Information and Modification tips for
2T-G, 18R-G, and 3T-GTE Toyota Engines
Info about Toyota 2T-G/18R-G/3T-GTE
Toyota built their formidable Twin Cam reputation on these engines.
Based on the popular T block and R block of the early 70's, these
engines were the envy of all car manufacturers. These engines evolved-
from the early stock ohv and sohc variety to the pure high performance
G models, then the smog controlled models, and finally the fuel
injected and turbo models. Originally the 2TG (1588cc) started at 115
HP, and the 18RG (1968cc) at 145 HP. Both engines had a twin- the 2TGR
and 18RGR which had low compression pistons, but identical cylinder
heads. In the mid 70's both the 2TGU and 18RGU saw a further drop in
compression, emission controlled carburetors, and shorter duration
camshafts. However, the heads were upgraded with bigger valves and
hardened valve seats (for unleaded fuel). Horsepower figures typically
dropped about 10/15 HP. By the late 70's, the fuel injected models
arrived as the 2TGEU and 18RGEU, to regain all the lost horsepower.
These models, despite still shorter duration cams and lower
compression, had the best cylinder heads with still bigger valves.
The 3TGTE (1770cc) replaced both engines by 1983. The well-proven head
design- now had 2 spark plugs per cylinder and a turbocharger to
develop 160 HP. Despite claims of Toyota that the 503 race engine was
based on the 3SG design- the bottom end was patterned after the 3T
block (which had become wider in the lower block skirt to accommodate
the longer stroke crankshaft. The crankshaft saddles are identical!
The competition models of the 2TG and 18RG, developed with parts from
TRD saw many worldwide wins for Toyota- Corolla Levins, Sprinter
Truenos, and Celica 1600 GTs with the 2TGs. In Asian and European
Formula racing, the 2TG in the 1600cc category regularly beat all the
other engine manufacturers. The Celica 2000 GTs saw many race and rally
victories worldwide, including the European based WRC (World Rally Cup).
In the ultimate WRC Group B series, "the super class" in the World
Rally Cup- the 4TGTE (homologation model of the 3TGTE) powered the
Celicas of Toyota Team Europe to the Championship. The Group B class
was soon cancelled after the general public and some rally entrants
protested that the cars were unsafe because of the powerful engines.
The ultimate versions of the 2TG and 18RG were the 151E and 152E. These
were not production engines. The heads and blocks were not
interchangeable to the production units. (These heads were the design
forerunners of the 503E heads.) Both engines had 4-valves per cylinder
with either carburetors or mechanical fuel injection. These racing
heads were fitted on heavily modified T and R blocks- basically to
accommodate the new heads’ chain set-up (for the fuel injection and the
dry sump oiling system). Originally they came in the same 1588cc and
1968cc configuration that were targeted to the specific 1600 and 2000
classifications for FIA (Federacion Internationale Automobile)
regulations. For the U.S. IMSA (International Motorsport Association)
the 152E was bored to 2200 to qualify in the "under 2.5 class"-
normally aspirated at 330 HP.
The first race engine based on the 2TG was made by TMC (Toyota Motor
Corporation) in 1970 and was known as the 100E. Toyota built about 25
engines with full racing specifications- specially casted head
(11111-______) yes, blank numbers!, special intake manifolds, dry-sump
oil system, 50mm Mikunis, ND igniter and instrumentation, ND fuel pump
and some other trick stuff. Of the 25 engines- 8 went into Corollas
(Levin and Trueno), 10 went into Celicas, and the rest were spares.
Eventually TOSCO (Toyota Sports Corner) was organized and some parts
from this project became available individually. TOSCO later became TRD.
The success of these engines has been greatest in the streets. The
Celicas with built 18RG could outrun the 240Zs and Skylines, of that
generation. The Levins and Truenos with prepared 2TGs outran all
Japanese models and all European Twin Cam models- the Alfa-Romeos,
Lancias, including the Lotus Cortinas and Escort Cosworths (of the
16-valve BDA variety. The Toyota Twin Cams was regarded highly by all
competitors. It was the envy of the other manufacturer tuners. Some
tuners in European formula racing made valve covers with their
corporate names, to hide the Toyota origin.
