Chevrolet gasoline Straight-6 Third generation 250 CID (5.7 L) High Torque 125 hp engine DIY maintenance and service manual

General Information

Chevrolet gasoline Straight-6 Third generation 250 CID (5.7 L) High Torque 125 hp is an 250 in³ (4.1 L) internal combustion reciprocating Inline 6 engine. It has bore/stroke ratio of 3.875 in × 3.53 in (9.842 cm × 8.97 cm), and uses 8.5:1 compression. This engine was rated 125 hp (93.21 kW) at 3800 rpm and 220 lbf⋅ft (298.28 N⋅m) of torque at 1600 rpm. It was used in Chevrolet and GMC cars.

Engine Performance Rating

SAE J1995 (SAE Gross)

Chevrolet gasoline Straight-6 Third generation 250 CID (5.7 L) High Torque 125 hp engine performance rating according to SAE J1995 (SAE Gross) standard.
Parameter	Output
Power Rating	155 hp (115.58 kW) at 4200 RPM
Torque Rating	318.62 N⋅m235 lbf⋅ft235 lbf⋅ft at 1600 RPM

SAE J1349 (SAE Net)

Chevrolet gasoline Straight-6 Third generation 250 CID (5.7 L) High Torque 125 hp engine performance rating according to SAE J1349 (SAE Net) standard.
Parameter	Output
Power Rating	125 hp (93.21 kW) at 3800 RPM
Torque Rating	298.28 N⋅m220 lbf⋅ft220 lbf⋅ft at 1600 RPM

Specifications

General

Chevrolet gasoline Straight-6 Third generation 250 CID (5.7 L) High Torque 125 hp engine general specifications.
Parameter	Value
Type	Internal Combustion Reciprocating
Fuel Type	Gasoline
Cylinder Configuration	Inline 6
Engine Displacement	4.1 L250 in³250 in³
Bore	9.842 cm3.875 in3.875 in
Stroke	8.97 cm3.53 in3.53 in
Compression Ratio	8.5:1
Firing Order	1-5-3-6-2-4
Curb Idle Speed	700 RPMs

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Block, crankshaft and pistons

Chevrolet gasoline Straight-6 Third generation 250 CID (5.7 L) High Torque 125 hp engine block, crankshaft and pistons specifications.
Parameter	Value
Block Material	Cast alloy iron
Crankshaft Material	Nodular iron
Piston Material	Cast alloy aluminum; 3 ring grooves above piston pin; flat notched head
Piston Pin Material	Chromium steel
Connecting Rod Material	Drop forged steel

Compression

Chevrolet gasoline Straight-6 Third generation 250 CID (5.7 L) High Torque 125 hp engine compression.
Parameter	Value
Compression (standart)	9.53 atm.140 Psi140 Psi

Spark Plugs and Wires

Chevrolet gasoline Straight-6 Third generation 250 CID (5.7 L) High Torque 125 hp spark plugs and wires specifications.
Parameter	Value
Spark Plugs	AC Delco C44N
Spark Plug Size	0.55 in0.55 in14 mm

Engine head and valvetrain

Chevrolet gasoline Straight-6 Third generation 250 CID (5.7 L) High Torque 125 hp engine head and valvetrain specifications.
Parameter	Value
Head Material	High chrome cast alloy iron
Valvetrain Type	OHV
Valves per Cylinder	2
Camshaft Material	Cast alloy iron

Air Intake

Chevrolet gasoline Straight-6 Third generation 250 CID (5.7 L) High Torque 125 hp air intake specifications.
Parameter	Value
Air Intake Method	Naturally Aspirated

Fuel Injection

Chevrolet gasoline Straight-6 Third generation 250 CID (5.7 L) High Torque 125 hp fuel injection specifications.
Parameter	Value
Injection Type	Carburetor
Injection Info	1-barrel downdraft Rochester with manual choke control

Valve Timings

Chevrolet gasoline Straight-6 Third generation 250 CID (5.7 L) High Torque 125 hp valve timings.
Parameter	Value
Intake Opens	16° B.T.D.C.
Intake Closes	48° A.B.D.C.
Intake Duration	244°
Exhaust Opens	46.5° B.B.D.C.
Exhaust Closes	17.5° A.T.D.C.
Exhaust Duration	244°
Valves Overlap	128°
Ignition Timing	4° B.T.C.

Chevrolet gasoline Straight-6 Third generation 250 CID (5.7 L) High Torque 125 hp valve timing diagram.

Oil Pump

Chevrolet gasoline Straight-6 Third generation 250 CID (5.7 L) High Torque 125 hp oil pump specifications.
Parameter	Value
Oil Pump	Spur-gear type driven by distributor shaft
Oil Pump Pressure	4.08 atm.60 Psi60 Psi at 2000 RPM