Oil pressurising into throttle body

[Dynion Araf Uchaf]

I have just built a TU5 4J (106 GTI) engine for racing, it's essentially standard spec, cams, pistons etc all as per factory. At the weekend, my track time was curtailed as it was blowing oil out of the throttle body and over the engine bay. Additionally, the home made catch can was collecting 200 ml of oil in around 20 mins.

I have completed a compression test, (dry) all within 5 psi, 166, 170, 170, 171
I have done a leak down test, all less than 3%, with no 'air' coming from TB, head gasket, exhaust, dipstick. Usual air from the oil cap.




I am now of the opinion that is something to do with the breathing/breather. I have checked and cleaned the various pcv and other oil breath pipes. I can say that the vent to the TB, is venting more vapour with the aftermarket oil breather than without. So I have now removed that and fitted JP4 cam covers and a 'proper' catch can. This has two breathers ( 1 on each cover) and no direct vent to the TB. It runs, but difficult to tell if I've fixed it until I get on track.

before I waste another day at track, is there anything else I need to consider or have any ideas for me to run through.

before new cam cover

after new cam cover

Edited by Dynion Araf Uchaf on Saturday 4th November 20:06

Edited by Dynion Araf Uchaf on Saturday 4th November 20:08

[stevieturbo]

not following what you're saying or doing.

First image shows an alloy rocker cover, with a plastic breather shoved into the side of it and then into an open bottle. Not exactly pretty or professional...but I guess functional.
And also a pipe for I assume some sort of PCV from rocker cover to intake.

The second image shows some sort of plastic rocker cover, with some pipe fittings in the middle going nowhere. No real breather setup as such, and an open pipe now at the throttle ?
So any "breathing" if those are breathers in the valve cover will just get spewed all over the engine ?

Or am I missing something otherwise obvious ?

[Dynion Araf Uchaf]

Second pic the catch can and pipe work not fitted as currently making a bracket to mount the can properly but you can assume that there is a pipe from the rear rocker cover to the catch can, and the same for the front rocker cover

TB pcv that is now without the pipe work sucks not blows. Will need a bung on it as it’ll impact idle.

Edited by Dynion Araf Uchaf on Monday 6th November 10:05

[GreenV8S]

If it's blowing oil out then either you're getting oil pooling / splashing in the area of the crank case breather, or your oil separator isn't effective enough. You haven't shared any ionformation about whatever baffles or separators you have so we can't guess what the problem is, but if it's blowing out oil then there is clearly something wrong. This is separate from the issue of whether it has a sufficient crank case breather capacity. If it's a track car you probably don't want crank case gases contaminating your incoming charge in any case.

[Dynion Araf Uchaf]

GreenV8S said:

If it's blowing oil out then either you're getting oil pooling / splashing in the area of the crank case breather, or your oil separator isn't effective enough. You haven't shared any ionformation about whatever baffles or separators you have so we can't guess what the problem is, but if it's blowing out oil then there is clearly something wrong. This is separate from the issue of whether it has a sufficient crank case breather capacity. If it's a track car you probably don't want crank case gases contaminating your incoming charge in any case.

The baffle in the sump is a home made one by the looks of it (I didn’t make it, but have used it on race engines for 10 years) my first engine had a proper PTS baffle kit , but looking at the oil pressure gauge from on boards taken back then the gauge fluctuates almost exactly the same as you corner hard . So I never bothered to upgrade it.

The engine is standard, so whatever crank case breather capacity it has is as Peugeot intended. Lots of people race these engine in various states of tune, but I’d have thought that a standard engine revving only 250rpm higher than normal could take the track work.

The oil separator (catch can) was a bottle with hole put in it to put the oil pipe into. Clearly heath robinson, so maybe the later rocker covers and a proper catch can might sort this. Which is where I came in on this thread.

Other things I am thinking about is -oil fill level, can too much cause this ?
Did I over tighten the rocker covers alongside the use of the thermatec gaskets ?

