Oil Overfilling Catch Can

[The Bogan]

My new engine is the devil, 25/30 with 1 mm restrictors, opened up drains, return lines from the back of the head, catch can with return line, Tomei pump, bigger sump with windage tray.

Every track day the catch can fills with oil and sprays everywhere, the pump has been adjusted to lower pressure, extra drains in the top of the covers, its slightly less than it was but still spat 2 ltrs after 3 warm up laps and 1 hot lap. Im going mad with this.

Sump holds about 7 ltrs of oil and dip stick reading is at the top of the hatching when I go out and it was half way down it after the 4 laps.

Comp is good as is leak down.

Limited to 7200, balanced, 18 lb 310kw.

Is my only other option a scavenger pump from the head to the sump ????

1. Have we missed something in the build.

2.To much oil in the sump causing trouble.

3. Needs scavenger Pump.

Any ideas are most welcome.

Stevo if you see this whats your pump and stuff, Ill be PM you about it anyway if you dont see this thread.

Some pics.

[r33_racer]

Where does the back of head line goto?

You need a breather line from the inlet side of sump to your catch can.

[The Bogan]

Where does the back of head line goto? Goes into the sump on the inlet side and into the turbo oil drain on the hot side

You need a breather line from the inlet side of sump to your catch can. the return from the head to the sump on the inlet side has a tee which is connected to the front of the sump and the tee going to the catch can

Thanks mate.

[r33_racer]

Interesting. All that done and it still spews oil out.

What size is the inlet side of sump to your catch can from the tee piece?

The only other thing I can think of that might be causing the issue is the breather can filter size. It looks way too small. It also appears to be the only one on the can, there isnt a second one hiding somewhere?

What sort of leak down were you getting too?

[The Bogan]

Interesting. All that done and it still spews oil out.

What size is the inlet side of sump to your catch can from the tee piece? 3/4"

The only other thing I can think of that might be causing the issue is the breather can filter size. It looks way too small. It also appears to be the only one on the can, there isnt a second one hiding somewhere? Its a 3/4" outlet to filter which has 6 square inchs of surface area.

What sort of leak down were you getting too? 15, I think, tuner said it was OK for a forged engine running hard rings

[Dobz]

If the breather hoses added to the back of the rocker covers don't have good baffling it will definatley contribute to some oil getting into the can.

[DVS JEZ]

Sorry to hear its still happening. I remember seeing it at wakie on its 1st outing.

Wat did ur builder think.

Wat does Yavuz think?

[The Bogan]

Its got baffles behind the vents.

They think its possessed by demons from hell, going to try running slightly less oil, mucking around with the catch can and hoses, maybe redirecting some oil from the pump straight back to the sump, and if none of that works a scavenger pump may be the next option.

All this for a daily driver / occasional weekend track day car

I do need to win LOTTO right about now.

Marks prayer, "Dear JEBUS let me win LOTTO and Ill shout the boys a free track day, AMENS"

Stupid oil doing stupid stuff, FFS, how hard is it..............................

[T04GTR]

cp pistons?

ps. all oil returns to the sump need to be below the windage tray and on passenger side.

[The Bogan]

cp pistons? NO

ps. all oil returns to the sump need to be below the windage tray and on passenger side. The return line on the hot side is by using the turbo oil drain point but the cold side goes into the drivers side at the top of the sump, could this be a problem you think ??

Thanks, Mark

[r33_racer]

How new is the engine build? 15% leak down seems alot if its pretty new.

What pistons and piston to bore clearance if you know?

Does the engine breathe heavy when its warm as in does blowby vapour come out the breather filter normally?

[The Bogan]

Gets a lot of blow by when cold but when warm its a lot less, tolerance was apparently in spec for the piston and rings used, wisco piston if I'm recalling right.

And yes the motor is new.

[r33_racer]

hmmm it shouldnt really be breathing heavy at all after its all bed in and running right. Our leak down is always around the 2-3% mark across the board and my road car was about 6-7% before I started my new build.

Unless its something silly like an out of round bore or too tight in piston to bore and its grabbing slightly. You shouldnt have so much blow by and oil spewing, especially with all the mods you've done.

