View single post by Esprit2
 Posted: 06-20-2019 07:36 am
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Joined: 05-01-2005
Location: Minneapolis, Minnesota USA
Posts: 512
See the file attachment in the previous message, #9. The upper-left view shows the pulleys. There's a dot on the bottom side of the aux pulley, on the rim. That dot is supposed to be on the imaginary centerline between the aux pulley and the crankshaft. "IF" that's the way the pulley was aligned before you took it all apart, and "IF" you put it back in that position, then the ignition timing should be the same as it was before. That could be either right or wrong, depending upon how the ignition was timed before.

The distributor shaft and rotor turn with the Aux pulley. Technically, the distibutor doesn't care where the rotor is, you just rotate the body as required to 'time' it to the rotor's position. However, if the distributor has a vacuum capsule, then aligning the dot on the centerline puts the capsule closer to the oil filter than I like... not enough hands-room when you're changing the filter. I prefer to rotate the aux pulley ~2 teeth clockwise from the position shown in the illustration (dot on the centerline). Or, as far as I can to clockwise (toward the carbs) short of having the vac capsule interfere with the carbs or intake.

Accurately set the crank to your desired static ignition timing. If your goal is 10 BTDC, then set the crank/ #1 cylinder to 10 BTDC.

Remove the distributor cap and note the rotor's location. As you look at the open end of the distributor, the rotor rotates counter-clockwise. The plug wire terminal on the distributor cap that the rotor is 'approaching' is now #1. Connect the plug wire from the front spark plug there, and the rest of the plug wires in 1-3-4-2 order, counter-clockwise around the cap.

For a crude 'eyeball' initial timing, loosen the distributor clamp and rotate the body clockwise until the #1 spark plug terminal aligns with the 'leading edge' of the rotor's metal blade terminal. If that's clearly not going to work because the vacuum capsule interferes with something, or one of the distributor cap's snap clips hits the block, or 'something' doesn't like that set-up, then...

You can rotate the distributor body 90 degrees at a time, using one of the other plug wire terminals as #1 (remove & re-install the plug wires on the distributor cap). Does that get you to a set-up that satisfies all needs... nothing interferes with anything? If not, then rotate the distributor body to where it wants to be... where nothing interferes. Now you must turn the rotor to bring it into alignment with one of the plug wire terminal's leading edge. But turning the rotor means turning the auxiliary pulley along with it, and that requires removing the timing belt.

Technically, any rotor/ aux pulley position that doesn't cuse something to interfere with something can be timed to work. The only 'magic' associated with putting the aux pulley's dot on the centerline between it and the crank is that Lotus determined that position wouldn't cause anything to interfere with anything else. It has nothing to do with making the engine run or not, it's just about making things fit together without interfering. And personally, I like to rotate the aux pulley about two teeth clockwise from there (viewed looking at the front of the engine) just to get the vacuum capsule as far away from the oil filter as possible, freeing up the maximum amount of 'hand space' around the filter. That's optional. So...

1) Set the crank to your target static timing position (like 10 BTDC),
2) Pick your rotor/ distributor's starting position... adjusting the Aux pulley on the T-belt if required.
3) Rotate the distributor body until the most convenient plug wire terminal aligns with the rotor's leading edge (remember, the rotor turns counter-clockwise).
4) Install the plug wire from the #1 plug on that terminal, and the rest in 1-3-4-2 order, counter-clockwise around the cap.

Static Timing:
Distributor clockwise (CW) and counter-clockwise (CCW) are defined while looking at the end of the distributor cap... or the open end of the distributor. Auxiliary & cam pulley rotation is defined while looking at the front of the engine, and hence, the opposite direction.

When the points are closed, the coil-current goes directly to ground thru the points, so the light sees little current and is dim or off, depending upon the wattage of the blulb. When the points are open, the coil-current's only path to ground is through the bulb, so it turns on or goes from dim to bright.

Using a simple continuity light, connect one wire to the coil's (-) terminal, and the other wire to a solid ground, like the engine block or battery (-) terminal. With the crank at your target timing point, switch the ignition 'ON', then loosen the distributor clamp (hold inward pressure).

If the light is initially 'OFF', (or 'ON', but dim) rotate CW until the light turns on or goes from dim to bright... the points just opened..

If the continuity light is initially ON and bright, (or BRIGHTER than dim), rotate it CCW until the the light goes from 'on'/ 'bright' to 'off'/ 'dim'... the points just closed. Cleanly off or on doesn't matter... off is just an extreme case of 'dim'. The key pint is to watch for a transition point between bright/ on and dim/ off.

Once you have found the on-off point, go CCW from there until the light goes off or dim, then a little more to allow for any slack. Reverse and slowly go CW until the light JUST goes on or bright... stop immediately. If you over-shoot, repeat the process until you successfuly stop JUST as the light turns on or goes bright. Tighten the distributor clamp, and switch off the ignition.

Once you switch the ignition 'ON', work quickly to complete the process, then switch off right away. When the engine is running, the points open & close and don't carry full current long enough (duty cycle) to overheat. But if the ignition is 'ON' when the engine isn't running, then the points can be closed full time, overheat, and burn. It's a little like roulette... where will the breaker point be when the engine stops. So make every effort to work quickly and NOT keep the ignition switch 'ON' any longer than necessary.

Start the engine. When it has settled down to a steady idle, check the timing with a strobe light. It should be very close to where you set the crank at the beginning of the static timing process. If need be, re-set the timing with a strobe light. If you don't have a strobe, then static setting the timing with a continuity light is more than accurate enough.

If you don't have a continuity light, but do have an electric multimeter, then you can use the meter to replace the light. Select either the ammeter or continuity function, and watch for indictaions of On-Off (continuity), or More-Less current (ammeter).

Tim Engel