Rb3025 New Oil Catch Can Issue (again ! Sorry !)

[lolo.37]

HI There,

I have oiling issue on my RB3025 néo engine. I HAVE READ NUMBERS OF TOPICS ABOUT THAT... BUT... found no solution.
A complete drawing will be the best to explain my sittuation.
Engine is pulling hard, I don't think there is too much blow-by...

I really hope a solution to fix that and raise up my boost !

See attached file !

Cheers from France

[White GTS-T]

First, ensure that the breathers from the rocker covers to the catch can are both seperate. T-ing these lines effectively halves the breathing capacity.

Secondly, introduce some vacuum into the system. Either via the pcv valve or pre-turbo but preferably both. Vacuum in the crankcase is a good thing.

Lastly, if that doesn't work, hide under some coats and hope that somehow, everything will work out.

[r32-25t]

Also make sure every line that goes to the sump is above the oil level, cause if air needs to go thru the oil to get out of the engine, then it's going to take the oil with it

[KiwiRS4T]

Your plumbing looks ok but

1. are your sump breathers both above the oil level in the sump?\

and

2. is your catch can 300ml? It needs to be 2L (2000ml)

also what oil pump and do you have any restrictors in the oil feeds?

[89CAL]

also what oil pump and do you have any restrictors in the oil feeds?

Have another look at the drawing he's done

Rear blocked, front 1.2mm, VCT feed 2mm

N1 pump

[Dobz]

As has been said get a bigger catch can because 300ml is way too small

Also needs one way check valve on the drain back from catch can so oil doesn't pump out of it. As r32-25t said it needs the sump breather to the can well above oil surge level or you are just pumping oil up the breather.

And I just saw you have the rear head breather teed to the turbo oil drain. That's not a good idea because you could be causing oil to back up into the turbo drain.

Edited June 7, 2015 by Dobz

[Ben C34]

You need a proper separator. A dodgy home made job in a 300ml can is never going to be good enough dealing with any amount of blow by

[Franko07]

how are people getting a hole above the oil surge line on stock sump? I was looking at my block today and couldn't really find a good place to drill a hole in the side of it without it coming close to the structure of the main caps which I don't really want to drill into the block anyway...

[XGTRX]

As has been said get a bigger catch can because 300ml is way too small

Also needs one way check valve on the drain back from catch can so oil doesn't pump out of it. As r32-25t said it needs the sump breather to the can well above oil surge level or you are just pumping oil up the breather.

And I just saw you have the rear head breather teed to the turbo oil drain. That's not a good idea because you could be causing oil to back up into the turbo drain.

This

[KiwiRS4T]

how are people getting a hole above the oil surge line on stock sump? I was looking at my block today and couldn't really find a good place to drill a hole in the side of it without it coming close to the structure of the main caps which I don't really want to drill into the block anyway...

Well its easy with an RB26 sump but I imagine with a steel sump you could have an elbow facing up til its well clear of the oil level so long as it doesn't get in the way of the crank etc.

[Franko07]

^ Im liking the way youre thinking!

In regards to dobs post he said that you need a one way check valve from the drain of the catch can to the sump to stop oil from flowing out the can, im a little confuzed as to how crank gasses can get out then? As i thought that was the point?

[Dobz]

Frank there is a breather hose and a drain back hose. The drain back is the lowest hose.

[KiwiRS4T]

^ Im liking the way youre thinking!

In regards to dobs post he said that you need a one way check valve from the drain of the catch can to the sump to stop oil from flowing out the can, im a little confuzed as to how crank gasses can get out then? As i thought that was the point?

Frank there is a breather hose and a drain back hose. The drain back is the lowest hose.

Some people put a check valve in one line and it works for them. I have no check valve - my theory is at full WOT pressure escapes via both hoses and I haven't found an uphill straight long enough to fill my 2L catch can so when I lift off it drains back fairly quickly via the bottom hose. But others have a check valve in one line with no problems.

[lolo.37]

OK buddies! thanks a lot for your comment ! ! !
1. I must have forgot the check valve trick. Whitch seems a great solution for me !
2. Aswell as the 2 liters can !

Dobz : "I could be causing oil to back up into the turbo drain T'ing it with the rear head drain."
I thought the rear head drain was a drain. You think it is more a blow-by vent? (it shoudn't be as the bottom end is already vented on the intake side (as much as possible))
And I never saw my ball bearing turbo smoke oil (my exhaust piping is clean). And I have no other place to T the rear head drain.

Does some people here think the rear oil drain is useless?

White GTS-T : 1. I thing venting it (pcv etc...) in the engine intake is the risk of putting oil in it and knocking. Quite risky i think whith my E85 setup (high timing).
2. T'ing the 2 top lines of the cam cover minimise the amount of air venting out of the head ; then minimize the amount of gaz coming up from the cranckcase... => Better oil drain from head to cranckase then IMO. Don't you think ?
3. what does mean : "hide under some coats" (english is not my first language )

Attached is a bigger picture of my sump. My holes are all above the oil level. I was just hoping that the oil wasn't comming in front of those holes when accelerating... It would cause oil to get up in the catch can. (But it is meant to be a RIPS model...)

Edited June 8, 2015 by lolo.37

[89CAL]

My spool head drain tees in with the turbo drain. Havent had any issues yet. Checked my catch can the other day and its bone dry. I run a line from the catch can to the intake pipe and a PCV though so different setup.

[Blackkers]

My spool head drain tees in with the turbo drain. Havent had any issues yet. Checked my catch can the other day and its bone dry. I run a line from the catch can to the intake pipe and a PCV though so different setup.

Needs more rpm

[Dahtone Racing]

Are you actually getting oil from the breathers?
For an N1 pump to push that much oil there's something funny going on.
I would be looking at your catch can drain, being on the intake side isn't a good idea IMO.

[lolo.37]

OK This seem to be solved!

As you advised me :

I have put a check Valve in the oil drain. (was a 14mm on picture but replaced by a 17mm model)

I bought a 2 Liters can; (I baffled it myself just to do things perfectly right)

See attached files !

And TA DAAAA ! Done! No more oil coming out ! This is great !

But now there is a question that haunts me... How much oil can I put in my catch can and in my heads. There must be some oil stocked by those 2. It needs to get down on the boost/revs so oil can return back in the sump.

From how many seconds to the limiter do I take a risk of sucking air in the oil pump (while cornering mostly, using extended oil sump)

Anyone as ideas ofhow to check that?

Edited July 22, 2015 by lolo.37

[KiwiRS4T]

That's what the restrictors are for - to minimize excessive oil in the head - and if you have a 2 litre catch can that's the most that can fit so if you have an extended sump (8-9 litres?)_ you are unlikelyu to empty it. As soon as you lift off the oil in the catch can should flow back pretty quickly. If you have an aftermarket ecu you should be able to log the oil pressure but I doubt you are emptying the sump now.