Classic Inlines
603 W Pecos Ave
Mesa, AZ 85210

Installing the DUI Distributor

First, familiarize yourself with your new DUI distributor. The top of the coil cover has two terminal markings, "TACH" on the left, and "BATT" on the right. The TACH terminal is for connecting a tachometer and is used for connecting diagnostic equipment during tune-up. The BATT terminal is for the 12 volt power supply (12-14.5 volts).

Caution: The connections should never be reversed, or used for purposes other than intended, as electronic damages may be extensive.

Your new DUI distributor requires a full alternator voltage. For those converting from a breaker point distributor, as in most cases, you must eliminate any ballast resistor or OEM resistance wiring to supply full alternator voltage. For full RPM operation, the DUI distributor requires 14.5 volts.

Note that the factory calibrations are stenciled under the base of the DUI distributor.

Removing the Old Distributor

First, remove the distributor cap and all vacuum hoses or lines. Next, remove the distributor hold down clamp and bolt. Note the position of the rotor (we suggest bumping the motor so that the rotor is pointing towards the cylinder head and making a reference mark on the side of the cylinder head with caulk). Pull the distributor up and out of the engine. Also note the position of the rotor just as the distributor clears the engine. This is where you will want to position the rotor when installing the new distributor. The rotor should then line up with the reference mark after it is fully seated.

Installing the DUI Distributor

Remove the distributor cap. Position the rotor to the point where it was, when it cleared the engine while removing the old distributor. Slide the distributor down into the engine. Be sure the rotor turns so that it points to the reference mark when the distributor is fully seated. It may be necessary to reach down into the engine with a long screwdriver and turn the oil pump drive, so the slot is properly aligned with the distributor shaft. Once the distributor is fully seated and the rotor is pointing to the reference mark, re-install the distributor hold down clamp and bolt and snug it down lightly.

If you are starting fresh and installing a DUI Distributor in a new or rebuilt engine, then you will need to bring the number one cylinder up to top dead center (TDC) on the compression stroke. Note: Make sure you are on the compression stroke or you will be 180 degrees out on the timing. If necessary, have someone spin the engine over while holding your thumb over the number one spark plug hole until you feel it "blow", this will be your compression stroke. Turn the engine by hand to line the timing mark up to 0 on the balancer. Once this is established, drop the distributor in the block (without the cap) and point the rotor toward the terminal you want to designate as number one. Any terminal can be selected, as long as you maintain the firing order when installing the remainder of the plug wires.

Caution: Do not force the distributor into place or tap in with a rubber hammer as this may cause severe damage to the distributor, distributor shaft, gears, oil pump, and/or the cam. Make sure the distributor does not BOTTOM OUT. The best way to do this is to temporarily install the distributor without the gasket or o-ring, then check the distributor shaft for a slight up and down movement. Do not check for movement by pulling on the rotor or reluctor (the part the rotor attaches to). Check by moving the plate that is attached directly to the shaft (the plate that the weights ride on), or the shaft itself, making sure to hold the distributor housing snug to the block. If you have a slight up and down movement, re-install the distributor with the gasket and O-ring in place and proceed. If you do not have movement, purchase and install distributor shims to obtain ample clearance. We recommend using shims by Mororso (part # MOR-26150), which can be purchased from most performance shops. Once adequate clearance is provided, re-install the distributor with the gasket and o-ring in place and proceed.

Re-install the distributor cap, vacuum hoses or lines, and transfer the plug wires from the old cap (or install your new LiveWires) making sure you do not mix up the firing order. If you did not purchase DUI LiveWires when you purchased your DUI distributor, we recommend using a quality set of 8mm metallic core wires. Firing Order: 1-5-3-6-2-4

If you have converted from a breaker point ignition, this is a good time to open the spark plug gaps now that you have the firepower available. We recommend setting the plug gaps at .050-055".

Power Supply and Wiring

There are two methods we recommend for supplying power to the distributor. Your new DUI distributor requires a full alternator voltage. For those converting from a breaker point distributor, as in most cases, you must eliminate any ballast resistor or OEM resistance wiring to supply full alternator voltage. For full RPM operation, the DUI distributor requires 14.5 volts.

