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Toyota 12H-T Engine Specifications
The Toyota 12HT is a 4.0 L (3,980 cc, 242.9 cubic inches) six
cylinders, 4-stroke water-cooled turbocharged internal combustion diesel
engine, from the Toyota H-family, manufactured by the Toyota Motor
Corporation. The 12H-T diesel engine has a cast-iron cylinder block with
91.0 mm (3.58 in) cylinder bores and a 102.0 mm (4.02 in) piston stroke.
Compression ratio rating is 18.6:1. The motor has a cast iron cylinder
head with the overhead valves (2 per cylinder, 12 in total), direct
injection fuel system and turbocharger. The Toyota 12HT engine produced
136 PS (100 kW; 134 HP) at 3,500 rpm of maximum power and 315 Nm (32.1
kgm, 232.2 ft-lb) at 1,800 rpm of peak torque.
Engine code identification:
1 - Direct injection
2 - 2nd generation engine
H - Engine family
T - Turbocharger
| GENERAL TECHNICAL DATA |
Engine model ............... 12HT
Cylinder layout ............... Straight-6, vertical
Fuel type ............... Diesel
Production ............... No data available
Total displacement ............... 4.0L, 3,980 cc (242.9 cubic inches)
Injection pump ............... Mechanical
Power adder ............... Turbocharger
Rated power ............... 136 PS (100 kW; 134 HP) at 3,500 rpm
Torque output ............... 315 Nm (32.1 kgm, 232.2 ft-lb) at 1,800
rpm
Firing order ............... 1-4-2-6-3-5
Dimensions (L x H x W) ............... No data available
Weight ............... No data available
| CYLINDER BLOCK |
The cylinder block is made of cast iron. The crankshaft is supported by
7 bearings. The crankshaft bearings are made of aluminum alloy. Pistons
are made of highly temperature-resistant aluminum alloy.
The cylinder bore is 91.0 mm (3.58 in), piston stroke is 102.0 mm (4.02
in) and compression ratio rating is 18.6:1.
Cylinder block alloy ............... Cast iron
Compression ratio ............... 18.6:1
Cylinder bore ............... 91.0 mm (3.58 in)
Piston stroke ............... 102.0 mm (4.02 in)
Number of piston rings (compression / oil) ............... 2 / 1
Number of main bearings ............... 7
Cylinder bore inner diameter ............... 91.000-91.030 mm
(3.5827-3.5839 in)
Piston skirt diameter ............... 90.940-90.970 mm (3.5803-3.5815
in)
Piston ring groove ............... First ............... 0.139-0.204 mm
(0.0055-0.008 in)
Second ............... 0.060-0.100 mm (0.0024-0.0039 in)
Oil ............... 0.020-0.060 mm (0.0008-0.0024 in)
Piston ring end gap ............... First ............... 0.200-0.470 mm
(0.0079-0.0185 in)
Second ............... 0.200-0.440 mm (0.0079-0.0173 in)
Oil ............... 0.150-0.490 mm (0.0059-0.0193 in)
Piston pin outer diameter ............... 32.000-32.012 mm
(1.2598-1.2603 in)
Connecting rod small end diameter (standard) ...............
32.008-32.020 mm (1.2602-1.2606 in)
Crankshaft main journal diameter ............... 69.980-70.000 mm
(2.7551-2.7559 in)
Crankpin diameter ............... 54.980-55.000 mm (2.1646-2.1654 in)
Crankshaft center distance ............... 51.0 mm (2.01 in)
Main bearing cap tightening procedure and torque specs:
136 Nm; 13.9 kgm; 100 ft-lb
After securing bearing cap bolts, make sure crankshaft turns smoothly by
hand.
Connecting rod bearing nut
88 Nm; 9.0 kgm; 65 ft-lb
Crankshaft pulley bolt
441 Nm; 45.0 kgm; 325 ft-lb
Drive plate (A/T) fixing bolts
98 Nm; 10.0 kgm; 72 ft-lb
Flywheel (M/T) fixing bolts
118 Nm; 12.0 kgm; 87 ft-lb
| CYLINDER HEAD |
Cylinder head alloy ............... Cast iron
Valve Arrangement ............... OHV
Valves ............... 12 (2 valves per cylinder)
Intake valves diameter ............... No data available
Exhaust valves diameter ............... No data available
Intake valves length ............... 120.7 mm (4.752 in)
Exhaust valves length ............... 120.6 mm (4.748 in)
Intake valve stem diameter ............... 8.973-8.989 mm (0.3533-0.3539
in)
Exhaust valves stem diameter ............... 8.954-8.970 mm
(0.3525-0.3531 in)
Valve spring free length ............... Inner: 44.3 mm (1.7441 in)
Outer: 48.1 mm (1.8937 in)
Camshaft journal diameter ............... 1: 51.151-51.170 mm
(2.0138-2.0146 in)
2: 50.951-50.970 mm (2.0059-2.0067 in)
3: 50.751-50.770 mm (1.9981-1.9988 in)
4: 50.551-50.570 mm (1.9902-1.9901 in)
Camshaft lobe height (intake) ............... 41.400 mm (1.6299 in)
Camshaft lobe height (exhaust) ............... 41.800 mm (1.6457 in)
Head tightening procedure and torque specs:
113 Nm; 11.5 kgm; 83 ft-lb
| MAINTENANCE DATA |
Valve clearance (Hot)
Intake valve ............... 0.20 mm (0.0079 in)
Exhaust valve ............... 0.36 mm (0.0142 in)
Compression pressure
Standard ............... 30.0 kg/m2 (2,940 kPa, 427 psi)
Minimum ............... 20.0 kg/m2 (1,960 kPa, 284 psi)
Compression differential limit between cylinders ............... 2.0
kg/m2 (196 kPa, 28 psi)
Oil system
Recommended engine oil ............... 10W-30 or 5W-30 (“CC”, “CD”)
Engine oil capacity ............... Dry fill: 10.3 L (10.9 US qt, 9.1
Imp. qt)
With oil filter change: 9.7 L (10.3 US qt, 8.5 Imp. qt)
Without oil filter change: 8.1 L (8.6 US qt, 7.1 Imp. qt)
Oil pressure ............... At idle: 0.3 kg/m2 (29 kPa, 4.3 psi) or
more
At 3,00 rpm: 2.5-6.0 kg/m2 (245-588 kPa, 36-85 psi)
Fuel system
Injection nozzle opening pressure ............... Reused: 180-210 kg/m2
(17,650-20,600 kPa, 2,560-2,990 psi)
New: 200-210 kg/m2 (19,610-20,600 kPa, 2,845-2,990 psi)
Idling ............... M/T: 650 ± 50 rpm
A/T: 700 ± 50 rpm
Maximum speed ............... 4,100-4,170 rpm
Turbocharger
Turbocharging pressure ............... 0.39-0.53 kg/m2 (38-52 kPa,
5.5-7.3 psi)
| VEHICLE APPLICATIONS |
Model ............... Years Produced
Toyota Land Cruiser (HJ61) ............... No data available
Toyota Coaster (HB20, 30) ............... No data available
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