8 months back I performed the PCV delete and a catch can. Everything seemed good although I seemed to be using more oil. I then installed a turbo back catless exhaust a few months later. Shortly after installing the exhaust I started noticing that when the car was at idle for more than 20 seconds or so blue smoke (oil smoke) would come from the tail pipe, just a bit at first but after 45 seconds or so I had a nice cloud coming from my car. It never ran different just smoke. I then started looking up possible causes for this. I found that the turbo shaft seals on these and all cars are only designed for holding air pressure out of the oil passage not oil in the turbo so to speak. The turbo oil feed and exit are sealed in the crank case. If there is any pressure in the crank case exceeding the pressure in the exhaust or compressor side oil will leak. I then reinstalled the PCV tube on the intake side with a catch can on both. The smoke in the exhaust was gone completely and oil consumption went back to where it was before the PCV delete. It appeared that the CAT converter was stripping/burning off the extra oil thus no smoke. I know the idea of eliminating the PCV (oil in the intake) sounds like a good idea but I think it is causing more problems long term to other parts. My theory is that the PCV valves in the cover have a cracking pressure of .5 PSI according to the bently manual which would be higher pressure than the pressure in the exhaust/intake creating a leak.

Below is a link to where I obtained my limited turbo knowledge. It was a very good read and left me with a lot better understanding of turbos. I also would note that there was a significant amount of oil residue in the compressor side with the PCV delete that all but went away when I reinstalled the intake PCV tube. Keep in mind that when the PCV is hooked up as manufactured the crank case is held between -8 psi to -10 psi below ambient. Just think of it this way... deleting the PCV has changed a vacuum of -10psi to pressure of +.5 psi. I also forgot to mention that when the engine was above idle I.E. while driving the smoke was gone.

http://www.procharge.com.au/turbotor...he-turbo-blues

I'm not sure if this is how I am supposed to display a link... sorry if its incorrect.
By the way this is my first post so go easy on my please.

 

I wonder if you have a faulty PCV valve. There should never be positive pressure in the crankcase, if the PCV valve is working properly.

I have the PCV line to the throttle body blocked off with a BSH dual boost tap, which has the same effect as a PCV hose delete.

The other PCV hose goes through a BSH oil catch can and to the turbocharger intake. My oil catch can collects some oil, though very slowly, mostly it collects water, when the weather is cold.

My with this set up, my MINI uses little oil, if any. I change the oil at about 5000 mile intervals and don't have to add oil in that time.

Unfortunately, the PCV valve on a MINI is integral with the head cover, so it is not cheap to change out ($285.34), but it might be worth it to you to swap it out and see if that fixes the problem.

Dave

 

Interesting. I don't have the blue smoke but, I do have higher oil consumption. A lot higher oil consumption. I might be putting back my PCV line and gett another can.

 

I only see one flaw in your explanation. The oil in the turbo lines is under pressure at "ALL" times when the engine is running. Somewhere around 40 PSI minimum i believe. And changing the pressure in the oil pan/crank case from -10psi to +.5PSI should really not make any difference in the oil pressure running to the turbo oil lines.

Also of note is that the bearings in the turbo that are fed by oil would have to take as much if not a lot more pressure than what the oil pump will put out maximum.

The oil pressure in the lines will be well over the pressure generated by the turbo so by your explanation the oil would always be passing thru the bearing seals. And I am pretty sure that it would not be designed to do that.

Now as to the pressure in the oil pan/crank case not being a vacuum and actually being a positive pressure may be causing bypass on other parts such as piston rings or other parts but I would have to look into that in more detail as to what could be by passed by oil.

now of course i could be totally wrong on all my thoughts here but oil being pushed out of the turbo bearing seals because the crankcase is under a slight bit of pressure is highly suspect in my eyes.

 

schatzy62,
Please read the info in the link I attached. It is lengthy but jam packed with useful info. According to the info in the document there is only oil pressure on the oil inlet side of the bearings, after the bearings it is a gravity drain back to the crankcase. If there is any abnormal pressure on the oil exit side (crank case) the oil can seep out the piston ring seals on the turbo shaft and into the exhaust and intake tubes.

Parthos,
I had oil residue in the turbo inlet and in the hot side tube after the turbo. I had no smoke either when I had the stock exhaust installed. I didn't notice any smoke until I removed the converter.