MODIFIYING THE 2TG AND 18RG
The 2TG and 18RG, in all the different varieties- offer immense tuning
Block: The 2TG blocks were similar to the 2T and 3T blocks of the same
year generation. For modification purposes the 3T block is preferred
because it has the longer stroke crank, and with a bore-up to 89mm
becomes a 2000cc. The later model 2TGEU block is the same as the 3T,
and will take the 3T crank with no modifications. The 2TG stock block
can be bored to 1750cc, with a similar bore-up to 89mm. To fit the 3T
crank in an original 2TG block can be done with a lot of work- grinding
the inside of the block skirts to clear the rods. The 2T and 3T cranks
are forged. There is also available a 2150cc. using a modified Toyota
4Y crankshaft. The 4Y crank is not forged, but there is an aftermarket
steel billet unit. In converting a single cam block to a twin cam,
aside from switching over all the front valve train components, the
original cam bearings have to be turned and repositioned. You must have
a complete donor Twin Cam to do the conversion. Installing the 2TG into
any T engined Corolla is a bolt-in deal with no modifications to the
crossmember or brackets.
The 18RG block can be bored to 2200cc (92mm) or stroked to 2400cc
(using a modified 20/22R crank). No the 18RG head will not bolt on a
20R/22R block! The stroker crank is not recommended. Aside from the
very expensive to modify to fit the 18RG block, it seriously cuts into
the revving characteristic of the Twin Cam. The 18R blocks did not
change that much, but installing into the later model pick-up and
Celica will need the newer block that have the extra engine support
holes embossed on the sides of the block. Because of the wider variety
of models the engines originally came in, there are 4 different oil
pans, six different engine brackets. Fitting into specific applications
will be a matter of matching the oil pan configuration to the original
engine; and the engine brackets to the width of the crossmember. On the
older Celicas with the 18R engine- it is a bolt on by using the pan and
brackets off the original engine.
Cylinder Head: The early
generation 2TG and 18RG heads had the best camshaft profiles and
carburetors. They will respond extremely well to porting and big
valves. If the block is bored out or the compression raised, longer
duration cams will be needed. The mid-generation 2TGU and 18RGU heads
had bigger valves, hardened seats, lower duration cams, and problematic
carburetors. This is the head to use for turbocharged applications-
since the head can be used with the original cams with the hardened
valve seals and the (piston) compression is lower. The 2TGEU and 18RGEU
had the reinforced heads, bigger valves, and the lowest compression
(pistons). The EFI intake can be retrofitted back to carburetors.
The Twin Cam head must only be machined by experienced machine shops.
Valve service and installation is very critical. If not properly
machined there will be a problem adjusting the shims, valve spring
tension, and camshaft timing adjustment. The head must not be surfaced
more than 1 mm or .040 in. Please read notes under Recommended Set-ups
/ Race configuration!
Fuel System: The best
performance can be achieved by using Fuel Injection over the
carburetors. The standard Toyota ECUs are in short supply, but the most
reliable set-up. For the EGU engines- the early 4AG Corolla GTS and MR2
computers can be used, since they operate within the same rpm range.
Programmable Fuel Management systems will allow high compression, and
radical cams- even turbo. Carburated motors will need Mikunis or
Webers- if the stock Mikuni-Solex are not serviceable or to up-grade
the GU carbs. For bored-out 18RGs the minimum carburetor size is at
least a 44, and 40s will be sufficient for the 2TG up to 2000cc. The
chokes must be changed to match the displacement. Turbocharging through
carburetors is limited to about 10 psi using a fuel pressure-adjusting
regulator. Do not rely on the Toyota mechanical or electric pump- use a
low pressure, high volume pump.
Ignition System: The latest
generation 2TGEU and 18RGEU use a breakerless distributor. Older units
can be up-graded using original Toyota distributor components from
later models. Ignition amplifiers and knock sensors must be used to
avoid high RPM misfires and detonation. Wire sets that have the
original configuration are the best to use- they keep dirt out of the
deep sparkplug pockets that may enter the block when the plugs are
Some Recommended Set-ups:
For Stock configuration- the early model 2TG and 18RG will give the
best performance. Update the heads for unleaded fuel. This is ideal for
vintage restorations. The 2TGU and 18RGU are also good, but change the
carburetors and remove the exhaust air recirculating system. The 2TGEU
and 18RGEU can be run with the early Toyota 4AG computers and will be
excellent low maintenance fuel injection systems. Since these are high
performance engines- assembly specifications are different from the
regular variety Toyota single cams. Do not attempt to overhaul without
the correct 2TG or 18RG manual! There have been a lot of heads and
complete engines destroyed- when an important Twin Cam detail was
overlooked even by "expert" Toyota mechanic. Set-up properly these
engines will last a long time- like any Toyota engine.
