2TG Dedicated Thread

[ctrain]

Since theirs an 18rg thread and a 3tgte thread I thought I'll make a 2tg thread.

Now I dont know much about the 2tg but I know the basics thats why im hoping this thread will help me and everyone else seeking info about these great engines

History:
Toyota built their formidable Twin Cam reputation on these engines. Based on the popular T 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. This engine had a twin, the 2TGR which had low compression pistons, but identical cylinder heads. In the mid 70's the 2TGU 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 model arrived as the 2TGEU , 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 ultimate versions of the 2TG was the 151E. These were not a production engine. The head and block were not interchangeable to the production unit. (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 block 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.

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 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.

Modifications:

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.

Cylinder Head: The early generation 2TG 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 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 had the reinforced heads, bigger valves, and the lowest compression (pistons). The EFI intake can be retrofitted back to carburetors.

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 2TG's the minimum carburetor size is at least a 40 and will be sufficient for 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.

The latest generation 2TGEU use a breakerless distributor. Older units can be upgraded 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 serviced.

Some Recommended Set-ups:

For Stock configuration - The early model 2TG will give the best performance. Update the heads for unleaded fuel. This is ideal for vintage restorations. The 2TGU are also good, but change the carburetors and remove the exhaust air recirculating system. The 2TGEU 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 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. Setting up properly and 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 without changing crankshafts. The 3T crank can be used in the 2TG to give 2000cc. Avoid stroking the engines beyond this, 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 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. If you need a 2-liter engine, use the 2TG (it is lighter and has slightly better Connecting Rod / Stroke geometry. 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 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.

Source:
2TG 18RG 3TG Tech Notes

Please feel free to add anything else 2TG related like 3t/2tg hybrid information
Cheers,
Callum

[BrianGT]

That was a really good read......thank you!
I have a 2tg in my 76 st Celica.....a great engine!

[71TA22]

I just thought that I would throw in a picture of the 2TG cylinder head family tree. There is one deliberate mistake at the bottom:

[ctrain]

Whats the difference between the two 2t-gue's?

[jezz]

Does anyone have a picture of the very rare 11111-________ head ?

[71TA22]

Here goes. 100E race engine:

[caam]

http://www.toymods.org.au/forums/tec...uide-pics.html
about half way through the first post, jezz

[caam]

Index of /~rod/2TG Pics/Racing 2TG

[moltenash]

. .

[moltenash]

Whats the difference between the two 2t-gue's?

I think the second one is an 88262 head, have a look a caams link to 2tg rocker cover guide.

Does anyone know why this head didn't have the head casting number on the front?

[SilverRA23]

This thread would be useful for 2tg people

http://www.toymods.org.au/forums/tec...-diagrams.html

[71TA22]

Was tidying up my shed at the weekend and found a selection of 2TG flywheels.

Weight info as follows for bare condion (no clutch or pressure plate):

for 88220 and early 88222 engines - 10.8kg
for mid and late 88222 engines - 8.8kg
for 88260/61/62 engines - 7.3kg

In comparison a TODA Racing flywheel from the early 80's - 3.7kg

[72GT]

I have a 2T-GEC 11111-88261 with EFI and i would like to do the following conversions and was wondering if anyone knows if the below will work:

1. Remove EFI and EFI manafold and replace with Mikuni Solex 40-PHH-3 carbies and matching manifold
2. Remove cam cover and replace with one from a 2T-G 11111-88220

Basically i have a TA22 with a 1978-1980 EFI engine and i want to have the benefits of the Yamaha head but looking like the original motor

Thanks for you input.

[caam]

Yep will work I did the exact opposite a few years ago.
Cheers Cam

[73GTV]

I have a 2T-GEC 11111-88261 with EFI and i would like to do the following conversions and was wondering if anyone knows if the below will work:

1. Remove EFI and EFI manafold and replace with Mikuni Solex 40-PHH-3 carbies and matching manifold
2. Remove cam cover and replace with one from a 2T-G 11111-88220

Basically i have a TA22 with a 1978-1980 EFI engine and i want to have the benefits of the Yamaha head but looking like the original motor

Thanks for you input.

All of the heads were manufactured by Yamaha, you can find that out pretty easy.