1HDT vs. 1HDFT: What Is the Difference Between Them?

The Japanese automotive manufacturer produces some of the most sophisticated engines in the industry. Toyota manufactures some of the most sophisticated vehicles in the world. And for those who are looking for the most reliable engine for their Toyota Landcruiser, 1HDT vs. 1HDFT is definitely a major contemplation.

1HDT vs 1HDFT

While both engines offer great performance and durability, their differences should be considered carefully before making a decision. In this article, we’ll outline the key differences between these two engines and help you decide which one is right for your needs.

1HDT Engine

The Toyota 1HD-T engine is a 4.20 l (4,164 cc, 254.1 cu-in) six cylinders, four-stroke cycle water-cooled turbocharged internal combustion diesel engine, manufactured by the Toyota Motor Corporation.

The 1HD-T engine has a cast-iron block with 94 mm (3.7 in) cylinder bores and a 100 mm (3.94 in) piston stroke. Compression ratio rating is 18.6:1. The motor has a cast iron cylinder head with a single overhead camshaft (SOHC) with two valves per cylinder; direct-injection design and Toyota CT26 turbocharger with a boost pressure of 0.48 bar.

The 1HD-T engine produces peak power of 107 kW (144 PS, 142 hp) at 3,600 rpm and peak torque of 410 N·m (300 lb·ft) at 1,600–2,400 rpm.

Information About 1HDT Topics

Engine Specifications

Engine code1HDT
Production1988-1995
Injection pumpMechanical
LayoutStraight-six, vertical
Fuel typeDiesel
Power adderToyota CT26
Horsepower net165 PS (121 KW; 162 HP) at 3,600 rpm
167 PS (123 KW; 165 HP) at 3,600 rpm
Torque output360 Nm (36.7 kg·m; 265.7 ft·lb) at 1,800 rpm
363 Nm (37.0 kg·m; 267.9 ft·lb) at 2,000 rpm
Displacement4.2L, (4,164 cc)
Firing order1-4-2-6-3-5
ValvetrainSOHC 12 & 24 valves
TurbochargerAlong with an intercooler, inclusive
Fuel systemFuel injection
System of coolingWater-cooled

BLOCK OF CYLINDERS

The 1 HD-T engine is a high performance, direct injection type engine. It is made up of a cast iron cylinder block and a crankshaft that is supported by 7 bearings on the inside of the crankcase.

The crankshaft is integrated with 12 balance weights. The crankshaft bearing cap is of ladder-frame construction and is incorporated into the crankcase. The top of the cylinders is closed off by the cylinder head and the lower end of the cylinders becomes the crankcase, in which the crankshaft is installed.

Pistons are made of highly temperature-resistant aluminum alloy. As the 1 HD-T engine is the direct injection type, a deep combustion chamber has been provided. The first compression ring is made of steel and the second compression ring is made of cast iron. The oil ring is made of steel.

The cylinder bore on the Honda CBR1000RR Fireblade SP is 94 mm (3.7 in), with a piston stroke of 100 mm (3.94 in). The compression ratio rating for this motorcycle is 18.6:1.

Alloys used in cylinder blocksCast iron
Number of compression ratios18.6:1
Groove on piston ringFirst: 0.0020-0.0037 in (0.050-0.095 mm)
Second: 0.0024-0.0039 in (0.060-0.100 mm)
Oil: 0.0012-0.0028 in (0.030-0.070 mm)
End gap of piston ringFirst: 0.0106-0.0212 in (0.270-0.540 mm)
Second: 0.0157-0.0244 in (0.400-0.620 mm)
Oil: 0.0079 – 0.0204 in (0.200-0.520 mm)
Flow of pistons3.94 in (100 mm)
Bore of the cylinder3.7 in (94 mm)
Bearings on main shaft7
Dimensions of the piston pins1.2992-1.2997 in (33.000-33.012 mm)
Number of compression/oil piston rings2 / 1
Inner diameter of the cylinder bore3.7001-3.7019 in (94.000-94.030 mm)
Diameter of piston skirt3.8947-3.8951 in (93.845-94.855 mm)
Diameter of the piston pin1.2995-1.3000 in (33.008-33.020 mm)
Diameter of main journal of crankshaft2.6375-2.6379 in (66.994-67.004 mm)
Diameter of crankpin2.3225-2.3230 in (58.994-59.004 mm)
Diameter of the crankshaft1.9685 in (50.0 mm)

Procedure and torque specs for tightening bearing caps:

  • The first step is 103 Nm; 10.5 kg·m; 76 ft·lb
  • The second step is to rotate all bolts 90 degrees

Check that the crankshaft turns smoothly after the bearing cap bolts are secured.