[The Bogan]

Will be blocking the middle restrictor in a couple of weeks, so only a 1mm at the rear and the 1mm at the VCT, the TOMEI pump pumps coupious amounts of oil, we will see if the lifters like that if not then may need to go solids, will hit the track ASAP after fix and post results, as for the leak down Ive been told for a forged engine with the rings that have been used (hard ?) that 15% is OK by as many people that say its not, LOL.

A guage was put where the dip stick goes and at WOT there was not a significant amount of pressure in the sump.

I suppose every engine is different in its own way, it goes like the powers of piss, I just need the oil to stay where its meant to.

On a side note my syncros came out the drain hole when I changed the oil in the gearbox for some Redline, not sure if the Redline will mask the damage anymore, LOL.

Fingers crossed.

Mark

[T04GTR]

we had a pretty breath heavy rb30 at work. (1,2,3 15-20% leakage 4,5,6 10-15%) it had the oil drains going to the drivers side front of the sump. oil came UP the drain hole on the dyno... if anything id leave the passenger side drain and block the drivers one and see how you go.

[r33_racer]

we had a pretty breath heavy rb30 at work. (1,2,3 15-20% leakage 4,5,6 10-15%) it had the oil drains going to the drivers side front of the sump. oil came UP the drain hole on the dyno... if anything id leave the passenger side drain and block the drivers one and see how you go.

lol yeh the blowby would have been carrying oil up that line to head.

Maybe just block off the Tee joint and leave the line going from sump to catch can. Get rid of that half of the back of the head drain/vent thats going to that Tee joint on the inlet side.

[NYTSKY]

Try some Mines/Mines copy cam cover baffles. Works wonders.

If you are still getting alot of oil in the catch can id say excessive clearances.

[T04GTR]

what a rip they are.. just fuel cell foam.. go to any place that does race cars and im sure tey have a pile of off cuts you can jamm in the rockers,

[Dale FZ1]

How much hard/high load running has the thing actually done?

And what spec oil has it run (and currently running)?

Sounds like there may well be issues in bedding those rings properly yet. Different experiences for different builds, but it appears that chrome rings aren't always easy to achieve a good bedding until the engine has had plenty of work. Also don't make the move to full synthetic engine oil too quickly - it will work against you getting rings bedded. That's something well documented in motorcycling circles.

The earlier comment regarding filters on your catch can are close to the mark too. There might be lots of filter area, but have a look at the total cross sectional area in the hoses running from the cam covers, and compare it to the size of the nipple your catch can filter is mounted to. It is reducing, effectively makes a venturi so the air velocity increases as it is pushed out of the catch can. Give some thought to redesigning your catch can for internal baffling, and at least another filter.

Heavy breathing is fairly common but doesn't seem to be much talked about as there are so many different approaches to sorting it. And you probably won't see the issue raise its head in thousands of road km because you can't drive hard enough, long enough to create the same conditions.

FWIW I've seen Subarus spit 1 litre (and more) in 3 laps of the Morgan Park "A" track (pretty short circuit). Another mate has told me of an engine that took an entire season of racing for his heavy engine breathing to resolve itself as the rings finally bedded.

[The Bogan]

10W-40, The motor has done maybe 2000k of road use, and only about 12 laps at Wakefield 3 sessions of 4 laps super spints and 6 laps of Eastern Creek (but in the wet), so not even getting hot, catch can is being redesigned as more of a oil air seperator style of thing and restricors are being changed to a 1 mm at the rear (whats in there now) and blocking the middle one (has a 1mm in here), the VCT drain is being reconnected and the drains are being rerouted to the left hand side of the sump(VCT has a 1mm restrictor).

Hopefully that fixes the problem, if the lifters get noisey the spring will go back in the Tomei pump to give it some more oil as it was removed to try and stop the oil surge before but that was unsuccessfull.

Goes in again tomorrow for the next week or so.

So with a new TO4Z, recoed gear box, new clutch and the oil under control I may be able to get some fun hot laps in with the new motor, finally.

Hopefully.