Toyota M engine

Infobox Automobile engine
name=Toyota M engine


manufacturer=Toyota Motor Corporation
production=1965–1993

Toyota Motor Corporation's M family of engines were a longitudinally mounted straight-6 engine design. They were used from the 1960s through the 1990s. All M family engines were OHC designs. While the M family was born with a chain-driven single camshaft it evolved into a belt drive DOHC system after 1980. All M family engines used a cast-iron block with an aluminum cylinder head. The Japanese market only M-E was the first Toyota engine to be equipped with fuel injection (at the same time as the 4 cylinder 18R-E). The 4M-E was the first Toyota engine to be equipped with fuel injection for non Japanese markets. The M family were Toyota's most prestigious engines (apart from the uncommon "V family" V8) for 30 years. They were commonly found on the large Toyota Crown, Cressida, Celica Supra, and Supra models.

M

The first M was a 2.0 L (1988 cc) version produced from 1965 through 1988. It was a 2-valve SOHC engine. Cylinder bore and stroke was square at 75 mm (2.95 in). Output was 110 hp (82 kW) at 5600 rpm and 116 ft·lbf (157 Nm) at 3800 rpm.

An LPG version, the M-LPG, was produced from 1966 through 1988.

Twin SU sidedraft carburetors pushed output for the M-B and M-D to 129 hp.

Anti emissions versions, the M-U, M-U LPG and M-EU, replaced the M, M-LPG and M-E on the Japanese market in mid 1976.

Applications:
* Toyota Crown "MS41"
* 1972-1980 Toyota Corona Mark II

M-E

The M-E appeared in the 1972-1976 Toyota Corona Mark II LG sedan and hardtop as sold in Japan. It was not sold outside of Japan.

The M-E was replace by the anti emissions M-EU in mid 1976.

Applications:
* M-E
** 1972-1976 Toyota Corona Mark II LG sedan and hardtop

M-T

The turbocharged M-TEU appeared in 1980 with 145 hp (108 kW) at 5600 rpm and 156 ft·lbf (211 Nm) at 3000 rpm. It used a Garret T-03 turbo.

In 1983, Toyota added an air/water intercooler to the M-TEU. Output was bumped to 160 hp (119 kW) at 5600 rpm and 170 ft·lbf (230 Nm) at 3000 rpm.

Applications:
* M-TEU
** 1980 Toyota Supra "MA46"
** 1980 Toyota Soarer "MZ10"
** 1980 Toyota Crown
** 1980 Toyota Corona Mark II
** 1982-1986 Toyota Celica Supra MKII (Australia/Asia)

2M

The 2-valve SOHC 2M was stroked (to 85 mm/3.35 in) for 2.3 L (2253 cc). It was produced from 1966 through 1972. Output was 109-115 hp (81-86 kW) at 5200 rpm and 117-123 ft·lbf (158-166 Nm) at 3600 rpm.

2M engines were placed in the Crown, Corona Mark II, and 9 special "MF-12" 2000GTs. [http://www4.tpgi.com.au/users/loats/technical/mhistory/mhistory.html]

Applications:
* Toyota Crown "MS45", "MS50"
* Toyota Corona Mark II
* Toyota 2000GT "MF12"

3M

Another 2.0 L (1988 cc) inline 6 engine, the 2-valve DOHC 3M, was produced from 1966 through 1971. This special engine shared the original M's block but featured an aluminum sump, a special Yamaha-designed aluminum head with wide 79° valves and a hemispherical shape. It powered the Yamaha/Toyota 2000GT, the original Japanese supercar. Output was 150 hp (112 kW) at 6600 rpm and 172 ft·lbf (233 Nm) at 4800 rpm.

Applications:
* Toyota 2000GT

4M

The engine was bored out to 80 mm (3.15 in) to create the 2.6 L (2563 cc) 2-valve SOHC 4M. Produced from 1972 through 1980, output was 108-122 hp (81-91 kW) at 5600 rpm and 134-141 ft·lbf (181-191 Nm) at 3600 rpm.

