1937-1938 Hudson Six, Model 73 (1937), 83 (1938) Tune-up Specifications


SERIAL NUMBER: First No. 73-101 (1937), 83-101
(1938). Stamped on plate on right front door hinge pillar post. Number prefix (73-, 83-) indicates model.
ENGINE NUMBER: First No. 73-101(1937), 83-101
(1938). Stamped on left side of cylinder block opposite #6 cylinder (1937), top of block between #1 and #2 exhaust flanges (1938). Number prefix (73-, 83-) indicates model.


COMPRESSION: Compression Pressure
6.25-1 std. CI. head 103 lbs. @ 170 R.P.M.
7.0-1 Optl. Al. head 119 lbs. @ 170 R.P.M.
NOTE-7.0-1 aluminium head - Super Power Dome.
VACUUM READING: - Gauge should show steady reading of 18-21", with engine idling at 350 R.P.M.
FIRING ORDER: 1-5-3-6-2-4.
SPARK PLUGS: Champion Type J-8A (Std. 6.25-1 Eng.), Type H-10 (Optl. 7.0-1 Eng.). 14 mm. Metric.
Gaps - . 032"
IGNITION: See Coil, Condenser, and Distributor.
Breaker Gap - .020". Cam Angle 35 (closed).
Automatic Advance - 14 max. at 1580 RPM
Std. Setting - At TDC. Flywheel mark "UDC.1-6/" at indicator in left front face of housing.
Idle Setting -Both idle screws - turn open. Idle
speed 7 MPH.
Accelerating Pump - Inner hole Warm Temperatures,
Outer hole - Cold Temperatures.
Float Level - 15/64" from gasket seat on cover to top of float (not soldered seam). Invert to check.
Fuel Pump Pressure: 4 lbs. maximum.
MANIFOLD HEAT CONTROL: - Thermostatic coil
type. Located within manifold housing behind carburettor. No adjustment required,
Tappet Clearance - .006" Int., .008", Exh. Hot.
STARTING: See Battery, Starter, Generator, Regulator.


IGNITION SWITCH: Mitchellock Model 24-B, Type 7063 (1937), 7642 (1938). Connected to coil by armoured cable.
Ignition Lock - Briggs & Stratton, Mitchell No. 6095.
B&S No. 50184. Key Series - H601-H1100.
COIL: Auto-Lite Model IG-4644 (1937), IG-4650
(1938). Service Coil (less Switch & Cable) IG-3224JS.

Ignition Current - 2.5 amperes idling, 4.5 stopped.
CONDENSER: Auto-Lite Part No. IGB-1025 (1937), IGB-1025J (1938). Capacity-.20-.25 microfarad.


Auto-Lite Model IGW-4013-A (1937), IGW-4103-A (1938). Single breaker, 6 lobe cam, full automatic advance type.
Breaker Gap - Set at .020".
Cam Angle or Dwell - 35 (closed), 25 (open).
Breaker Arm Spring Tension-16-20 ounces.
Rotation - Clockwise viewed from the top.
Automatic Advance

Distributor Engine
Degrees R.P.M. Degrees R.P.M.
Start 300 0 600
3 400 6 800
4 500 8 1000
9 1040 18 2080
14 1580 28 3160

Fuel Compensator - provides manual adjustment at distributor for octane rating of fuel used. See Fuel Compensator Setting (following).
Distributor Removal: - Mounted on right side of crankcase. To remove, take out hold-down screw in advance arm.
IGNITION TIMING: - Initial Setting as shown. See
Fuel Compensator Setting following.
Flywheel Degrees Piston Position
All engines 0 TDC .000" TDC.
NOTE - High octane fuel must be used in engines
with 7.0-1 Super Power Dome head.
To Set Timing - With #1 piston on compression, turn engine over until flywheel mark 'UDC.1-6/', lines up with pointer in left front face of flywheel housing. Loosen hold-down screw In advance arm, rotate distributor clockwise to limit of slot, then slowly rotate distributor counter-clockwise until contacts begin to open, tighten hold-down screw.
To Set Timing (Using Synchroscope) - Hudson recommends this method. Clip lead to #6 spark plug fill, in timing mark with white chalk and direct light on flywheel through hole in housing.
Fuel Compensator Setting - Road test car and note performance when accelerating from 10-15 M.P.H. with wide open throttle on level road (engine must be warm). Slight spark knock should be evident. Adjust by loosening hold-down screw and rotating distributor one graduation on scale counter-clockwise (if no knock), clockwise (if knock too severe). Repeat test. Final setting must not be advanced beyond " before'UDC.1-6/' mark on flywheel.

Courtesy http://www.hudsonterraplane.com/