Posts Tagged ‘1930 Chrysler De Soto.’

Chrysler DeSoto 1930 to 1931 S-CF flat head “8” Ignition adjustments.

Wednesday, July 10th, 2013

1930 DeSoto ¬?8¬? Ignition adjustments.

The distributor, which is of the four lobe cam and double breaker arm type with condenser on the outside of the base, is accessibly mounted on the cylinder head and driven through a vertical shaft from the camshaft. The ignition coil is mounted on the dash.
Firing order is 1-6-2-5-8-3-7-4

Spark Advance
For all ordinary road and driving the spark control button should be in the advanced position, which is pushed ¬?in¬? to the instrument panel. When cranking the engine by hand, the spark control button should be pulled all the way out. The automatic advance will take care of all other conditions.
To Adjust the Point Opening
Two sets of breaker points are actuated by a four lobe cam which causes one pair of breaker points to open at a time. One set of breakers controls the spark to one set of four cylinders (1-2-8-7) and the other set of breaker points to the other four cylinders (6-5-3-4); therefore, the opening of both sets of breaker points must be equal or the spark timing will be different in the two sets of four cylinders. The points open alternately.
The rotor should be removed and the engine turned by means of the hand crank until one breaker point rests on the high point of the cam. The gap between the breaker points that have opened should be 0.022¬?. If necessary to correct the adjustment of the gap, the breaker point lock screw should be loosened and the gap increased or decreased, as required, with a 0.022¬? feeler gauge on the gap, by means of the breaker point adjustment screw.
The engine should then be turned until the other breaker point is resting on the high point of the cam, and the gap adjusted as for the previous breaker set.

To Set Ignition Timing
The spark control button should be checked for full advance and retard. The breaker points should be adjusted to 0.022¬? opening and the manual spark control placed in the fully advanced position. The 1/8¬? pipe plug should be removed from the cylinder head above Number 8 piston and a gauge rod placed through the hole and in contact with piston head. The crankshaft should be rotated until No. 8 piston is coming up on exhaust stroke and stopped when the piston is 0.037¬? before top dead center. The screw which clamps the distributor should be loosened and the distributor rotated in an anti-clockwise rotation, as viewed from above, until No. 1 piston cam begins to separate the breaker points. Before doing this, the distributor should be pressed against the direction of rotation to be certain that all backlash is removed. The clamp screw should then be tightened and the distributor cap reinstalled as well as the spark plug cables connected to the proper spark plugs and terminals of the distributor cap.
Firing Order
The firing order of the cylinders is 1-6-2-5-8-3-7-4. No. 1 cylinder is nearest the radiator.
The breaker points will in time change their synchronization slightly because of wearing or burning off unequally. Ordinarily when the points are cleaned and readjusted to the proper opening synchronization is automatically corrected. If after the breaker points have been cleaned and adjusted the engine seems rough in its operation, especially so when idling and accelerating, then synchronization should be checked.
Spark Plugs
The spark plug gaps should be set to 0.027¬? to 0.030¬?. Care should be taken to set all sparking plug gaps uniformly.