How to Set the Points on Vehiclesby Contributing Writer; Updated June 12, 2017
The ignition points in a Vehicles motor function like any other ignition points, in that they transfer a magneto spark through two point contacts. The point contacts open and close according to the camshaft rotation, which opens and closes the valves. The points send voltage to the spark plug wire and onto the spark plug. Ignition points can suffer from wear, carbon soot and burning. When the point contacts wear or accumulate carbon buildup, the dwell (ignition timing) changes, resulting in a poorly running engine.
Under The Hood:
- How to Set the Points on a Ford 390
- How to Set Points on Ferguson TE20 Tractors
- How to Set Points With a Fluke Meter
- How to Set the Points on a 1973 Volkswagen Super Beetle
- How to Set the Points in a Ford 8N
- How to Set the Points on Johnson Outboards
- How to Set Points on a Small Block Chevy
Unfasten the two clips that secure the distributor cap to the distributor. Remove the cap by prying the clips away from the cap with a screwdriver.
Lift the rotor arm off of the distributor's spindle. The spindle is the vertical metal rod in the center of the distributor. The rotor is the plastic piece that features a metal tip. The rotor arm is located on top of the spindle.
Loosen the two sheet metal screws that secure the points assembly to the bottom of the interior of the distributor.
Rotate the distributor's spindle until the cam fitting at the bottom of the spindle opens the points. The cam fitting is located at the base of the spindle and resembles a large nut that would otherwise secure a bolt.
Insert a feeler gauge of the proper thickness between the tips of the points. Use a 0.017-inch (0.43 mm) gauge if adjusting the points on the standard 390 or a 0.021-inch (0.53 mm) gauge if adjusting the points on the high-performance 390 from 1969.
Adjust the points to their proper adjustment by moving the bottom of each point's assembly with a screwdriver. The assembly is properly adjusted when the feeler gauge fits snugly between the points.
Tighten the two sheet metal screws that secure the points assembly to the bottom of the distributor.
Press the rotor arm onto the distributor's spindle.
Lower the distributor cap onto the distributor and press the cap's two clips onto the cap to secure it in place.
Items you will need
Park the Ferguson TE20 on a flat surface and turn the engine off with the transmission in gear. Place the wheel chocks in front of each rear wheel and behind each rear wheel. Move the gear shifter to the neutral position.
Unsnap the hold-down clamps on the side of the distributor cap. Pull the distributor cap off and place it on the tractor seat.
Locate the electrical points assembly inside of the distributor base. The points are made as one assembly. The points assembly has a single prong that moves up and down against the prong contact. The points assembly twill be secured next to the distributor shaft. The points have a prong that opens and closes as the distributor is turning. Inspect the prongs to ensure that they are in the open position. If not, bump the engine over by turning the key on and off until the points are in the open position.
Loosen the points assembly hold-down screw with a flathead screwdriver. The hold-down screw is located to the side of the points assembly. Slide the end of a points feeler gauge under the points prong.
Turn the adjustment screw located at the top of the points assembly clockwise with a flathead screwdriver until the single point prong is touching the feeler gauge. Continue turning the adjustment screw until the feeler gauge has a small amount of drag when moving the gauge in and out between the prong and the prong contact. The feeler gauge should move in and out between the prong and the contact with a small amount of drag to be properly adjusted.
Tighten the points assembly hold down screw back down tight with the screwdriver and place the distributor cap back over the distributor base. Lock the distributor cap in place by pulling the hold-down clamps over the side of the cap.
Items you will need
Electrical points feeler gauge
Set the transmission selector of the vehicle in "Park" for an automatic, or "Neutral" for a standard gearbox. Set the emergency brake and raise the hood. Consult your vehicle repair manual for the location of your coil, or coil pack, if so equipped. Find the negative (-) terminal on the coil or coil pack and remember its location.
Insert the red lead wire in the socket of the Fluke meter, which is denoted by a "VU" symbol on the lower part of the meter case. Insert the black lead into the socket jack directly below it, which is marked by a "COM" symbol. Attach the red lead to the coil or coil pack negative terminal. Attach the black wire lead to a good ground source, like the outside body case of the distributor. You can also attach the black lead wire directly to an engine bolt.
Turn the rotary switch on the Fluke meter so the pointer aligns with the (%) symbol, which is accompanied by a small diagram of an angle representing degrees. If you have a 4-cylinder engine, the meter is set for this position by default. If you have a 5-, 6- or 8-cylinder engine, you must press the small tab button, which is located on top of the rotary switch, to step through the cylinder selection process. Press the button the number of times required to arrive at the cylinder selection for your engine, which will be displayed on the screen.