DneprDave,
The first thing I did when I got the car was to install the updated valve cover as an attempt to get away with not using a catch tank and yes it was expensive. The manufacturer stating that the internal labyrinth is more affective is B.S. the actual valves on each side are different as they are more piston like V.S. flaps like the old one though. If I had known what I know now I wouldn't have wasted my money on the cover and gotten a good catch can. Here is the link to the catch can I installed by the way.
http://www.saikoumichi.com/Stage0_S2000.htm

 

Just my 2 cents' worth... back in the olden days, crankcases vented to the atmosphere through a breather cap or some such. The main reason they were vented in the first place was that combustion blow-by could pressurize the crankcase, the chief problem with that being that oil could then be forced past gaskets and seals by the pressure, and leak all over the place.

For example, on the MG forum I frequent, many complaints of excessive oil leakage are followed by replies that involve making sure the crankcase is breathing properly. Earlier MGs vented through catch cans with steel wool inside, later ones had a closed system with PCV valves. Whichever setup is used, any blockage of said system can make for a leaky engine.

I'm saying all of this just to mention that actually deleting the PCV system - that is, removing any sort of venting, or blocking hoses - is probably a bad idea, for the reasons mentioned above. I say that because I think I've seen it mentioned in some posts here. A catch can is fine, provided it doesn't vent to the outside, which is illegal. Crankcase vapors should be drawn through the can by intake vacuum and fed back to the engine.

Cheers,

Spridget

 

Firstly let me explain a little about the PCV, PCV is an acronym for Positive crankcase ventilation, inside the the cam cover there are a few entrapment passages and direction chambers, which do their best to separate the suspended oil particles from the passing vapour, this vapour is then vacuum drawn from the cam cover passageways through a valve flap, the first direction is through the rear PCV line into the intake manifold, next, when the vacuum draw from the turbo (building boost pressure) is greater than the vacuum draw of the induction stroke from the pistons, the rear PCV valve flap is closed, as is the diaphragm in the cam cover, this then changes the direction flow of the vapour, and the vapour is vacuum drawn through the passenger side PCV valve flap into the air intake flow pre-turbo, once off boost and steady throttle is resumed then the vapour is once again vacuum drawn through the rear PCV line.

Now the actual valve flaps themselves are merely free falling self closing rubber diaphragms, there is no spring or piston actuation on either valve flap, however there is a sprung chamber diaphragm, which opens/closes under the vacuum draw from both the inlet manifold and turbo vacuum draw, this dictates the flow direction, and in the later re-designed cam cover allows excess pressure to vent through the inbuilt pressure release sprung valve.

 

czar,
First of all let me say that of my time lurking on this forum I have enjoyed reading your posts more than any other for the wealth of information I have gained from them. Thank you. Back to topic... Yes as I have a 2007 MCS I had the flap type design and replaced it with the piston type gravity closing valves thinking that this would help keep the oil vapor from exiting the crankcase. I also noticed that they have no actual springs although the Bentley manual says they do. For what its worth they also say that it takes 30mbar (.435 psi) to open. I know that PCV stood for positive crankcase pressure but the Bentley book calls it a "Pressure Control Valve" which makes more sense for the function these valves serve.

 

I wanted to throw something else in there for those who have installed catch cans on the turbo inlet side. There is a heating element installed between the inlet tube and the valve cover if you have noticed this is where the two wire plug goes. I found out the hard way this is a very much needed part if you live in an area of the world that has ambient temps around freezing or below. This element is installed to prevent the PCV valve from freezing shut. There is a TSB on this part. It must be installed close enough to the valve cover to be effective. I had the PCV valve blocked on the intake side and a catch can on the turbo inlet side and the heating element in the original position. I live in central Indiana U.S. and although we had a mild winter we did have a -13 degrees Celsius morning and the functioning PCV froze shut. I had to pull over and break it loose with a hex wrench. I have since moved it up next to the valve cover. I had no further Issues but I don't think we had another day cold enough to verify my fix was effective.

 

HaHa! I just realized I didn't spell ISSUES correctly in the title. oops.

 

Thanks for sharing you experience. I'm curious if any folks have measured their crankcase pressure with the BSH boost tap installed with the plug out and blocked after the tap. This could help explain the actual behavior of the turbo inlet side PCV port's ability to scavenge the crankcase through a catch can. Maybe the additional restriction of a catch can, once its started to foul with oil, plus longish plumbing runs, is too much resistance for the marginal vacuum signal that exists pre-tubo inlet to work effectively at idle.

 

That's a great Idea, I may machine up an adapter to place into the dipstick hole with a hose barb to connect to my boost gauge to get an Idea of internal pressure/vacuum. Keep in mind these are all just my experiences and I am in no way an expert on all things mechanical. My hope is that these shared experiences help others out.

 

I did the pcv delete, bg44k induction cleaning, got the dos seafoam fogger and will clean out intake every oil change. Car runs a lot quieter and after 3000k miles have not used any oil. It's amazing. I have confidence this will also help those people that don't do frequent oil changes save their timing chains.

