TG engine info!

[MitchE]

OK this is my first post on this forum, the reputation system is a bit intimidadting but i'll get used to it.
after searching on this forum for a while i was slowly gathering info on 2TG/3T hybrids not that any of it was inacurate but it wasnt all in one place, whilst lookin gthrough the vast amount of info on the old forums i stumbled across this and was hesitant about posting it incase i am just reposting but here it is. (props to the member who gatherd all this onfo)
__________________________________________________ ________________________

The 2T and 2T-G inlet manifolds have a different stud and are not interchangeable.

The Water pump shaft on 2T-G is shorter and the pully has a different offset. Pumps, pulleys and fans are not interchangable with 2T. (A modified 2T pump and pulley CAN be fitted to a 2-TG)

All T series blocks have the same Gearbox bolt pattern

The 2T-G twin carb manifold is standard DCOE pattern.

Later 2T-GEU has electronic distributer.

2T and 2T-G mechanical fuel pumps are not the same. 2T-G pump actuator arm is longer. 2T item might be made to work on 2T-G.

2T-G requires dummy cam to drive distributer and fuel pump. Ensure unused cam bearings are fitted so as to block oil journals and maintain oil pressure.

Early 2T-G uses same block as 2T. Late (2T-GEU) uses same block as the T18 13T. (Kinda true)

The 2TG's with 1600 on the top are the very first of the Early 2TGs the cam covers varied with the later 2TGs and 2TGEUs
The First 2TG (11111-88220) Had "Toyota" and "1600" on the rocker cover.

The 11111-88222 Rocker cover did not have "1600" on it. It had its EGR valve mounted there so only had "Toyota" on the Left Hand Side.

The 88260 Head appears to have received two styles of Rocker cover. The 88222 Version and the one used for the 88261.
The 2TGEU 11111-88260 and 11111-88261 heads Had "Toyota DOHC" on them and the DOHC lettering had raised edges.

The 2TGEU 88262 Rocker Cover had "Toyota DOHC" on it and the DOHC was not with raised edges.

The other type is the 11111-88262 head. It is not marked on the casting anywhere. The number can however be found on the cam itself as the second half of the cams part number. ie xxxxx-88262

There only variant to the above numbering code is the Early TRD race heads. These were only cast as 11111 - "blank"

Standard 2T-GEU injectors flow 220cc/min
Later 2T-G heads (>260) had double valve springs.

I have removed the flopw figures from this post, figures like that have no factual basis and are misleading heresay. To be of any merit head flow figures need to indicate the cfm @ specified valve lift and size plus the unit/method of measurement. Ie @ 28 inches.

Specs for the 88220 and 88222 Cams:
2T-G Engine modifications as per April 1973 were from Engine Number 2T-8038333
Firing Order: 1-3-4-2
Ignition Timing: 16 Degrees BTDC / 800 rpm
Compression ratio: 9.8:1
Bore and Stroke: 85.0 x 70.0
Valve Size: Intake ? 43mm (Up to April 1973)
? 44.5mm (April 1973 Onwards)
Exhaust ? 37mm (Up to April 1973)
? 38.5mm (April 1973 Onwards)
Cam Shaft: Lobe Height In 45.87 ~ 45.97 (Up to April 1973)
Lobe Height In 46.37 ~ 46.47 (April 1973 Onwards)
Lobe Height Ex 45.87 ~ 45.97 (Up to April 1973)
Lobe Height Ex 46.37 ~ 46.47 (April 1973 Onwards)
Cam Lift: In 9.82 (Up to April 1973)
In 10.27 (April 1973 Onwards)


2T-G/3T Hybrids
---------------

3T pistons must be used together with a 3T crank.
2T and 2T-G pistons must be used with a 2T crank.
3T-GT block will require modification to seal the oil return.
the 3TGTEU ECU DOES NOT control spark. It is a fuel only system, based on an early bosch design, similar to the 2TGEU EFI system. The spark is controlled only by the distributor, which has internal weights & vacuum advance/retard, whereas an ECU controlled dizzy would have the advance mechanisms locked, like the early distributor 4AGE's. The 3TGTEU ECU doesnt know squat about whether it has 4 or 8 spark plugs. each pair fire together anyway.

3T-GTE exhaust manifold is the same port and mounting as for 2T-G (and therefore 2T)
The 3TGTEU inlet manifold will not fit the 2TG head. the ports are completely different spacing & size.
The 3TGTEU head can be put on the 2TG block.

3T crank WILL fit early 2T-G/2T block BUT the Block requires clearnacing internally. Late 2-TGEU blocks should not require clearancing

When using 3T crank in late block, the 3T pistons will need to be fly cut to avoid valves.


