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Sunday, January 23, 2011

RB26 Oiling : Oil Pumps : Oil Restrictors : Oil Pan Modifications

The oil pump is the engines heart. Oil is its blood.  Carrying good stuff to all the parts in the engine, taking bad stuff away.  If the heart fails, the engine fails.  In the case of an RB26, when something goes wrong, you normally have a rod exit the block. When that happens, you end up with a lot of scrap metal. To avoid large, expensive pieces of scrap metal, you should read though a few of the items I have posted below.
This is what happens when you spin a rod bearing at 8,000 rpm on the road course
That same rod, which is usually #2 due to oil, also took out the oil pan. Trash, everything
  • Oil pump
  • Spline drive oil pump gears
  • Oil restrictor
  • Oil pan baffle plates
  • Oil pan modifications
  • Oil pickups
  • Oil drain back
  • Accusump
  • Cam Cover
  • Dry Sump - Street car 



Oil pump


A cool fact about the oil pump, its not generally possible to replace in the car due to the oil pump relief valve being in the way. Also to get the oil pan off, you need to drop the subframe. When you drop the subframe, nothing supports the engine.
Its a much easier job to take the motor out. A few people have changed them in the car. I have changed them in the car, but after the rig supporting the motor slipped one time, I will never do that again. 450 lbs of motor crashing down on my head is not how I want to die.
  • Stock
  • N1
  • Nismo
  • JUN
  • Broken Jun gear at the flat
    •  
  • Greddy
  • HKS
  • Reinik
  • Tomei

    • Tomei Oil Pump
  • Dry Sump

Oil pump drive

There is an early and a late oil pump drive.  The early drive only very minimally engages the flats on the oil pump gear to drive it.  You can see when Nissan went to the later style pump that the width and engagement about doubled. If you have an early crank, you should think about swapping the crank out for a later crank, or purchasing a crank collar.

Early oil pump drive
Early drive- Notice how much smaller it is than the late drive. Also notice the small shiny spot. That area is the only part that actually engages the pump. 


Late oil pump drive









Late drive - Notice the wear on the flat spot. Compare the width here to the early drive shown below.








Spline Drive replacement gear set 

The Spline Drive gear set was launched in 2014 after a long R&D process to offer a product that not only improves the over all strength of the pump gears as upgrades for the N1 and OEM pumps, but also changes in the way in which the gears engage with the crank. As per Toyota’s 2JZ GTE engine the best solution would be to incorporate a spline engagement which would totally eliminate the underpinnings of Nissans troublesome flat drive design.
Spline Drive Gear installed on RB26 crankshaft

The RB26 is a legendary engine in its own right and an iconic powerhouse amongst enthusiasts and tuners all over the world. One aspect of the engine that is considered its Achilles heel is certainly the oil pump. Over the years there have been reports of numerous failures where the inner and sometimes the outer gears have broken during hard use of the engine be it on the road or on track or drag. Contrary to popular belief the wider nose crank which was introduced on BNR32 models from Feb 93 onwards and standard on BCNR33 and BNR34 models, while reducing the possibility to a degree did not eliminate the issue fully.
Various attempts were made over the years to address the issues, Tomei, Jun, Greddy, HKS and Reimax (Japan) and Nitto (Australia) all made uprated pumps with bigger diameter and thicker pump gears to increase flow and overall strength which is much needed on track or on a high revving RB26 to ensure the engine has ample oil supply and durability. However they are based on the flat drive design.
Tomei oil pump with Supertec Spline Drive
Nissans own OEM pump (81mm outer pump gear) as supplied from the factory along with the N1 pump (77mm) utilise gears made from sintered metal which is weaker than billet steel equivalents. The Nismo pump is a steel version of the N1 with same flow and pressure. Reimax offers a billet steel gear upgrade kit for both OEM and N1 pumps, but upon testing we found clearances to be greater than stock N1, OEM and Nismo pumps, which in our view would increase potential failure.
Buy a Spline Drive gear set here!

Oil restrictor

Located in block. Limits the amount of oil that flows to the head. As the RB26
is solid lifter, it does not need as much oil up in the head as a hydraulic lifter RB25.