Bearing nut for connecting rods

  • The first step is 37 Nm; 3.75 kg·m; 27 ft·lb
  • The second step is 90 degrees for all bolts

Bolt attaching the crankshaft to the pulley

  • 369 ft*lb; 500 Nm; 50.0 kg*m

Fixing bolts for flywheels (MT) and drive plates (AT)

  • Its dimensions are 127 Nm, 13.0 kg*m, and 94 ft·lb

The Cylinder Head

On the cast-iron cylinder head, intake and exhaust are arranged in a cross-flow arrangement. The camshaft journal and camshaft caps are made of cast iron and aluminum alloy, respectively, on the cylinder head side. Camshafts are driven by timing belts.

In the 1HD-T engine, each cylinder has two valves. On the intake and exhaust systems, the valves have diameters of 42.5 mm and 36.0 mm, respectively. It is possible to track the valves even at high engine speeds when irregular pitch springs are used on the intake and exhaust valves. The 1HD-T engine is equipped with two types of exhaust manifolds.

A valve adjusting system consists of valve adjusting shims installed above the valve lifters that are used to adjust the valve clearance.

CYLINDER HEAD MATERIALCast iron
Configuration of the valvesSOHV
Diameter of the intake valve is42.5 mm (1.6732 in)
Diameter of exhaust valves36.0 mm (1.4173 in)
Number of valves12 (2 valves per cylinder)
Intake valve lengths103.29-103.69 mm (4.0665-4.0822 in)
The exhaust valves measure103.14-103.54 (4.0606-4.00764 in)
The diameter of the valve stem is7.975-7.990 mm (0.3140-0.3145 in)
Height of the camshaft lobes (intake)54.440-54.460 mm (2.1433-2.1441 in)
Diameter of journal on camshaftFirst: 34.969-34.985 mm (1.3767-1.3774 in)
Additional measurements: 27.986-27.998 mm (1.1018-1.1023 in)
Height of the camshaft lobes (exhaust)55.940-55.960 mm (2.2024-2.2031 in)
Dimensions of exhaust valve stems7.960-7.975 mm (0.3133-0.3140 in.l

How to tighten the head and what torque specs to use:

  • The first step is 69 Nm; 7.0 kg*m; 51 pounds
  • The second step is to turn all bolts 90 degrees
  • Next: Turn all bolts 90 degrees


Casing for the camshaft

  • The torque is 25 Nm, the mass is 2.5 kg/m, and the weight is 18 lb

1HDFT Engine

1HD-FT is a water-cooled turbocharged four-cylinder engine that was designed. It features a cast-iron block with 94.0 mm (3.7 in) cylinder bores, and uses a 4.20 l (4,164 cc, 254 cu-in) displacement.

The 1HD-FT engine is a high-performance gasoline engine that was designed specifically for drag racing and off-road applications. It features a mechanical rotary fuel injection pump, central vertically mounted injectors, and a Toyota CT26 turbocharger with a boost pressure of 0.62 bar. This combination makes the 1HD-FT Engine one of the most powerful gas engines on the market today!

The Toyota 1HD-FT was a 4WD SUV that was produced by the Japanese automaker Toyota in 1996. It used the Toyopet V6 engine, which had a displacement of 3.0 L and produced 170 PS (125 kW; 167 HP) at 3,600 rpm of horsepower and 380 Nm (38.76 kg·m; 280.

LS1 or LS6 engines with less than 400 horsepower can compete with this power level. Detailed specifications regarding the 1HD-FT will follow in the following subsection.

