5MGE 2800cc DOHC (dual overhead cam) was introduced in the U.S. Supra in 1982.
This Twin Cam was also used on the U.S. Cressida in 1983.
This engine was the first production 6 cylinder Toyota Twin Cam- since
the 3M Toyota 2000GT (a limited production model).
This power plant was one of the main reasons the Supra became very
popular, and a Toyota milestone model. In
1984 the EFI (electronic fuel injection) was updated to a digital system and the
compression raised, this brought the horsepower up from 145 to 160.
Japan, a 6MGE 3000cc model was introduced in 1986 that was rated at 200 HP.
The engine was identical to the 5MG in design, but related parts to the
pistons and crankshaft were different. It
is interesting to note that the 6MG was rated by Toyota with the same horsepower
as the successor 7MGE 3000cc (a 24 valve model) but with a better torque band!
In fact it used a 7MG crankshaft before the 7MG was introduced.
Twin Cam head is a G type- meaning Sports Type.
Also a first for Toyota- the
head featured hydraulic valve adjustment, eliminating the shims (which most
mechanics feared). This engine
allowed Toyota to position the Supra above all the other Japanese models and on
par with the leading European manufacturers.
philosophy in product design, which is based on continuing evolution, shows
distinctly in this engine. The M
block started life as a 2000cc, became the 2M 2300cc., the 4M 2600cc., and the
5M 2800 cc. The 5MG and 6MG Twin
Cam (12 valves), which preceded the 7MG (24 valves), allowed Toyota Twin Cam
power in a whole new market segment (the 6 cylinder Twin Cam heads were
previously available only in the 3M). Toyota's
vaunted dependability and reliability is evolved.
The Twin Cam head is a crowning act on Toyota's legendary block.
competition we used the 5MG-powered Supras for showroom stock racing (SCCA SSA)
and in the IMSA Firestone Endurance Series.
The cars ran trouble free, won a lot of races, and even held track
records in Willow Springs. (In fact
Nissan supplied us with an Anniversary 300ZX to campaign also, but it was not as
successful.) As a real GT (Grand
Touring) the 5MG was incomparable to any engine in its class.
engine ignited a lot of interest for aftermarket parts manufacturers.
Engine kits for 2900cc and even 3100cc were available, but very
expensive. Powerboat racing saw
many 5MGs screaming in open sea events- another testimony to the engines
durability. In power boat racing
the engines are revving flat-out like in 1st gear all the time.
THE 5MG/ 6MG
The 5th generation 5MG has a tested and proven bottom end.
The 5MG responds extremely well to the 2900cc conversion or the 3100cc
engine kit. In 2900cc form we have
proved that the Supra will out accelerate Mustangs and Camaros in the racetracks
and actually outrace them on the straights. Basic block preparation is all that
is needed, no secrets here. The
head gasket can cause serious wear on the block surface, so it is a good idea to
deck them. A cost effective upgrade
is to go 6MG.
the 6MG looks externally similar- internal components are different.
You cannot drop a 6MG crank on a 5MG without changing related pieces-
timing cover, pulleys, pistons, etc. For
practical and cost purposes if you want to have 3000cc., get a complete 6MG. The
5MG / 6MG has a durable bottom end and will out last the cylinder heads before
The cylinder heads suffer from abnormal wear from carbon build up.
The EGR causes oil to deteriorate sooner than some engines and leaves a
lot of accumulated carbon. Prepare
the head with a port and polish treatment, this is a good value in terms of
added performance. Headers and
exhaust systems will help allow the engine to breath since the cars they powered
were tuned for quiet GT luxury touring.
6MG intake manifold uses bigger intake runners.
This will bolt to the 5MG head, but does not have provisions for EGR.
In fact, if you are upgrading to a 6MG- you have to transfer all the
related 5MG EGR pieces to the new engines.
Everything is transferable. Make
sure that the EGR is clean and decarbonized- it will ensure passing smog
are aftermarket cams available, but unless the compression is raised the cams
are of no use. Adjustable cam gears
are also mandatory because these engines are very sensitive to camshaft
settings. The cam towers need close
inspection during rebuilding. Since
the cams have a tendency to wear out- the towers may also be bad.
all-out power Turbo charging is the way to go.
Mandatory forged pistons will allow the engine to see and survive boost
levels higher than the 7MGTE. An
advantage is that the valves are bigger (although less in number) which will
survive the heat better than the smaller valves of the 7MGTE (24 valves).
Under boost the advantage of 24 valves is minimized.
EFI upgrades are necessary to maintain the correct A/F ratio.
There are Twin Turbo manifolds available from HKS and we have a couple
remaining, this includes a new plenum! Properly
set-up, a 5MG Turbocharged easily outrun 7MGTs similarly equipped with upgrades
(the bodies were considerably lighter and the engines responded better- pound
for pound of boost.
fuel injection system was upgraded in the later models, but the effect on
performance was from raised compression. Unless
the engine is turbocharged there is no need for any modification.
modified engine will need step colder spark plugs.
The standard ignition is adequate, but can be supplemented with ignition
upgrades. Although advancing the
timing setting helps, be conservative (past the factory specs) since the knock
sensors will automatically retard the ignition.
Some Recommended Set-ups:
Stock configuration- The
six cylinder in-line engine is a smooth power plant.
The Twin Cam head allows it to rev much higher than any head
configuration. This provides a
smooth and powerful power source. Upgrade
to the 84 pistons if you need to oversize.
The cylinder head can be ported with no effect on emissions.
Use a machine shop that is experienced in working with these aluminum
heads and thoroughly inspect the cam towers also.
Modified configuration- The
2900cc piston set or the 3100cc will be the ultimate set-up in naturally
aspirated form. These will produce
over 230 (2.9L) / 250 (3.1L) HP with no further modifications.
Head preparation must be done to allow the bigger displacement to breathe
6MG is a cost effective alternative. The
fuel injection system on the late 5MG and 6MG are the same, to install the 6MG
in an early 5MG- all the sensors including the TPS (throttle positioner sensor)
must be transferred.
Racing configuration- Race
regulations allow specific limited modifications.
If allowed the displacement upgrades will be ideal.
Radical camshafts will need a reprogrammed ECU or an entirely new one
(Tech II or similar unit). Anticipated
horsepower over 400 will need new connecting rods, the crankshaft will be fine
with correct bearing clearances and chamfered oil holes.
Disable the EGR. We have
available a limited number of Triple side draft manifolds- which will also need
a direct fire ignition system (since the distributor is disabled).
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