Hudson 1938 Terraplane, Owner'S Manual

Page: 45 / 82

I g n i t i o n T i m i n g
The ignition timing is determined by the position of the piston when the
distributor breaker points begin to open. In general, the points should begin
to open when the piston reaches its highest position in the cylinder. This
position of the piston is referred to as upper dead center and is indicated by U.
D. C. Marks are placed on the flywheel
to indicate when this position of the
piston has been reached.
Since the piston in a four-stroke cycle
engine may be completing the exhaust
stroke, or completing the compression
stroke and ready for the power stroke
when it reaches U. D. C., it is necessary
to determine the stroke as well as the
piston position.
To determine this, remove the spark plug
from number one (front) cylinder.
Place the finger over the spark plug
hole and crank the engine slowly, using
the hand crank. Air pressure against
the finger indicates that the piston is
coming up on the compression stroke.
After this is felt, continue cranking
the engine slowly until the mark "U.
D. C. 1 and 6" is directly in line with
the pointer on timing inspection hole in the rear support plate of the motor, as
indicated at (A), Figure 36. The piston is then at U. D. C. and ready to move
downward on the power stroke.
Setting Ignition Timing
Loosen distributor clamp screw (D), Figure 35, and turn the distributor
housing clockwise to the limit of the slot in the clamping plate (E). Remove
the central cable from the distributor cap and place the bare end about
1
/8" from
the intake manifold. With the ignition turned on and the U. D. C. 1-6 mark
on the flywheel in line with the pointer on the inspection hole, Figure 36,
turn the distributor body counter-clockwise slowly just until a spark jumps from
the high tension wire to the intake manifold. Tighten clamp screw (D),
Figure 35, replace central cable in distributor cap, and clamp cap on distrib-
utor.
When the distributor cap is put in place, the metal strip on the rotor arm should
he directly under the terminal to which number one spark plug wire is attached.
The other cables should be in the cap terminals in the order 5-3-6-2-4, following
in a clockwise direction. The cable in the center terminal of the distributor cap
should go to the central (high tension) terminal of the ignition coil.
O W N E R' S M A N U A L 43
Figure 36