Edited by Dynion Araf Uchaf on Sunday 5th November 09:38

[stevieturbo]

Dynion Araf Uchaf said:

The baffle in the sump is a home made one by the looks of it (I didn’t make it, but have used it on race engines for 10 years) my first engine had a proper PTS baffle kit , but looking at the oil pressure gauge from on boards taken back then the gauge fluctuates almost exactly the same as you corner hard . So I never bothered to upgrade it.

The engine is standard, so whatever crank case breather capacity it has is as Peugeot intended. Lots of people race these engine in various states of tune, but I’d have thought that a standard engine revving only 250rpm higher than normal could take the track work.

Other things I am thinking about is -oil fill level, can too much cause this ?
Did I over tighten the rocker covers alongside the use of the thermatec gaskets ?

baffle in the sump ???

Absolutely nothing whatsoever to do with crankcase breathers in your rocker covers.

We've still no idea what you're doing, or trying to do regarding crankcase breathing for this new cover, and whatever the change was supposed to achieve.

[DVandrews]

PCV systems work by drawing air through the crankcase to the inlet manifold where the fumes are consumed, any blow by or crankcase pressure ends up heading to the inlet manifold, the connection to the TB is where air filtered air is drawn in to purge the crankcase, this flow and circulation is driven by the manifold vacuum.

If you are using a catch tank then that circuit is compromised and the crankcase pressure/fumes will be vented wherever the course of least resistance is, in this case it seems the TB. If the PCV system is not being used as intended then I would block the circuit to the TB and improve the ventilation from the cam cover.

You might also want to consider making the PCV system work as intended, also check the connections, particularly where the hoses connect to ensure that there is a correctly sized and clear pathway for the airflow connections. sometimes these are drilled out to ‘improve’ engine breathing but do just the opposite.

Dave

[Dynion Araf Uchaf]

DVandrews said:

PCV systems work by drawing air through the crankcase to the inlet manifold where the fumes are consumed, any blow by or crankcase pressure ends up heading to the inlet manifold, the connection to the TB is where air filtered air is drawn in to purge the crankcase, this flow and circulation is driven by the manifold vacuum.

If you are using a catch tank then that circuit is compromised and the crankcase pressure/fumes will be vented wherever the course of least resistance is, in this case it seems the TB. If the PCV system is not being used as intended then I would block the circuit to the TB and improve the ventilation from the cam cover.

You might also want to consider making the PCV system work as intended, also check the connections, particularly where the hoses connect to ensure that there is a correctly sized and clear pathway for the airflow connections. sometimes these are drilled out to ‘improve’ engine breathing but do just the opposite.

Dave

Yes I think you get where I am at.

Better rockers covers with improved venting, better catch tank, close up the vent to the TB.

I suspect if I still have a problem the. The catch tank will fill fast.

For StevieTurbo what I am trying to achieve is better crank case ventilation so that the fumes etc don’t just dump them selves into the TB, whilst at the same time working out whether my previous breathing set up was the cause of the high vol of oil.

I did the other checks to try and remove issues with pistons rings or valves. Which I think the results show that there are no issues.

So to summarise I think a new rocker cover ( which is an upgrade to the engine that Peugeot developed) and a better catch can should fix the issue.

But if you know of something else I should be looking at I am all ears🙃

[andburg]

I’d follow whatever Dave has said, he’s a highly respected engine builder.

[GreenV8S]

Dynion Araf Uchaf said:

But if you know of something else I should be looking at I am all ears??

Just dumping everything that comes out of the crank case into a catch tank is going to be a problem if the crank case gases are carrying significant amounts of oil with them. You need to have enough breather capacity to keep crank case pressure to acceptable levels, but you also need to prevent oil being carried out with the breather gases. That's why I mentioned baffles and oil separators. You need to ensure that the breather output is not in an area where oil will pool under acceleration, that there are baffles to prevent oil spashing into the outlet and that there is an effective separator to remove oil from the breather gases and return it to the engine.

