I'll give a dollar (euro) to anyone that could honestly say that's what you were getting at, based on what you wrote. It was all about the filler neck, which is the subject of this thread. Most would be interested in reducing oil flow to the catch can, and the spare turbo vent will do it/has done it.

You stated it would not work. I think it will ... no big deal, but the turbo return line is a separate issue, and was not what you were talking about.

 

Kevin, I think rex uk was implying that the same principal/theory applies to both cases. Since the open filler vent still allows G forces to push oil up the turbo drain and block them, then the open vent you suggest on the unused drain would stillo allow for oil to be pushed up the filler neck. If one then the other kind of thinking. The only problem with this is that most turbos drains can be blocked off real easily since they are much lower. Once they are blocked off, even if it is only at the pan, you will restrict flow for the drain and cause a back up which could end in turbo smoke. This is a lot different then a situation where the left hander would push oil all the way up a vent as to overflow as is the case with the filler neck on right handers.

My 2 pennies

 

Yes MFilipello i think you have got the jist of what i was trying to say.Kevink2 yes i said the turbo drain vent wouldn't work i meant it wasn't an ultimate solution to the problem .This you can see when i said it would help but would still be overcome at some point.I think what MFilipello said sums it up and Gene is living proof of this.If it fails to work at some point then it hasn't really worked, again 'ultimately'.
This is why i pointed at the dry sump set-up.This would work ultimately because it would keep the sump in a vacuum mode scavenging all the oil leaving none for blocking up the vent path(s) and no starvation or aeration,the be all and end all of the problem albeit at a cost.I wouldn't have pointed to this if there was anything else that i thought would cure the problem outright.
AS said before this is my opinion only, as i haven't done any tests to bring anything concrete.

 

The turbo vent is a great, practical, simple solution to unwanted case pressurization. Vapor pressure is the root cause of excessive oil ejection into catch cans, not the fact that oil rises up the fill tube part way during hard rights ... that is not a problem! This is a very simple solution for single turbo FD's that chuck up oil.

I brought up the point of oil over the turbo oil drains during long lefts. This is not a show stopper, as long as the case is still vented, which it is, especially if you put a big elbo in the filler cap and use 10mm+ vent lines. High mounted singles help minimize this minor issue.

IF you have excessive rotor seal leaks, then you need big vent lines.

IF you have a BB turbo, it may not be set up for 100+ psi oil pressure. Ball Bearings require litteraly drops of oil at turbine speeds, and any more will churn it and fling excessive amonuts at the seals. Even with a properly vented case, letting off after a hard pull will create a temporary vacuum at the turbine wheel, which will tend to pull any excess oil from the seal area and smoke it in the turbine housing.

Knowing full venting is possible, vacuum pumps (if possible at 8K) and dry sumps are extreme fixes for BB turbo installations that are not properly oiled. They are also for anyone that can't stand to see an occasional puff of smoke after track hard lefts.

 

I did the extra crankcase vent via the oil drain. I will let everyone know how it works out after tomorrow. Big night out this Sat. Hope it gets colder. My preliminary observations after a drive around the block is that I now have regular colored oil(like whats in the pan) in the new line. I will see how this pans out.

The way I set it up is as follows. I took the existing block off plate and drilled a 37/64 size hole in it. I then tapped it for a 3/8 npt fiiting. I used a 3/8 90 deg elbow and attached a 1/2 nipple on it. The nipple faces straight up when bolted in. I ran the line straight up to the back of the intake manifold and then it makes a 90 deg turn and runs along the back of the UIM. when it gets to the throttlebody it comes foward to where the line from my oil filler cap is. I have a 3 way there that picks up the 2 smaller lines(oil filler cap vent and new oil drain vent) and out puts them via a larger hose to the catch can. I have a filter on the other side of the can.

If this does not work I plan on running each hoese directly into the catch can and then drill a large hole in the top to put a larger vent.

My initial question is how is oil making it all the way up the oil drain vent and over to the catch can. That is a pretty steep climb and then some distance to the can?
I will do more work on it tomorrow.