Information About 1HDFT Topics

Engine Specifications

Engine code1HDFT
Engine displacement:4.2L (4,164 cc)
Arrangement:Vertical, straight 6
Pumps for injectionMechanical
A type of fuel isDiesel
Net horsepower170 PS (125 KW; 167 HP) at 3,600 rpm
Order of firing1-4-2-6-3-5
Adding power toToyota CT26
There is a torque of380 Nm (38.76 kg·m; 280.44 ft·lb) at 2,500 rpm
Valvetrain SOHC 24 valves
bore size94 mm (3.70 in)
Piston stroke100 mm (3.94 in)
Fuel systemFI

BLOCK OF CYLINDERS

Thanks to its cast-iron monoblock structure and seven bearings, the cylinder block is highly durable. One of the important features of the 1HD-FT engine is that it has twelve balance weights and seven forged journals.

As well as carbon steel connecting rods and aluminum alloy pistons, the 1HD-FT motor has two compression and one oil control rings for high strength, light weight, and good heat conductivity. 94 mm (3.71 in) is the bore measurement, followed by 100 mm (3.94 in) and a stroke-to-bore ratio of 18.6:1.

Components of a cylinder blockCast iron
Number of compressions18.6:1
Length of piston100 mm (3.94 in)
Principal bearings7
Center of crankshaft50.0 mm (1.9685 in)
Diameter of cylinder94 mm (3.7 in)
In addition to compression, the oil/principal piston rings2 / 1
Diameters of the bore of the cylinder94.000-94.010 mm (3.7001-3.7012 in)
Groove on piston ringFor the first 0.050-0.095 mm (0.0020-0.0037 in)
Secondly, 0.060-0.100 mm (0.0024-0.0039 in)
The oil is 0.030-0.070 mm (0.0012-0.0028 in)
Gas gap between piston ring and pistonFor the first 0.270-0.470 mm (0.0106-0.0185 in)
Secondly, 0.400-0.650 mm (0.0157-0.0256 in)
The oil is 0.200-0.500 mm (0.0079 – 0.0197 in)
Diameter of piston skirt93.845-94.855 mm (3.8947-3.8951 in)
Dimensions of the crankpin58.982-59.000 mm (2.3221-2.3228 in)
The diameter of the piston pin bore33.008-33.020 mm (12.995-1.3000 in)
The outer diameter of a piston pin33.000-33.012 mm (1.2992-1.2997 in)
Diameter of the main journal of the crankshaft66.994-67.000 mm (2.7953-2.7955 in)

Procedure and torque specs for tightening bearing caps:

Head with 12 points:

  • First step: 103 Nm; 10.5 kg·m; 76 ft·lb
  • Second step: 90° turn all bolts

Head with six points:

  • 13 ftlb; 18 Nm; 1.8 kgm

Make sure that the crankshaft spins smoothly after securing bearing caps.

Bearing nut for connecting rods

  • First step: 37 Nm; 3.75 kgm; 27 lbft
  • Second step: Turn all bolts 90 degrees

Bolt that secures the crankshaft pulley

  • Nm: 430; kg: 44.0; ft: 317

Bolts used to fix flywheels (MT) or drive plates (AT)

  • 13 kgm; 94 ftlbs; 127 Nm

The Cylinder Head

An eccentrically shaped cylinder head is mounted on a three-layer steel laminate type head gasket on the 1HDFT. The head is made of one-piece high-strength cast iron. The SOHC engine has a rocker arm made of aluminum and a camshaft made of carbon steel. Each rocker is controlled via a bridge that activates a pair of valves. Instead of glow plugs, this engine uses an intake glow screen heater.

A camshaft is driven by gears and timing belts. Timing belts are equipped with automatic tensioners. As well as powering all of these components, the timing gear train is responsible for operating the oil pump, vacuum pump, steering gear pump, injection pump, and camshaft.

This engine possesses OHV, where each cylinder has four valves: two intakes and two exhausts made from heat-resistant steel. There are 33.0mm (1.2992 in) and 30.5mm (1.2007 in) valve diameters for the intakes and exhausts, respectively. 224° and 246°, respectively, are the intake and exhaust durations.

