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Sunday, November 25, 2007

RB26DETT information : The myths , the truths

Twin T51R SPL RB26DETT
The RB26DETT. An engine of much myth. We are going to try and set out some truths. Remember to trust nothing you read on the internet, or is it trust everything that you read on the internet?

1000 horsepower stock?
Just put a chip to make 500 horsepower?
Is it true that the RB26 early block from the BNR32 is very durable compared to other standard blocks?














  • Rated at 280 ps (Pferdestärke) or 276 horsepower stock from 1989-2002
    • Found in the R32, R33, R34 GT-R
    • Also found in the Stagea 260RS (aka Nissan Skyline GT-R Wagon)
    • The RB26DE was available in the Autech R32
  • Inline 6 cylinder
  • Iron block
  • Aluminum head
    • 24 valve
  • 2568cc of displacement
  • 86mm bore x 73.7mm stroke
  • Twin turbo
  • Individual throttle bodies - that is six in groups of 2
  • Coil on plug ignition
  • Interference engine
  • Stock R32 Dyno chart
R34 - Nissan Skyline GT-R


Top of the motor
  • Valve/Cam covers
    • Aluminum.Black on R32/R33. Red on R34. Nur on the Nurs. Two
      breathers located at the back of the plenum. Drivers side goes to PCV
      valve. There is a crossover tube. Left side goes to the inlet
      side of the rear turbo. 
  • Spark plug cover
    • We like to leave them off to keep the coils cooler. The engine looks
      more finished with the spark plug cover. You know the piece. Says
      Nissan Twin Cam 24 valve on it.

  • Front cover
    • The part that says RB26. Covers the timing belt. Not recommended to leave off. 
      • Aluminum on R32/R33. 
      • Plastic on R34.
  • Igniter box
    • R32/R33 located at the back of the spark plug cover. 
    • Igniters are build into the coils in the R34.
  • Coils
    • Coil on plug. R32/R33 are the same.
      • The front two coils on a early 90's Infiniti Q45 are the same 
      • 22433-60U01 
    •  R34s have the igniter built in. 
      • 22448-25U00 (coil assy)
      • 22465-59S00 (boot)
    • How to clean/repair misfires. 
    • RB26 coils or coil packs

  • Spark Plugs
    • PFR6A-11 are the stock plugs
      • Heat range 6
      • 1.1 mm gap
    • NGK are the best plugs
      • BCPR7EIX are one heat range cooler and iridium
      • We like the racing NGK when we are serious. Double fine wire heat range 10
  • Camshafts
  • Valves
    • Intake 34.5 mm
    • Exhaust 30 mm(sodium filled)
  • Head bolts
    • (14) 12 mm head bolts
  • Head
    • 4 valves per cylinder
    •  Twin cam
    •  Cam on bucket
    •  Shim under bucket adjustment
  • Head gasket

RB26 combustion chamber


Induction side
    • Lean cylinder is #6.
  • Throttle body
    • 6 individual throttle bodies. Cars have done over 1000 whp on stock throttle bodies.

  • Balance tube
    • Vacuum/boost and water pass though the balance tube


Exhaust side
  • Exhaust manifold
    • Stock
    • N1
    • Stock manifold on left, Modified N1 on the right
  • Turbocharger
    • Ceramic exhaust wheels that break off
      • The RB26 used a ceramic exhaust wheel to reduce the weight and interia, plus increase the heat capacity of the turbocharger. Great in theory, but in real life, overspinning the turbo, or detonation causes the ceramic wheel to become detached from the turboshaft.  Anything above about 14 psi, about 1 bar is considered dangerous. However even with less boost, and bouncing off a rev limiter (like a Bee-R limiter) will most likely result in missing exhaust wheels, and normally aspirated, low compression RB26's.  
  • Exhaust elbow/Outlet pipe
    • Contains 02 sensors
      • R32 are narrow/small 02 sensors
      • R33/R34 are "normal" size
    • Cast piece for the R32/R33
    • R34 Vspec has EGT in rear turbo outlet
  • Downpipe(Frontpipe)
    • Stock is relatively small diameter
    • Has a flex tube in it. The flex tube is important due to the rocking motion of the engine