Mike

 

I'm interested to see if this really works, the fact that it's already being pulled all the way up the line has me doubtful. Even if it isn't a complete solution and only helps to relieve the problem it would be beneficial for all of us folks that are having this problem. Please keep up updated!

 

Thats a good question. Many people I've talked to say thiers is mostly fuel but its just dark like oil. Then I read on a V8 website somewhere (now I cant find it) that as blow by vapor goes thru the crank case it gets dirty because the oil splashing around mixes a oil "mist' into the blowby. Then I thought maybe as the blowby vents into the catch can (still in a vapor form with a mist miced in) that it cools off and condensates into a dark liquid into the can.

Thats just about the only way I could come up with how a liquid could get into the can (for street cars). Now of course the problems with making long rights is obvious, but I'm really refering to people that have a street car and are just doing normal driving on the street and get dark junk in thier catch can.

Maybe some of you can come up with a better theory

 

well, for what its worth, the results are in. twice the vent- twice the oil in the catch can. After a total of 1 hr worth of driving, and no hard corners, I have a complete half of my greddy catch can full of brown stuff, and oil/gas/whatever under my hood from where it still blew out through the small filter on the catch can. I drove a half hour to get to dinner with some long hard pulls in 3rd and fourth, and a half hour home with some hard pulls in 1st,2nd, and 3rd. All of this was done in straight line. Like I said, when I got home and popped the hood, the catch can is half full already. This is from less than 20 WOT pulls.

The lines where still full of vapor so I do not know where most of the stuff was coming from but I do not think this is a vent problem. I mean that I do not think that my results have a bearing on whether the extra vent is a good idea or not. I think it means that I have bigger problems to adress.

if some one else does this please post your results.

mike

 

ok, thinking out loud here so I don't want people to get too worked up, but if crankcase pressure can cause oil to seap by the turbine seals on these bb turbos, then why not a situation where exhaust pressure while under boost causes exhaust gas/pressure to enter the bearing housing thus pressurizing the crank case. Someone while back said to carl, " what does blowby have to do with the turbo". At first this sems true. But what if Carls thinking is actually close to reality. I do not know this to be the case but If I can blow air into my crankcase, and hear it coming out the down pipe, then why not exhaust in the downpipe getting into the bearing section and thus building pressure in the case.

My situation is either this or bad side seals which I know that I have one seal on the front rotor which is a little low but within Mazda Specs, less that 1.5 off.

please help, this has to stop.

 

It could well be a bad turbine seal. The rear turbo vent mod assumes each vent path, by itself, is adequate. Under hard strait acc'n the rear turbo case opening could be covered with sump oil .... if the filler vent is too small for your amount of blowby, it will blow clean oil up the back vent.

Try some high rpm low boost runs ... if oil still fills the can, more likely side seals. But it really seems like you have a rotor seal or turbo seal problem.

Keep in mind the stock vent, adeqate for modest power increases, is just a single 3/16" port on the filler neck when under boost, as the pcv is closed under boost. BTW, sure you are not pressurizing the case through a bad pcv????

This is my data point: track FD running 18 psi on a gt35 or 40: his pm:

"Hi, sorry for the delay.
The new "old turbo" vent line worked GREAT!.
Only about 1 inch of oil in the catch can (Jaz 1 quart catch can)
The track was not the usual one though (I forgot to mention this before) but I feel that the problem has been corrected and/or greatly improved....."

 

Yea, it sounds like you have larger issues.

What is you entire setup? What turbine side? What exhaust? The back pressure sounds like an interesting idea but I've never heard of it before (doesnt mean it cant happen though).

How does your car idle and run? What type of port job? Whats your entire setup?

 

Ok, more results. I took the car out yesterday for an hour and a half drive. During this time I hit some twistys and some long straights. I am running 1 bar of boost. I really got on it in the corners and the long straights. Hard braking and accel on the curvy stuff. wot in the straights. It didn't smoke at all until I was near my shop. This was at the end of the play session. I was playing with a new E55 and after getting on it hard in 2nd and 3rd, it smoked bad when I let off. Pretty embarrising to be honest.

