Oil Control In Rb's For Circuit Drag Or Drift

[r33_racer]

I do 9.5mm with a cordless hand drill. Very simple and easy. You can go 10mm as that is the hole size in the head gasket.

[KiwiRS4T]

It would be good to get some hard evidence about the rear "drain". Some say, and I tend to agree, that it really functions as a sump breather in which case it might as well go to the catch can as to the back of the head. Someone talked about putting a plastic hose on the head drain and sticking a video camera in there but there is a much simpler way.

What is needed is someone who has overcome the problem of filling the cam covers with oil on the track (not someone still experiencing this problem because if the cam covers really are filling up with oil - as happens - then some of that oil is bound to go down a rear head drain pipe) to take the end that goes to the sump and stick it (securely) in a container and run a breather to atmosphere or a catch can from the fitting on the sump it came off. Then give it some stick for a few laps and see how much, if any, oil is in the container. It wold take a selfless searcher for truth to do this because this person would have already solved their problems and for them it would only be of academic interest but for the rest of the RB world it would be valuable information!!

[BoostdR]

I couldn't do 2 laps without filling my catch can. I had a reinmax pump and revving to 9200rpm on a 3ltr. Changed the restrictor to 1.1mm from 1.5 and installed a head drain. I then had not a single drop of oil out the catch can after 20 laps. Cams had plenty of lubrication. The rear head drain hose burnt closed and made no difference to how much oil was in the head. It just comes down to matching your oil pump flow to your restrictor size.

I also had mines triple flow baffles and a 1.1 litre increased baffled sump.

Matt

[KiwiRS4T]

Thanks for that. So you're saying the rear drain doesn't drain. Was the head an RB26 or 25, solid or hydraulic lifters? Just one oil feed no vct? And the mines triple flow baffles are they in the cam covers (as opposed to sump baffles)?

Thanks

Bob

[BoostdR]

26 head, cam baffles

[JustinP]

I bought 2 x Tomei 1.5mm oil restrictors for my RB25DET Neo build. Yes I know best practice is to block 1 completely and run the restrictor in the other. Anyway I just went to put them in and realised the standard Nissan restrictors are already 1.5mm each.

My understanding was that the standard restrictors are 2mm. Maybe they are 1.5mm on the Neo as they come standard with an N1 oil pump?

Anyway I think I will get 2 x 1.2mm restrictors and run with those.

[JonnoHR31]

rb30 are 2mm. all rb25s are 3 x 1.5mm factory, with the front being solely for vct

[kitto]

rb30 are 2mm. all rb25s are 3 x 1.5mm factory, with the front being solely for vct

Interesting. I'm about to pull the head off of my NEO engine. Jonno, What would you suggest to do with the restrictors if i'm retaining the factory N1 oil pump the NEO comes with.

I tried to follow sydney kids table as best as i could and also worked out the cross sectional area of different size restrictors. But still pulling my hair out as to which one to choose.

Now going by Simon-S14's NEO which is a full on drift car which sits on the limiter like no tomorrow, he says he has no issue with oil pumping into the head. However he is at high revs for shorter periods of time than a circuit car.

I was thinking of blocking the centre oil feed as per SK's table and maybe going down to a 1 - 1.3mm oil restrictor in the rear.

Any thoughts?

[KiwiRS4T]

I just pulled my engine out as it was filling the can covers with oil and putting out great clouds of smoke on the track and oiling up the whole engine bay. The block was bought already prepared so I was suprised to find it already had 2 x 1.2mm restrictors. We are fitting 2 x 1.0mm restrictors and two 20mm breathers to the sump. Will let you know how it pans out.

[kitto]

I just pulled my engine out as it was filling the can covers with oil and putting out great clouds of smoke on the track and oiling up the whole engine bay. The block was bought already prepared so I was suprised to find it already had 2 x 1.2mm restrictors. We are fitting 2 x 1.0mm restrictors and two 20mm breathers to the sump. Will let you know how it pans out.

What engine and oil pump do you have?