The first method requires running a 12 gauge wire from the ignition switch to the "BATT" terminal in the distributor. Make sure to connect to the correct terminal on the ignition switch, so that the power is supplied only when the key is in the ON position. Also make sure you have full alternator voltage and that any resistance is removed or eliminated.

The second method uses a relay, the old coil HOT wire, and a new 12 gauge wire to the positive side of the battery. With this method, you don't need to worry about removing or eliminating the old ballast resistors or resistant wiring. When the ignition is turned on, power is supplied to the relay, which activates the relay and sends full alternator voltage to the distributor via a new 12 gauge wire connected directly to the battery.

Stock wiring diagram

DUI wiring diagram with relay

Install a 12V-15A weatherproof relay to the firewall or inner fender. Connect the old coil HOT wire (usually red) to the proper relay terminal. Run a 12 gauge wire from the positive side of the battery to the correct terminal on the relay, and another from the relay to the "BATT" terminal on the distributor (using the clips supplied).

Relay wiring diagram

We recommend setting your initial timing at 12 degrees BTDC while the engine is idling very slow (+ or - 600 RPM) and with the vacuum advance disconnected and the vacuum hose plugged.

Trouble Shooting

If you are having a problem with the distributor not producing a spark, then follow these steps to help determine the problem. First and foremost, check to make sure your hot wire has 12 volts going into the distributor. Your hot wire must be at least 12 gage and have no resistors inline. Also, check to make sure all your grounds are good. A bad ground will keep the distributor from firing. If the hot wire and ground checks good then the problem could be with one of the electronic components inside the distributor. The distributor has three electronic parts which make it fire. The magnetic pick up coil, the module and the coil.

The magnetic pick up coil is located inside the distributor underneath the rotor and weight and spring assembly. It has a white and green wire coming out of it that plugs into the module with a yellow plastic insulator. The magnetic pick up coil can be tested using an ohm meter. With the green and white wires disconnected from the module, touch the meter leads to the terminals of these wires. The reading should be between 800-900 ohms. A normal reading is about 830-850. But as long as it is within the 800-900 range then the part is good.

The coil (in the cap) can be tested with an ohm meter as well. The resistance values for the coil are as follows. To check the primary side of the coil, touch the meter leads to the red and yellow wires. The reading should fall between 0.3-1.0 ohm. Usually 0.6 - 0.9 ohms is normal. Note that the red wire is positive (+) and yellow is negative (-). To check the secondary side of the coil, it must be removed from the cap. Touch one lead to the center black wire and the other to the bottom of the coil where the rotor bushing makes contact. This reading should be between 6.00K-30.00K ohms. The normal reading is about 8.5K - 9.0K for our Street/Strip coil. Refer to illustration 1 for proper testing of the primary and secondary resistance of the coil.

For the module, there is no resistance check that you can perform to see if it is good or bad. If you suspect the module is bad, you can replace it with another module to see if this will get the distributor to fire. A stock GM module can be used for this test. Or you could take the module to an auto parts store such as Auto Zone or NAPA and have them test it. It is recommended to have the test procedure performed 4-5 times. Reason is, each time the module is tested it develops more heat and heat is a major factor in the breakdown of the module.

Excessive Gear Wear

Excessive distributor gear wear or premature gear failure is a common problem with Ford engines. For more information on premature gear failure, please read our tech article.

New Oil Pumps

Ford oil pump mounting brackets have elongated holes, therefore the distributor shaft and oil pump shaft must be aligned so that the distributor turns freely before tightening the mounting bracket bolts. Failure to do this will cause a binding situation, thus damaging the distributor gear.

Brass Distributor Gears

Brass distributor gears can be used to avoid damaging the cam gear, however brass gears are soft and wear out quicker than cast gears. If using a brass gear, check it frequently for gear wear.

If you encounter a problem not covered here, or are having issues you can't resolve, you may call Performance Distributors direct at 901-396-5782. You can also email them at for further technical assistance.

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