Bottom end of the motor

  • Pistons
    • 86mm. Stock pistons are oil cooled.
      •  1.5 mm top ring, 1.5 mm 2nd ring. 
    • N1 has 1.2 mm top and 2nd ring
  • Rods
    • 121.5mm center to center. 
    • RB28's have 119.5 c-c except in a GT block(RRR)
  • Oil squirters
  • Crankshaft
  • Main cap/girdle
    • Seven main bearings. 
      • #4 being the center main bearing and containing the thrust bearing. 
    • The other six main bearings are all the same construction.
    • Bottom end of the RB26 showing the main girdle
  • Oil pump
    • The early cars- pre 1991 had a narrow oil pump drive as listed above
    • The only way to remove the oil pump, is to pull/drop the pan, as the oil pump relief valve prevents you from pulling it straight off the end of the crank
    • The OEM design leaves some areas to address, as it has a tendency to be loose on the crank drive. The looseness eventually causes the oil pump to crack at the flats. This causes oil to push out the front main seal
    • We had tons of problems with N1 oil pumps, and won't use them on any of our builds
    • There are some aftermarket solutions, such as spline drives.
  • Oil pan
    • Cast aluminum
    • Contains the front differential
    • Weighs about 55 lbs
The front differental is on the right side of this picture
    • 05U on the side. A standard block.
    • 24U on the side. An N1 block
    • RRR on the side .GT Block . That one is special
    • RB30
    • RD28



  • Water pump
    • Stock
    • N1 
    •  
      Far pump is N1, close is normal. Notice the N1 backing plate
Engine Control Unit
  • MAF
    • 65mm. Each will meter air up to about 200 whp each.
  • Fuel injectors
    • 444 cc. 
    • Yellow top.
    • Top feed
    • Low impedance
  • Fuel pump
    • 195 liters per hour - R32
  • Crank angle sensor
  • R34 CAS on the left, R32/R33 on the right
    • R32-R33
      • Late R32 and early R33 had a slightly different looking sensor
      • R34
    • The R34 uses a different cam drive for the sensor.
    • R34 CAS

    • Checking ignition timing and TDC

Induction

  • Inlet piping
Divided twin turbo pipe
    • Rear inlet piping collapses under boost.Replacing it with hardpipe is recommended.





  • Intercooler
    • Stock intercooler will provide better response to approximately 600 wheel horsepower.
    • The factory cooler is front mount, fairly large for a stock part, with large inlets and outlets. 
Buy RB26 , RB26DETT parts here. Gasket kits , water pumps , timing belts , camshafts. New OEM, and aftermarket parts. .

4 comments:

Anonymous said...

Is it true that the RB26 early block from the BNR32 is very durable compared to other standard blocks?

Oh this is bugging me in a while as well- what is the OEM head gasket thickness of the RB26? I've been seeing different posts on forums, some say 0.9 while others up o 1.2 just like aftermarket ones.

Sean Morris said...

Everyone says the early blocks are better. Not sure if there is any truth, or just urband legend.

The stock headgasket is 1.2 mm.

https://sites.google.com/site/tyndago/gt-renginespecifications

Anonymous said...

Hi Sean! Do you consider the RB26's PCV valve a "maintenance part" lets say every 100k kms or so? Coz I've heard some mechanic says so to avoid horror stories of oil leaks. If so when do we GT-R guys replace them?

And does it literally just screws in w/o any need of teflon seal tape? I also read some blunders on stripping the threads of manifolds because of replacing this part.

Sean Morris said...

Everything in a car is a maintenance part. I am sure the PCV valve has a schedule, but like most, its replace when it has an issue. I would use sealant on it when I put it in. As far as damaging it, well its dissimilar metals, so you have to be a bit careful. The valve is stronger than the manifold piece. At worst you can always helicoil.

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