Start the engine and let it idle. Pick up the meter and look at the digital readout on the screen. The digital number that appears will represent the amount of dwell angle expressed in degrees. For example, you might see 30, 32 or 34 degrees, depending upon your type and make of engine. Refer to your vehicle repair manual for the correct degree angle number required of your engine. A lesser degree angle number equates to a wider point gap. The narrower the point gap, the higher the degree angle number will be.
Place an Allen wrench through the distributor cap window if your cap has this feature. Turn the Allen wrench in the appropriate direction, which will give you the correct angle degree number, according to your manufacturer's specifications. If you have no external adjustment for the points (i.e., no window), shut the engine off and use a screwdriver to remove the distributor cap. Unscrew the cap screws or turn the screws so the hold-down retaining pins face outward.
Disconnect the coil wire from the top of the cap and ground it against the engine. Use a slot screwdriver to loosen the adjustment and mount the screws to the points. Do not mount the screws so loosely that the points move freely over the distributor base plate--you need them slightly tight. Place the slot screwdriver in the adjusting slot on the points, have an assistant turn the key to the "Start" position and allow the engine to crank.
Turn the screwdriver to open or close the points, but do so in very slight increments until you reach the proper dwell angle number displayed on the screen. Shut the engine off. Tighten the ignition points mounting screw and adjustment screw. Start the engine and recheck the number on the display. Shut the engine off and disconnect the Fluke meter. Replace the distributor cap and tighten down the hold-down screws, or turn the retaining pins inward to lock the cap in position.
Items you will need
Vehicle repair manual
Remove the screws that secure the distributor cap to the top of the distributor and lift the cap off of the distributor, taking care not to disturb the spark plug wires, to reveal the rotor and the points.
Lift the rotor off of the center of the distributor.
Rotate the large bolt in the center of the crankshaft pulley at the bottom of the engine in a clockwise direction with a wrench to turn the engine. Turn the engine until the points open to their extreme open position.
Insert the blade of a feeler gauge into the opening of the points. The distance must be 0.016 inches.
Adjust the points if necessary. Loosen the point's locking screw with a screwdriver and open the points until the distance between the point's tips is 0.016 inches as measured with a feeler gauge, then tighten the locking screw.
Press the rotor onto the rotor shaft in the center of the distributor.
Lower the distributor cap onto the distributor.
Tighten the distributor cap's securing screws with a screwdriver.
Items you will need
Place a chock in front of each rear wheel. Get on the tractor and put the transmission in neutral. Double check the transmission to make sure it is in neutral by attempting to start the engine. Get off the tractor and stand on the left side in front of the rear wheel and face the engine.
Look at the engine and find the four spark plugs. Trace any spark plug wire from the top of the spark plug to its source, which will be the distributor. Look at the distributor, which resembles an upside-down cup, with five wires coming out of it. Find the two flat metal springs on its sides holding it to the base.
Put on the safety glasses. Place the blade of a straight blade screwdriver between the distributor housing and the spring. Rotate the screwdriver either direction and the spring will pop loose. Repeat the process on the other spring.
Lift the distributor cap off its base without disconnecting any of the wires. Place it to the side, allowing full access to the distributor base.
Find the rotor in the middle of the distributor. The rotor looks like a black pointer with a brass-colored metal piece on the end. Grasp the rotor firmly using your thumb and forefinger. Pull straight up, removing the rotor from the distributor.
Reach up to the floor of the tractor. Push and hold down the foot-starter button. Look at the distributor as the starter turns. Watch for a small chrome armature that is opening and closing a small gap. Stop pushing the starter button when the gap created by the armature is fully open.
Push the starter button again to be ensure that the gap is fully open. Stop when the gap is at its widest point. Use the feeler gauge to measure its spacing. Check the 8N service manual for the proper spacing.
Look at the side of the gap arm that does not move. Find the small screw holding it in place if the gap needs adjusting. Loosen the screw, but do not take it out Place a straight blade of a screwdriver against the side of the gap arm that does not move and turn it either direction until the gap gets larger or smaller. Adjust and measure the gap as needed until it has the correct spacing.
Items you will need
Wheel chocks, 2
Place the motor, if trailered, in an accessible spot. Remove the key from the ignition, if so equipped, and activate the main ignition cutoff switch. Trim the motor level, if you have electric trim. Place the motor in the full down position by removing the motor tilt pin and adjusting the motor for the full down position. Replace the tilt pin. Unclasp the top engine cowl snaps and pull the case off. Use a socket to remove the case, if it uses bolts for fasteners.
Place a flywheel strap around the perimeter of the flywheel and hold it taut. Use a socket and long-handled ratchet to loosen and remove the flywheel nut. Have an assistant to help you with this operation if you need more leverage. Place the three holding hooks of a harmonic balancer puller underneath the bottom lip of the flywheel. Screw the threaded pulley bolt onto the depression in the crankshaft end. Turn the pulley bolt clockwise with a socket and wrench, breaking the flywheel loose from the shaft.