Any Bosch wide body top feed injector should fit the fuel rail and manifold !

A set of 3TGTEU injectors would probably are 295cc.


Generally, when going from standard 2TG pistons to generic 3T pistons and crank, the compression will be increased a bit, from about 8.8:1 standard, to about 9.8:1 or thereabout depending on oversize.

Using the 3T setup, the cheapest is to use regular 3T-C pistons with the exhuast relief cut a bit deeper. 86mm are available new.

2T-G pistons had different compression depending on the year and other things. Older ones were about 9.8:1, latter ones were 8.8:1, some were 8.4:1, some 8.3:1.

A standard 3T will have a compression of about 9 to one. Using this bottom end with a 2T-G head increases the compression because the 2TG head chamber is slightly smaller, 62 vs 68cc.

Wiseco sells 10.5:1 3T-C pistons off the shelf. They will clear the 2T-G valves just fine and with the 2T-G head they come out closer to 10.8:1 1941cc with 89mm bore.

18 R Pistons fit 2T Conrods and they take your bore out to 88.5mm However depending on type Compression may be awkward to calculate.

If you're using 2T-G head on your hybrid you should use a 2T-G block as supplimentary drive cam will suit your application. With creative fitment of cam bearings 3T-G block can be used.
The oil pumps interchange between 2T and 3T(GTEU). The 3TGTEU pump is a Higher volume unit!

All the T series engine use the same size Rods. They vary in strength but are all the same length (Excluding the 1400cc T engine)
The 3TGTEU and 2T, 2TGEU etc also all use the same basic block design. there are some minor differences but the deck height is the same on all of them. It is the Pin height in the piston itself that counters the increased stroke of the 3T crank, Hence the need for 3T style pistons and the inability to use 2TGEU pistons with a 3T crank.

CAMS.

Firstly 2TG and 3TG cams will interchange ! So any cam grind you can get for a 2TG will fit in a 3T-GTE. (Distributor drive gear is NOT on 2TG or 2-TGEU cams)

The reason there are more grinds for the 2TG is that not many people play with the cams in the 3T-GTE, Turbo performance is relativly new when compared to N/A performance !

Then you have to consider that in a N/A engine the cam does all the work as far as dictating how much air gets into the head. (Valve size and ports aside) With a Forced induction engine the Turbo jams it in there so the cams are generally paid alot less attention.

A Turbo's cams also use a whole different set of rule as depending on your desired result Overlap is a debatable thing !


VALVES

Ok excluding the 11111-88220 head the 2TG's and 3T-GTE's have the same size valves ! The first version of 2TG head (88220) has smaller valves on both the inlet and exhaust.

2TG Valve Size: Intake - 43mm (Up to April 1973) (88220 Head)
- 44.5mm (April 1973 Onwards)
Exhaust - 37mm (Up to April 1973) (88220 Head)
- 38.5mm (April 1973 Onwards)


HEAD FLOWS

Ok Head flow is ONE of the more important characteristics of a head. But it isn't everything. You also need to consider the chamber design, Sqish area's, the actual flow direction and turbulence, the

placement of the spark plug or plugs, Airspeed and probably a dozen other things I have no idea about.

The second thing to remember is the cams will dictate just how much air gets in. Headflow figures are measured at certain lift points of the valve. If your cams only give you 300 tho lift then there is no point worrying about what happens inside the head when you have 400 tho Lift as the cams don't get there !

In turn the intake manifold and Throttlebody needs to meet the same flow requirements or its all a waste of time.


2TG v's 3TGTE

To be honest I can't answer which one is best ! There is still so much I haven't had the time or money to test! The heads use a different port design and both work very well in their designed
applications. In stock form the cams and intake manifolds limit the engine operation long before the heads do.

If you take the cams and manifold out of the equation then in stock form you can make a base line comparison. I used a 88261 EFI 2TG head (As per my engine build) And yes it does perform better than a 3T-GTE Head flow wise how much better varies at each lift point.

As for chamber design and squish areas etc. The 3T-GTE head is apparently a better design. I am not really able to offer an opinion on that as it is too far out of my ability and learning.

BUT

Before you all go ditching your 3T-GTE heads bring it all back into context ! You only need the head to flow as well as your cams and intake manifold can support! You also need to remember that an intake manifold can not only restict but increase the airflow thru a bare head. A well designed intake manifold will channel in more air than a bare head will flow alone (Even on a flow bench when the air is being channeled)

Then there is the ancient mystical voodoo art of head porting! I can only evaluate the performance of my Personal 2TG head. I am still trying to obtain a well ported 3T-GTE head for comparison. Given the 3T-GTE's better chamber design then it would be desireable for a ported 3T-GTE head to outflow a Ported 2TG head. I honestly have no idea if it will but I have never seen Toyota, TRD or TTE use a Turbo 2TG head !

