1928 Plymouth 1937 Plymouth Plymouth: The First Decade

1929 Plymouth Model U Detailed Specifications

Detailed specifications, including tolerances and tune-up data are from [Chrysler 1934a] unless otherwise noted.

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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° [Sk 2002 27]

Set points to open before top dead center

 0.050" piston travel 

Spark plugs

 7/8"-18 S.A.E. 

Original Plugs

 AC C7 [SK 2002 27]

Gap

 0.025" 
   
Lamps 

  

Head

 1110 [Chilton 1931 292]

Instrument

 63 [Chilton 1931 292]
   
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" 

Botton

 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 nickle 

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"