Turbo m20 oil consumption issue

[cleanasse30]

So I did a quick search and found this thread for anyone interested in using a 2.7L ETA bottom end:
http://www.mye28.com/viewtopic.php?p=1141375

Turns out the ETA oiling rings can't keep up in the higher RPMs resulting in the oil burning during decel (high vacuum conditions). So I guess its either live with the oil burning, swap in my 225k mile 2.5L engine or rebuild one of them.

[digger]

not that familiar with what guys do with crank vents on turbos but what size lines are you using out of the VC? i used to have an oil control problem with oil making its way back up the intake runners and blowing a little smoke can see it at night in headlights of a car following. i theorize that since i had a ghetto system which reduced down shitloads in diameter like to 1/4" (yeah i know the VC hole is like 5/8" lol) , that under load the crank case was being pressurized. since fixing this the intake is perfectly clean so far.

[ahrensNW]

Curious to see how this will get resolved.

[cleanasse30]

So..... Autox-ed the e30 for the first time with the turbo in the rain lol. Basically had no traction once the turbo spooled but the car is fast as hell when it hooks.

Aside from that, I did notice that the car is STILL shitting oil smoke during decel above 4-5k rpm... I heard from another member that the ETA piston rings are "low drag" or something and have been known to cause oil burning in high rpm turbo m20s. Has anyone heard that before?

I think my next plan of action is a leak down test. Ugh

[cleanasse30]

I figured out that I was running 5W-30 oil instead of 20W-50 as the owners manual recommends. I'm 99% sure the oil burn issue has been solved with the catch can, check valves and heavier weight oil.

DON'T RUN 5W-30 IN YOUR M20!!!!

[cleanasse30]

Welp just got done driving it to work. I think the check valves helped, but it still poops oil smoke during decel in the higher rpms... Not as much as before, but definitely pooping oil smoke. I'm lost at this point. Don't know where to go from here...

HELP!?!?

[cleanasse30]

So I ordered the boomba check valves and just finished installing them. As far as I can tell, its fixed and runs great! :) After a pull in the tunnels and watching to see if it dumped oil smoke during decel like it did before the install, the exhaust looks clean. I'm going to drive it to work tomorrow to to check the exhaust in daylight to double check.

[cleanasse30]

So I just got back from my road trip last night. The engine still burns a considerable amount of oil, but from what my friends tell me when driving behind me it doesn't burn oil under boost. This got me thinking that maybe the m20 needs a constant vacuum source on the crank case. So I came up with an idea to achieve that by modifying my current oil catch can setup.

Here is a crude diagram:


Boomba Racing makes a 3/8" barb check valve which are the boxes inline in the diagram. This would allow the intake manifold to pull vacuum during cruising and decel, just like the stock system. When making boost, the valve inline to the manifold closes and the valve inline to the turbo inlet opens pulling vacuum during acceleration.

What do you think about this design? Mostly looking for a sanity check before I drop $70 on check valves.

[ak-]

Oh okay. If it's 20inhg with a steady idle, you have a "healthy engine" by the standards mentioned.

[cleanasse30]

Well I have the econoboost gauge by justrack and it says psi on the gauge. Idk if the vacuum readings are also in psi, or inhg since vacuum isn't labeled. It may be about 20inhg if vacuum is in fact inhg on the gauge

[ak-]

40 inhg? :shock: How high of an altitude do you live?
Actually no, are you sure it's 40 lol?

[cleanasse30]

I'm assuming you have a boost gauge, what's the vacuum at idle..?

It's at about 40 inhg at idle.

They may not of used the little condom for the valve stem before installing the seals and cut a seal, was it a reputable place?

It was rebuilt by someone who has done work for pro3 teams and has lots of experience with m20s, but I've heard from someone who used him recently that his work has been less than spectular lately. So I'm not sure. My next guess is to get the catch can to pull vaccum constantly, I think I've figured or how to do that. If I can find all the materials to make it, I'll give it a shot while I'm on the roadtrip

[Good & Tight]

I'm assuming you have a boost gauge, what's the vacuum at idle..?

[whodwho]

They may not of used the little condom for the valve stem before installing the seals and cut a seal, was it a reputable place?

[cleanasse30]

So it seems that it only burns oil now during decel after a hard pull. Starting to think the valve seals are blown, although I thought they were replaced when the head was rebuilt...