The Nissan RD engine series is basically a Nissan RB engine design, except that it is only a single overhead cam six-cylinder diesel engine. It was the successor to the Nissan LD and SD six-cylinder engines and was joined by the six-cylinder Nissan TD engine.
From 1997 onwards the turbocharged versions were fitted with electronic fuel injection. The turbodiesel version known as the RD28T (or RD28ET with electronic fuel injection) and were also fitted to the Nissan Safari (also known as the Nissan Patrol) off-road vehicle.
Since the Nissan RD engine is based on the Nissan RB engine, they have many similarities and many parts are interchangeable. The engine block was similar to the RB30 engine except it had more material, was heavier and had 85mm bore vs the 86mm bore of the RB30 and a 83mm stroke vs 85mm stroke. One issue is that the stronger vibrations from the diesel engine can loosen the crank/harmonic balancer bolt (originally from the RB engines) and in turn become loose or fall off causing major engine damage. It is recommended to use thread locking fluid when installing.
The cylinder head was of a non-crossflow design, meaning that the exhaust and intake ports were on one side of the cylinder head.
RD28
SOHC, bore
RD28 Series 1
12 valves (two per cylinder). When originally introduced, JIS gross were used rather than JIS net, meaning that early information claims and at the same engine speeds.
at 4,800 rpm at 2,400 rpm
Nissan Skyline R31 series 1985–1987
Nissan Laurel C32 ~ C34 series 1986–1993
Nissan Cedric / Nissan Gloria Y30 ~ Y32 series 1985–1993
Commercial (taxi) Nissan Cedric / Nissan Gloria Y31 series sedan 1987–1999
Nissan Crew K30 series 1993–1999
Nissan Cefiro A31 series 1988–1993
No PCV on the tappet cover.
RD28 Series 2
at 4,800 rpm at 2,400 rpm
Nissan Cedric / Nissan Gloria Y32 & Y33 series 1993–1999
Nissan Laurel C34 - C35 series 1994–1999
RD28E
at 4,800 rpm at 2,400 rpm
Commercial (taxi) Nissan Cedric Y31 series sedan 1999.08-2002
Nissan Laurel C35 series 1999–2001
Nissan Crew K30 series 1999-2009
Vacuum pump located on tappet cover.
RD28T
SOHC turbodiesel
at 4,400 rpm at 2,400 rpm
Nissan Safari Spirit series Y60 2-door soft-top 1996–1997
Nissan Civilian Bus
RD28ETi1
electronically controlled turbodiesel with an intercooler
at 4,000 rpm at 2,000 rpm
Nissan Safari Spirit series Y61 2-door soft-top 1997–1999 (automatic transmission)