Pontiac Gasoline Straight-4 Iron Duke Tech IV (Van) 1985-1986 engine DIY maintenance and service manual

General Information

Pontiac Gasoline Straight-4 Iron Duke Tech IV (Van) 1985-1986 is an 151 in³ (2.47 L) internal combustion reciprocating Inline 4 engine. It has bore/stroke ratio of 4 in × 3 in (10.16 cm × 7.62 cm), and uses 9:1 compression. This engine was rated 92 hp (68.6 kW) at 4400 rpm and 134 lbf⋅ft (181.68 N⋅m) of torque at 2800 rpm. It was used in Chevrolet, GMC, and Pontiac cars.

Engine Performance Rating

SAE J1349 (SAE Net)

Pontiac Gasoline Straight-4 Iron Duke Tech IV (Van) 1985-1986 engine performance rating according to SAE J1349 (SAE Net) standard.
Parameter	Output
Power Rating	92 hp (68.6 kW) at 4400 RPM
Torque Rating	181.68 N⋅m134 lbf⋅ft134 lbf⋅ft at 2800 RPM

Specifications

General

Pontiac Gasoline Straight-4 Iron Duke Tech IV (Van) 1985-1986 engine general specifications.
Parameter	Value
Type	Internal Combustion Reciprocating
Fuel Type	Gasoline
Cylinder Configuration	Inline 4
Engine Displacement	2.47 L151 in³151 in³
Bore	10.16 cm4 in4 in
Stroke	7.62 cm3 in3 in
Compression Ratio	9:1

Photos

Please help our community. Upload your photos of Pontiac Gasoline Straight-4 Iron Duke Tech IV (Van) 1985-1986 engine.

Block, crankshaft and pistons

Pontiac Gasoline Straight-4 Iron Duke Tech IV (Van) 1985-1986 engine block, crankshaft and pistons specifications.
Parameter	Value
Block Material	Cast iron

Compression

Pontiac Gasoline Straight-4 Iron Duke Tech IV (Van) 1985-1986 engine compression.
Parameter	Value
Compression (standart)	9.53 atm.140 Psi140 Psi

Spark Plugs and Wires

Pontiac Gasoline Straight-4 Iron Duke Tech IV (Van) 1985-1986 spark plugs and wires specifications.
Parameter	Value
Spark Plug Gap	1.52 mm0.06 in0.06 in

Engine head and valvetrain

Pontiac Gasoline Straight-4 Iron Duke Tech IV (Van) 1985-1986 engine head and valvetrain specifications.
Parameter	Value
Head Material	Cast iron
Valvetrain Type	OHV
Valves per Cylinder	2

Air Intake

Pontiac Gasoline Straight-4 Iron Duke Tech IV (Van) 1985-1986 air intake specifications.
Parameter	Value
Air Intake Method	Naturally Aspirated

Fuel Injection

Pontiac Gasoline Straight-4 Iron Duke Tech IV (Van) 1985-1986 fuel injection specifications.
Parameter	Value
Injection Type	Single Point
Injection Info	TBI, via a single injector in the throttle body

Valve Timings

Pontiac Gasoline Straight-4 Iron Duke Tech IV (Van) 1985-1986 valve timings.
Parameter	Value
Ignition Timing	8° B.T.C.

Oil Pump

Pontiac Gasoline Straight-4 Iron Duke Tech IV (Van) 1985-1986 oil pump specifications.
Parameter	Value
Oil Pump Pressure	2.79 atm.41 Psi41 Psi at 2000 RPM