Stock 2.0mm
N1 1.2 mm
Tomei 1.5 mm


Swinging oil pickup

  • Special Nismo part
  • Was used in the Super Taikyu spec motors
Swinging oil pickup in an RB26dett


     

     

     

     

     

     

    Oil pan baffle plates and modifications

    Stock RB26 oil pan. Front differential is on the right side.

     

    Tomei baffle plate


    Extension on left side of the pan.
    Subaru owner removing RTV from an RB26 oilpan

    Extended sump on Australian GT-R

    Greddy Oil pan extension installed. I do not like that the oil drain bolt is the lowest thing on the car

    Greddy Oil pan extension installed. I do not like that the oil drain bolt is the lowest thing on the car

    Greddy Oil pan extension installed. I do not like that the oil drain bolt is the lowest thing on the car

    Oil Drainback





    Oil drainback for rear of RB26 head

    Some people modify their RB26 to return oil that accumulates at the back of the head directly back to the oil pan. Some will return to the oil drain, others to other places on the engine. You can buy an oil drainback here.

    Accusump

    .
    The Accusump is an oil accumulator that stores a reserve of oil under pressure. Under conditions of a drop in oil pressure, the oil that is in the Accusump pressurizes the oiling system. Once the oil pressure comes back up, the Accusump fills back up



     

    Cam Cover

    The cam covers, or valve covers in an RB26 have breathers at the back of the engine.  An RB26 moves a lot of aerated oil around in the engine and though the top of the engine. An oil catch can, and baffled breathers are important to prevent oil contaminating the intake air.

    Stock valve cover baffling at the top. Nismo N1 baffling at the bottom.

    Dry Sump

    Why do you need dry sump? If you have to ask that question, then you probably don't need it. It is seriously for the 2% of people out there that exceed the capacity of their oiling systems. They are expensive, complicated, and belt driven. However they are the most positive way to insure you have oil pressure at all times. There is a reason that all serious race engines use some kind of dry sump to ensure oil pressure. 

     Imagine an engine. Imagine G-forces. 1 G is the force of gravity. Many cars can accelerate with more than 1 G. Laterally we can see over 1 G. Braking we can see more than 1 G.  Oil is the fluid that cools and protects components in the engine. It carrys away the bad stuff (dirt, debris), and is a non compressible fluid between the rotating and stationary parts of the engine. In the case of a rod bearing its rotating and reciprocating, but you get the idea.  At 1 G, laterally, imagine standing the engine on its side. Where does all the oil in the pan go? It all goes to the opposite side. Now if you are turning big RPM, and the oil pump is sucking up as much oil as it can, what happens when it sucks air? At some point it runs out of oil in the pan. This air, supplied to the oiling system is compressible. Things happen like the bearings and rotating equipment comes into contact. If this happens enough, we spin a bearing. Heat turns the spun bearing into mush. Spin it long enough and that same heat weakens a part, and if you are unlucky enough, it ends up looking like the engine at the top of this post. 

    A dry sump setup actively scavenges oil from the engine. So not only is it picking up from the pan, it is pulling oil from certain sections of the engine. It takes this oil that is scavenged and puts it in a oil tank. The oil tank helps to separate any air from the oil and then maintains a positive head of oil on the supply side of the dry sump pump. Air is the enemy in the oil system. Keep it out, your bearings will thank you for it.  Dry sump isn't for everyone. However if you are big into circuit, or drag racing, I highly recommend it. If you can't afford to do it right once, then you certainly can't afford to do it twice. 

    Dry sump on a street car R32 GT-R
    Dry sump pump

    Ross Dry Sump

    Ross dry sump pump. Also visible is their damper with crank trigger. 
    Four Stage Dry Sump pump. 1.5" Pressure. 3 x 1.75" Scavenge with integral regulator. RB25/26/30 configuration
    More information on the Ross dry sump kit
    Modified RB26 oil pan. 4 stage dry sump pump. Pulley and Belt. Bracket. Cam trigger, Crank trigger

    Some more dry sump pans








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