Also a mild port job on a 3T-GTE will generally cost less than fitting a 2TG head.

[sillycar chick]

Nice writeup. There is a LOT of information on these engines on both old and new forums, unfortunately none of it is centralised I think it would still be very difficult to centralise this information unless its a sticky of FAQ (I think the FAQ would be a very good idea). I too have done numerous searches on the hybrid engine when I was building mine, and found that even though theres a lot of info i still needed to ask plenty of questions.

Here's a link to the "2TG spotters guide" which I also found very helpful, and I still reference back to it a lot of the time when comparing head numbers (eg 88261 etc)

http://www.geocities.com/Colosseum/4883/2tg-info.html

I'll add in anything else I can think of about this engine if it comes to mind.
(im a bit brain dead at the moment - Monday-itis im afraid).

Cheers,
Dana

[shelldrake]

I'm still glad you posted this.

[wheel rim]

Good post mate,
You have been able to summarise most of the tech info available.
If you are after some more practical info there is a workshop in Ipswich that builds these hybrids for race and rally.The name of the company is Road and Track, the guy who owns it builds them, his name is Terry.I can't find his number right now but will PM you when I have.

Cheers,
Wheel Rim.

[Night Rider-TA23]

The Water pump shaft on 2T-G is shorter and the pully has a different offset. Pumps, pulleys and fans are not interchangable with 2T. (A modified 2T pump and pulley CAN be fitted to a 2-TG)

Water pumps can be interchanged between 2t and 2t-geu, i assume the 2tg and 2tgeu water pump set up is the same, so theoretically water pumps can be changed between 2t ang 2tg

Pumps dont need to be modified to be fitted.

[shelldrake]

Actually the 2tg and 2t/3t waterpumps are slightly different. There is an outlet on the single cam t series waterpumps that needs to be blocked - either by tapping a thread and then putting a short bolt in there, or plugged by other means.

[old_school_jap1]

ok sorry to drag up real old stuff, but just want to know which heads have hardened heads and valve seats designed for unleaded????? can't find this info anywhere

[jfallen]

All jap cars should run fine on unleaded, but all 2TG's were recomended to run 98RON

Cheers
Jordan

[Rodger]

old school,

All T series heads are alloy and they have steel valve seats that are suitable for un-leaded fuel.

All alloy heads need a hard seat material, it is mostly the old cast iron headed motors that have trouble with un-leaded.

The 18R's iron head has suitable steel seats installed to run un-leaded also, remembering that Japan went "un-leaded" in the early 70's.

[old_school_jap1]

so a 11111-88222 head for example would have the hardened seats necessary for unleaded???

on a side note does anyone have the duration and lift stats of the cams in a 88261 head??? i've looked on the 2tg spotters guide and that but it just has a blank in the box

[Rodger]

yes it is a T series head

[GTA22]

very informative, I like alot

[AE25]

nice info!
i'll add my bit. pics to go with it http://www.toycrazy.net/tech/3tgte.htm
feel free to challenge any info on the page

88262 cam cover with non raised lettering?? got a pic?
the 260, 261 and 262 heads ive got/seen either have large or small raised lettering, but say the same thing.. 'toyota dohc'

theres also an 88223 head that came in norwegian spec te71. its a carby version made in early 80's with large 'toyota dohc' on exhaust side. looks to be 88222 type mikuni's on an efi head. has 88223 cams also. roy and sigve in norway have these te71's.
http://www.toycrazy.net/gallery/coro.../pics/roy3.jpg

intake comparison.. 2tgeu has extra stud in the center compared to 2tg. 3teu same as 3tc. 3tgte is unique


from a toymods post.. 3tgte rods fatter than 2tg http://www.toymods.net/forums/showth...?t=7349&page=2

[Neverland]

So just out of curiosity, are the EFI head interchangable, eg which heads could you fit to the 2tgeu?

[AE25]

they all interchange with the associated parts, as the block is usually the same casting with different parts fitted to it to make it pushrod or dohc.. the difference being in the cam and timing gear, crank, rods, pistons etc. so you need to use whatever ancillaries and parts that go with the variant you're building.

heres one of the later 2tgeu blocks.. but has the bosses for oil return and knock sensor.. is same block casting as 3tgte. have seen a 3t pushrod in tx76 cressida wagon with this casting also.

you could use a 2tgeu head on a 2tg block still using the 2tg carbies etc.. just remove the extra stud from the efi head.

http://www.toycrazy.net/tech/pics/2tgeu-oilreturn.jpg