Engine Specifications

Condition	Value

expand_moreGeneral specifications

expand_moreCylinder block


Bore out-of-round	0.0014 in0.0014 in0.0356 mm
Maximum
Bore taper	0.0005 in0.0005 in0.0127 mm
Maximum

expand_morePiston


Top clearance in bore	63.5–83.82 μm0.0025–0.0033 in0.0025–0.0033 in
Bottom clearance in bore	0.0017–0..0041 in
Piston diameter	10.1526–10.1534 cm3.9971–3.9974 in3.9971–3.9974 in

expand_morePiston rings


Compression ring side clearance (top)	38.1–76.2 μm0.0015–0.003 in0.0015–0.003 in
Compression ring side clearance (bottom)	38.1–76.2 μm0.0015–0.003 in0.0015–0.003 in
Compression ring-width (top)	1.575–1.588 mm0.062–0.062 in0.062–0.062 in
Compression ring-width (bottom)	1.9685–1.9812 mm0.0775–0.078 in0.0775–0.078 in
Upper compression ring gap	254–558.8 μm0.01–0.022 in0.01–0.022 in
Lower compression ring gap	254–685.8 μm0.01–0.027 in0.01–0.027 in
Oil ring width	4.801 mm0.189 in0.189 in
Oil ring gap	381–1397 μm0.015–0.055 in0.015–0.055 in

expand_morePiston pin


Diameter	2.383–2.393 cm0.938–0.942 in0.938–0.942 in
Length	7.62 cm3 in3 in
Pin to piston clearance	7.62–12.7 μm0.0003–0.0005 in0.0003–0.0005 in
Loose
Fit in rod	Press

expand_moreCrankshaft and connecting rod

expand_moreMain bearing journal


Diameter	5.84 cm2.3 in2.3 in
Out-of-round	12.7 μm0.0005 in0.0005 in
Maximum
Taper	12.7 μm0.0005 in0.0005 in
Maximum
Clearance limit new	12.7–55.88 μm0.0005–0.0022 in0.0005–0.0022 in
Crankshaft end play (when new)	88.9–215.9 μm0.0035–0.0085 in0.0035–0.0085 in

expand_moreRod bearing journal


Diameter	5.08 cm2 in2 in
Out-of-round	12.7 μm0.0005 in0.0005 in
Maximum
Taper	12.7 μm0.0005 in0.0005 in
Maximum
Clearance limit new	12.7–66.04 μm0.0005–0.0026 in0.0005–0.0026 in
Rod side clearance	152.4–558.8 μm0.006–0.022 in0.006–0.022 in

expand_moreCamshaft


Intake	1.011 cm0.398 in0.398 in
Exhaust	1.011 cm0.398 in0.398 in
Journal diameter	4.747 cm1.869 in1.869 in
Journal clearance	17.78–68.58 μm0.0007–0.0027 in0.0007–0.0027 in
End play clearance	38.1–127 μm0.0015–0.005 in0.0015–0.005 in

expand_moreValve train


Lash intake and exhaust
Rocker arm ratio	1.75:1
Push rod length	24.775 cm9.754 in9.754 in

expand_moreValve lifter


Leak down rate	12 to 90 seconds with 50 lb. load
Lifter body diameter	2.139–2.14 cm0.842–0.843 in0.842–0.843 in
Plunger Travel	3.175 mm0.125 in0.125 in
Clearance in boss	63.5 μm0.0025 in0.0025 in
Lifter bore diameter	2.1425–2.145 cm0.8435–0.8445 in0.8435–0.8445 in

expand_moreValves

expand_moreIntake


Face Angle	45°45°45°
Seat angle	46°46°46°
Head Diameter	4.37 cm1.72 in1.72 in
Stem diameter	8.6995–8.6817 mm0.3425–0.3418 in0.3425–0.3418 in
Overhall Length	12.507 cm4.924 in4.924 in
Stem to guide clearance	25.4–68.58 μm0.001–0.0027 in0.001–0.0027 in
Valve seat width	896.62–1897.38 μm0.0353–0.0747 in0.0353–0.0747 in
Valve installed height	4.29 cm1.69 in1.69 in

