Verify crankcase pressure relief function?

[Galway]

So, 4k miles after an engine rebuild and new turbo ( flow and return oil lines replaced on turbo also)
Part of previous fail included turbo passing oil and cracked piston.
Anyhow, just went to fit an oil- catcher between cam cover and air intake.
Found oil in turbo and an axial (in/out) play of approx 0.5mm. Not acceptable.
About 50ml fluid oil out of intercooler.
Going to methodically check all possible root causes such as oil flow rate to turbo etc.
I understand that if crank pressure is too high, it can reduce return oil flow from turbo?
My cam cover outlet (where I was going to fit catcher) pipe seems dry.
I would have expected some moist oil residue?
I am trying to get my head around how it works on this mk7 eur4?
Is it a pressure release or an internal valve of some sort?
Any guidance much appreciated.

[trnx]

Plenty of good info' on the net some animated re' engines.

[Galway]

Thanks for that.
Would you be able to take a few minutes out to post some, or even 1 link which details the mk7/eur4 crankpressure release system in terms of function, test, repair etc?

[metalworker0]

There are various cam covers for these engines, so things can get mixed up when replacing things E4 cam cover is different to E5 - that would mess the breathing up if you got this wrong.

50ml .. is about 3 table spoons full

other things

Fuel injector sealing washers could be the main culprit here .. the fuel injectors are within the cam cover .. so they pressurise the engine crankcase when the washers fail .

How to tell
Start engine .. remove oil filler cap , and it will be chuffing out of it, if the washers have failed.

all the best.mark

[Galway]

Thanks mw.
I guess, irrelevant of quantity of oil found, I have significant axial play on turbo, compared to my understanding that an almost "zero" tolerance is acceptable?
Around the rocker cover, I was trying to understand how these ones function, as in, pressure release or non return valve or what, and how could I verify if functioning ok.
Boost parts all disassembled at present and turbo cartridge ordered.
Once restarted, I will evaluate for excessive chugging as per your advice.
Injectors fitting and reseating were carried out to the book, but I guess that doesn't guarantee anything.
Thanks again.

[metalworker0]

As i understand it, there is not supposed to be any float backwards and forwards of the turbo shaft .. but there will be a little play in the impeller up and down as it is plain bearings with oil film under pressure taking the space up as it self centres whilst spinning... other Turbos have ball bearings, where there is hardly any play in any direction.

all the best.mark

[Galway]

Thanks.
Any tips on verifying rocker cover pressure relief function without running engine?
At least I can pinpoint a correct replacement.
Unfortunately carcar.info doesn't seem to be able to call up my parts for last few days.

[metalworker0]

put a pipe on it and suck and blow
catcar based in Russia, i suppose that's why

all the best.mark

[Galway]

Thanks.
What results should I be expecting here? A 2 way flow or what?

[metalworker0]

Without owning one of these i cant tell you

Blowing and sucking .. if no restriction is felt .. result is: its not blocked.
Blowing and sucking .. if it sucks one way and does not suck the other .. maybe that's how it works - result: its working as it should be.
Which way it sucks blows and stops, what way/ direction - is not relevant, only that if it stops one way. (if that is how its supposed to function)

They look like they are sealed up to me ... and there is a round sort of disc shape in the plastic casting .. which i suppose is where the valve is .. if it has one. this may be removable - i don't know.

If it does not blow or suck .. then you need to spend sometime removing the cover , cleaning or replacing it

As usual, rather than type hundreds of words saying what i was going to say.. it's already pre-wriitten here:

https://www.google.com/search?q=rocker+ ... w+to+clean

all the best.mark

[trnx]

Verify crankcase pressure relief function? (How is crankcase pressure relieved?)

The function of the crankcase pressure relief system is to reduce the effect of crankcase explosions - on big diesels there are crankcase explosion doors on the crankcase access panels. The explosion doors when operated relieve pressure in the crankcase. The doors are operated by an explosion within the crankcase (pressure build up).
The small diesel in your van does not have such doors. The crankcase is ventilated to the air inlet system via the rocker box. Within the rocker box outlet there maybe an oil seperator. There is no need for a valve so there isn't one. The oil you found at the intercooler is there due to condensation of the atomised oil.

Info' re' how engines work is available on the internet some of which is animated.

Google search type in - how an engine works - the workings of an engine etc etc. Youtube has a search bar the same can be entered there.

Just in time. Made for life. Recent use of groups of words that have a meaning. Made for life does not mean forever. Just in time is used in manufacturing often means that the part or parts are not made in the assembly factory.

The turbo was likely made - just in time for fitting it. The turbo made for life - could mean several things - life of the engine - life the time the manfacturor of the vehicle has given for the usuable time of the vehicle. Things aren't made to last. The vehicle manufacturer expects the vehicle to be good for the 1st and second customer which could be 5 to 10 yrs.

The turbo is made to clearances and tolerances. What they are could depend on how long the thing is expected to last. Throw away - replace - don't fix it. The yanks filled canyons with stuff, chuck it buy new. The turbo - it's inards - The .5 mm 0.020" end float - does it matter?