Range of Nissan engines for Nissan Skyline – RB20-RB24-RB25-RB26-RB30

The Nissan Skyline began the life of the RB Engine line. The Technical Specifications of the Line are the following:

• RB20-2 LITERS 1998CC, 78MM BORE, 69.7MM STROKE
• RB24-2.4 LITERS 2428CC, 86MM BORE, 69.7MM STROKE
• RB25-2.5 LITERS 2498CC, 86MM BORE, 71.7MM STROKE
• RB26-2.6 LITERS 2568CC, 86MM BORE, 73.7MM STROKE
• RB30-3.0 LITERS 2962CC, 86MM BORE, 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 engine cam equipped with factory installed turbocharger
• Camshaft indicated by TT engine equipped with two turbochargers

The first of the RB20 engines arrived in the R31 Skyline in 1986. Early incarnations of these engines had two main variants. The older version was a twin overhead cam using 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 better low-end performance. This system was later replaced by a system called ECCS (Electronic Concentrated Control System), this system replaced the twelve small runners in exchange for six larger ones although they still retained twelve ports in the stock, these were divided with air divider plates.

Different variations of the RB20 over the years were denoted by the addition of a letter code system.

• RB20E-denoted a single cam variant
• RB20ET – turbocharged single cam
• RB20DE Double Top Chamber
• RB20DET-dual overhead cam turbocharged
• RB20P – another single cam variant
• RB20DET-R – Turbocharged Double Overhead Camshaft
• RB20DE-NEO: Enhanced low torque double overhead camshaft designed to reduce fuel consumption and lower emissions.

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

The RB25 engine was mass-produced in four main forms:

• RB25DE – non-turbo twin cam
• RB25DET-twin cam turbocharged
• RB25DE-NEO – twin cam without turbo
• RB25DET-NEO-twin cam turbocharged

Beginning in 1993, the RB25DE and RB25DET cam equipped with NVCS (Nissan Variable Cam System) allowed the engine to produce more torque and power at lower RPM ranges than was possible in earlier versions. Other changes that were made were the addition of a revised electrical system, the turbocharger on the Rb25DET was changed from an aluminum to a plastic one, the ignition system was updated with the introduction of ignition coils with built-in igniters, removing the need for a separate coil igniter. 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 in series 1 and 2.

The RB26DETT engine was produced from 1989 to 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 instead of 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 the boost to 10 psi. This engine is known for its strength and potential power. It’s not unheard of to see people get 600 hp out of these engines with no internal modifications. Also from a reliability standpoint, these engines regularly get 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 crankshaft meets the oil pump was machined a bit too small, eventually leading to an oil shortage problem and oil pump failure at higher RPMs. Later versions of the engine fixed this problem and aftermarket performance part manufacturers make oil pump extension units to eliminate this problem.

The RB30 engine came in the following configurations:

• RB30S – single cam with carburetor
• RB30E – single cam fuel injection
• RB30ET – Single Cam Turbocharged Fuel Injection

The RB30DET engine was not actually produced by Nissan, the demarcation RB30DETT 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/DET . they were not used due to the difference in hole size.

You may be able to find slightly different variations of the above motors, which are commonly made by motor manufacturers with a bit of knowledge in the field. These engines are used quite often when people are doing transplants on different vehicles and intend to use them for performance applications. The engines are powerful and reliable and are capable of generating massive amounts of horsepower when built correctly.