ENGINE SPECS

1954 Mercury 256 V8 Engine Specs

GENERAL SPECIFICATIONS

Model Designation: BR
Wheel base: 118
Valve Location: In head
Bore and Stroke: 3.62 x 3.10
Piston displacement, Cubic Inches: 256
Compression ratio: 7.50
Maximum Brake Horsepower: 161 @ 4400 RPM
Maximum Torque Lbs.Ft. @ RPM: 238 @ 2200 RPM
Normal Oil Pressure Pounds: 40

TUNE UP SPECIFICATIONS

Spark Plug Make: Champion H10
Spark Plug Gap, Inch: .030
Firing Order: 15486372 (front to rear: Right bank 1-2-3-4, left bank 5-6-7-8)
Timing Mark: 3 degree mark on Pulley
Engine Idle Speed, RPM:  Standard trans: 475; w/automatic: 440 (in drive)
Cylinder Head Torque Lbs.Ft.: 65-70
Compression Pressure & Cranking Speed: 115 Min.
Voltage & Polarity: 6 volts, positive ground

PISTON AND RING SPECIFICATIONS

Fitting Pistons with Scale: Pistons removed from above. Shim thickness: .002;
Pounds on a Pull Scale: 5 to 10
Ring End Gap: In tapered bores, fit rings in tightest portion of ring travel
Compression: .010
Oil: .010
Clearance in Groove: Compression: Upper ring: .002-.0035; Lower ring: .0015-.003; Oil: .0015-.003
Wristpin Diameter, Inch: .9120-.9123

VALVE SPECIFICATIONS

Operating Clearance:
     Intake: .019 Hot  Exhaust: .019 Hot
Valve Seat Angle, degrees: 45
Valve Timing: (BTDC = before top dead center; ATDC = after top dead center)
         Intake opens: 15 BTDC
         Exhaust Closes: 19 ATDC
Valve Spring Pressure Pounds at Inches Length:
    Inner Spring: 54 @ 1.82
Valve Stem Clearance: Intake: .001-.002; Exhaust: .002-.003

ENGINE BEARING SPECIFICATIONS

Connecting Rod Bearings:
    Journal Diameter, Inches: 2.1880-2.1888
    Bearing Clearance, Inch: .0021-.003
    Rod End Play, Inch: .006-.016
    Rod Bolt Tension: Lbs.Ft.: 45-50
Main Bearings:
    Journal Diameter, Inches: 2.4980-2,4988
    Bearing clearance: .002-.005
    Shaft End Play: .002-.006    (Thrust on Center Bearing)
    Main Bolt Tension: Lbs.Ft.: 80-90

CAPACITY DATA

Cooling System:
    Without heater: 19 quarts
    With heater: 20 quarts
Fuel Tank: 19 gallons
Engine Oil: 5 quarts
Transmission: w/out overdrive: 3 pints; w/overdrive: 4-1/2 pints; Automatic: 9-3/4 quarts
Rear Axle: 3-1/2 pints

LOADAMATIC DISTRIBUTOR SPECIFICATIONS

Distributor part number: FAE-12127C (distributor rotates counter-clockwise)
Cam Angle, degrees: 28
Breaker Point opening, Inch: .014-.016
Condenser Capacity: .21-.25 Mfds.
Breaker Arm Spring Tension: 17-20 Oz.
Vacuum Advance: (degrees at RPM of distributor)
    At 500 RPM: 1-1/2 - 2-1/2 Degrees advance; .24 Inches Vacuum
    At 1000 RPM: 7-1/4 - 8-1/4 Degrees advance; .64 Inches Vacuum
    At 1400 RPM: 11-3/4 - 12-3/4 Degrees advance;
1.13 Inches Vacuum
    At 2000 RPM: 15 - 15-1/2 Degrees advance; 1.52 Inches Vacuum

GENERATOR SPECIFICATIONS

Generator Number: FBA-10000A (generator rotates clockwise, 6 volts, Positive Ground)
Generator output: 40 @ 1700 RPM
Brush Spring Tension: 30 oz.
Field Current @ 6 volts: 2.0-2.5

REGULATOR SPECIFICATIONS

Regulator Number: FAD-10505
Cutout Relay:
    Voltage to close points: 6.3
    Reverse current to open points: 0-8
Voltage Regulator Setting: 7.4 volts
Current Regulator Setting: 40 amps

STARTING MOTOR SPECIFICATIONS

Part number: FAC-11001B
Bush Spring Tension, Ounces: 48-56
No Load Test: 70 amps, 6 volts @ 3000 RPM
Torque Test: 700 Amps, 3.5 volts, Torque, Lbs.Ft.: 16

WHEEL ALIGNMENT SPECIFICATIONS

Caster, Degrees
    Limits: -1-1/2 to 0
    Desired: -3/4
Camber, Degrees
    Limits: 0 to +3/4
    Desired: +3/8
Toe-In, Inches: 3/32 to 5/32
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: 24°9'
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)
    7 @ 3/4 Camber


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