:: Introduction

For a 27-year period Toyota relied on a single engine as the power plant of the six cylinder production vehicles it produced.  Spawning from 2 litres to 3, the M series engine is hailed as one of the most versatile and reliable engines of their time.  It was the pioneer of Toyotas twin overhead cam, electronic fuel injection, turbocharger and multi-valve technology, while powering many different models of car.   Rarely does an engine series run for such a long time to be regularly referred to as bullet-proof while keeping up with changes in technology and metallurgy.  So lets take a journey to discover the history of Toyotas M series engine.

:: M

When the M engine first hit the streets in 1965 powering the MS-41 Crown, it was given a warm reception. Being hailed as smooth and quiet, vibration free. It was technically superior to most other production sedan engines of the day.  With a displacement of 2 litres, chain driven single overhead cam, hemi chambers, cross flow 12 port head, seven main bearings.  It can be claimed that it was competitive with the most advanced production engines at that time.

image:: The Original M

That same year debuting at the 1965 Tokyo motor show. A prototype was unveiled like none had ever seen before and was something that no other Japanese manufacturer had at the time.  This car was simply the most awe-inspiring machine that anyone had seen from Japan, full stop. It was the Toyota 2000GT.

image:: The basic engine block was derived from the all new 2000cc M series Crown of the day.  Designated the 3M, major changes to this engine were to the top and bottom.

The sump was an aluminium cast unit whilst the head was a brand new twin-cam, 12 valve design with hemi' chambers from Yamaha.  The spark plugs were located centrally whilst recessed piston crowns allowed valves to be angled at 79 degrees.  Interestingly Yamaha has was involved with head design of Toyota twin cam sports engines for many years to come, examples of this are the 2T-G, 18R-G and 1G-GE engines.  

image:: Carburetion is done via three SU type carburettors and sported around 150 horsepower while retaining the 2 litre displacement.

Engineers thoroughly tested the 2000GT in various racing venues from 1965 to 1967 before finally offering the car to the general public in May of 1967. The car performed admirably, shattering 11 international racing records including one in which the 2000GT averaged 206.18km/h for 10,000miles and 72 hours.

In 1979 Toyota ran its first production fuel injection system on the M engine designated as the M-EU (also seen at the same time on the 4M-E) in the MA-46 Toyota Celica Supra or Celica XX.  It was still SOHC, ran a Bosch L-Jetronic multi-point fuel injection system and it developed 110HP at 4800 rpm.

Not only did Toyota push the production engine envelope with twin cams and electronic fuel injection, but also the M engine was the first to receive turbo-charging technology.  While still SOHC and EFI the M-TEU ran a non-intercooled Garret T03 turbo in 1980 to power the Japanese domestic markets MA-46 Supra, MZ-10 Soarer plus other models such as the Crown and Mark II. 

image:: Pumping out 145HP at 5600rpm Toyota then added in 1983 a water to air intercooler to raise it to 160HP at 5600rpm.

:: Pics And Engine Data for the M below

:: M-B

image:: The M-B with its twin SU carbs.

:: M-D

 

image:: The M-D with its twin down draft carbs.

:: 2M

In March 1967 the 2M with its capacity increased to 2.3 litres was released in the MS-45 Crown.  Although still a similar horsepower to the M the 2M gained some torque in order to quieten the American and Australian motoring journalists who complained that the M was an overall excellent engine it did lack the same pulling power of the American built six cylinders of the time.  This engine went on to power the MS-50 series crown as well as some Mark II Coronas. 

:: Pics And Engine Data for the 2M below

image:: An interesting addition, the 2M was also put into a special run of 9 2000GT’s called the MF-12.

:: 4M

From 1972 the 2.6 litre 4M was powering the all new MS-60 series Crowns, spouting more displacement and more load pulling torque this engine still has noticeable M heritage.  All the way up to 1979 the 4M was then released with Multi-Point Electronic Fuel Injection (in conjunction with the M-EU in Japan) in the USA powered MA-46 Celica Supra.  Interestingly enough power is down from 122HP in the 4M to 110HP in the 4M-E, but with the Bosch EFI, driveability and fuel consumption considerably improves.

