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 Posted: 01-21-2015 06:28 pm
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Esprit2

 

Joined: 05-01-2005
Location: Minneapolis, Minnesota USA
Posts: 289
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Mark Rosenbaum wrote about using a multi-meter. That will work, but I prefer to use a continuity light. The light only requires peripheral vision, while a meter (to me) demands more attention.

Connect the light between one of the 12v terminals on the coil and a good ground... like the engine block.

The coil gets 12 volts from the ignition switch, then it's ground wire passes through the distributor on it's way to ground. The breaker points or the electronic ignition amp switch the ground wire on and off. On charges the coil, and off causes the magnetic flux field to collapse, firing the spark. What you're looking for is the instant it switches off.

With the points/ amp 'on', the current has another path to ground besides going through the continuity light. Depending upon the Watt rating of the bulb, it may burn dimly, or not at all. When the points/ amp switch 'off', all of the coil's current has no where to go but through the light, so it will either get brighter, or turn on. Both "dim-to-bright" and "off-to-on" tell you the same thing... the points/ amp just switched off (fired the spark).

1) Set the #1 cylinder to TDC. Looking at the front of the engine, rotate the crankshaft in it's normal direction of operation (Clockwise... CW). A 19mm or 3/4" socket on the V-belt pulley bolt head is an easy way to turn it.

Next to the V-belt pulley, at the 10-11 o'clock position, there's a metal tab with timing marks cast into it: 30... 20... 10... 0 (0 = TDC). And there's a notch cut across the outside rim of the pulley, front to back. No matter how many v-grooves the pulley has, the notch goes all the way from front to back. The notch is the moving pointer, so align it with '0' on the number scale. Cylinders 1 & 4 are now at TDC.

Now look at the timing dots on the rims of the cam pulleys. If the dots are adjacent to one another, and on the imaginary centerline between the cam centers, then it's cylinder #1 that's at TDC... what you want.

If the dots are on the centerline, but on far opposite sides of the pulleys, then #4 is at TDC. Rotate the crank through one more CW revolution, and back to TDC. The pulley timing dots should now be next to one another, and #1 is at TDC.

The #1 cylinder is the one at the front of the engine, closest to the radiator. Grab it's spark plug wire, and follow it to the distributor cap, noting to which terminal it's attached. Release the snap clips and remove the distributor cap. Note where the rotor is pointing.

Note: Even when perfectly timed, the rotor won't point directly at a terminal at TDC... on center. The rotor has a wide metal terminal on it's end, and it rotates CCW as you look at the top of the distributor. When timed, the leading edge of the rotor's terminal will be aligned with the cap's terminal, making the rotor look like it's off-center. So imagine the rotor is moving CCW, which cap terminal is it just approaching. That terminal "IS" #1.

Since the distributor isn't timed yet, the rotor may be between terminals, and you have your choice. Since the #1 plug wire is already attached to one terminal, it makes sense to target that one. Since you measured the static timing as way advanced at 29 BTDC, expect to see that the rotor has already passed that #1 plug wire terminal and is moving away from it CCW. Rotate the distributor body as required to put the terminal just CCW from the rotor.

If there were no plug wires attached to the cap, you could choose any terminal as #1, and align it just CCW from the rotor, as above. That would now be #1, so install the #1 spark plug wire there. Then the rest of the wires go clockwise around the cap in 1-3-4-2 order. Replace the cap.

The only reason for setting the engine to TDC was to confirm the #1 cap terminal, and the plug wire installation.

2) Rotate the crankshaft in it's normal CW direction one more revolution, stopping at the desired Static Timing. If you want the static timing to be 14 BTDC, then set the notch on the V-pulley rim next to 14 on the metal timing mark tab. This time it doesn't matter where the cam pulley dots are since the distributor will fire at TDC for both #1 & #4. You can time the distributor using either one.

3) Attach the continuity light's alligator clip attached to one of the coil's small 12-volt terminals. Turn the ignition key to on/ run. Left hand on the distributor cap, apply inward pressure on the distributor (remember the spring?). With your right hand, loosen the distributor clamp enough that the distributor can be rotated in the oil pump housing. With your right hand, pick up the continuity light and press it's ground probe against the engine or other good ground.

4) Rotate the distributor Clockwise (CW) until the light goes brite or on. Reverse and go CCW until the light goes dim or turns off. Go back and forth a few times until you get a feel for the switch point.

5) Rotate the distributor CCW until the light goes dim/off, and a little more to allow for any slop. Reverse, and slowly go CW, watching for the light to on/ brite. Stop the instant it does. If you have any doubts that you stopped at the exact point, then back up and try again. When satisfied, put the light down and tighten the distributor clamp. The static timing is now 14 BTDC... or whatever value to which you set the crank timing.

Turn the ignition switch off right away.

NOTE: When the engine is running, the points/ amp is constantly switching the coil's ground wire on-off. Therefore, the points/ amp don't carry the coil's current full time, and don't get dangerously hot. But if the ignition is switched on while the engine isn't running, it's possible for the points/ amp to be in the 'on' position for an extended time. Be aware that the Pertronix Ignitor (not the Ignitor II), can NOT tolerate full coil current for very long, and will permanently fry in only a few minutes (10... guessing).

So don't dilly-dally. Get your ducks all lined up in a row, tools all laid out, and steps memorized. When you're ready, then switch on, do the job, switch off. Allow no extra "on" time. The Ignitor amp is the worst risk. But if the power is left on long enough, the dumb old breaker points can be burnt as well.

Mark Rosenbaum's procedure with the meter is the same, except you're looking for a change in the reading. With a little adjustment to your thinking, you can use the voltmeter, ammeter, ohmmeter or continuity meter functions. Anything that reacts when the points/ amp switch a 12-volt ground wire on-off.

*~*~*
Now that you're done, that knurled nut/ knob can come into play if you wish. Some distributors have them, some don't. On some distributors, what looks like an adjusting nut is really just the mounting nut for the vacuum capsule. When an adjuster is present, they're just a convenient fine adjustment with a very limited range. Get the timing as close as you can by rotating the distributor body, then use the knurled nut to fine tune to perfection. But when the static timing is 29 BTDC, it's not even within shouting distance of the knob's effective range. Take care of the big changes before worrying about any knob.

Regards,
Tim Engel

Last edited on 01-26-2015 04:29 am by Esprit2