[TiTAN]

I bought 2 x Tomei 1.5mm oil restrictors for my RB25DET Neo build. Yes I know best practice is to block 1 completely and run the restrictor in the other. Anyway I just went to put them in and realised the standard Nissan restrictors are already 1.5mm each.

My understanding was that the standard restrictors are 2mm. Maybe they are 1.5mm on the Neo as they come standard with an N1 oil pump?

Anyway I think I will get 2 x 1.2mm restrictors and run with those.

the tomeis squash down to around 1.2-1.3mm once installed.

[KiwiRS4T]

What engine and oil pump do you have?

RB30/25 N1 pump. I know SK's chart says to completely block one feed but my mechanic thinks that's not safe. Engine is back in and should be running tomorrow. He has also had good results with putting RB26 cam covers with Mines baffles but there is no room on my engine because of the position of the w/g on my custom made manifold.

[kitto]

RB30/25 N1 pump. I know SK's chart says to completely block one feed but my mechanic thinks that's not safe. Engine is back in and should be running tomorrow. He has also had good results with putting RB26 cam covers with Mines baffles but there is no room on my engine because of the position of the w/g on my custom made manifold.

Yeah id like to put RB26 covers on mine with the baffle plates but factory plenum doesnt allow to.

[kitto]

RB30/25 N1 pump.

By the way, hydraulic RB25 head or NEO with solid lifters?

[KiwiRS4T]

By the way, hydraulic RB25 head or NEO with solid lifters?

Hydraulic lifters and VCT enabled

[kitto]

Hydraulic lifters and VCT enabled

Ok then, well i have a NEO with factory N1 oil pump. If you were pumping too much oil into your head with 1.2mm restrictors then i'll probably block one feed and run something like a 1.3mm in the other.

I have solid lifters so i can block one completely, probably not the best to do it with yours as you still have hyd buckets.

When will it be on the track again so you can compare results by going with 1.0mm restrictors?

[KiwiRS4T]

Ok then, well i have a NEO with factory N1 oil pump. If you were pumping too much oil into your head with 1.2mm restrictors then i'll probably block one feed and run something like a 1.3mm in the other.

I have solid lifters so i can block one completely, probably not the best to do it with yours as you still have hyd buckets.

When will it be on the track again so you can compare results by going with 1.0mm restrictors?

As well as the restrictors I am hoping that the two 20mm breathers in the sump will help with oil return from the head.

Also have Tomei baffle kit in the (awd) sump.

Hampton Downs 25 March but I should get some indications on the dyno as I am upping the boost from the initial 10psi to 18 - 21. When it is tuned I may be able to fit in a test day at Pukekohe late in Feb. Will keep you posted with any results.

[kitto]

As well as the restrictors I am hoping that the two 20mm breathers in the sump will help with oil return from the head.

Does this mean your running 2x 20mm breathers from the top of the intake side of the sump to the top of the catch can?

[JustinP]

I am going to drill out the 5 x oil return galleries in the block (9.5mm) and will clean up the 2 larger oil returns at the back of the block (RB25DET Neo).

I don't currently have the head with me as it is currently being checked and machined etc, but I assume I am correct in thinking that the galleries in the head will need to drilled out to match.

As I don't have it with me so I cant quite remember where those galleries end up in the head, but I assume you need to drill them out with the cams not installed?

Trouble is it will comeback all clean and assembled, I would rather not go drilling into it

[kitto]

I am going to drill out the 5 x oil return galleries in the block (9.5mm) and will clean up the 2 larger oil returns at the back of the block (RB25DET Neo).

I don't currently have the head with me as it is currently being checked and machined etc, but I assume I am correct in thinking that the galleries in the head will need to drilled out to match.

As I don't have it with me so I cant quite remember where those galleries end up in the head, but I assume you need to drill them out with the cams not installed?

Trouble is it will comeback all clean and assembled, I would rather not go drilling into it

Get your machinist to do the drilling for you.

But yes i'm doing the same. But i'll probably strip the head myself, do the drains, then get my machinist to just face the head for a new head gasket. Done.