E85 AFR so I’m using it a lot. My 800cc injectors run close 90% DC

As I’m not the only one my area who has to empty catch-can once a week I'm sure it has to do something with the special blend E85 that we use here (a.k.a. RE85). More info here: In English - St1's Sustainable Bioethanol

Ok, I've searched n00b search! (I even like searching.) But here's a question.

I'm getting what seems to be boost leaking through the PCV, pressurizing the crankcase and then oil leaks out from all over the place on the block. Only happens on track - I don't WOT on the street (scared of civilians).

I had reduced this a lot before with a 323GTX PCV but now it's back. New wastegate actuator is at 8 psi or so, I think the old one maybe was a tick lower.

I'm tired of this and just want it to go away. I'm planning to plumb in a proper check valve (I'll leave the PCV in there to make the car look as CA compliant as possible in case of any roadside inspections). Also doing a catch can, but was planning closed loop on that rather than vent through a breather (but I'll do that if I can't fix this crankcase pressure otherwise).

Question is... exactly what kind of check valve should I get and where do I get it?