An exhaust manifold gasket made of five layers of steel laminate attached to the cast iron and aluminum intake manifold of the 1HD-FT engine.

made of alloyCast iron
valve configurationOHV
The length of the intake valves126.85-127.45 mm (4.9941-5.0177 in)
Diameter of intake valves33.0 mm (1.2992 in)
diameter of exhaust valves:30.5 mm (1.2007 in)
Dimensions of exhaust valves126.43-127.03 mm (4.9775-5.0012 in)
number of valves24 (4 valves per cylinder)
Diameter of the camshaft journal:First: 34.969-34.985 mm (1.3767-1.3774 in)
In addition: 27.986-27.998 mm (1.1018-1.1023 in)
Diameter of intake valve stem6.970-6.985 mm (0.2744-0.2750 in)
Intake cam lobe height48.498-48.598 mm (1.9094-1.9133 in)
Diameter of exhaust valves6.960-6.975 mm (0.2740-0.2746 in.l
Measurements of the exhaust cam lobes50.734-50.834 mm (1.9974-2.0013 in)

How to tighten the head and what torque specs to use:

  • First step: 69 Nm; 7.0 kg·m; 51 ft·lb
  • Secondly, turn all bolts 90°
  • Finally, tighten all bolts

Casing for the camshaft

  • 18 ftlb; 25 Nm; 2.5 kgm

What is the difference between the 1HD-FT and 1HDT?

Despite the fact that both diesel engines are made by Toyota Motor Company, the 1HDFT and 1HDT engines differ in a few ways. Below are some factors to consider.

Aspects1HDFT
Output powerHorsepower: 315 – 420Horsepower: 164 – 420
Output torqueThere is 380 Nm (280 pounds-feet)Between 361 and 430 Nm (266 to 316 lb.ft)
Adaptation of valvetrainTwenty-four valvesTwelve valves
The ratio of compression18.6:118.6:1 and 18.8:1

FAQ

1. What do you think of the 1HD-FTE engine?

One of the most reliable engine types is the 1HD-FTE. With 3,600 rpm, it can produce 122kW of power. Around 1,400 rpm, the engine produces 361Nm torque. It also requires a lot less maintenance.

If you change the oil and filter every 5,000 kilometers, you’re good to go. Maintaining a regular maintenance culture ensures that all vehicles are operating efficiently and at peak performance.

This is true for the 1HD-FTE as well. While less complicated to maintain, it still cannot compare to the latest versions of V6 and V8. Keep up with regular maintenance for a 1HD-FTE engine, and you’ll enjoy its incredible performance for many years to come.

2. One HZ vs. one HDT, what’s the difference?

1HZ and 1HDT differ in their combustion operations fundamentally. Approximately around the cylinder head area of the 1HZ indirect injection engine is the combustion chamber where combustion takes place.

In the meantime, combustion occurs in the piston of the 1HDT direct injection engine. Due to the 1HZ injector’s direct injection into the engine’s cylinder head, the cylinder head has a high tendency to crack.

1HDT engines are not prone to this problem. It is difficult for a cylinder head to crack since the combustion occurs within the piston, far from the cylinder head. Injectors with a flat surface make it hard for cylinder heads to crack. On the other hand, the nozzles on the 1HDT injectors protrude outward. Fuel consumption on the 1HDT engine is quite good.

3. Can a 1HDT handle a lot of boost?

The maximum boost pressure for a 1HDT is between 11 and 12 PSI. As the turbo cannot handle more boost than necessary, this will help keep the engine reliable. If you follow this recommendation, you will keep your engine safe.

The power of an engine can be boosted by turbo boosts, but more boost may not always mean more power.

Turbochargers work best at a boost pressure of approximately 6 – 8 PSI. A turbocharger or engine that is subjected to excessive boost may experience unexpected failure.

Final Word

There isn’t a clear cut answer when it comes to which engine is better, as they both boast their own set of advantages and disadvantages.

From a performance stand-point, 1HDT is typically faster than 1HDFT, while HFTs tend to offer lower latency and less chance of system crash. However, 1HDFT has become more popular in recent years due to its enhanced scalability.

Ultimately, the best engine for your particular needs depends on your specific application and goal. As always, we recommend consulting with an expert if you’re not sure which one is right for you!

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