Oil Control In Rb's For Circuit Drag Or Drift

[djr81]

Well mate why would you drill only the block?? something can only flow as fast as its biggest restriction (we put restrictors in the block, theres like 7mm? of oil gallery and then our 1.3mm? restrictor, only 1.3mmDIA. of oil can flow

same principal for oil returns, if you don't drill the head oil returns too, the head oil returns will basically act as the restrictor making it pointless to drill ONLY the block.

I didnt say that. If you look at the early thread it has always been drill out the head. No mention of the block. More recently it has become head and occasionally, block. No one is saying just drill the block. Unless I havent been paying sufficient attention there is a change there somewhere? Just trying to get clarity for people.

[B-rice]

It's been stated from the start to drill the block aswell. Ok they didn't use drill but they said enlarge the holes on the head and block to match. It's like porting them.

[ScreamerNewbie]

Yeah I was just saying if you only drill 1 and not the other then the "other" will be the restriction and the drilling would have been pointless.

[djr81]

The rear drains are dead easy as the casting is narrow at the top off the block. The other oil returns less so. Lots of posts in the thread just talk about the head, not the block. But you are right re-reading the original post it references the block too.

[danny14]

Whoops, yes i did mean catch can, corrected it now.

Yes i understand that now. The two goals are to reduce the amount of oil entering the head, and equalize crankcase pressure.

The oiling issue is solved by selecting the appropriately sized oil restrictor/s that vary with each engine set up. What must be taken into account is the head that you are using, and the oil pump that you are using. Heads with hydraulic lifters (IE R33 RB25) require more oil in the head than heads with Hydraulic lifters (RB26, RB25 NEO) and as such larger restrictors (IE providing less oil restriction) are used in those engines.

Here is a slight update on the original Skydneykid table created way back in 2006. It is pretty much exactly as it was just more user friendly and now includes the NEO. I left the RB20 off the table as nobody seems to be interested in them RE oil control issues, questions about them were asked nowhere near as frequently as RB25/26. They can be added back in if you wish.

The other issue is that of crankcase pressurization. The steps taken to achieve this are drilling out the oil returns in the block to 10mm, and giving them a chamfered edge to promote oil drainage. To displace the oil that is in the head, air must be moved into the head allowing the oil to drain (I am going to use the 'turning a drink bottle upside down' analogy here even though its not 100% accurate i think it gives everyone a good idea of what is going on) Increasing the oil drain cross-sectional area by drilling not only promotes oil drainage but gives air a larger path to travel up into the head, which increases drainage yet again.

A Combination of these two mods is a very good start to sorting out the problems associated with RB oil control, and should be the starting point for anyone looking into this.

A good catch can setup will help even further by acting as an equalizer for crankcase pressure and catching any oil that would otherwise be making its way back into the engine. I will use the method that KiwiRS4T has mentioned and others seem to be using with success. Both cam covers are individually run to a catch can mounted at approximately battery height in the engine bay. 2x -10AN fittings are welded onto the sump above the oil level in the sump. One is run to the highest point in the catch can, and the other run to the lowest point. The catch can can then be either vented to atmosphere, or run to another catch can that does the final oil/air separation before being piped back into the turbo intake.

All of the things mentioned above should be supported by other basic modifications such as

• Baffling in the cam covers, whether it be mines baffles or something similar
• Trapdoors in the sump to keen a consistent oil pickup
• Increasing the capacity of the sump
• Using an oil cooler

Even better control of oil would be done by having

• A Nissan N1 oil pump, or any aftermarket item (Nitto, Tomei etc)
• Fitting your standard nissan on N1 pump with billet gears (Reimax, Nitto etc)
• Fitting a crank colllar to your crankshaft to widen oil pump gear engagement
• Running an ACCUSUMP accumulator to control split second oil pressure loss and for the benefit of pre-oiling

Pics below of what SimonR32 has done with his catch can, which is what i was trying to explain in the diagram above.

