Model A Engine Specifications Specs

Ford Model A Engine Specifications

Nut Sizes:

• Front Motor Mount Castle Nut: 7/16″-20
• Engine Head Nuts (grade 8): 7/16″-20
• Connecting Rod Castle Nut: 7/16″-20
• Ratchet Nut (attaches bottom pulley to crankshaft): 5/8″-18
• Main Bearing Bolt Castle Nut: 1/2″-20

Stud Sizes:

• Regular Head Studs: 3 1/2″ Long
• Water Neck Studs: 5 3/4″ Long

Bolt Sizes:

• Flywheel to Crankshaft Bolts: Four 7/16-20 by 13/16″ Long
• Flywheel Housing to Block: Four 7/16″-14 by 1 1/16″ Long and two 7/16-14 by 1 11/16″ Long
• Timing Cover Bolts: 3/8″-16 by 1 1/8″ Long
• Side Timing Gear Bolts:One 7/16″-14 by 2 3/16″ Long and one 7/16″-14 by 1 3/8″ Long (lock washers can be used)

Torque Specs:

• High Compression Head: 65 lbs
• Standard Head: 55 lbs
• Main Bearing Cap Torque 80-100 lbs
• Flywheel Bolt Torque 65 ft/lbs

Specifications:

• The stock compression ratio was about 4.22:1
• Piston displacement 200.5 cu. Inches
• Bore 3.875″
• Rated H.P. 24.03 SAE
• Brake H.P. 40
• Firing Order 1-2-4-3
• Stroke 4.250″
• Gas Tank
  • 28/29– 10 GAL.
  • 30/31– 11 GAL.

Valves:

• Valve lift .287″
• Seat Angle: 45°
• Stem Diameter: .311″
• Port Diameter: 1 3/8″
• Valve Opening Diameter: 1 3/8″
• Valve Guide Clearance:
• Exhaust: .002″
• Intake: .001-.0015
• Valve Spring Length:
• Free: 2 15/16″
• Compressed Length: 2 1/4″
• Valve Spring Force (compressed): 57-64 lbs.
• Valve Timing:
  • Intake:
    • Opens 7 1/2° before TDC (top dead center)
    • Closes 48 1/2° after BDC (bottom dead center)

• Exhaust:
  • Opens 51 1/2° before BDC
  • Closes 4 1/2° after TDC

Flywheel:

• Weight: 63 lbs., 4 oz.
• Balance: Within .15 In/oz.
• Clutch Mounting Surface: True with crankshaft within .005″ TIR.
• Clutch Mounting Shoulder Diameter: Concentric with crank flange diameter within .005″ TIR.

Carburetor:

• Throat Size: 1″
• Float Level: 1″ from float to machined surface.
• Main Jet: #63 drill bit
• Cap Jet: #63 drill bit
• Idle Jet: # 75 drill bit

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Exhaust System:

• Exhaust Pipe: 2″ ID (Inside Diameter)
• Tail Pipe: 1-5/8″ ID

Miscellaneous:

• To remove a stuck head from a “firing” engine you can loosen the head nuts about 1/8″ from the head and start the motor the compression will pop the head up and the motor will stall.
• Crankshaft weight 28 lbs.
• Engine Oil Capacity:

• From Empty: 5 Quarts
• Oil Change: 4 1/2 Quarts

• Spark Plugs: Champion 3X, 7/8″-18
• Spark Gap: .035″

Source:  http://www.motormayhem.net/model-a-ford-reference-page/engine-specifications/