Nissan engine range for Nissan Skyline – RB20-RB24-RB25-RB26-RB30

The Nissan Skyline started the life of the RB engine line. The Technical Specifications of the Line are as follows:

  • RB20-2 LITERS 1998CC, 78 MM BORO, 69.7 MM STROKE
  • RB24-2.4 LITERS 2428CC, 86MM HOLE, 69.7MM STROKE
  • RB25-2.5 LITERS 2498CC, 86MM HOLE, 71.7MM STROKE
  • RB26-2.6 LITERS 2568CC, 86MM HOLE, 73.7MM STROKE
  • RB30-3.0 LITERS 2962CC, 86MM HOLE, 85MM STROKE

Common letter designations across the range were:

  • D-indicates double overhead camshaft (DOHC)
  • E-indicates that the engine has fuel injection
  • S-indicates that the engine is carbureted
  • T-indicates that the engine is equipped with a factory installed turbocharger
  • The TT-rated engine is equipped with two turbochargers.

The first of the RB20 engines arrived in the R31 Skyline in 1986. The first incarnations of these engines had two main variants. The first version was double overhead cams that used a NICS (Nissan Induction Control System), this was an injection system with twelve small intake runners, it included a butterfly system that divided the air intake ports for a better low-end performance. Later this system was replaced by a system called ECCS (Electronically Concentrated Control System), this system replaced the twelve small corridors in exchange for six larger ones, although they still conserved twelve ports in the cylinder head, these were divided with air divider plates.

The different variations of the RB20 over the years were indicated by the addition of a letter code system.

  • RB20E-denoted a single cam variant
  • RB20ET- single cam turbo
  • RB20DE-double camshaft
  • RB20DET-Twin Turbocharged Camshaft
  • RB20P-another single cam variant
  • RB20DET-R-Turbocharged Twin Camshaft
  • RB20DE-NEO double camshaft with improved torque designed to reduce fuel consumption and emissions.

The RB24 was a very rare engine. It was made mechanically from different parts of the RB line engine. The block was from an RB25DE / DET, the cylinder head was from an RB30 and the crankshaft was from an RB20DE / DET with 34mm pistons. This engine was not injected but came with carburettors. This configuration allowed the engine to have essentially the same displacement as the RB25DE / DET, but higher revs.

The RB25 engine was produced in series in four main forms:

  • RB25DE-non turbo twin cam
  • RB25DET-twin cam turbocharged
  • RB25DE-NEO-non turbo twin cam
  • RB25DET-NEO-twin turbocharged cam

Since 1993, the RB25DE and RB25DET came equipped with NVCS (Nissan Variable Cam System), allowing the engine to produce more torque and power at lower RPM ranges than was possible in previous versions. Other changes that were made were the addition of a revised electrical system, the turbocharger on the Rb25DET was changed from an aluminum compressor to a plastic one, the ignition system was updated with the introduction of ignition coils with built-in ignitors, eliminating the Need for a separate coil lighter. Other changes during this time to the engine were the revised engine ECU, new throttle position and cam angle sensors, and a newly designed mass air flow meter. Mechanically, the engines were identical on Series 1 and Series 2 engines.

The RB26DETT engine was built throughout 1989-2002 primarily for the Nissan Skyline GT-R. The intake for the RB26DETT varies from the other RB series engines because it uses six individual throttle bodies rather than a single throttle body. It also uses a twin turbo system that runs in parallel. Both turbochargers are the same size and the wastegate is set to limit boost pressure to 10 psi. This engine is known for its strength and power potential. It is not uncommon to see people getting 600hp from these engines with no modifications to the internal components. Also from a reliability standpoint, these engines regularly hit 100,000 miles and even 200,000 miles as long as they are serviced regularly.

RB26DETT engines produced before 1992 were found to have a common lubrication problem. The surface where the crank meets the oil pump was machined a little too small, this eventually leads to a low oil problem and oil pump failure at higher RPM. Later versions of the engine fixed this problem and aftermarket performance parts manufacturers manufacture oil pump extension units to eliminate this problem.

The RB30 engine came in the following configurations:

  • RB30S- single cam carburetor
  • RB30E- single cam fuel injection
  • RB30ET – Fuel Injected Single Cam Turbocharger

The RB30DET engine was not actually produced by Nissan, the RB30DETT demarcation actually refers to a turbocharged engine that commonly had an engine block from an RB30E, this was mated to a cylinder head from an RB25DE, RB25DET or RB25DETT, RB20DE / heads DET were not used due to the difference in hole size.

You may be able to find slightly different variations of the above engines, these are commonly made by engine manufacturers with a bit of knowledge in the field. These engines are used quite frequently when people transplant different vehicles and intend to use them for performance applications. The engines are powerful and reliable and are capable of generating enormous amounts of horsepower when built correctly.

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