1947 Oldsmobile 238 Inline 6 Engine Specs

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GENERAL SPECIFICATIONS

Model Designation: Special 6: 66; Dynamic 6: 76

Wheel base: Special 6: 119; Dynamic 6: 125

Valve Location: In block

Bore and Stroke: 3-1/2 x 4-1/8

Piston displacement, Cubic Inches: 238.1

Compression ratio: 6.50

Maximum Brake Horsepower: 100 @ 3400 RPM

Maximum Torque Lbs.Ft. @ RPM: 185 @ 1200 RPM

Normal Oil Pressure Pounds: 33

TUNE UP SPECIFICATIONS (all models)

Spark Plug Make: AC 45

Spark Plug Gap, Inch: .040

Firing Order: 153624

Timing Mark: TDC, location: flywheel

Engine Idle Speed, RPM: Standard transmission: 425; w/automatic 375 (in drive)

Cylinder Head Torque Lbs.Ft.: 60-70

Compression Pressure & Cranking Speed: 115

Voltage & Polarity: 6 volts, negative ground

PISTON AND RING SPECIFICATIONS

Fitting Pistons with Scale: Pistons removed from above. Shim thickness: .002

Pounds on a Pull Scale: 4 to 11

Ring End Gap: In tapered bores, fit rings in tightest portion of ring travel
Compression: .009
Oil: .009

Clearance in Groove: Compression: .002-003; Oil: .001-.0025

Wristpin Diameter, Inch: .8554-.8557

VALVE SPECIFICATIONS

Operating Clearance:
Intake: .008 Hot Exhaust: .011 Hot

Valve Seat Angle, degrees: Intake: 30; Exhaust: 45

Valve Timing: (BTDC = before top dead center; ATDC = after top dead center)
Intake opens: 5 BTDC
Exhaust Closes: 5 ATDC

Valve Spring Pressure Pounds at Inches Length:
Inner Spring: 55 @ 2-1/4

Valve Stem Clearance: Intake: .002-.004; Exhaust: .0025-.004

Clearance for Timing Intake: .0125

ENGINE BEARING SPECIFICATIONS

Connecting Rod Bearings:
    Journal Diameter, Inches: 2.123-2.124
    Bearing Clearance, Inch: .0005-.0025
    Rod End Play, Inch: .005-.010
    Rod Bolt Tension: Lbs.Ft.: 50-55

Main Bearings:
    Journal Diameter, Inches:
        Front: 2.478-2.479
        No. 2: 2.5405-2.5415
        No. 3: 2.6655-2.6665
        No. 4: 2.6855-2.6865
    Bearing clearance: Rear main: .0005-.0025; all others: .001-.003
    Shaft End Play: .004-.008    (Thrust is controlled by thrust plate at front bearing)
    Main Bolt Tension: Lbs.Ft.: Nos. 1, 2, 3: 100 ft/lbs; No. 4, 140 ft.lbs

CAPACITY DATA

Cooling System:
Without heater: 18-1/2 quarts
Without heater: 19-1/2 quarts

Fuel Tank: 19 gallons

Engine Oil: 5 quarts

Transmission: w/out overdrive: 2 pints; Automatic: 11 quarts

Rear Axle: 3-3/4 pints

DELCO-REMY DISTRIBUTOR SPECIFICATIONS

Distributor part number: 1110213 (distributor rotates counter-clockwise)

Cam Angle, degrees: 31-37

Breaker Point opening, Inch: .022

Condenser Capacity: .18-.23 Mfds.

Breaker Arm Spring Tension: 17-21 Oz.

Centrifugal Advance: (degrees at RPM of distributor)
    Advance starts: 2 @ 300 RPM
    Full Advance: 12 @ 1600 RPM
    Inches of Vacuum to Start Plunger Movement: 5-7
    Inches of Vacuum for Full Plunger Movement: 16-20
    Maximum Vacuum Advance Dist., Degrees: 8

DELCO-REMY GENERATOR SPECIFICATIONS

Generator Number: 1102664, 1102680 (generator rotates clockwise, 6 volts, Negative Ground)

Generator output: 30 amps @ 2050 RPM

Brush Spring Tension: 28 oz.

Field Current at 6 Volts: 1.75-1.95

DELCO-REMY REGULATOR SPECIFICATIONS

Regulator Number: 1118201, 1118242

Cutout Relay:
    Voltage to close points: 6.4
    Reverse current to open points: 0-3
    Armature Air Gap: .020

Voltage Regulator Setting: 7.4 volts

Current and Voltage Armature Air Gap: .075 inches

Current Regulator Setting: 36 amps

DELCO-REMY STARTING MOTOR SPECIFICATIONS

Part number: 1107034 (rotates clockwise)

Bush Spring Tension, Ounces: 24-28

No Load Test: 65 amps, 5.67 volts @ 5000 RPM

Torque Test: 525 Amps, 3.37 volts, Torque, Lbs.Ft.: 12

WHEEL ALIGNMENT SPECIFICATIONS

Caster, Degrees
Limits: -3/4 to - 3/8
Desired: - 3/8

Camber, Degrees
Limits: -3/4 to +3/4
Desired: 0

Toe-In, Inches: 1/16 to 1/8

Toe-Out on Turns, Degrees: (If toe-out is incorrect, when other adjustments are correct, look for bent steering arms.)
Outer wheel: 20
Inner Wheel: 22-1/2 to 23-1/2

Kingpin Angle, or Steering Axis Degrees: (If king pin or spindle support angle are incorrect, but camber is correct, look for bent suspension arms or steering knuckle support)
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