Or you could just fit a massive oil capacity sump and a massive catch tank and hope for the best - your call.

[stevieturbo]

Dynion Araf Uchaf said:

Yes I think you get where I am at.

Better rockers covers with improved venting, better catch tank, close up the vent to the TB.

I suspect if I still have a problem the. The catch tank will fill fast.

For StevieTurbo what I am trying to achieve is better crank case ventilation so that the fumes etc don’t just dump them selves into the TB, whilst at the same time working out whether my previous breathing set up was the cause of the high vol of oil.

I did the other checks to try and remove issues with pistons rings or valves. Which I think the results show that there are no issues.

So to summarise I think a new rocker cover ( which is an upgrade to the engine that Peugeot developed) and a better catch can should fix the issue.

But if you know of something else I should be looking at I am all ears??

Then let's see exactly how the breather setup is configured now. You've only posted pics of how it was, and how it is not yet.

And if you are allowing the intake access to the crankcase, then you need to have damn good oil/air separation. And unless it is an actual proper PCV setup, I would prefer not be linking any hoses to the intake or TB itself.
By all means route a well separated/filtered breather pipe to the area of the air filter so it can be drawn in, with zero risk of actually pulling anything unwanted in. But I dislike actually linking things to the intake, as all too often, it's going to suck oil on

[Dynion Araf Uchaf]

The proposed solution will look a lot like this. In fact the parts I am using are these but bought second hand from the guy that owns this car

[stevieturbo]

Again, you're posting what it may look like. Not what it looks like whenever you've had the problems you're talking about.

And without seeing that actual can...can't say good or bad. Lots of egay ste can's are literally unvented cans that when piped up, do nothing whatsoever. Apart from plug up the crankcase so it cannot breathe

https://www.burtonpower.com/tuning-guides/tuning-g...

[Dynion Araf Uchaf]

The top picture on this thread is how the breather system looked when I had the problems.

The article you linked to also suggests that new seals etc can exacerbate the problem.

The new to me catch can doesn’t appear to have a filter/breather/vent. I need to look into that some more.

This is the catch can I will be using

Edited by Dynion Araf Uchaf on Monday 6th November 22:13

[Maxdecel]

Dynion Araf Uchaf said:

The top picture on this thread is how the breather system looked when I had the problems.

The article you linked to also suggests that new seals etc can exacerbate the problem.
The new to me catch can doesn’t appear to have a filter/breather/vent. I need to look into that some more.
This is the catch can I will be using

demon-tweeks said:

The special cap allows the tank to breathe without oil bypassing and a sight gauge on the side lets you know when it's time to empty the tank via the drain plug in the bottom

[Dynion Araf Uchaf]

Maxdecel said:

Dynion Araf Uchaf said:

The top picture on this thread is how the breather system looked when I had the problems.

The article you linked to also suggests that new seals etc can exacerbate the problem.
The new to me catch can doesn’t appear to have a filter/breather/vent. I need to look into that some more.
This is the catch can I will be using

demon-tweeks said:

The special cap allows the tank to breathe without oil bypassing and a sight gauge on the side lets you know when it's time to empty the tank via the drain plug in the bottom

yes I spotted that after I posted. So clearly it'll now be fixed....

[stevieturbo]

Yes, the lid on those allow breathing.

I think I did see one of those a while back, not sure how they are inside for oil/air separation.

Ideally you'd make it the highest point in the system anyway, all pipes running uphill, to discourage any actual oil getting that far.

[Dynion Araf Uchaf]

coming back to this to update and close the thread.

I did install the JP4 cam covers and breather pipes into a catch can. Blocked the breather hole on the TB, and then went and did a track day at the weekend.

Can confirm that the problem is solved, indeed there was about 5 mm of oil in the catch tank after a 120 miles of lappery. So pretty happy with that.

Edited by Dynion Araf Uchaf on Wednesday 6th March 17:48

[Krikkit]

Great news, shame I hadn't seen this thread originally or I'd have recommended the JP4 covers as the baffling and venting is better.