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154 9903 Msd Distributor Upgrade - jumper Harness - Photo 36060717

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  • Here's the tricky part. If you decide to run the MSD control box, just plug things in according to the instructions. However, to use the factory Ford Duraspark box and save some bucks, make a jumper harness. The harness from MSD, PN 8866, is used from the distributor to the MSD box. We found that by hooking the green and purple wires on the harness to the factory plug and grounding the third wire, the unit functioned perfectly. MSD says that it's working on a direct hookup jumper harness to aid installation.
Here's the tricky part. If you decide to run the MSD control box, just plug things in according to the instructions. However, to use the factory Ford Duraspark box and save some bucks, make a jumper harness. The harness from MSD, PN 8866, is used from the distributor to the MSD box. We found that by hooking the green and purple wires on the harness to the factory plug and grounding the third wire, the unit functioned perfectly. MSD says that it's working on a direct hookup jumper harness to aid installation.
154 9903 02 o+154 9903 msd distributor upgrade+hood open The first step to swapping a distributor is to unhook the battery cables. That way, the rotor-to-camshaft relationship can't be altered accidentally by your buddy cranking the engine while you're not looking. To get things properly aligned, pull off the distributor cap and mark to which tower on the cap the rotor is pointing. This will be the same tower on the new cap once the wires are swapped. Unplug the connector from the distributor to the control box as shown, and remove the vacuum advance hose also. Plug the hose going to the carb so crud won't get inside. Note the approximate location of the vacuum-advance canister on the side of the old distributor. The new unit will be installed in approximately the same location, so remember where it belongs. Use a special wrench or a swivel socket to remove the distributor hold-down bolt and clamp. You might as well go and get the special wrench now since the swivel style won't work with the MSD. With the cap pulled off and set aside, mark where the tip of the rotor points. In this situation, it points directly toward the front of the engine. The new distributor must be installed with the new rotor facing the same point or the timing will be off. Gently (if possible) pull the distributor straight up and out of the engine front timing cover while observing how the rotor will rotate counterclockwise. Once the rotor ceases to rotate, mark this position as a reference for installing the new rotor. The old Ford unit on the left and the MSD on the right are fairly similar. Note that while they both use the same style of magnetic pickup, the MSD only uses two wires and the stock unit features three. The MSD also has a secure GM-style screw clamp for better cap retention instead of the old spring-clip style. The old distributor also reveals why the engine would experience a no-start at times. With one tooth missing and two partially broken off, the engine wouldn't always fire, since the distributor wasn't turning. The excessive endplay seen between the gear and the base of the housing also led to severe timing changes. Sure, we pulled the gear pieces out of the oil pan. The new gear comes with a special packet of lube and instructions to check tooth wear regularly. This lube helps the camshaft teeth and distributor teeth to wear evenly since the stock oiling system doesn't do a great job on initial startup. Make sure the gasket is on the base of the new unit.
The oil pump drive gear indexes into the base of the distributor gear and may need to be adjusted if the new distributor won't fully seat. A long screwdriver with a flat blade is needed to turn the shaft, and it may take a few tries before it all lines up. With the vacuum advance canister and rotor pointed to about the same place as original, drop in the distributor and hope that the gears rotate into the right position. Note that the new rotor is pointing toward the front of the engine, just as the old one was. Put the distributor clamp and bolt back on and tighten slightly. A real distributor wrench works much better than using the one shown. Pop the new distributor cap in place and push down on the screws with a quarter-turn clockwise to secure them. Hook up the vacuum-advance hose that was previously plugged off. Transfer the wires from the old cap to the new, starting with the one you marked that the rotor was pointing to. If you screw up, you'll have to find top-dead center on the crankshaft and start wherever the rotor is pointing. The firing order of the AMC V-8 is 1-8-4-3-6-5-7-2, starting at the driver-side front and alternating side to side. Here's the tricky part. If you decide to run the MSD control box, just plug things in according to the instructions. However, to use the factory Ford Duraspark box and save some bucks, make a jumper harness. The harness from MSD, PN 8866, is used from the distributor to the MSD box. We found that by hooking the green and purple wires on the harness to the factory plug and grounding the third wire, the unit functioned perfectly. MSD says that it's working on a direct hookup jumper harness to aid installation. If everything was done right, the engine should fire. If it doesn't fire, recheck all the connections and move the distributor slightly retarded or advanced. Once the engine fires, set the timing with a quality timing light and check the centrifugal and vacuum advance, then tighten the distributor clamp. The advance curve can be adjusted on the MSD distributor, which is handy with a nonstock engine. Increases in compression, vacuum, temperature, and other factors may need to be compensated for by changing the advance curve. The rate at which the mechanical advance comes in is adjusted by the different springs supplied, and is changed with a pair of needle-nose pliers. The total amount of mechanical timing advance can be changed from 18 to 28 degrees by simply swapping in the supplied bushings located under the weights. The MSD distributor comes with a 21-degree bushing installed and heavy springs for the slowest rate of advance. Local speed shops can give you an idea of what your engine needs, depending on the style of driving, but the settings supplied should be sufficient.
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