Ford Full-Size Cars 1968-1988 Repair Guide

Dwell Angle



Using a Feeler Gauge
  1. 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 stationary bracket part of the point assembly, not the movable contact.
  3. Turn the engine until the rubbing block of the point 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 (bumping the engine) or by using a wrench on the crankshaft pulley bolt and rotating the crankshaft. Be sure to remove the wrench before starting the engine!
  5. Place the correct size feeler gauge between the contacts. Make sure the feeler gauge is parallel with the contact surfaces. Refer to the Tune-Up Specifications Chart in this section.
  7. With your free hand, insert a small screwdriver into the notch provided for adjustment or into the eccentric adjusting screw, then twist the screwdriver to either increase or decrease the gap to the proper setting.
  9. Tighten the adjustment lockscrew and recheck the contact gap to make sure that it did not change when the lockscrew was tightened.
  11. Install the rotor and distributor cap, along with the high tension wire that connects the top of the distributor and the coil. Make sure that the rotor is firmly seated all the way onto the distributor 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 retainer springs 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.

Using a Dwell Meter

See Figure 1

  1. Adjust the points with a feeler gauge as described earlier.
  3. Connect the dwell meter to the ignition circuit according to the tool manufacturer's instructions. One lead of the meter should 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.
  5. If the dwell meter has a set line on it, adjust the meter to zero the indicator.
  7. Start the engine.

Be careful when working on any vehicle while the engine is running. Make sure that the transmission is in PARK or NEUTRAL depending on type of transmission, and that the parking brake is applied. Keep hands, clothing, tools, and the wires of the test instruments clear of the rotating fan blades.

  1. Observe the reading on the dwell meter. If the reading is within the specified range, turn OFF the engine and remove the dwell meter. Refer to the Tune-Up Specifications Chart in this section.
  3. 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. After making the adjustment, start the engine and check the reading on the dwell meter. When the correct reading is obtained, disconnect the dwell meter.
  5. Check the ignition timing and adjust if necessary.

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Fig. Fig. 1: Tachometer installation for dwell check