Ew10 Breather Setup - Catch Tank Over Fill Issue?

[sam jfm 0]

Morning All,

 

Can any of you shed some light on my problem?

 

I may have an issue with my gti180's breather setup.Yesterday whilst on an event. My best deduction as to what happened is the engine filled the catch tank, and then chucked about a litre of oil out of the top of the catch tank (oil everywhere,smoke, the works).

 

I am trying to get to the bottom of why it has happened, the catch tank is plumbed up as follows. Two inlet manifold breathers blanked off, cam cover breather and the breather on the side of the head connected together and plumbed into a catch tank. The catch tank then returns to the sump.

 

 

I am thinking have misunderstood how the breather setup works on this engine. Or maybe it was something stupid like overfilled with oil (although i still wouldn't expect it to lose containment in such a big way!)

 

All advice appreciated.

 

Sam

 

 

[dcc 855]

Sounds like you have a lot of piston blow by, but some is to be expected.

 

The breather / catchtank system seems sealed and you have no vent to atmosphere. Where does the build up of pressure go? Contually building by piston ring blowby. Personally I'd introduce a t piece back to your inlet for the release of pressure in the crank case, oil vapour would be burnt, else you'll just get compound pressure build up

[sam jfm 0]

Thanks for your reply,

 

The catch tank/can has a breather in the top to release any pressure buildup.(it's a Mocal one)

 

I can't figure out how I ended up with so much oil in the catch tank, and out of it - unless something strange happens at high RPM. I initially thought that it must be piston blowby, but the engine doesn't breath noticeably at all.

 

It's as though oil is getting stuck at the top of the head at high rpm maybe? or the oil is being forced up the return to sump pipe and out of the top?

[dcc 855]

Well the ew10 has 2 large oil return galleries, i have a few heads and block kicking round so will have a look later to see if anything obvious from your description, the only thing I can suggest is you have a lot of oil pooling at high rpm.

 

Potentially your system cannot offload the pressure quick enough.

[Tom Fenton 1,561]

Most breather filters are just not sized big enough. Why have you altered it from standard? To be honest you are probably better putting it back, as you are finding quite a bit of thought is needed to make a breather system work properly, part of it is separating the oil from the air efficiently so you don't blow it out of the engine, at the same time it needs a large enough bore breather. Most of these so called breather filters have a pathetic small bore of something less than 10mm at the smallest point be it breather rubber or hose stub. Just not big enough.

[sam jfm 0]

Thanks Guys,

 

The reason I changed it was because it was a mess, and I was trying to simplify. Reading around about fitting throttle bodies to the engine it was suggested that you could get away without using the inlet manifold breathers. so I did!

 

 

The breather pipes from the rocker cover and the head are half inch, which is the same as the standard hose.

 

I am intrigued to find out what is causing the problem and why.

[dobboy 231 2 Cars]

Malc just had a similar problem, but not as severe sounding (but oil was filling up the catch tank and messing up engine bay), and it was a piston ring, on a charged XU10J4RS engine proved by a compression test.

[calvinhorse 870]

Is your catch tank mounted as high up as possible, does the oil have an easy return path to the sump?

[sam jfm 0]

Is your catch tank mounted as high up as possible, does the oil have an easy return path to the sump?

 

 

yes on both counts! As high as I can get it, and a 19mm id pipe back to the sump.

[calvinhorse 870]

19mm sounds very small, is the the size of the pipe into the sump?

Actually that's not terribly small

[sam jfm 0]

it's the same size as the drain boss on the sump

[dobboy 231 2 Cars]

Can you read the oil pressure from the dash/cockpit?

[RossD 44]

Have you blocked off the two circular breathers on the inlet manifold side of the head? As standard, there are drillings on the manifold which connect to the standard catch tank setup. If so, I suspect this is your problem, these relieve crank case pressure via the PCV valve on the standard setup.

[dudaionescu 2]

Hi Sam,

If I were you, I would immediately have an engine compression and leakdown test. Most probably you have a cracked fire ring in one of your pistons and there might be still hope you can save the engine. Forget the PCV, it's designed only for fumes, when you have liquid oil spurting out from there then you're in big trouble. One more sign: oil cap smelling strongly like gasoline.

[dcc 855]

Are you running vvt?

[welshpug 1,677]

Just what I was thinking now

[dcc 855]

Haha

[Schumi 2]

Are you running vvt?

Are you thinking its removed VVT but not fill the hole of selenoid ?

[dcc 855]

If you remove vvt you need to leave solenoid in place, problem you have is full oil pressure without restriction to head. This then fills the head with oil, the returns can return oil fast enough to sump. The beathers get used as a oil pipeline back to the sump, filling any breather set up. The head fills within seconds. Had personally seen it myself.

 

The cure? Leave vvt solenoid in place when removing the vvt pulley.

[sam jfm 0]

I believe that my VVT is still in place, how would i check to make sure?

[dcc 855]

Have a look for the solenoid on top of head

[sam jfm 0]

Yes - still in place

[drmo 5]

These engines need a stock oil/air separator or like it, retained. The breather on the side of the intake cam ladder and on the exhaust cam cover are both un-baffled, that means that the oil will go directly out when the engine is running in medium to higher revs and overfill the catch can. This is more likely to happen if you get rid of the VVT cam pulley and/or you change hydraulic followers for solid ones.

 

On our race engine we kept stock oil/air separator under the intake manifold and used an aftermarket catch can to vent the fumes from oil/air separator to it. That is the only way the catch can wasn't overfilling.

 

Keeping a stock separator is a problem if you are not using a stock intake manifold as the separator bolts onto it. In this case you need to make a custom separator.

[speaksgeek 5]

Good to know.

Does the separator flow back down to the sump? From memory there is a single ~20mm hose running back into the sump on a stock engine - is that from the intake separator?

If I was to use a catch can with separator built in, I assume that would drain to the sump instead?

 

These engines need a stock oil/air separator or like it, retained. The breather on the side of the intake cam ladder and on the exhaust cam cover are both un-baffled, that means that the oil will go directly out when the engine is running in medium to higher revs and overfill the catch can. This is more likely to happen if you get rid of the VVT cam pulley and/or you change hydraulic followers for solid ones.

 

On our race engine we kept stock oil/air separator under the intake manifold and used an aftermarket catch can to vent the fumes from oil/air separator to it. That is the only way the catch can wasn't overfilling.

 

Keeping a stock separator is a problem if you are not using a stock intake manifold as the separator bolts onto it. In this case you need to make a custom separator.

Edited February 13, 2017 by speaksgeek

[drmo 5]

Yes, the separator flows the oil back to the sump. The engine is vented from the head, through the intake manifold into the separator. There is a second breather that goes from the back of the cam ladder to the separator. The oil gets separated in the box and the fumes get recycled through the engine, the oil goes back to the sump.