Toyota R engine

The Toyota R family was a series of straight-4 engines produced from 1953 through 1995. It was designed for longitudinal use in such vehicles as the Celica and Cressida. OHC versions featured a chain-driven camshaft.

History of the R family

R

The 1.5 L (1453 cc) R family was produced from 1953 through 1964.

Bore was 77 mm (3.03 in) and stroke was 78 mm (3.07 in).Corona 1500 Parts Catalog, No.53282-67] 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 chain 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).x] Induction was by a twin throat down-draft carburettor, the compression ratio was 8.0:1 and the total weight was 155 kg.x] 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:
* 1964–1967 Toyota Stout, 85 hp (63 kW)
* 1969–? Toyota Hilux
* 1967–1969 Toyota Corona (US)
* 1959–1967 Toyota Crown
* 1959–? Toyota Masterline

4R

The 1.6 L (1587 cc) 4R family was produced from 1965 through 1968.

Bore was 78 mm.

Applications:
* 1967 Toyota Corona (Japan)

5R

The 2.0 L (1994 cc) 5R family was produced from 1968 through 1986.
An LPG version, the 5R-LPG, was produced from 1968 through 1983.

It was a 2-valve OHV engine. Cylinder bore was 88 mm (3.46 in) and stroke was 82 mm (3.23 in).
Output was 106 hp (79 kW) at 5200 rpm and 125 ft·lbf (169 N·m) at 3000 rpm.

6R

The 1.7 L (1707 cc) 6R was produced from 1969 through 1974.
Output was 107hp at 5300 rpm The 6R-B was produced those same years.
The 6R-LPG was produced from 1970 through 1973.

7R

The 1.6 L (1591 cc) 7R was produced from 1968 through 1971 with a twin throat down-draft carburettor.Toyota Corona Deluxe, Parts Catalog, No.53212-68]
The 7R-B was produced from 1968 through 1969 with dual SU carburettors 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 86 mm bore and shorter 68.5 mm stroke of the 7R gave different power characteristics.

Applications:
* 18R/18R-C/18R-U/18R-E
** 1972 Toyota Corona "2000"
** 1972 Toyota Corona "2000 MK. II"
** 1972 Toyota Celica "2000"
** 197X Toyota Cressida "2000"/"Gen1"
* 18R-C
** 1972-1974 Toyota Hilux, 108 hp (80.5 kW)
** 1974-1981 Toyota Celica "2000"

18R-G

The 2-valve DOHC 18R-G and its variations were produced from 1973 to 1982. While most 18R-Gs had a head designed and made by Yamaha, a very few had Toyota heads. Yamaha's tuning-fork logo can be seen on the Yamaha heads. Except for the head and related timing components, most parts were shared or interchangeable with the SOHC 18R.

In 1973, air injection was added to the Japan-market 18R-GR for improved emissions. A fuel injected Japan-market version, the 18R-GEU, was produced from 1978 through 1982.

Competition versions of the 18R-G and -GE include those used in rally Celicas of the period. Some of these engines had 4-valve heads and developed up to 240 HP (180 kW) of power.

Applications:
* 1973-1981 Toyota Celica GT 2000
* 1982-1983 Toyota Celica GT 2000 (RA63)
* 1974-1983 Toyota Carina GT 2000
* 1978-1983 Toyota Celica Camry GT 2000
* 1973-1982 Toyota Corona GT 2000

20R

The 2-valve SOHC 2.2 L (2189 cc) 20R was produced from 1975 through 1980.
Cylinder bore was 88.4 mm (3.48 in) and stroke was 88.9 mm (3.5 in). Aluminum alloy heads were used.

Initial output was 96 hp (72 kW) at 4800 rpm (90 hp in California) and 120 ft·lbf (162 N·m) at 2800 rpm. Power was down slightly from 1978 through 1979 at 95 hp (71 kW) at 4800 rpm and 122 ft·lbf (165 N·m) at 2400 rpm. The final version, from 1979 through 1980, was down again at 90 hp (67 kW) at 4800 rpm and 122 ft·lbf (165 N·m) at 2400 rpm.