The fuel injected 4M-E was produced from 1978 through 1980. It was also a 2-valve SOHC engine. Output was 110 hp (82 kW) at 4800 rpm and 136 ft·lbf (184 Nm) at 2400 rpm.

Applications:
* 1979-1981 Toyota Celica Supra MKI
* 1977-1980 Toyota Cressida "MX32"
* Toyota Crown "MS60"
* Toyota Corona MKII "MX13 and MX29"

5M

The Bore was up again to 83.1 mm (3.27 inches) in the 2.8 L (2759 cc) 5M, produced from 1979 through 1988. Although 2-valve SOHC and carbureted versions were made, it is the fuel injected DOHC 5M-GE that is the most common.

The SOHC engine produced just 116 hp (87 kW) at 4800 rpm and 145 ft·lbf (196 Nm) at 3600 rpm.

In Australia the 5M-E (in 1985) was just 103 kW at 4800 rpm and 226 Nm at 3600 rpm due to the leaded petrol at the time.

In Europe the 5M-E produced 145PS/ 107kW in Crown MS112 and CelicaSupra MA61.

Applications:
* 5M
** Toyota Crown "MS110"
* 5M-E
** 1979–1983 Toyota Crown "MS112" (European edition)
** 1979–1981 Toyota Celica Supra MKI "MA47"
** 1982–1986 Toyota Celica Supra MKII "MA61" (European & Australian)
** 1981–1982 Toyota Cressida "MX62"

5M-GE

The 12-valve (2 valves per cylinder) DOHC 5M-GE is familiar as the engine of the Toyota Supra and Toyota Cressida of the 1980s. It was quite different from any previous member of the M family, with Bosch L Jetronic-derived electronic fuel injection (using an AFM intake measuring scheme), wide-angle valves, and belt-driven dual camshafts. It used hydraulic valve lifters, a first for Toyota. This version of the M made its US debut in 1982's Toyota Celica Supra MK2. The 1982 version had a vacuum-advance distributor, whereas the 1983-1987 versions found in the Celica Supra and Cressida had full electronic control of the ignition system and distributor. The newer engine control system found in these later cars was named TCCS, or Toyota Computer Control System.

Output ranged from 145 to 175 hp (108 and 130 kW respectively), depending on exhaust system, emissions controls, compression ratio, intake runner shape (earlier models had round intake runners and later models had D-shaped intake runners), and ECU tuning.

There were aftermarket crank and piston kits offered for the 5M-GE that took the displacement up to 2.9 L (for 230 hp/171 kW) and 3.1 L (for 250 hp/186 kW). Outfitted with kits like the Kuwahara 3100, these engines were often used quite successfully in powerboat racing in the mid 1980s.

Applications:
* 1982–1986 Toyota Celica Supra MKII "MA60 and MA61" (US)
* 1983–1988 Toyota Cressida "MX63 and 73"
* Toyota Crown "MS120"
* Toyota Soarer "MZ11"

Differences between years on US model of the Celica Supra:
* 1982 Supra 5M-GE had vacuum-advance distributors and 9-to-0 volt output AFMs.
* 1982-1983 Supra 5M-GE had dual V-belt accessory drive, 65 amp alternator, square-tooth camshaft belts, 8.8:1 compression ratio, shallower oil pan, and round intake runners.
* 1983-1985.5 Supra 5M-GE had 0-to-5 volt output AFM's and TCCS.
* 1984-1985.5 Supra 5M-GE had 7-rib serpentine accessory drive belts, 60 amp alternator, round-tooth camshaft belts, 9.2:1 compression ratio, knock sensor, deeper oil pan, and D-shaped intake runners.

6M-GE

The 5M-GE was stroked to 91 mm (3.58 in) to create the 3.0 L (2954 cc) 6M-GE. Only produced in 12-valve (2 valves per cylinder) DOHC/fuel injected versions, it was available as the 6M-GE and Japan-spec 6M-GEU from 1984 through 1987. The 6M engine used the same crank, machined to accept a different torsional damper, as the 1986-1989 7M-GE engines; this fact is witnessed by the designation "7M" stamped on the counterweight of the crank on the later 1989-1992 7M engines. The 6M crank did not have counterweights on cylinders 2 and 5, making it lighter and prone to rev slightly higher.

