The Nissan H series of automobile engines is an evolution of the Nissan "R" engine which was based on the 1.5-liter, three-main bearing "G" engine used in the 1960s. Both inline-four and inline-six versions were produced. It is a pushrod OHV design with iron block, early models with an iron head, later models with aluminum head. Versions of this motor have been used in many Nissan autos and forklifts, well into the eighties and a version called H20II was in production until 2003. The SD diesels are based on this series of motors (bore spacing and basic block layout)

Inline-4

1H

The 1H is not related to the later H engines. It was also an all-iron, OHV engine, but this was a licensed BMC (Austin) B engine. With a bore and stroke of 73x89 mm it displaced 1489 cc, power was 50 PS at 4,400 rpm in 1956, but this increased to 57 PS in August 1958. The license agreement terminated in the late 1950s and the Nissan G engine was a more compact replacement, which in turn became replaced by the (below) Nissan H engines. The 1H would also be de-stroked from 89mm to 59mm to become the 1.0 L (990 cc) to create the Nissan C engine at the suggestion of former Willys-Overland engineer Donald Stone. Applications:

H

The basic H is a 1883 cc engine produced from 1962 for Nissan's Cedric. Bore and stroke was 85x83 mm. The 8.0:1 compression version produced 92 hp and 159 Nm, while a high-compression engine (8.5:1) produced 95 hp and 163 Nm. Applications:

H20

The H20 is the most-common member of the family. Displacing 1982 cc thanks to a larger 87.2 mm bore, H20 engines produced around 99 hp and 167 Nm. Applications: Also N230S, T40, forklifts and other machinery

H20P

The H20P is the LPG-powered version of the H20. Applications:

H25

The H25 was developed as a high-output version of the H20. This engine was used in forklifts. 2472 cc bore x stroke: 92x93 mm.

R (H16)

The R engine used essentially the same block as the H20, but a 17 mm shorter piston stroke resulted in a capacity reduction of 387 cc. The R was later named H16. The "R" motor made the switch from 3 to 5 main bearings in 1967 for improved reliability, and the H20 was developed from this arrangement. The R/H16 bore and stroke is 87.2x66.8 mm displacing 1595 cc. With 9.0:1 compression, the engine produced 96 hp and 103 lbft. Applications:

U20

The U20 was similar to the H20 but with an SOHC cylinder head for motorsports applications. Although Prince Motor Company is credited in many sources with designing the U20, it was actually designed in-house at Nissan by Kenichi Sasaki. The U20 was produced in two forms: a stock 135 hp version with twin SU carburetors, or a 150 hp version with twin Mikuni/Solex carburetors and a "B" model camshaft. Applications:

Straight-6

K

The K engine is a 2825 cc straight-6 engine produced from 1963 to 1965. The K engine is an H engine with two extra cylinders. The K engine produced 118 hp. Applications:

H30

The H30 is a 2974 cc straight-6 version produced from 1965. Output ranged from 120 to 130 PS and torque is 163 lbft. The H30 is an H20 with two extra cylinders. Applications: This engine is used in large forklifts