the vibration is an indication of a ground in the system. Remove the ground and the vibration will stop.

The Ammeter.-The ammeter on the right side of the combination switch is to indicate the current that is going to or coming from the storage battery, with the exception of the cranking current. . When the engine is not running and current is being used for lights, the ammeter shows the amount of current that is being used and the ammeter hand points to the discharge side, as the current is being discharged from the battery. When the engine is running above generating speeds and no current is being used for lights or horn, the ammeter will show charge. This is the amount of current that is being charged into the battery. If current is being used for lights, ignition and horn in excess of the amount that is being generated, the ammeter will show a discharge as the excess current must be discharged from the battery, but at all ordinary speeds the ammeter will read charge.

Construction of 1916 Delco Ignition Distributor.-It is well understood that a rich mixture burns quicker than a lean one. For this reason the engine will stand more advance with a half open throttle than with a wide open throttle, and in order to secure the proper timing of the ignition due to these variations and to retard the spark for starting, idling and carburetor adjusting, the Delco distributor also has a manual control. The automatic feature of this distributor is shown in Fig. 43. With the spark lever set at the running position on the steering wheel (which is nearly all the way down on the quadrant), the automatic feature gives the proper spark for all speeds excepting a wide open throttle at low speeds, at which time the spark lever should be slightly retarded. When the ignition is too far advanced it causes loss of power and a knocking sound within the engine. With too late a spark there is a loss of power (which is usually not noticed excepting by an experienced driver or one very familiar with the car), and heating of the engine and excessive consumption of fuel is the result. The timer contacts shown at D and C (Fig. 43) are two of the most important points of an automobile. Very little attention will keep these in perfect condition. These are of tungsten metal, which is extremely hard and

3. AUTOMATIC
WEIGHTS

H

DISTRIBUTOR

CONTACT BREAKER
CAM

requires a very high temperature to melt. Under normal conditions they wear or burn very slightly and will very seldom require attention; but in the event of abnormal voltage, such as would be obtained by running with the battery removed, or with the ignition resistance unit shorted out, or with a defective condenser, these contacts burn rapidly and in a short time will cause serious ignition trouble. The car should not be operated with the battery removed.

B

F

DIL

ADVANCE

-K

-ROTOR

AUTOMATIC
WEIGHTS

It is a very easy matter to check the resistance unit by observing its heating when the ignition button is out and the contacts in the distributor are closed. If it is shorted out it will not heat up, and will cause missing at low speeds. A defective condenser such as will cause contact trouble will cause serious missing of the ignition. Therefore, any one of these troubles are comparatively easy to locate and should be immediately remedied. These contacts should be so adjusted that when the fiber block B is on top of one of the lobes of the cam the contacts are opened the thickness of the gauge on the distributor wrench. Adjust contacts by turning contact screw C and lock with nut N. The contacts should be dressed with fine emery cloth so that they

Fig. 43. Showing Construction of 1916 Delco
Distributor for Six Cylinder Ignition. Note
Six Lobe Cam.

meet squarely across the entire face. The rotor distributes the high tension current from the center of the distributor to the proper cylinder. Care must be taken to see that the distributor head is properly located, otherwise the rotor brush will not be in contact with the terminal at the time the spark occurs.

Combination Switch.-The combination switch is located on the cowl board and makes the necessary connections for ignition and

lights. The "M" button controls the magneto type ignition and the "B" button, the dry battery ignition. In addition to this both the "M" and "B" buttons control the circuit between the generator and storage battery. When the circuit between the generator and the storage battery is closed by either the "M" or "B" button on the combination switch, the direction of flow of the current is from the battery to the generator when the engine is not running,

as well as when it is running below 300 R. P. M. But the amount of current that flows from the battery at the lowest possible engine speeds is so small that it is negligible. That used on Buick 1915

cars is shown at Fig. 44, the type supplied on 1916 cars is outlined at Fig. 42.

To Time the Ignition.-1. Fully retard the spark lever. 2. Turn the engine to mark on flywheel about one inch past dead center to the "7 degree" line, with No. 1 cylinder on the firing stroke. 3. Loosen screw in center of timing mechanism (Fig. 45) and locate the proper lobe of the cam by turning until the

Fig. 46.-How Cover is Removed from Delco Distributor.

button on the rotor comes under the high tension terminal for No. 1 cylinder. 4. Set this lobe of the cam so that when the back lash in the distributor gears is rocked forward the timing contacts will be open, and when the back lash is rocked backward the contacts WILL JUST CLOSE. Tighten screw and replace rotor and distributor head. The construction of the distributor head is clearly shown at Fig. 42, which shows the internal view, while Fig. 46 shows the exterior and plan of contact brushes.

Westinghouse Vertical Ignition Unit.-The Westinghouse vertical ignition unit, shown at Fig. 47, can be used for ignition from storage batteries or plain lighting generators. This set contains interrupter, spark coil and condenser, and distributor, all in one unit. One wire from the battery or generator to the ignition unit and one wire to each spark plug are all that are requiredthe simplest possible connections. The interrupter, located at the lower end of the set, has the same type of circuit-breaker as that