See Figures 1 through 15
When you replace a set of points, always replace the condenser at the same time.
When you change the point gap or the dwell, you will also have changed the ignition timing. So, if the point gap or dwell is changed, the ignition timing must be adjusted.
There are two ways to check the breaker point gap; it can be done with a feeler gauge or a dwell meter. Either way you set the amount of time that the points remain closed or open. The time is measured in degrees of gap between the breaker points with a feeler gauge, you are setting the maximum amount the points will open when the rubbing block on the points is on a high point of the distributor cam. When you adjust the points with a dwell meter, you are adjusting the number of degrees that the points will remain closed before they start to open as a high point of the distributor cam approaches the rubbing block.
INSPECTION OF THE POINTS
- Disconnect the high tension wire from the top of the distributor and the coil, and unsnap the distributor retaining caps.
- Remove the distributor cap by prying off the spring clips on the 4-134, or depressing and turning the holddown screws on the side of the cap on all other engines.
- Remove the rotor from the distributor shaft by pulling it straight up. On the 304 cu in. V8 and 225 cu. in. V6, the rotor is attached to the distributor shaft by screws. Remove the screws to remove the rotor. Examine the condition of the rotor. If it is cracked or the metal tip is excessively worn or burned, it should be replaced.
- Pry open the contact points with a screwdriver and check the condition of the contacts. If they are excessively worn, burned, or pitted, they should be replaced.
- If the points are in good condition, adjust them, and replace the rotor and the distributor cap. If the points need to be replaced, follow the replacement procedure below.
REPLACEMENT OF THE BREAKER POINTS AND CONDENSER
Most vehicles were equipped with Autolite ignition systems. However, some were equipped with Delco systems. Never interchange parts during replacement.
- Remove the coil high tension wire from the top of the distributor cap. Remove the distributor cap from the distributor and place it out of the way. Remove the rotor from the distributor shaft.
- Remove the dust cover that is in the top of the distributor on some models, covering the points. It is pressed in handtight.
- Loosen the screw that holds the condenser lead to the body of the breaker points. Remove the condenser from the points.
- Remove the screw that holds and grounds the condenser to the distributor body. Remove the condenser from the distributor and discard it.
- Remove the points assembly attaching screws and adjustment lockscrews. A screwdriver with a holding mechanism will come in handy so you don't drop a screw into the distributor and have to remove the entire distributor to retrieve it.
- Remove the points by lifting them straight up off the locating dowel on the plate. Wipe off the cam and apply new cam lubricant. Discard the old set of points.
- Slip the new set of points onto the locating dowel and install the screws that hold the assembly onto the plate. Do not tighten them all the way.
- Attach the new condenser to the plate with the ground screw.
- Attach the condenser lead to the points at the proper place. On American Motors engines, and the V6, the primary wire from the coil must now be attached to the points also. Make sure that the connectors for these two wires do not touch the body of the distributor; they will short out the primary circuit of the ignition if they do.
- Apply a small amount of cam lubricant to the shaft where the rubbing block of the points touches.
ADJUSTMENT OF THE BREAKER POINTS WITH A FEELER GAUGE
- If the contact points of the assembly are not parallel, bend the stationary contact so they make contact across the entire surface of the contacts. Bend only the bracket part of the point assembly, not the contact surface.
- Turn the engine until the rubbing block of the points is on one of the high points of the distributor cam. You can do this by either turning the ignition switch to the start position and releasing it quickly or by using a wrench on the bolt that holds the crankshaft pulley to the crankshaft.
- Place the correct size feeler gauge between the contacts. Make sure it is parallel with the contact surfaces.
- With your free hand, insert a screwdriver into the notch provided for adjustment or into the eccentric adjusting screw, and then twist the screwdriver to either increase or decrease the gap to the proper setting. V6 and V8 engines have to be adjusted at the adjusting screw with an allen wrench.
- Tighten the adjustment lockscrew and recheck the contact gap to make sure that it didn't change when the lockscrew was tightened.
- Replace the rotor, distributor cap, and the high tension wire that connects the top of the distributor and the coil. Make sure that the rotor if firmly seated all the way onto the distributor shaft and that the tab of the rotor is aligned with the notch in the shaft. Align the tab in the base of the distributor cap with the notch in the distributor body. Make sure that the cap is firmly seated on the distributor and that the retainers are in place. Make sure that the end of the high tension wire is firmly placed in the top of the distributor and the coil.
ADJUSTMENT OF THE BREAKER POINTS WITH A DWELL METER
- Adjust the points with a feeler gauge as described above.
- Connect the dwell meter to the ignition circuit as according to the manufacturer's instructions. One lead of the meter is to be connected to a ground and the other lead is to be connected to the distributor post on the coil. An adapter is usually provided for this purpose.
- If the dwell meter has a set line on it, adjust the meter to zero the indicator.
- Start the engine.
Be careful when working on any vehicle while the engine is running. Make sure that the transmission is in neutral and that the parking brake is on. Keep hands, clothing, tools, and the wires of the test instruments clear of the rotating fan blades.
- Observe the reading on the dwell meter. If the meter does not have a scale for 4-cylinder engines, multiply the 8-cylinder reading by two. If the reading is within the specified range, turn off the engine and remove the dwell meter.
- If the reading is above the specified range, the breaker point gap is too small. If the reading is below the specified range, the gap is too large. In either case, the engine must be stopped and the gap adjusted in the manner previously covered.
On the V6 engine and V8 engines, it is possible to adjust the dwell while the engine is running.
- Start the engine and check the reading on the dwell meter. When the correct reading is obtained, disconnect the dwell meter.
- Check the adjustment of the ignition timing.