Applications:
* 1975-1980 Toyota Hilux
* 1975-1981 Toyota Celica U.S. Version
* 1975 Toyota Corona U.S. Version

21R

The 2-valve SOHC 2.0 L (1972 cc) 21R was produced from 1978 through 1987.
Cylinder bore was 84 mm (3.31 in) and stroke was 89 mm (3.5 in).

Output in 1978, constrained by emissions, was 105 hp (78 kW) at 5200 rpm and 116 ft·lbf (157 N·m) at 3600 rpm. Air injection and California emissions equipment for the 21R-C (1982-1985) dropped power down to 90 hp (67 kW) at 5000 rpm. The air-injected Japanese version, the 21R-U, produced 105 hp (78 kW) at 5200 rpm and 120 ft·lbf (162 N·m) at 3600 rpm but dropped to 101 hp (75 kW) at 5400 rpm and 114 ft·lbf (154 N·m) at 4000 rpm in 1986.

22R

The 2-valve SOHC 2.4 L (2366 cc) 22R was produced from 1981 through 1995.
Cylinder bore was 91.9 mm (3.62 in) and stroke was 88.9 mm (3.5 in).

Initial output was 97 hp (72 kW) at 4800 rpm and 129 ft·lbf (174 N·m) at 2800 rpm.
By 1990 the 22R was producing 108 hp (81 kW) at 5000 rpm and 138 ft·lbf (187 N·m) at 3400 rpm.

The first fuel injected 22R-E engines appeared in 1983.
Output of these engines is commonly rated at 105 hp (78 kW) at 4800 rpm and 137 ft·lbf (185 N·m) at 2800 rpm.

In 1985, the engine was significantly reworked, output was up to 112 hp (84 kW) at 4600 rpm and 142 ft·lbf (192 N·m) at 3400 rpm. Many parts from the newer 22R-E are not compatible with those from the older pre-1985 engine. Non-compatible parts include the cylinder head and many of the associated parts such as the timing chain.

Toyota swapped the dual row timing chain used in older engines for a single row chain with plastic guides. This system reduced drag on the engine, but was inherently problematic. Every 80,000 to 100,000 miles, the chain stretches to the point that the hydraulic-operated chain tensioner can not take up any more slack. When this happens, the timing chain impacts driver's side chain guide, breaking the plastic within a few hundred miles of driving. If the engine continues to be operated after the guide breaks, the chain will stretch rapidly (an unfortunate characteristic of single row chains.) The loose chain causes inaccurate ignition timing which usually results in noticeable rough running. It may also rub a hole in the soft aluminum timing cover, resulting in engine coolant being forced into the oil sump and ultimately destroying the engine. In continued operation the chain can jump a tooth on the drive sprocket or break entirely, with either case resulting in engine damage from valve-piston collisions.

The turbocharged 22R-TE (sold from 1986 through 1988) produced 135 hp (101 kW) at 4800 rpm and 173 ft·lbf (234 N·m) at 2800 rpm.

However, its weakness is high-end power. Thus, most "performance" enthusiasts usually prefer the Toyota 18R-G, 2T-G, 4A-GE and 3S-GE 4-cylinder engines, The 22R has a bigger displacement and a strong block, but its comparatively long stroke limits its use in high revving applications.

The engines are extremely well known for their durability, high fuel efficiency and good low to mid range torque.

Applications:
* 22R
** 1981 Toyota Celica
** 1981 Toyota Corona
** 1981-1988 Toyota Hilux
** 1982-1984 Toyota Celica
** 1981-1996 Toyota Pickup
** 1984 Toyota 4Runner
* 22R-E
** 1985-1995 Toyota Hilux
** 1983-1985 Toyota Celica
** 1985-1995 Toyota Pickup
** 1985-1995 Toyota 4Runner
* 22R-TE
** 1986-1988 Toyota Hilux, 135 hp (101 kW)
** 1987 Toyota 4Runner

References

ee also

* List of Toyota engines
* [http://www.toysport.com/Technical%20Information/22r_tech_notes.htm 22R Tech Notes] (Toysport)
* [http://www.toyoland.com/engines/20R.html Toyota 20R engines: details and photos] (Toyoland)