For Modified configuration- Prepare the head with big valves and a good
port and polish job, this is the best modification that can be done.
The blocks can be bored to 1750cc (2TG) and 2200cc (18RG) without
changing crankshafts. The 3T crank can be used in the 2TG to give
2000cc. Avoid stroking both engines beyond these, the loss of RPM
capability and inherent internal imbalance are not worth the power
gain. Anytime high compression pistons are used- the cams must be
replaced to avoid extremely high cylinder pressures- that will call for
retarded ignition timing (and a loss of RPM and HP). The stock
carburetors should be changed to at least Mikuni 44s or Weber 45s.
For Race configuration- Treat the head to a competition port and polish
with the most aggressive cams usable. You may need a custom intake
manifold because stock manifolds will be the limiting factor to the
port job. The big valves and dual valve springs are mandatory (they are
bigger than the largest stock valves). The crankshaft and rods must be
prepped- stress reliefed, heat treated, line-bored. Optionally rods may
be upgraded to Carillos. Piston clearance is critical since these are
high revving engines, follow the piston manufacturers tolerances.
Piston valve pockets must also match the camshaft and valves used. The
oil pumps in the 2TG and 18RG are different from the single cam models,
try to use the original Twin Cam pumps, specially when converting to
the 3T block. If available the TRD oil pumps must be used for the
2000cc 2TG. The oil pan has to baffled, specially for race and rally
use. For the Full Race set-up use 320 intake and 304 cams. For the
Rally set-up use 304 /288 or 304/272 cams. For the Street racer, the
304/304 set-up is very streetable and have a nice mild lobe at idle. It
is very discrete! These cams cannot be used with stock pistons!! (The
288/272 cam set-up maybe used with stock pistons, as long as the head
has not been cut.) Naturally adjustable gears are needed for the cams.
The fastest 2TG set-up we have done used 330/310 cams with 1750cc
pistons. The fastest 18RG used 320/304 cams with 2200cc pistons. If you
need a 2-liter engine, use the 2TG (it is lighter and has slightly
better Connecting Rod / Stroke geometry. The 18RG will ultimately
produce more HP and torque. The Twin Cam engines will respond to tuning
like real race engines. Cam timing, ignition, compression ratios,
exhaust design, port profiles- all have their own advantages and
disadvantages. The most popular set-ups are the 2000cc 2TG and 2200cc
18RG with all camshaft combinations. There are proprietary set-ups that
may be used but try these recommendations first. Do not forget water
treatment as these aluminum heads will corrode fast- and there are not
enough of them left.
If you have a RWD Toyota- these are the ultimate engines to upgrade to.
All the popular cars had them as factory options! The late model 16
valves- aside from the 4AG which at one point was available in RWD, are
almost impossible to convert because of they were installed at an
angle, although we have conversion kits!
Note: The 3TGTE will respond to tuning also. Since it is a turbo- all
the turbo tricks will give more power than internal work- aside from
the mandatory forged pistons.
The 3TG engine is an 1800 twin cam, twin spark, fuel injected turbo
engine. The engine puts out 160hp standard, the standard turbo and
injectors are limited to around 200hp. This is a great engine, but it
lacks an intercooler and blow off valve in its standard form. If the
turbo and injectors are upgraded, it is possible to get around 300hp
from this engine using the standard computers.
ENGINE CROSS MEMBER
Once you have your old engine out you should make the following
changes. The cross member needs to be modified to suit the 3TG engine.
The drivers side can remain the same if you use a standard 2T or 2TG
engine mount and bracket. You can fit the 3TG mount to the drivers
side. To do this the 2T engine mount bracket which is bolted to the
engine block, needs to be shortened by around 11mm. I did it this way
because I think the 3TG mount is a bit more solid than the standard 2T
The turbo side needs to be modified to clear the turbo oil return line.
I used the standard 2T rubber mount for this side because there isn't
much room to play with. The cross member bracket needs to be cut off
and moved out by around 2 inches. I cut the bracket off completely and
then sat the engine up to the cross member to make sure of the correct
position before rewelding. You don't have to do it this way, but it is
While the engine is out the fuel lines should be upgraded from 1/4 to
5/16. Also the original fuel filter needs to be thrown out and an EFI
filter fitted. The standard paper filter will not cope with high fuel
pressures so make sure of this if you don't want a fire.