expand_moreExhaust


Face Angle	45°45°45°
Seat angle	45°45°45°
Head Diameter	3.81 cm1.5 in1.5 in
Stem diameter	8.6817–8.6995 mm0.3418–0.3425 in0.3418–0.3425 in
Overhall Length	12.5 cm4.92 in4.92 in
Stem to guide clearance top	25.4–68.58 μm0.001–0.0027 in0.001–0.0027 in
Stem to guide clearance bottom	50.8–93.98 μm0.002–0.0037 in0.002–0.0037 in
Valve seat width	1.473–2.466 mm0.058–0.097 in0.058–0.097 in
Valve installed height	4.29 cm1.69 in1.69 in

expand_moreValve spring pressure and length-valve


Closed	78-86 lb. at 1.66 inches
Open	122-180 lb. @ 1.254 inches

Fastener Tightening Specifications

Condition	Value


Main bearing to the engine block screws	70.07 lbf⋅ft70.07 lbf⋅ft95 N⋅m
Nut connecting rod	32.45 lbf⋅ft32.45 lbf⋅ft44 N⋅m
Front oil pan lateral and rear side screws	4.43 lbf⋅ft4.43 lbf⋅ft6 N⋅m
Plug Oil Pan Drain	25.08 lbf⋅ft25.08 lbf⋅ft34 N⋅m
Nut oil screen support	36.88 lbf⋅ft36.88 lbf⋅ft50 N⋅m
Oil pump to the engine block screws	22.13 lbf⋅ft22.13 lbf⋅ft30 N⋅m
Oil pump cover screws	10.33 lbf⋅ft10.33 lbf⋅ft14 N⋅m
Push rod cover to the engine block screws	7.38 lbf⋅ft7.38 lbf⋅ft10 N⋅m
Bolt crankshaft hub	162.26 lbf⋅ft162.26 lbf⋅ft220 N⋅m
Flywheel to crankshaft screws	44.25 lbf⋅ft44.25 lbf⋅ft60 N⋅m
Nut EFI assembly to the manifold	14.75 lbf⋅ft14.75 lbf⋅ft20 N⋅m
EFI assembly to the manifold screws	14.75 lbf⋅ft14.75 lbf⋅ft20 N⋅m
Intake manifold to the cylinder head screws	29.5 lbf⋅ft29.5 lbf⋅ft40 N⋅m
Exhaust manifold to the cylinder head screws	44.25 lbf⋅ft44.25 lbf⋅ft60 N⋅m
Fuel pump to the engine block screws	18.44 lbf⋅ft18.44 lbf⋅ft25 N⋅m
Distributor retaining clamp screws	22.13 lbf⋅ft22.13 lbf⋅ft30 N⋅m
EGR valve to manifold screws	10.33 lbf⋅ft10.33 lbf⋅ft14 N⋅m
Water outlet housing screws	19.91 lbf⋅ft19.91 lbf⋅ft27 N⋅m
Thermostat housing screws	19.91 lbf⋅ft19.91 lbf⋅ft27 N⋅m
Water pump to the engine block screws	25.08 lbf⋅ft25.08 lbf⋅ft34 N⋅m
Timing cover to the engine block screws	7.38 lbf⋅ft7.38 lbf⋅ft10 N⋅m
Timing cover to oil pan screws	7.38 lbf⋅ft7.38 lbf⋅ft10 N⋅m
Fan and pulley to the water pump screws	17.7 lbf⋅ft17.7 lbf⋅ft24 N⋅m
Radiator hoses clamps	1.48 lbf⋅ft1.48 lbf⋅ft2 N⋅m
Rocker arm screws	19.91 lbf⋅ft19.91 lbf⋅ft27 N⋅m
Cylinder head to the engine block screws	92.2 lbf⋅ft92.2 lbf⋅ft125 N⋅m
Rocker arm cover screws	5.9 lbf⋅ft5.9 lbf⋅ft8 N⋅m
Camshaft thrust plate to the engine block screws	7.38 lbf⋅ft7.38 lbf⋅ft10 N⋅m