Anyway, when I got back and popped the hood, the can was 70% full. This is the new style greddy polished can. It holds more than a quart I believe. When I started the day, I was a half quart low on the dipstick. When I returned I was 1 quart low. I lost a whole quart of oil in 2 days(2 1/2 hours of driving). Not all this time was spent boosting of course, probably only 1/2 hour or less. The rest is just drive/fill time due to traffic and such. The reason it smoked is by the time the can got that full, the little breather/filter on top was soaked in oil and restricted the flow of air. This lead to a build up in the crankcase and the dreaded smoke screen.

also of note, when I lifted throttle after the hard pull with the e55 and started smoking, i could make it immediately quit smoking if I lightly got back on the gas. This points to turbine seal blowby. I have been reading Carl's new threads and agree that we have too much oil pressure in our cars for these turbos to cope with. This makes these dbb turbos more succeptable to smoking. My problem is to find out why I have excessive oil spill over. I am going to try and put a boost gauge on the crankcase with all the vents sealed and see what I get for presure.

stephen, my mods are as follows:

street ported motor with 2mm RA seals and oil pressure mod
ported and polished upper and lower intake manifold
gt40r .96 a/r/ turbosmart 48mm waste gate/avc r solenoid
greddy type R BOV
greddy old style front mount
TB coolant removal, double butterfly removal, AWS disabled, PCV removed
3" full exhaust/ resonated mid pipe/ PFS cat back
Greddy underdrive altenator and water pump pulley
775 pri/1200 sec upgraded fuel pump
pfc/commander/datalogit/wideband
ngk 9's and 10's/magnecor 10mm wires
pwr radiator/evans coolant/0 psi system with no ast
Rotary Aviation OMP bypass adapter running 2 cycle oil

crankcase vents at filler neck and rear oil drain and greddy catch can

car starts, idles, and runs fine. other than this catchcan issue, one would think the car was perfect. this is what puzzles me. nohard starts hot or cold. pull hard, and idles smooth at 800 rpm. vacuum was low, 12in. need to retest this also.

hope this helps

 

don't close the vents, but get a low pressure gauge (dwyer)... 50 inches h20.

 

I think he wanted to close off all the vents to see how much pressure its actually making. Then open them back up after he finds out. I think that would be a pretty good idea to see what we're really dealing with and how much pressure is really being built up. I was planning on doing something similar when I get my car up and running.

You are right about how oil pressure can make the turbo smoke but I dont think thats your problem. That would make oil get by the turbo seals and into the exhaust where it would burn. I dont see how it would cause oil to build up in your catch can. Now, if you can get your oil pan into vacuum that will help the oil flow faster out of the turbo which will lower the pressure on the other side of the turbo. Your oil pressure at the turbo feed more than likely isnt near as high as your engine oil pressurd reading on your gauge. I think if anyone has a gauge that will work it would be a good idea to put a gauge there and test it to see how high its getting.

 

Kevin, please explain how to setup this test and what is a dwyer gauge. where would it go. I have to be able to see it while driving.

 

http://www.hvactool.com/catalog.php3...essure%20gauge

$59

search dwyer differential for better pics, etc.

hose the high pressure port to the xtra filler neck nipple. get passenger to read gage. guess case pressure must be at least 12-15" h20 to push oil up that rear vent. nice gage for checking pressure drop in intake, or between turbo and tb.

12" vac sounds low for street port, time for compr check, if not recently done. only quick short term fix for very excessive case pressurization is a 1/2" copper pipe elbo in the cap, to a 1/2" id fittiing into catch can, and big port to breather. similar separate line from the back turbo hole to catch can.

 

well the motor is out.....again

I will post what went wrong when we tear it down. The turbo is going out for inspection just to be on the safe side. I highly doubt they will find anything wrong with it, but you never know. Only 2500 miles on both motor and turbo. The blow by is getting worse.

Ls1 looking pretty good right about now. No **** from you Dewain, I know your reading this. I'm sure I'll here about it

 

After conversations directly with Garrett and indirectly through Diesel Performance, a local Garrett shop, I believe that there are inter-related contributing factors.

