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Engine Timing & Towing

Posted in How To on March 1, 2001
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Advance or retard the timing by 15 degrees with a dial in the driver's compartment. Advance or retard the timing by 15 degrees with a dial in the driver's compartment.
Here’s what can happen if the engine’s timing is way off under load. This entire piston is missing due to severe detonation, which finally blew the aluminum slug to smithereens. Computer controls on modern engines can prevent this from happening, but old-fashioned ears should have noticed the noise before the piston popped off. Here’s what can happen if the engine’s timing is way off under load. This entire piston is missing due to severe detonation, which finally blew the aluminum slug to smithereens. Computer controls on modern engines can prevent this from happening, but old-fashioned ears should have noticed the noise before the piston popped off.
The MSD adjustable timing control is easy to install as well as operate. After disconnecting the battery cables for safety, select a mounting position away from direct engine heat sources. We found an open area on top of the inner fenderwell for a clean-looking job. Make sure the wires are long enough to reach the components it hooks up to. The MSD adjustable timing control is easy to install as well as operate. After disconnecting the battery cables for safety, select a mounting position away from direct engine heat sources. We found an open area on top of the inner fenderwell for a clean-looking job. Make sure the wires are long enough to reach the components it hooks up to.
Under a small cap on the end of the box are three wires used to select four-, six-, or eight-cylinder operation. One of the wires is to be cut for four or six, but not with eight cylinders. However, if you are using a magnetic pickup distributor such as the MSD unit we run, the white wire must be cut anyway. While the instructions are excellent on the whole, it was a bit confusing on this part. Under a small cap on the end of the box are three wires used to select four-, six-, or eight-cylinder operation. One of the wires is to be cut for four or six, but not with eight cylinders. However, if you are using a magnetic pickup distributor such as the MSD unit we run, the white wire must be cut anyway. While the instructions are excellent on the whole, it was a bit confusing on this part.
Meanwhile, the white wire on the MSD-6 ignition box needs to be hooked to the yellow wire on the adjustable timing control. When we installed the ignition box we cut the white wire back, since it was not to be used. Luckily we didn’t snip it off at the base of the connector. Meanwhile, the white wire on the MSD-6 ignition box needs to be hooked to the yellow wire on the adjustable timing control. When we installed the ignition box we cut the white wire back, since it was not to be used. Luckily we didn’t snip it off at the base of the connector.
The original MSD plug used on the distributor that went to the MSD ignition box was unhooked. The plug simply goes to the new timing control, for a minimum of wiring hassles. The instructions include charts for every conceivable wiring situation, and a toll-free number for help is also available. The original MSD plug used on the distributor that went to the MSD ignition box was unhooked. The plug simply goes to the new timing control, for a minimum of wiring hassles. The instructions include charts for every conceivable wiring situation, and a toll-free number for help is also available.
The other wires go to a ground and the keyed ignition source like the MSD ignition box. In our case the white wire was not used from the timing control, and was taped off and secured out of harm’s way. The other wires go to a ground and the keyed ignition source like the MSD ignition box. In our case the white wire was not used from the timing control, and was taped off and secured out of harm’s way.
Mounting the dash control is a snap due to the double-sided tape on the back. The only location we had left was on the glovebox, but since we routed the wires through there and into the cowl, it worked great. Be sure to use a grommet where the wires pass through the firewall to prevent rubbing the wire insulation away. Mounting the dash control is a snap due to the double-sided tape on the back. The only location we had left was on the glovebox, but since we routed the wires through there and into the cowl, it worked great. Be sure to use a grommet where the wires pass through the firewall to prevent rubbing the wire insulation away.
Final timing of the engine can be done to simply allow the knob to advance the timing, but we chose to set the dial at the 7.5-degree position. After timing the engine to where it was before, this procedure allows the ignition control to advance the timing 7.5 degrees advanced, or 7.5 degrees retarded. This allows for the optimum control right at your fingertips. Now we can adjust the timing as we drive to our engine’s exact needs. Final timing of the engine can be done to simply allow the knob to advance the timing, but we chose to set the dial at the 7.5-degree position. After timing the engine to where it was before, this procedure allows the ignition control to advance the timing 7.5 degrees advanced, or 7.5 degrees retarded. This allows for the optimum control right at your fingertips. Now we can adjust the timing as we drive to our engine’s exact needs.

The times they are a-changin’. With apologies to Mr. Dylan, the ignition timing of your 4x4s engine is pretty well set. Ignition timing is what is used to make sure that the distributor fires the spark plug at the right time. This right time depends on many factors such as engine rpm, quality of gas, compression ratio, and load on the engine. The timing setting changes to adjust to these conditions. For instance, at engine start-up, the timing should be retarded for easier cranking, while at high rpm the spark has to come long before the piston comes to the top of its stroke. If the timing is not correct, hard starting, spark knock (detonation), and engine damage can occur—not to mention poor performance, poor fuel economy, and increased engine emissions. When you tow a heavy load behind your rig, these factors are compounded, especially when climbing a grade.

On older vehicles the static timing (the position of the distributor) is set for the best combination of all variables. The distributor advances the timing as the engine is running through a set of centrifugal weights inside the distributor, and a vacuum chamber as engine rpm increases. With newer rigs, this is a thing of the past. Computer controls handle all of the engine functions, including the timing advance. Spark knock, or detonation, is also eliminated by a sensor that retards the timing when spark knock occurs. As always both older and modern rigs are set to provide the best combination for all variables, which isn’t the best setting for all situations. On flat land with light loads, this setting is usually OK, but strap on a loaded trailer and head to the mountains, and you could be in trouble.

Luckily, for those of us that can still adjust the distributor to advance or retard the timing on our 4x4s, we have the option of adjusting it to our particular requirements. The folks at MSD have a slick little gadget that allows you to advance or retard the timing by 15 degrees with a dial in the driver’s compartment. This is extremely useful when you’re towing a heavy load up a hill and the engine starts to knock or rattle from detonation or preignition. Simply dial the knob back to reduce the timing, and engine knock is gone. For straight and level cruising, better fuel economy can be obtained by advancing the timing, but not so far as to produce knocking or pinging. While the control needs to be used with an MSD ignition, that alone can help an engine run better and smoother.

Check out how we installed the MSD Adjustable Timing Control on our tow rig. It was simple, and we now have full control of our engine’s timing at our fingertips.

Sources

Autotronics Corp.
El Paso, TX 79936

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