The standard T50 gearbox will bolt straight onto the 3TG engine.
Depending on how you drive, this maybe ok. If you drive hard the T50
may fail. If the standard gearbox is used, simply bolt the original
flywheel to the 3TG. It fits straight on and the standard gearbox and
tailshaft will remain unchanged. The 3TG engine has the same block
design as the 2T and 2TG.
If you want a better gearbox, a W55 from a Supra will bolt up to the
3TG. This is actually the gearbox that is used on the 3TG. The W55 does
fit into a Celica without too much trouble. To do this, another gearbox
cross member is needed. I used a cross member from an automatic early
Celica as it only needs minor changes to fit properly.
The tailshaft also needs to be changed, the easy thing to do is find a
tailshaft from an early automatic Celica. I found this out by mistake,
but it's the way to go because it will bolt straight onto the W55
gearbox and the TA22 diff centre. It is even the right length, you
gotta be lucky sometimes.
The W55 is a pretty neat fit under the Celica and it may be necessary
to make a bit more room for the gearbox. In other words a bit of hammer
work to widen the gearbox tunnel. It doesn't need much and will fit
straight away, just will be very close to the body panels around the
The standard linkages can be removed. A cable needs to be fitted
instead. Again, there are many ways of doing this depending on the
quality of the job you want. I used a cable out of a Corona as it was
the right length and had the same end as needed for the 3TG. The end
that goes on the pedal needs to be modified as well. I just attached
the end of the Corona pedal onto my original Celica pedal arm. Its no
An electric fuel pump needs to be fitted. A surge tank should really be
used to stop the engine from leaning out around corners when the tank
is less the 1/4 full. An external or internal surge tank can be used.
An internal surge tank is the best as you only need one pump and it is
Otherwise an external surge tank will be ok, just need to find room for
it. Two pumps are needed for this, one to supply the surge tank and one
to supply the engine from the surge tank. The pump supplying the surge
tank needs to have a flow rate at least equal to the pump supplying the
engine, but it doesnt have to be high pressure.
The pump supplying the engine must be able to supply a pressure of
around 4 bar. The standard fuel rail pressure for the 3TG is 255kPa.
The excess fuel from the rail is sent back to the fuel tank. The fuel
pump must be able to supply the 255kPa, plus your boost pressure.
Now this is the tricky bit. If you are not good with electrics then
leave this to the experts. I have done this work myself. Once you break
it all down, its not that bad. There are two computers, an EFI and a
knock control with the standard system. It is possible to get good
results from a standard computer. For the engine to function properly
using the standard system you need to use the standard air flow meter.
This is a flap type meter which feeds info back to the EFI computer
regarding the required fuel mixture.
The standard system also has two coils and three pressure switches. Two
of the pressure switches are used by the EFI computer. One is for fuel
enrichment above boost pressures of 0.15 bar (connector PE), the other
is for fuel cut off when the boost gets above 7.3 bar (connector PC).
The knock control computer uses the other pressure switch, this is
because the knock control is not active at low boost pressures.
For more info on the ECU plugs, click here.
Here's the 3TG TEU wiring diagram, it's broken down into four pieces.
I fitted the computers under the drivers seat for easy access. There
really isn't much room to fit them anywhere, unless you put them in the
You can use an after market computer, this will give the ability to
reprogram. The standard computer cannot be changed much that I know of.
The 3TG engine has an alternator with an internal regulator. The
standard Celica used an external regulator. This old regulator needs to
be removed, it has 6 wires going to the regulator. Only three of these
are needed for the internal regulator, the other three can be cut off
and covered over.
The standard radiator needs to be modified to suit the 3TG. The current
set up has the radiator to far back and it will hit against the 3TG
fan. The top outlet pipe also needs to be changed to some sort of bend.
The bottom outlet is ok as it is. The radiator needs to be moved
forward around 1 inch to allow enough clearance.
Once moved forward the bracket that goes across the top of the radiator
also needs to be modified, as it will now foul on the radiator as it
has been moved forward. Another option is to use a radiator bracket
from a GT model as it already had this offset as standard. Pretty hard
to find if you don't already have one.
The 3TG originally had a 2 inch system. But if you want more power a
2.5 inch system is needed, 3 inch is even if you can fit it under the
car. Turbo engines are pretty quiet, a big pipe allows the exhaust gas
to flow more freely, therefore the turbo can spool up quicker. A
catalytic converter should be fitted to meet emission standards, get a
free flowing cat for this.