Oil Control In Rb's For Circuit Drag Or Drift

[Dan_J]

can anyone that actually knows answer this, if breathers are restricted will this rise oil temps ?

also is it ok to weld a barb on the intake side of the sump at any height/location, any reason why not the exhaust side of the sump ?

[GTSBoy]

High level because otherwise it's not a breather, it's a swimmer. Intake side because windage from crank,

[ToF]

Thanks #@KiwiRS4T and #@Shoota_77. Gives me a clearer picture now.

[SimonR32]

I agree with the above.

This is my pretty picture I just made. With the hoses coming from the rockers you can either do two hoses if you have enough inlets on your catch can or or like Kiwi says you can run one hose (on mine I joined the two together with a tee piece and ran one hose off the middle outlet of the tee to the catch can.

New Picture.png

To do one better I just had my fittings welded today so I have photos

Sump on intake side is 2 x -10

Catch can has one -10 drain at bottom that will go to the sump, 2 x hose tails on top to go to cam cover breathers and one -10 that will go to the other fitting on the sump as a vent.

Edited September 21, 2013 by SimonR32

[Looney_Head]

is there a reason people put the breather and drain on the same side of the sump? shouldn't the breather be on one side of the sump (windage) and the drain on the opposite side?

[KiwiRS4T]

If you have the drain coming off the bottom of a catch can it would be pretty hard to get the line all the way round to the other side of the block. Besides it probably drains back after you lift off (fills up under WOT).

is there a reason people put the breather and drain on the same side of the sump? shouldn't the breather be on one side of the sump (windage) and the drain on the opposite side?

[SimonR32]

If you have the drain coming off the bottom of a catch can it would be pretty hard to get the line all the way round to the other side of the block. Besides it probably drains back after you lift off (fills up under WOT).

Agree with all of that and in addition if the drain isn't draining it can double as a second vent.

Now my only considerations are putting a check valve and/or filter in the drain line

[R32 TT]

Just wondering - I see people talking about check valves on these - but don't really get why.

Isn't it better to simply be a drain when it can be, and a vent at other times? why restrict its flow direction?

Also - I don't see the need for a filter. Think of the Catch Can as a third rocker cover. Air and Oil mist flow to it and air passes out of it (via a filter to atmosphere, or back to intake) Oil drains back to the sump just as if it had come from the rocker cover..

[SimonR32]

I'm leaning towards no check valve or filter at the moment.

[KiwiRS4T]

^^^me too!

I'm leaning towards no check valve or filter at the moment.

[fletch rb30]

I have read the last few pages out of curiosity and thought i would throw my 5c into the ring

Nah, the NEO doesn't have anymore internal drains compared to a Normal RB25.

I dont see the reason in deleting that small vent / drain on the NEO just because they went to solid lifters. Yes the oil is fed less (smaller restrictors) but i dont know if that was the justification to remove the vent.

.

First, the reason the neo rb25 does not have the external drain from the front of the head is the way the vct system was changed from r33 to r34.

On the r33 vct head there is 2 holes in the front cam journal. The vct solenoid is in the open position when de-energised. The oil pressure from the front(vct) oil feed is constantly feeding the front cam journal to lubricate it, and it drains out the other hole, via the vct solenoid and into the head.

When the vct solenoid is activated, the oil cannot drain, the cam pulley is pressurised and advances.

The front oil drain is designed to allow this extra oil to drain to the block when the vct is not activated. This is not an ideal system for a drain, but it is probably the easiest system for nissan to manufacture without significantly changing the block and head casting for an extra oil drain at the front.

This is shown by the internal vct feed mod threads in the rb30det forum, you modify the plug in the end of the gallery to allow the inlet oil gallery to feed the front cam journal/vct

The NEO vct system also has 2 oil holes in the front cam journal, but placed differently. I could not find the pics of google images to show this sorry. The small hole feeds the front cam bearing constantly and is fed from the oil gallery in the head that feeds the lifters and other inlet cam bearings.

The vct oil feed runs directly to the solenoid instead of the journal first and the solenoid OPENS when energised and pressurises the cam pulley to advance the cam. When de-energised, the pressure in the cam gear flows back through the solenoid and into the head.

This way, only the small volume of oil in the cam pulley is discharged into the head.

Clear as mud?

As for the other controversial topic...

On a few race cars i muck about with we often dont have any breathers on the head at all! We vent the lower part of the block and block all the holes in the head. That way oil in the head can only go down.

As it has been said often, the RB problems are caused by the blow-by trying to escape the sump. The only way for this to happen is up through the oil drain holes in the block and head and out the rocker covers. This is whats causing the oil to pool in the head and blow out the breathers.

The stock setup is good for stock driving.

Early next year to plan to drag my rb25/30 out of storage and rebuild the engine. It was thrown together and blows oil everywhere when driven hard. I fixed it by taking the dipstick out and keeping it in the glovebox.

Like kiwiRS4t and others, i will run a few big lines to the inlet cam cover, make some kind of internal baffles (mines copy) and run the front vents to some kind of small filtered catch can. I dont think it needs to be complex. And also drill out the internal head drains.

Plus maybe run 2x oil restrictors instead of blocking 1 incase a bit of shit blocks the restrictor and kills the cam bearings

Cheers

Edited September 29, 2013 by fletch rb30

[R32N1]

• Hey Guys, im from NZ and I was just wondering if you could potentially give me a bit of advice. I have a couple of R32 GTRs, the white one is a fully stock R32 GTR V Spec II N1 and a unregistered track car (grey).

