Isuzu 6H engine

The Isuzu 6H is a family of inline six-cylinder diesel engines installed in Isuzu medium-duty trucks, and also installed in GM medium-duty trucks as the Duramax LG4. It is mated to the Allison 2500, 3000, and 3500 series transmissions.

Isuzu 6H Engine
Isuzu 6HK1-TCN
Overview
Manufacturer	Isuzu and General Motors
Layout
Configuration	Inline six-cylinder
Displacement	7.1–8.2 L; 434.9–502.0 cu in (7,127–8,226 cc)
Cylinder bore	115 mm (4.53 in)
Piston stroke	125 mm (4.92 in)
Cylinder block material	Cast iron
Cylinder head material	Cast iron
Valvetrain	SOHC 4 valves × cyl.
Compression ratio	17.5:1, 17.0:1 for 300 hp (224 kW)
Combustion
Turbocharger	With intercooler
Fuel system	Injection pump (for 6HH1) High-pressure common-rail direct injection
Fuel type	Diesel
Cooling system	Water-cooled
Output
Power output	165–300 PS (121–221 kW)
Torque output	520–860 lb⋅ft (705–1,166 N⋅m)

Engine specifications

6HK1/Duramax LG4

• Displacement: 7.8 L; 475.4 cu in (7,790 cc)
• Bore and stroke: 115 mm × 125 mm (4.53 in × 4.92 in)
• Block: gray iron
• Cylinder head: cast iron
• Fuel cutoff: 2400 rpm
• Aspiration: Turbocharged and intercooled
• Valvetrain: SOHC 24-valve
• Compression: 17.5:1 (17.0:1 for 300 hp (224 kW))
• Injection: high-pressure common-rail direct injection
• Power/torque: 200–300 hp (200–300 PS; 150–220 kW), 520–860 lb⋅ft (72–119 kg⋅m)^[1]

6HH1

Isuzu 6HH1-S

• Displacement: 8.2 L; 502.0 cu in (8,226 cc)
• Bore and stroke: 115 mm × 132 mm (4.5 in × 5.2 in)
• Aspiration: Naturally aspirated
• Valvetrain: SOHC 24-valve
• Compression ratio: 18.5:1
• Injection: Reformed Bosch, inline injection pump with automatic timer, and all-speed mechanical governor
• Power/torque: 173–200 hp (175–203 PS; 129–149 kW), 340–370 lb⋅ft (47–51 kg⋅m)

6HE1

• Displacement: 7.1 L; 434.9 cu in (7,127 cc)
• Bore and stroke: 110 mm × 125 mm (4.3 in × 4.9 in)
• Aspiration: naturally aspirated or turbocharged
• Valvetrain: direct injection, SOHC 24-valve
• Compression ratio: 16.9:1
• Injection: direct injection
• Power/torque: 165–260 hp (167–264 PS; 123–194 kW), 330–560 lb⋅ft (46–77 kg⋅m)

Engine variants

Model	Displacement	Output	Notes
6HE1-N	7.1 L; 434.9 cu in (7,127 cc)	175 PS (129 kW)
6HE1-S		195 PS (143 kW)
6HE1-TCN		220 PS (162 kW)
6HE1-TCS		250 PS (184 kW)
6HH1-N	8.2 L; 502.0 cu in (8,226 cc)	175 PS (129 kW)
6HH1-C		185 PS (136 kW)
6HH1-S		210 PS (154 kW)
6HL1-N	7.2 L; 437.3 cu in (7,166 cc)	180 PS (132 kW)
6HL1-S		205 PS (151 kW)
6HK1-TCR	7.8 L; 475.4 cu in (7,790 cc)	205 PS (151 kW)
6HK1-TCN		240 PS (177 kW)
6HK1-TCC		260 PS (191 kW)
6HK1-TCS		280 PS (206 kW)
6HK1-TCH		300 PS (221 kW)
Duramax LG4 7800		275 PS (202 kW)	used in GMC medium-duty trucks

Vehicles

• Isuzu F-Series
• Chevrolet T-Series
• Isuzu H-Series