Pull the flywheel off. Use a screwdriver to remove the ignition points case screws. Set the case aside. Examine the ignition points, which might be a single set or a dual set. Each point unit has a lever arm, rubbing block, contacts and two screws each. If replacing the points, wedge the small spring retainer open that hold the condenser wire to the points -- two wires for two condensers. Pull the wires free.
Use a flat-head screwdriver to loosen and remove the two screws for one set of points. Remove the other two screws from the other set of points. Pull both sets of points out and discard them. Place the new points in their mounting grooves. Screw all four mounting screws in by hand, then tighten them with a screwdriver, just enough so they fit snug.
Place a flat-head screwdriver in the adjusting slot that opens and closes the points. Adjust the points so that the small amber-colored rubbing block on the points arm contacts the lobed shaft. Turn the flywheel shaft until the rubbing block rides up and sits upon the highest part of the shaft, which will be the lobe. Place a feeler gauge, set at .20 inch, between the two point contacts and adjust the contacts to close over the feeler gauge. Refer to your engine manual for the precise inch gap.
Pull the feeler gauge up and down, making sure you have a slight drag on the gauge. Tighten both screws. Perform the identical adjusting procedure on the other set of points. Place both condenser wires back under their spring clips on both sets of points. Apply a finger dab of marine grease on both shafts. Replace the points cover and screw it down with a screwdriver.
Dab grease on the crankshaft and threads. Place the flywheel over the shaft and push it down. Put the nut back on the shaft and turn it clockwise by hand. Wrap the flywheel strap around the flywheel. Tighten the flywheel nut with a long-handled ratchet and socket. Place the engine cowl case back on the top of the engine and clasp the hold-down snaps. Replace and tighten the cowl case bolts with a socket, if you have removed these types of fasteners.
Items you will need
Engine owner's manual
Flywheel strap wrench
Harmonic balancer puller
New points (optional)
Place the vehicle in park or neutral with the emergency brake set. Raise the hood and disconnect the negative battery terminal with an end wrench. Locate the distributor at the rear of the engine next to the firewall.
Use a slot screwdriver to turn the two distributor cap mounting screws 90 degrees out until they release. Pull the distributor cap off and set it aside in the engine compartment without removing the wires. Pull the distributor rotor straight up and off. In the case of a round rotor cap that has two screws, remove the screws with the slot screwdriver and lift off the rotor. Don't lose the rotor mounting screws.
Remove the small screws that hold the old points to the distributor base. Detach the points wire that connects to the small connector post. The points wire will either pull up from spring tension, or a screw will hold it in place. Only loosen the screw to remove the wire. Remove the condenser wire in the same fashion. Remove the screw holding the condenser to the distributor base. Discard the old points and condenser.
Place the new condenser and points on the distributor base, aligning their positions with their small mounting guides. The points will have a small pin that fits into a pivot hole in the distributor. Place the mounting screws on the points and condenser and tighten them down very lightly with the slot screwdriver. Tighten the condenser down fully; leave the points adjustment screw slightly loose. Push the points wire and the condenser wire back into their small, spring-loaded mount or tighten them with the screw, if so equipped.
Place the negative battery cable back onto the terminal. Instruct your assistant to "bump" the ignition key back and forth, turning the engine over in short bursts, until you see the high point on the distributor shaft---eight or six-sided cam---stop and rest directly under the small rubbing block on the points. This will be the correct adjustment position.
Disconnect the negative battery terminal. Use the proper width blade on the feeler gauge---refer to manufacturer's specifications---and place the blade between the two point contacts. Use a slot screwdriver to wedge the points open or closed by sticking the screwdriver blade into the small slot in the distributor base. Adjust the points closed over the feeler gauge until a slight drag can be felt when inserting it and pulling it out. Fully tighten the points' mounting screw after achieving the adjustment.
Use the distributor adjusting tool or the proper size Allen wrench to make the adjustment on the newer model Chevy distributor. Most gap points for Chevy small-block engines require .016 to .019 of an inch.
Reinstall the new or used rotor by pushing it down over the distributor shaft or secure it with the screws if equipped with them. Place the distributor cap back on in the same position you removed it and turn the mounting screws in the cap 90 degrees to secure into place. Reconnect the negative battery cable.
Hook up the positive lead of the dwell meter to the positive battery terminal. Hook up the dwell meter negative lead to the negative side of the distributor coil. Start the engine. Refer to your owner's manual for the correct dwell angle. On most small-block Chevy engines, the dwell will be 30 degrees. To adjust the dwell exactly, insert the distributor adjusting tool or the Allen wrench into the small adjusting window on the side of the distributor cap. Turn the wrench very carefully until you have reached the required dwell angle. Remove the dwell meter.
Items you will need
End wrenches (small set)
New points (condenser and rotor for complete tune-up)