:: Pics And Engine Data for the 4M below

image:: Interestingly enough power is down from 122HP in the 4M to 110HP in the 4M-E, but with the Bosch EFI, driveability and fuel consumption considerably improves.

:: 5M

Once again in 1980 the M engine gained a capacity increase to create the 2.8 litre 5M engine.  It also received an EFI system like the 4M-E and went on to power the 1981 MA-47 Celica Supra, MS-110 Crowns, and various other JDM models.

:: Engine Data for the 5M below

:: M Engines By Leaps And Bounds – DOHC

:: 5M-GE

In 1982 the M engine had a radical change for the better, gone was the chain driven single overhead camshaft, the rocker style valve system, the carburettor, and the analogue electronic fuel injection system.  By a leap and a bound the all new 5M-GE was introduced with wide angle double overhead camshafts driven by a timing belt, and fully digital ECU controlling sensors and fuel injection.  This powered the new MA-61 Supra with full options and Lotus designed suspension gaining praise from motorists all over the world. 

image:: This engine also eventually found its way into MX-73 Cressidas, MZ-20 Soarers, MS-120 Crowns and other various JDM cars

:: Engine Data for the 5M-GE below

:: 6M-GE

Not much information is known on the 6M-GE as it was never released out of Japan.  Identical to the 5M-GE but 3 litres, this engine went to power Crowns, Soarers and other JDM vehicles.

:: Engine Data for the 6M-GE below

:: 7M-GE

 

image:: It was smooth quiet and propelled the supra and other saloons with ease.

In 1987 the MA-71 Toyota Supra was released still with the 7M but running an air to air intercooled CT26 turbo, it was called the 7M-GTE.  With 234 horsepower the MA-71 became the choice Japanese sports car around the world.  With simple modifications tuners were able to extract globs of power from them, with figures over 300 horsepower being not uncommon.  Unfortunately there has been a head gasket problem with the 7M engines that has seemed to have tainted its reputation.  Fixing this problem with the recommended gaskets, head studs and torque settings, returns the engine to its bullet-proof state. 

 

image:: People still seem to be very quick to judge, especially now when there is a new series of engine on the block that has replaced the M.

:: Engine Data for the 7M-GE below

:: M Engines: What Did 27 Years Spawn?

It may be clutching straws here but its true, with out the M engines this engine would have never been spawned.  Regarded as one of the best turbocharged 6 cylinder engines of today, with awesome amounts of power on tap, hailed by tuners around the world as being more than bullet-proof, while still being driveable, fuel efficient, and clean.  Tuners run over 600 horsepower in them with stock bottom ends, engine conversions ranging from supras, cressidas to falcons, commodores and yes I even know of some nissans and mazdas that are powered by them **SHOCK HORROR** Why didn’t they use an RB engine or Rotary!?!?!? they say………

:: Behold the JZ Series

:: Engine Data for the JZ engines below

Due to the gentlemen’s agreement made by the Japanese car manufacturers maximum stated power figures are 280 horsepower.  You will find that in many cases engines that have this stated horsepower actually exceed it.

:: Finale

With 27 years of production history and over 30 years of development the M series Toyota engines were the flagship six cylinders of their day.  Toyota always striving for technical excellence while also being powerful and affordable, has made it one of the largest independently owned car manufacturers in the world.  Incorporating in-house design philosophies Toyota has been able to parallel itself with German technology, manufacturing and reliability, make it a shame we in Australia hardly ever get to see these fine automobiles due to protection of our lagging domestic market.

:: Various Pictures

 

image:: 2JZ-GTE in a MA-61 engine bay.

image:: Very worked 2JZ-GE in a MX-23 engine bay. Oohh baby.

image:: 5M-E with a turbo slapped on the side of it.  Custom intercooler and intake manifold all squeezed into a MS-75 crown.

image:: A clean M-B engine sitting in the bay of another crown.

image:: Another view of the spirited 3M engine.

Written By rob_RA40, any errors or emissions are welcome to be corrected, information has been taken from considerably reliable sources on the internet and Toyota enthusiast community.  If you have any questions, corrections or concerns feel free to email Ed at serotonergic@hotmail.com

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