Output was 170-190 hp (127-142 kW) at 5600 rpm and 170-192 ft·lbf (230-260 Nm) at 4400 rpm. The 6M-GEU is usually the lower powered variant of 6M engines.

Applications:
* Toyota Crown
* Toyota Soarer ("MZ12")

7M-GE

The Toyota 7M-GE introduced in the early months of 1986 is a 3.0 litre (2954 cc) 24-valve (4 valves per cylinder) DOHC/fuel injected engine. The valves are spaced at a performance-oriented 50° angle. Cylinder bore is 83 mm (3.27 in) and stroke is 91 mm (3.58 in).

The 7M-GE was produced from 1986 through 1992. Output was 190-204 hp (142-152 kW) at 6000 rpm and 185-196 ft·lbf (250-265 Nm) at 4800 rpm.

Not withstanding the technical sophistication and powerful output of the engine, it was plagued with the problem of regularly blowing head gaskets. This was because the head gasket was originally meant to be made out of asbestos; at the last second they changed the material--but not the 56 ft·lbf torque spec. The turbo version 7M-GTE suffered from the same problem. Permanent fixes typically involved a metal after-market headgasket, higher torque settings (usually 70-80 ft·lbf) and upgrading to head studs (through the ubiquitous ARP and their hardware) rather than bolts.

Specifications:

* Displacement: 2954 cc (180.2 cu in)
* Bore: 83.00 mm (3.27 in)
* Stroke: 91.00 mm (3.58 in)
* Compression Ratio: 9.1:1
* Weight: 119.5 kg (440 lb)

Applications:
* 1986.5–1992 (1987–1993 in Japan) Toyota Supra MkIII ("MA70")
* 1989–1992 Toyota Cressida Mark II ("MX83")
* Toyota Chaser
* Toyota Crown

7M-GTE

The turbocharged 7M-GTE was Toyota's top performance engine from 1987 through 1992. Output was 232 hp (173 kW) at 5600 rpm and 240 ft·lbf (325 Nm) at 4000 rpm for most 5 lbf/in²/0.35 bar versions.

A special 7M-GTEu version, with a modified CT26 high-flow turbocharger and large volume intercooler, pushed output to 267 hp (199.1 kW) at 5600 rpm and 264 ft·lbf (357 Nm) at 4400 rpm. This was used only in the racing homologation Toyota Supra Turbo A road and race cars. The Turbo A models also measured air based on manifold pressure rather than using an air flow meter, had a larger intercooler, larger throttle body, optimized CT-26 turbo, and various other differences. In fact, for the short time it was produced, it was the fastest Japanese car ever made.

The 7M-GTE was known to suffer from blown head gaskets due to improper torque specifications of the head bolts from the factory. Despite endless claims to this problem and obvious proof of a design error, Toyota never took responsibility or issued a recall. This problem could easily be prevented by the back yard mechanic by removing the valve cover and re-torquing the head bolts to a higher torque specification.It is recommended to replace the head gasket and torque the head bolts to 75 lbs.

Specifications:

* Displacement: 2954 cc (180.2 cu in)
* Bore: 83.00 mm (3.27 in)
* Stroke: 91.00 mm (3.58 in)
* Compression Ratio: 8.4:1
* Weight: 119.5 kg (440 lb)

Applications:
* 1987–1992 Toyota Supra MkIII ("MA71")
* 1986–1991 Toyota Soarer ("MZ20/MZ21")

ee also

* List of Toyota engines
* [http://www4.tpgi.com.au/users/loats/technical/mhistory/mhistory.html The Illustrated History of the M engine]
* [http://www.toysport.com/webpages/Techinfo/Enginemod/5m_6m_tech_notes.htm 5M and 6M engine Tech Notes]
* [http://www.toysport.com/webpages/Techinfo/Enginemod/7m_tech_notes.htm 7M engine Tech Notes]