1928 Plymouth Model Q Detailed Specifications

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

1. Axle, FrontI-Beam
   1. King Pin BushingsBronze
      1. Upper3/4" x 1-3/32"
      2. Lower3/4" x 1-3/32"
   2. Knuckle thrustBall - Top
   3. Wheel bearingsTaper-roller
      1. Maximum end play0.003"
   4. Toe in0" - 1/8"
   5. Caster0° - 2°
   6. Camber0° - 4°
   7. Pivot Angle7°
2. Axle, RearSemi-floating
   1. Gear ratio4.3 to 1
   2. Drive gearSpiral bevel
      1. Diameter and width8-5/8" x 1-3/16"
   3. Gear and Pinion backlash0.005" to 0.010"
   4. Pinion shaft end play0.0015"
   5. Differential side gear and pinion backlash0.017"
   6. Axle shaft diameter outer bearing1-3/8"
3. Battery
   1. Ampere hour capacity90
   2. Cells3
   3. Voltage6
   4. Specific Gravity
      1. Charged1.250
      2. Discharged1.150
4. Brake, HandExternal Contracting
   1. LocationRear of transmission
   2. Drum diameter7"
   3. Lining width2"
   4. Lining to drum clearance1/16"
5. Brake, ServiceHydraulic Internal Expanding
   1. Drum Diameter11"
   2. Shoe width1-1/2"
   3. Shoe to drum clearance:
      1. Bottom0.006"
      2. Top0.012"
   4. Pedal to floor board free play, maximum3/4"
6. Camshaft
   1. Bearings3
   2. Size, diameter and length:
      1. No. 11-1/4" x 1-9/16"
      2. No. 22" x 1"
      3. No. 31-1/4" x 1-3/8"
   3. End play0.003" to 0.005"
7. ClutchSingle plate
   1. Driven disc diameter8-7/8"
   2. Release bearingBall
   3. Release lever to bearing clearance5/32"
   4. Disc run-out at rim (Maximum)0.015"
   5. Spring tension160 lb. to 170 lb. at 1-11/16"
   6. Pedal free play1-1/4" to 1-3/8"
8. Connecting RodDrop forged I section
   1. Between centers7-7/8"
   2. BearingsBabbitt cast in rod
      1. Diameter and length1-7/8" x 1-1/2"
      2. Clearance0.0015" to 0.002"
      3. Side play0.003" to 0.005"
   3. Weight variation limit1/4 oz.
   4. Alignment limits at pin:
      1. Twist0.002"
      2. Bend0.002"
9. CoolingThermo-syphon
   1. Capacity3 1/2 Gallons
10. Crankshaft
    1. BearingsBabbitt
    2. Diameter and length
       1. No. 11-7/8" x 2 13/32"
       2. No. 22-1/4" x 1-5/8"
       3. No. 31-7/8" x 2-13/16"
    3. Clearance0.001" to 0.002"
    4. End play0.003" to 0.005"
    5. Run-out center bearing maximum0.001"
11. Cylinders
    1. Maximum taper before reconditioning0.0015"
    2. Maximum out of round before reconditioning0.002"
    3. Reconditioning working limits0.0005"
12. EngineL-head
    1. Number of cylinders4
    2. Bore3-5/8"
    3. Stroke4-1/8"
    4. Piston displacement170.3 cu. in.
    5. N.A.C.C. horsepower21.03
    6. Developed horsepower45
    7. Compression Ratio4.6
    8. Compression pressure68 PSI at cranking speed [SK 2002 27]
13. FramePressed steel
    1. Length153-1/4"
    2. Depth of channel5"
    3. Flange width1-3/4"
    4. Thickness9/64"
    5. Cross members4
14. Fuel SystemVacuum
    1. Tank capacity11 gal.
15. Generator
    1. Maximum cold charging rate at 20 MPH16 amp.
16. Horn
    1. Standard EquipmentKlaxon 12C
       1. Horn Type900-A
17. IgnitionSemi-automatic
    1. Breaker Points
       1. Breaker point gap0.020"
       2. Set points to open before top dead center0.050" piston travel
    2. Spark plugs7/8"-18 S.A.E.
       1. Gap0.025"
       2. Original Plugs
          1. Standard HeadAC A
          2. “Red Head”AC Y [Buton2009]
18. Lamps
    1. Head1110 [Chilton 1931 292]
    2. Instrument63 [Chilton 1931 292]
19. Lubrication, EnginePressure
    1. Oil capacity4 quarts
    2. Oil pressure at 30 MPH35 to 40 P.S.I.
20. Piston PinsClamped in rod
    1. Diameter and length3/4" x 3"
    2. Clearance in piston0.0005" to 0.001" (Light finger push at normal room temperature)
21. Piston Rings
    1. Number per piston3
    2. Width
       1. Upper - Compression1/8"
       2. Center - wiper1/8"
       3. Lower - oil control1/8"
    3. Gap clearance
       1. Upper - compression0.010" to 0.015"
       2. Center - wiper0.010" to 0.015"
       3. Lower - oil control0.005" to 0.010"
    4. Maximum side clearance in groove0.003"
22. PistonsLight alloy
    1. Length4-1/8"
    2. Feeler gauge clearance
       1. Head0.022"
       2. Skirt
          1. Top0.003"
          2. Botton0.001"
    3. Weight variation limit1/4 oz.
23. Speedometer Data
    1. Tire size4.75/20
    2. Axle ratio4.3 to 1
    3. Speedometer gear teeth in transmission5-15
24. SpringsSemi-elliptic
    1. Front:
       1. Length and width35-1/2" x 1-3/4"
       2. Leaves9
       3. Shackle washer clearance1/16"
    2. Rear:
       1. Length and width53-1/2" x 1-3/4"
       2. Leaves
          1. Coupe and Roadster7
          2. Touring8
          3. Sedans9
       3. Shackle washer clearance7/16"
25. Steering GearWorm and sector
26. Tires4.75/20
    1. Pressure
       1. Front40 lbs.
       2. Rear35 lbs.
27. Transmission3 speed
28. High and intermediateSliding gear
29. Type of gearsSpur
30. Valves
    1. InletChrome nickle
    2. ExhaustSilcrome
    3. Clearance diameter of opening
       1. Inlet1-9/16"
       2. Exhaust1-7/16"
    4. Stem diameter3/8"
       1. Clearance in guide
          1. Inlet0.002" to 0.004"
          2. Exhaust0.0035" to 0.004"
    5. Seat angle45°
    6. Lift9/32"
    7. Tappet clearance
       1. Hot engine
          1. Inlet0.004"
          2. Exhaust0.006"
       2. For valve timing
          1. Inlet0.008"
          2. Exhaust0.008"
    8. Timing
       1. Inlet opens past top center5°
       2. Piston travel0.010"
       3. Inlet closes past bottom center45°
       4. Duration of inlet220°
       5. Exhaust opens before bottom center49°
       6. Exhaust closes past top center3°
       7. Piston travel0.004"
       8. Duration of exhaust232°
    9. Springs
       1. Length, valve closed1-7/8"
       2. Tension, valve closed38 to 40 lbs.
       3. Limit of compression1-9/16"