Soon to be the one stop spot for 3tgte info... need to know anything in particular? ask away!
3tgte specs:

3TGTE Torque specs: ft/lb

Crank main bearings 58
Conrod big end bearings 36 (500 +/- 50)
Harmonic balancer to crank 65
Flywheel to crank 62
Clutch pressure plate to flywheel 14
Head bolts to block 58 (800 +/- 80)
Timing gears to cams 54 (750 +/- 50)
Cam bearing caps 14
Exhaust manifold to head 29
Intake manifold to head 14
Turbo to exhaust manifold 29
Exhaust dump pipe to turbo 16
Throttle body to intake manifold 9
Gearbox bellhousing to block
12mm bolt 47
10mm bolt 27
Waterpump 14
Oil Pump 15

Valve clearances
Intake 0.29mm +/- 0.05
Exhaust 0.34mm +/- 0.05

Source: Toyota 3T-GTEU (1982-89) factory manual
(cheers Geoff - HY Automotive website)

3tgte crank pulley timing marks = 0deg and 10deg btdc

3tgte emissions and tuning sticker found under bonnet of a TT142 corona GT-T
net sources say 10deg btdc @ 1000rpm for timing... does this say 12deg @ 800rpm?!

TA63 celica GT-T analogue instrument cluster. green led for boost, orange led for knock
7000rpm redline although 3tgte don't have a rev limiter

2tgeu (orange) & 3tgte (green) ecu plugs.3tgte ecu sticker
It seems that '31' found on oil cooled turbo ecu and '32' on water cooled turbo versions (from observation, not proof!)

Have found 3 different injector part numbers but when tested, all flowed the same amount

Oil Filter
OEM Toyota Nippon-Denso: 90915-20003
Fram:
Repco/Ryco: Z10 or Z89A

3TGTE wiring diagrams as found all over the net
someone please get hold of better quality ones.. even if still in japanese!

The 3TGTE workshop manual - (in japanese only)

rod comparison pic taken from toymods forum http://www.toymods.net/forums/showthread.php?t=7349&page=2

Modifications:
block off vacuum hose to the fuel cut pressure switch (connects to intake pipe before the throttle body).. not required if running std 7.5psi but becomes an issue when raising boost or have boost creep.
Fit larger exhaust. 2.5" works well with a mildly tuned engine.. port CT20 wastegate to reduce boost creep if possible
Washable type air filter (like K&N) to increase air intake flow.
If removing std cold air box, make a new one around the new filter as engine bay temps will kill any benefit of a pod filter
Replace the CT20! for the price of a rebuild, go buy a better turbo
Toyota CT26 will fit with minor mods, slotting the mounting holes to suit and adapting pipes etc.
apparently can fit CT26 compressor and compressor housing to CT20 (7mgte or 3sgte has CT26)
Interestingly a 5mge AFM works with the 3tgte efi, needs to be tuned to suit (otherwise runs rich) and adapter pipe fitted due to it being larger!
Fit a plumb-back BOV. can clearly hear the compressor stalling when throttle shuts
Fit an intercooler! do this before raising boost. heat wrapped piping will help heat soak too
EFI = old technology and pretty crude in operation.. runs rich from factory which the engine likes.. never ever let it lean out!
Although the factory efi system can be tuned using the afm and fuel injector size and fuel pressure adjustments, an aftermarket programmable ecu is preferred for accurate fuel and spark control. arguably more important than installing forged pistons. factory cast pistons have been known to handle 20psi for a short while on a properly tuned engine.
295cc Injectors and ct20 turbo have a limit around 200hp
A dip in power around 5000rpm could be caused by weak valve springs.
At this level of tune, an air/fuel meter, fuel pressure guage and exhaust temp gauge are useful instruments for safe tuning/driving
Fuel pump.. they do eventually wear out. don't forget to upgrade when upping power levels. Remember that fuel pumps will flow less fuel when higher pressures are used.. ie raising the boost will raise fuel rail pressure on an equal 1:1 ratio.. therefore 15psi boost will see around 58psi fuel rail pressure. Also good power feed to the fuel pump is important as a voltage drop makes a noticeable difference to how much it can flow.

