My 1929 Plymouth Model U

Chet's Old Plymouths

1929 Specifications

Axle, Front 

 I-Beam

King Pin Bushings

 Bronze

Upper

 3/4" x 1-3/32"

Lower

 3/4" x 1-15/32"

Knuckle thrust

 Ball - Top

Wheel bearings

 Taper-roller

Maximum end play

 0.003"

Toe in

 0" - 1/8"

Caster

 0° - 2°

Camber

 0° - 4°

Pivot Angle

 7°

   

Axle, Rear 

 Semi-floating

Gear ratio

 4.3 to 1

Drive gear

 Spiral bevel

Diameter and width

 8-5/8" x 1-3/16"

Gear and Pinion backlash

 0.005" to 0.010"

Pinion shaft end play

 0.0015"

Differential side gear and pinion backlash

 0.017"

Axle shaft diameter outer bearing

 1-3/8"

   

Battery 

 

Ampere hour capacity

 84

Cells

 3

Specific Gravity

 

Charged

 1.250

Discharged

 1.150

   

Brake, Hand 

 External Contracting

Location

 Rear of transmission

Drum diameter

 7"

Lining width

 2"

Lining to drum clearance

 1/16"

   

Brake, Service 

 Hydraulic Internal Expanding

Drum Diameter

 11"

Shoe width

 1-1/2"

Shoe to drum clearance:

 

Bottom

 0.006"

Top

 0.012"

Pedal to floor board free play, maximum

 3/4"

   

Camshaft 

 

Bearings

 3

Size, diameter and length:

 

No. 1

 1-1/4" x 1-9/16"

No. 2

 2" x 1"

No. 3

 1-1/4" x 1-3/8"

End play

 0.003" to 0.005"

   

Clutch 

 Single plate

Driven disc diameter

 8-7/8"

Release bearing

 Ball

Release lever to bearing clearance

 3/16"

Disc run-out at rim (Maximum)

 0.015"

Spring tension

 160 lb. to 170 lb. at 1-11/16"

Pedal free play

 1-1/4" to 1-3/8"

   

Connecting Rod 

 Drop forged I section

Between centers

 8-13/16"

Bearings

 Babbitt cast in rod

Diameter and length

 2" x 1-3/8"

Clearance

 0.0015" to 0.002"

Side play

 0.003" to 0.005"

Weight variation limit

 1/4 oz.

Alignment limits at pin:

 

Twist

 0.002"

Bend

 0.002"

   

Cooling 

 Thermo-syphon

Capacity

 3 1/2 Gallons

   

Crankshaft 

 

Bearings

 Babbitt

Diameter and length

 

No. 1

 2-1/4" x 2 1/8"

No. 2

 2-1/4" x 1-5/8"

No. 3

 2-1/4" x 2-3/8"

Clearance

 0.001" to 0.002"

End play

 0.003" to 0.005"

Run-out center bearing maximum

 0.001"

   

Cylinders 

 

Maximum taper before reconditioning

 0.0015"

Maximum out of round before reconditioning

 0.002"

Reconditioning working limits

 0.0005"

   

Engine 

 L-head

Number of cylinders

 4

Bore

 3-5/8"

Stroke

 4-1/4"

Piston displacement

 175.4 cu. in.

N.A.C.C. horsepower

 21.03

Developed horsepower

 45

   

Frame 

 Pressed steel

Length

 153-1/4"

Depth of channel

 5"

Flange width

 1-3/4"

Thickness

 9/64"

Cross members

 4

   

Fuel System 

 Vacuum

Tank capacity

 11 gal.

   

Generator 

Maximum cold charging rate at 20 MPH

 16 amp.

   

Ignition 

 Semi-automatic

Breaker Points

 

Breaker point gap

 0.020"

Cam Angle (Degrees)

 52°

Set points to open before top dead center

 0.050" piston travel

Spark plugs

 7/8"-18 S.A.E.

Original Plugs

 AC C7

Gap

 0.025"

   

Lamps 

 

Head

 1110

Instrument

  63

   

Lubrication, Engine 

 Pressure

Oil capacity

 4 quarts

Oil pressure at 30 MPH

 35 to 40 P.S.I.

   

Piston Pins 

 Clamped in rod

Diameter and length

 3/4" x 3"

Clearance in piston

 0.0005" to 0.001"
Light finger push at normal room temperature

   

Piston Rings 

 

Number per piston

 3

Width

 

Upper - Compression

 1/8"

Center - wiper

 1/8"

Lower - oil control

 1/8"

Gap clearance

 

Upper - compression

 0.010" to 0.015"

Center - wiper

 0.010" to 0.015"

Lower - oil control

 0.005" to 0.010"

Lower - oil control

 0.004" to 0.009"

Maximum side clearance in groove

 0.003"

   

Pistons 

 Light alloy

Length

 4-1/8"

Feeler gauge clearance

 

Head

 0.022"

Skirt

 

Top

 0.003"

Bottom

 0.001"

Weight variation limit

 1/4 oz.

   

Speedometer Data 

 

Tire size

 4.75/20

Axle ratio

 4.3 to 1

Speedometer gear teeth in transmission

 5-15

   

Springs 

 Semi-elliptic

Front:

 

Length and width

 35-1/2" x 1-3/4"

Leaves

 9

Shackle washer clearance

 1/16"

Rear:

 

Length and width

 53-1/2" x 1-3/4"

Leaves

 

Coupe and Roadster

 7

Touring

 8

Sedans

 9

Shackle washer clearance

 7/16"

   

Steering Gear 

 Worm and sector

   

Tires 

 4.75/20

Pressure

 

Front

 40 lbs.

Rear

 35 lbs.

   

Transmission 

 3 speed

High and intermediate

 Sliding gear

Type of gears

 Spur

   

Valves 

 

Inlet

 Chrome nickel

Exhaust

 Silcrome

Clearance diameter of opening

 

Inlet

 1-9/16"

Exhaust

 1-7/16"

Stem diameter

 3/8"

Clearance in guide

 

Inlet

 0.002" to 0.004"

Exhaust

 0.0035" to 0.004"

Seat angle

 45°

Lift

 9/32"

Tappet clearance

 

Hot engine

 

Inlet

 0.004"

Exhaust

 0.006"

For valve timing

 

Inlet

 0.008"

Exhaust

 0.008"

Timing

 

Inlet opens past top center

 5°

Piston travel

 0.010"

Inlet closes past bottom center

 45°

Duration of inlet

 220°

Exhaust opens before bottom center

 49°

Exhaust closes past top center

 3°

Piston travel

 0.004"

Duration of exhaust

 232°

Springs

 

Length, valve closed

 1-7/8"

Tension, valve closed

 38 to 40 lbs.

Limit of compression

 1-9/16"