If you cannot be bothered reading through the entire thread then read these posts, as i feel that they are some of the most important in the thread to get an understanding of what is actually happening inside the engine, which in turn is able to help us create a way in which to solve these problems.

http://www.skylinesaustralia.com/forums/topic/110680-oil-control-in-rbs-for-circuit-drag-or-drift/page-49#entry6798597

http://www.skylinesaustralia.com/forums/topic/110680-oil-control-in-rbs-for-circuit-drag-or-drift/page-49#entry6798648

http://www.skylinesaustralia.com/forums/topic/110680-oil-control-in-rbs-for-circuit-drag-or-drift/page-50#entry6929479

http://www.skylinesaustralia.com/forums/topic/110680-oil-control-in-rbs-for-circuit-drag-or-drift/page-53#entry7157413

http://www.skylinesaustralia.com/forums/topic/110680-oil-control-in-rbs-for-circuit-drag-or-drift/page-54#entry7159347

http://www.skylinesaustralia.com/forums/topic/110680-oil-control-in-rbs-for-circuit-drag-or-drift/page-54#entry7181463

http://www.skylinesaustralia.com/forums/topic/110680-oil-control-in-rbs-for-circuit-drag-or-drift/page-55#entry7208766

All the information in this above guide is purely my own thoughts/experiences on the whole RB oil control issue. Please do not take it as gospel and follow it to the letter. As always do your own research and come to the conclusion of what will suit you best based on your own setup.

Big thanks to everyone who posted in this thread.

r 33 gtr

is it correct to still run rear head oil drain to sump aswel as above ?? now that i have my engine out i want to do things right the first time as the engine is getting built. with oil restrictor in head if the car was not used as a daily and ocasionaly was used both street/track what size restictor to run if running tomei oil pump or equilevant >? also will be running e85 all the time

[Jazzadub]

No, the rear oil head "drain" is not required if you vent the sump and valve cover breathers to a vented catch can.

I would recommend a 1.2 or 1.25mm restrictor with a Tomei oil pump. Go to a 1mm if the car is a dedicated race car.

For E85, just make sure the oil you use is API SN rated, and that you change it regularly.

[danny14]

No, the rear oil head "drain" is not required if you vent the sump and valve cover breathers to a vented catch can.

I would recommend a 1.2 or 1.25mm restrictor with a Tomei oil pump. Go to a 1mm if the car is a dedicated race car.

For E85, just make sure the oil you use is API SN rated, and that you change it regularly.

ok cheers i was not aware about the engine oil specs .... when running e85 ,how often do you need to change the oil ?

[Jazzadub]

Yep the SN rating is the newest rating (2011) and supposedly has improved resistance to alcohol fuels.

It should be OK with normal change intervals (5000k) but I would check the condition of it regularly to make sure it isn't doing anything funky like greasing up.

If you can afford it I would also recommend full grade V synthetic such as Redline 15W-50 or Motul 300V as that will also have improved stability compared to a mineral blended oil.

[danny14]

ok i will keep those oils in mind for after engine run in

[danny14]

Hey guys just a quick one rob from rips racing nz doesnt use restrictors in head but does in block.

The setup for crank ventilation

Is same as described earlier in this thread

Rocker covers vented to top of catch can and 2 lines from top of sump 1 going to top of catch can and 1 going to bottom of catch can

[Ben C34]

No one uses restrictors in the head . They go in the block.

[danny14]

Ok got that straight then thanks alot superben

[Ben C34]

Ok got that straight then thanks alot superben

No worries dude.

[Jazzadub]

Hey guys just a quick one rob from rips racing nz doesnt use restrictors in head but does in block.

The setup for crank ventilation

Is same as described earlier in this thread

Rocker covers vented to top of catch can and 2 lines from top of sump 1 going to top of catch can and 1 going to bottom of catch can

Like superben said + Rob doesn't use the head drain/breather from the back freeze plug.

Maybe that's what you meant?

[Crossie]

Can someone plz shed some light on why people say you've gotta have the PCV in place if you've got a recirculating catch can set-up? Wouldn't the turbo be enough of a vacuum ??

[djr81]

Because with a shut throttle and a recirculating bov there isnt enough vacuum from the turbo inlet.

[Crossie]

Even with a 3076 ?

[B-rice]

Don't think it's anything to do with the size of your turbo might be wrong though. You'd need to calculate it to know excatly how much vacuum your engine has at shut throttle and how much the 3076 does.

[fatz]

will have my catch can v3 setup done soon

[GTSBoy]

Shut throttle says it all. The vacuum is ALL on the plenum side of the manifold.