We manufacture many different combinations of oil restrictors for the RB, CA and SR engines. The benefit of them is to restrict the oil flow to the top end ensuring the sump has as  much oil in it as possible to prevent oil starvation to the bottom end.  Our restrictor sizes and combinations are a decision made up of hundreds of hours testing on track and street cars. Use these combos below and please state when ordering what engine etc you have.

1. RB20   RB25 HYDRAULIC HEAD     2x 1.3mm restrictors

2. RB30/25 head HYDRAULIC            2X 1.3mm restrictors

3. RB30/25 NEO solid lifter head         1x 1.3mm  1x blockoff

4. GTR RB26 ALL solid lifter              1x  1.3mm  1x blockoff

5. CA 18 hydraulic                           1x  1.5mm restrictor

6. SR 20 hydraulic                           1x   1.5 mm restrictor

7. CA and SR solid lifter conversion     1x   1.3mm restrictor

8. RB25 NEO                                  1x   1.3mm  1x blockoff

9. RB30 single cam                           2x 1.3mm restrictors

Fitting...........simply knock existing restrictor down into hole and fit our restrictors on top. Lightly peen over around the edge of block surface....

Can be purchased from 'nissan' section of 'engine parts' area............  

OIL RESTRICTOR FITTING INSTRUCTIONS

Tap original factory restrictor down into hole until seated it will go down approx 10mm

Slightly deburr top of hole

Knock in new restrictor with punch no more than 1mm smaller than restrictor,knock in until 1mm below surface

Gently peen surface of block around edge of restrictor to ensure it doesnt lift under pressure.

oil pump failure  RB engines.....

Over the past few years there has been a hell of a lot of confusion as to why the RB engine suffers from oil pump breakage. Some interesting reading on some forums recently provided all the causes known to man .Some even threatening to sue nissan for their NEW N1 pump breaking !!!. 

Basically the nissan factory RB pump , and N1, therefore is good for and designed for a factory engine . At the factory rpm limits there is never an issue.

Lets look at a CA and an SR engines oil pump design . Identical to an RB pump in material ,design and strength. I have never heard of an oil pump failure in any CA or SR at any rpm !!!!! Consequently the difference being at high rpm the 4 cylinder engine is alot friendlier with crankshaft harmonics. Therefore i directly relate the RB pump problems to a high rpm crank harmonics issue where the front of the crank snout is whipping and buzzing crazily and what,s the weakest link?  the driven oil pump gear. Its thickness in material from the drive flat to the root of the geartooth is physically not strong enough to tolerate the inline sixes inbuilt harmonic problems. Along with the gears construction of sintered iron is not a unit likeable to the high rpm situations most often in these engines.

Pump breakage usually occurs over 7500rpm.   We rate the factory and N1 pumps good to 7500 rpm after that the only pump that will live is the TOMEI oil pump. The gear quality being chrome moly is a superior material along with the brute physical strength of the gear to driveflat dimension. In some combinations of turbocharger and engine setup the engine will rev so fast through its harmonic stages that it creates an even more severe harmonic problem where harmonic balancers can be literally thrown off the crank snout. The long stroke rb30 is not a favorite for high revs nor when its combination allows it to pass through its harmonic stages fast.  We consider for extended rpm and  rev limiter use in these combos to favor the use of an rb26 crank as maximum stroke.   These harmonic  problems can be helped by

1. high quality crankshaft balance

2. fitting of a ROSS drift balancer which will help dampen the harmonics and provide extra insurance.

One thing you can be assured of is that if you have oil pump issues you know that youre RB is revving hard and fast and is a good sign ,so to speak, of a good performing engine. We often hear of 'my mates 300rwkw RB with an N1 pump that hasnt broken'

,,, these cars are often street cars or big number dyno queens  that seldom see extended high rpm periods and do not pass through the harmonic periods fast  as drifting and track cars do. 

Also its not commonly the rpm,s that are the issue it is how quick the engine

goes through its harmonic periods. An engine that revs very fast will most often be a candidate for oil pump gear breakage and harmonic related breakages. Of course we recommend ,as would most builders,a dry sump style oiling setup in any race car, but in keeping with peoples budjets and their affordabilities we have to do the best with what we have..

The stroke/rod length and rotating weight of the 20/25 and 26 engine is perfect for excess of 9000rpm. The RB30 stroke length when exceeding 7500rpm is a disaster waiting to happen. Its stroke /rod length is not tolerent to 7500 and upwards rpm so any modifications made to help this is in the best interest of the customer and at his/her own risk when exceeding approx 7500rpm...

OUR BILLET RB oil pumps are currently in production for release next year, they have the strongest gears and a full spline drive collar, external regulator and will come with a lifetime garuantee against breakage when used on 20/25 and 26 engines ..

The old motto is ... ' better to spend $1800 on an oil pump than build 3 bottom ends'..................................