  The track car is just used as a fun club day car and pretty much only at Hampton Downs, with the occasional track day at Puke (both race tracks in Auckland). The mods are as follows

  - Coilovers - Slick tires - ballbearing turbos (about 290 kw at all four @1.3 bar) - JE forged pistons - Trust front pipes and Kakamoto Titanium exhaust - filters - Power FC - racing bearing - tomei sump baffle - tomei oil pump with head restrictor. - remote oil cooler and filter relocation - 400 lph walbro intake pump - Bosch 044 external pump and surge tank - Evo 8 Brembo calipers, DBA discs and project mu pads - along with other little things, like suspension arms and so on.

  Now, we have a bit of a problem. We are getting problems with oil when we are at the track after 5-7 laps. Oil is pissing out somewhere on the intake side of the engine. I cant locate where. Neither can my mechanic.

  We are running a higher oil level, to try and account for the fact that we have a tomei pump and we have slick tires at hampton downs (very hard on brakes and has a couple of big sweeping high G corners), which is hard on the G's. As yet we dont have an extended sump and we are not running an oil breather from the head.

  My assumption is that the head is filling with oil and it has no where to go. So it is forcing its way out of the engine somewhere. But we cannot replicate the problem on the dyno. After hours on the dyno on load, no oil leak. It only happens at the track, so must be G Force related. My mechanic is a little perplexed by it all, as he believes that if it was filling the head with oil, it should be coming out of the other side of the engine.

  Do you guys have any ideas of what the problem may be? Will getting an extended sump, running a more regular oil level and a oil breather tank stop the problem? Do we need to introduce some kind of head oil to sump return system? Does it even sound like it is a problem with oil in the head to you?

  Any help you can give me, would be much appreciated.

  Why does oiling an RB26 have to be so complicated!!!!!!

  Cheers Guys Lucas

[djr81]

It usually leaks out of the BOV's and no you dont usually get it happening on the dyno, only the track because that is where you get sustained high rpm/high loads and g forces to go with it. The oil recirculates back through the intake system so you will have an intercooler full of oil and from there it leaks out of the blow off valves.

The problem, as has been described on this thread is caused by a combination of engine blow by and small holes in the head of the motor for oil return. Simply put once load comes on the motor the oil wont return from the head as the blow by and the small cross sectional area prevents it from doing so. Add in gee forces and you get an oil puking mess like so many others. The fix is as described previously:
Good blow by control.

Oil restrictor.

Open up the drainage holes in the head.

Vent the sump to a catch can.

Which is an engine out job. RB's have had this problem since they were first built. The stock cast iron rings are good enough to prevent most of it until an engine gets old/powered up but unfortunately most of the forged piston ring sets do not take into account this particular RB idiosyncrasy. IF you want some decent rings talk to Pacific Engine Parts in Melbourne. See earlier.

Edited October 8, 2013 by djr81

[KiwiRS4T]

Read the thread - the answers are there. Are your restrictors small enough (I run 2 x 1.0mm). Forget the "head drain" you need to vent the sump. Spend half an hour reading at least the last third of this thread.

[djr81]

Just wondering - I see people talking about check valves on these - but don't really get why.

Isn't it better to simply be a drain when it can be, and a vent at other times? why restrict its flow direction?

Also - I don't see the need for a filter. Think of the Catch Can as a third rocker cover. Air and Oil mist flow to it and air passes out of it (via a filter to atmosphere, or back to intake) Oil drains back to the sump just as if it had come from the rocker cover..

My drain returns to the level of the oil in the sump - so the check valves helps stop oil surge under cornering.

[B-rice]

so read this thread for probably half my day. I can summarise it down to this

1. One of the middle oil feed is blocked and a restricter is put on the rear (VCT equiped RB25NEO)

2.Fitting an oil drain at the back of the head
3. Port matching the oil galleries to the gasket

Now there has been a discussing earlier in the thread regarding the side to which the placement of the drain line from the head to sump should be located. Mspeed/Japs seem like they're going via the intake side whereas SK suggest going via the exhaust side with the drain above the oil level. So up to this date which way would be sufficient for a street driven car with occasional track days. Didnt quite get to see a good conclusion between the two ideas. Or is there a better method for having a bit more control to the oiling issue and breathing.

[PN-Mad]

Has anyone gone and mapped out the Group A cars systems? It seems a little bit of a no brainer since it could go flat out for 1000kms, and not have an issue.

I have a few pics of the setup, but haven't bothered to draw it or anything. I know they run restrictors, cause I've seen them when the head was off, but don't know the size.

Good opportunity to go and map one out next time someone sees the car at an event.

[White GTS-T]

I snapped these at WTAC.

[SimonR32]

To do one better I just had my fittings welded today so I have photos

Sump on intake side is 2 x -10

Catch can has one -10 drain at bottom that will go to the sump, 2 x hose tails on top to go to cam cover breathers and one -10 that will go to the other fitting on the sump as a vent.

This is working a treat at the moment, 2 track days and have not even had to check the dipstick

I don't know if the vent is working and stopping lots of oil heading to the catch can or if the oil is getting there and draining back, either way I don't care because it's maintenance free and it appears to have stopped any oil surging on the track

Edited December 28, 2013 by SimonR32

[B-rice]

I think ill just stick to getting a bigger baffled sump and maybe put restricter with no drain. Ive read nearly the whole thread and actually more confused.