1) Oil slosh / overflow / "you better run a 1/2 quart low during track day"
All Rx-7s can pretty much show this behavior, with the right abuse/driving and oil levels.
Demonstrated behavior. Accepted fact.

2) GT40r are internally restricted, but with the greater pressures seen on our cars, we need to bring the pressure down at the CHRA. 12-30psi, idle to max is what I am told. Anything more than that, you could have issues. This is directly supported by Garrett.

3) The oil drain hose serves to drain oil, but also to vent. Too small, you'll get a have immediate smoking out the exhaust from oil backing up. Not large enough, you might have issues with crankcase ventilation.
My theory. Based on personal experience.

4) High boost (+20psi) exacerbates the problems.
Demonstrated behavior.

Assumptions are that nothing is wrong with my engine or turbo. After replacing my compressor wheel, I know my turbo passed inspection.



I run a Pineapple engine with all the oil mods and a large custom port.
I have the first GT40r kit. ATP's advice last winter was to restrict the flow. I followed Sean's direction and did not restrict.

I had smoking problems, letting off after a hard pull. Partially blocked oil drain hose (rubber bubbled internally) was the issue. I upgraded the rubber hoses with braided hose, -10 for the drain. Black smoke screen out the exhaust gone.

Once I had the engine ready for boost, I had the catch-can-filling-really-quickly issue. While I still fill it quicker at 20psi than at 18psi, I did manage to reduce it from daily drains to weekly checking. I went with a bigger oil drain fittings...to a minimum fitting orifice of 1/2" between the CHRA and the oil pan, and -12 hose. I have traction problems now, catch can draining is manageable.

I have installed the ATP restrictor. I monitor oil pressure. With some fancy T fittings I have moved the pressure gauge to read off the oil supply line for the turbo, pre restrictor. I’ll test post-restrictor too. Weather does not permit testing at this time.

Regards,

Tony
aka Badog

 

Ok, upon a preliminary inspection of the short block, this is what I noticed. I am going to start a new thread but figured I would put this here as well.

with the motor still together and the intake manifolds removed, I noticed the following. Looking in through the secondary intake port on the front rotor, I can see the outer oil control ring pass onto the inner edge of the port opening. It does not pass completely over to where it opens on the other side but about half way. I mean that the thickness of the oil ring is half exposed as it passes over the port. As you keep turning the motor by hand, it receeds back to where it disappears .

I know that I had a low compression reading on one of the front rotor faces after rebuild. This would indicate a side seal and would only be problematic under the combustion stroke. This is where the apex and side seals completely seal all 4 corners of the rotor face for the combustion process. If a side seal is weak or not up to par, then combustion would make it to the outer oil ring.

After the combustion and exhaust stroke, the rotor is coming up to the intake port. The side seals actually pass over the intake port as the rotor opens the port for the intake stroke. It is at this point that I can see the side of the rotor face and the outer half of the outer oil control ring. If this is too much encroachment, then Boost pressure in the intake manifold is pushing past the oil control ring and presurrising the crankcase. I would be getting fresh air in the crank case. This does seem to make sense as it does it more as boost gets higher.

I am unsure how much combustion pressures rise for each pound of boost, but I would imagine that it wouldn't be much different for 10 lbs vs 15 lbs. on the other hand 10 lbs vs 15 lbs directly on the oil ring might be the difference between blowby and no blowby.

Any input on port clearance would be helpful.

Mike

 

Any new data?

 

No pics yet.. well here is the contents of my catch can after 4-5 mo.(I let it settle for clarity) This mostly accumulated in the last few weeks when I was testing different lag times. When I first rebuilt my engine it would be this much every month for bout 3 months then only got this full every 6 mo or so. btw I went back to my original lag settings :}

 

Oh yeah when I threw a match in there it barely caught fire then all the fumes burnt off and went out ;>

It always filled up faster after autoX

 

Dam is that fuel or water? What ever it is its alot...!!

 

oil and water w/ little fuel

 

wow I really didn't think that much water accumulated. Seems very beneficial to run a catch can. Red 7 you are running a single set up correct? Vented catch can?