Interchangeable Parts
Many parts are interchangeable with the 2tgeu ie the timing chain, chain guides, valves and tensioner.
A 2tgeu head, intake and dizzy combo can be swapped onto the 3tgte block with a small gain in power. (note: there's no spark retard on 2t dizzy without changing the diaphragm). A 2tgeu has a forwards facing thermostat outlet suitable for corolla conversions.
1G-EU and 1G 6cyl variants share the same bolt pattern on the gearbox bell-housing (minus one hole).. BUT the clutch slave and fork is on the opposite side (exhaust side on a 3tgte) so may have clearance issues. 1G has identical clutch fork as 3tgte.
Injectors are low impedance top feed, which can be upgraded to 7mgte injectors (and others) with associated air/fuel tuning.
TE71 engine mount brackets are identical in size as 3tgte, but missing the bolt hole(s) for turbo support bracket (see pic). 3tgte has bigger rubber.

Maintenance - Things to watch for:
Remember the 3tgte is now 22+ years old, by now the seals have most likely gone hard.  Especially the cam cover gasket and half moon seals on back of the head, so expect a few oil leaks and vacuum leaks. Can buy these new from Toyota if they have access to jdm parts catalogue (we do in NZ).  An upper gasket set is approx nz$250 - $320.  (head gasket, valve seals, cam cover gasket, copper rings, turbo flange gaskets, intake and exhaust gaskets, timing cover gasket, thermostat housing gasket etc). OEM head gasket bought separately is $40-$50.  but to buy cam cover gasket alone (there's two parts) is over $100!  many gaskets are the same as 2tgeu which have better availability. Plenty aftermarket parts are available for internals from the States for the 3tc.. forgies, rods, bearings etc. (3tgte has a different bearing oil hole position than pushrod 3t! be warned).
CT20 turbo's aren't known for performance or reliability..  the turbos often start smoking after 150k or so, but as early as 100k, depends on usage.. mine done 180k before blowing smoke.  The wastegate seat usually develops a crack.  best thing you can do is upgrade to a better turbo!
Std exhaust manifold are prone to cracking of the 1st and 4th runners, usually on the inner side facing the engine.  Also the exhaust manifold flanges can get quite rough from oxidation, so exhaust leaks are common. Keep the exhaust manifold heat shields fitted as they stop sudden cooling of the manifold.
The diaphragm on the distributor can deteriorate and pop so there's no spark advance or more importantly spark retard under boost.
The rotor can split down the shaft... this may not always affect the spark
Rough idle and running rich can be caused by a split fuel pressure regulator.. which will flood fuel into the vacuum hose into the engine intake.
The plastic lobe in the 'throttle position sensor' (tps) wears. It needs to be adjusted or replaced.  The TPS is used for idle mode and closed loop? it not too major if unplugged.. but just makes it run smoother and more economical etc. A wavey idle can be caused by the tps not returning to idle mode so the oxy sensor is adjusting air/fuel ratio at idle.
Often see engines with burnt or cracked pistons after owners crank the boost up.  Pistons are cast alloy and need safe tuning to ensure reliability.  Have known people running temporarily up to 20psi on std internals.. but suitable bolt on mods required and good fuel/spark tuning to keep things safe.
Over pressurised oil systems: It seems a few owners have encountered this, mainly whilst revved on a cold engine.  Personally I had a repco filter balloon and split the seams quite sensationally.. also tried a Fram filter which didnt balloon as much, but still skewed the sealing face out spitting the seal. A toyota nippon-denso filter handled the pressure so I highly recommend using one in case such an event occurs!
Assuming the correct oil viscosity is used and the filter not clogged, first check the oil pressure releif valve found on the oil pump is free to move. Failing that, there's a possibility of blocked oil galleries!? I never did find the cause of my pressure probs. 3TGTE have a higher flowing oil pump in them, using a smaller pump from 3tc or 2tgeu is not such a good idea if in fact you have a problem elsewhere in the engine.  It'd probably pay to check engine not too gunky in the head (look thru oil cap hole or take cam cover off etc) as there could be a build up of gunk in the oil galleries too.

Many people don't know that the hydraulic chain tensioner needs adjusting.. If there's too much slack in the chain it'll rattle very noticeably on startup.  Evident with 3 scrape marks underneath the cam cover up near the front (as the chain attempts to jump teeth on the sprockets). This can also be made worse by not using the original rubber gasket which is about 3mm thick.
To adjust chain tensioner: on the tensioner (found under the distributor) in the middle of the long nut is a hole with a spring loaded piston inside... pushing the piston in with 5kg of force, there should be 0.5mm movement (give crank a clockwise turn so the slack in the chain is on the tensioner side).  If the engine oil is gunky then the tensioner may even be seized. Note: once the tensioner has been adjusted in too far (chain and/or chain guide and/or sprocket worn) the O-ring reaches a step in the tensioner bore which causes it to leak oil.

The 3TGTE may seem problematic these days... but so long as you know what to keep check on.. they're sturdy, reliable beasts and respond well to modifications.

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