The Toyota R family was a series of inline-four gasoline automobile engines. Designed for longitudinal placement in such vehicles as the Celica and Hilux and in production from 1953 through 1997, usage faded out as many of Toyota's mainstream models moved to front-wheel drive. Overhead cam (OHC) versions featured a chain-driven camshaft.
History of the R family
R
The R family was produced from 1953 through 1964, and was originally manufactured at the Toyota Honsha plant.
Bore and stroke was . In common with new engines of the time, it was made from cast iron (both the block and the head), water cooled, used a three bearing crank, 12V electrics and a side-mounted gear-driven camshaft controlling overhead valves via pushrods in a non-cross flow head (exhaust and inlet manifolds being on the same side of the engine). Induction was by a twin throat down-draft carburettor, the compression ratio was 8.0:1 and the total weight was . An LPG version, the R-LPG, was produced for the last two years.
The R engine was the Toyota engine used in the 1958 Toyota Crown, the first model to be exported to the United States. Road & Track was unimpressed with the engine on its introduction, noting that it idled quietly but was "not capable of very high revolutions per minute."
Applications: 1953–1955 Toyota Super 1955–1956 Toyota Master 1955–1958 Toyota Crown
2R
The 2R family was produced from 1964 through 1971. It is a square engine, with bore and stroke of .
Again, an LPG version, the 2R-LPG, was produced alongside the gasoline version. Production had been gradually transferred from the original Honsha plant to the new Toyota Kamigo plant in 1968.
Applications: 1964 – January 1970 Toyota Corona RT40/RT46V/RT50/RT56 February 1970 – January 1971 Toyota Corona RT80/90/86V 1968–1971 Toyota Mark II Toyota Bus RH15B 1965–1967 Toyota Stout RK43/RK47 Toyota ToyoAce PK41 Toyota Hilux RN10
3R
The 3R family was produced from 1959 through 1968.
When introduced it had a 7.7:1 compression ratio. In 1960 the 3R was uprated to 8:1 and the 3R-B version was offered from 1960 through 1968 with the old 7.7:1 compression ratio. The 3R-C was introduced to comply with California emissions laws. The 3R-LPG variant was produced for the last five years.
Applications: 1963–1968 Toyota Dyna 1964–1967 Toyota Stout, originally 1969–? Toyota Hilux 1967–1969 Toyota Corona (US) 1959–1967 Toyota Crown 1960–1967 Toyopet Masterline
4R
The 4R family was produced from 1965 through 1968.
Bore and stroke was .
Applications: 1967 Toyota Corona (Japan) 1967 Toyota 1600GT (Japan)
5R
The 5R family was produced from 1968 through 1986. An LPG version, the 5R-LPG, was produced from 1968 through 1983.
It is a 2-valve OHV engine. Cylinder bore and stroke are . Output was at 5200 rpm and at 3000 rpm. Trucks such as the Dyna received a version tuned for torque, with a maximum power of at 4600 rpm and torque of at 3000 rpm.
Applications: Toyota Crown: third through sixth generation (RS50, RS60/66, RS80/RS100, and RS110). Only with LPG for taxi use in the last two generations. 1969-1977 Toyota Coaster RU18/RU19 Toyota Dyna RU10/RU20/RU30 Toyota Stout RK101 Toyota ToyoAce RY20 Aug 1981–? Toyota Corona sixth generation (RT131), only LPG combined with automatic transmission.
6R
The 6R was produced from 1969 through 1974. Output is at 5,300 rpm. The 6R-B was produced those same years, while the natural gas powered 6R-LPG was produced from 1970 through 1973.
Applications
Sep 1970 – Jul 1973 Toyota Corona RT84/94
Jan 1972 – Aug 1973 Toyota Mark II RX16V –
7R
The 7R was produced from 1968 through 1971 with a twin throat down-draft carburettor. The 7R-B was produced from 1968 through 1969 with dual SU carburetors and higher compression. The 7R-LPG was produced from 1969 through 1970.
The 7R was similar in displacement and technology to the 4R except the wider bore and shorter stroke of the 7R gave different power characteristics.
Applications: 1968–1970 Toyota Corona (RT41 sedan, RT53 hardtop, RT54 hardtop) 1970 Toyota Corona (RT82 sedan) 1968–1970 Toyota Corona Mark II (RT6x) 1968–1971 Toyota Corona Mark II Wagon (RT76D)
8R
The 8R The engine was produced from 1968 through 1973. Cylinder bore and stroke was with a five bearing crank. It was also available as the 8R-D, dual SU 8R-B, EFI 8R-E, Californian-spec 8R-C and DOHC 8R-G.
It was a major departure for the R family. With a 2-valve SOHC head, it impressed contemporary reviewers – Road & Track praised its quietness and free-revving nature.