 

.......this forum has been great. I think it really helps those people that have been given the business by bmw/mini.

 

How funny I ran into this today.

I had run my '09 MCS last year with a PCV delete plug on the front of the valve cover and just ran the breather tube to the turbo inlet. This winter I put the PCV line back in because of oil consumption and very high amounts of smoke during extended idle. I tested it out by idling the car and the issue is gone.

I have the Bentley manual that shows the PCV valve strategy (there are actually two in the system) but I don't remember it like the back of my hand yet. Under load the PCV valve for the hose going to the intake manifold is totally shut so boost pressure can't enter the crankcase and the breather pipe valve (near the turbo inlet) is totally open to suck crankcase vapor out and send it through the turbo inlet. The way the system operates is a little different at idle and partial load. I will look it up tonight.

I know Peugeot are the ones that initially released the PCV line delete plug but now that I've seen the system can't operate correctly with one breather tube I'll just stay with the factory setup. I don't want to worry about being a smoke machine whenever I'm sitting at idle Tinted windows and racing stripes already attract enough attention.

 

I think there may be something else going on besides just going back to the stock PCV configuration that reduced oil consumption and smoke.

I have the BSH dual boost port, which blocks off the PCV line to the intake manifold like the Peugeot delete plug does. As well as a BSH Catch can on the PCV line to the turbocharger.
I installed these just after buying my MINI.

In the nearly three years of having this set up, my MINI has used no oil, other than 1/2 a quart when the engine was breaking in. I have not had any smoke either. I check my oil level and the level in the oil catch can weekly.

Like I said, there must be something else going on, if just putting the PCV line from the cam cover to the intake back solved your oil consumption problem.

Dave

 

For what it's worth, I had similar issues this past week.

I blocked off the intake manifold to valve cover port on both ends, and installed a catch can on the intake side that was re-routed to the turbo inlet. It was fine for normal driving. I frequently auto-x and go on "spiritied" drives on the weekends, and today I noticed smoking problems after hard runs at low load, as well as a wet valve cover.

To fix the issues I uncapped the port on the passenger side of the valve cover and vented it using a hose leading to the bottom of the car until I can add a port to my existing catch can. After another hard drive I haven't had any more leaks or smoking issues.

 

I too have a BSH OCC and PCV delete via a BSH dual port block. I installed it after a walnut blast and where I was using about a quart every 3k miles I no longer use any oil as its been 3k since installation.

Don't know why people are having issues but clearly something else is going on.

 

Hi guys, it's me, MNIPWR. I just thought I would drop in and give you some info. I have the PVC delete and I saw it mentioned that blocking the PVC port could starve the pistons from oil. This is false. I have seen my piston rings and cylinder walls and they are in great shape. As for the valve cover causing enough pressure to force oil past the seals and it leaking into the exhaust or intake side of the turbo, is also highly unlikely. If so, exhaust or compressed air could pass into the oil line. As we know, those both have pressure.

It seems like crank case and valve cover are being thrown around interchangeably, when they are very different parts.

In all seriousness, if you had the ability you could make a new valve cover with no diaphragm and put a draft tube on it. All these PVC systems are just things to prevent pollution.

 

Yes, they are different parts, but the space beneath the head cover is connected to the crank case, by some generously sized passages, it is how oil drains from the top of the head to the crankcase. These areas are under the same pressure, caused by blow-by past the rings.

Dave

 

There are passages for oil to drain back down. Are you saying these are the same passages used to vent crank case pressure? I would hope our engines have another vent for crank case vapor. As long as that vapor has a way to escape to the atmosphere all should be good.

 

Escaping to the atmosphere is exactly why they made a PCV. It is there to prevent all the blow by gases ending up all over the road causing environmental damage.

 

Yes, they do a dual duty of providing a path for oil from the cam bearings and such to drain back to the crankcase. They also provide a means for crankcase gasses to get to the PCV system in the head cover. It is not peculiar to our MINIs, most car engines are designed this way.

Dave

 

Like I said in my first post. The only real reason we have PVC is to prevent pollution.

Good to know. I wasn't sure positive how modern engines were designed. Old engines just had breather filters and draft tubes.

Now that we have this established. Can we go back to the PVC system. To reiterate my point that as long as there is a way for the pressure to escape it should be fine. If the passenger PVC port is open then where is the problem coming from?

Now I'm not trying to be rude. I am curious. I would just like to clear up some stuff up.

 

Before regulations started mandating pollution controls, cars had a draft tube. It was a pipe that extended from a space on the engine that was connected to the crankcase, often a tappet cover. It went down under the car into the area where air flows under the car. The movement of air across the end of the draft tube pulled crankcase vapors out of the engine.

Dave