Title:How to Rebuild your Smallblock Chevrolet Distributor

Small Hammer
• Small punch (about 1/4" in diameter at the punch end)
• Ratchet with long extension and flexible socket end attachment (picture here)
• Rags or a roll of Scott Shop Towels
• Tape
• Phillips Screwdriver
• A piece of wood or something about 1.5-2" high that will be used as a platform for the distributor shaft
• 5/16" Screwdriver with socket end, or a 1/4" drive ratchet with long extension and 5/16" socket
• Long blade screwdriver (at least 18" in length)
• Timing light
• Rubber glove

• Chevrolet V8 Distributor
• Chevrolet Pickup Coil
• Chevrolet distributor base gasket
• If needed: New Distributor Cap and Rotor with BRASS inserts. Do 'not' get the cheap ones with aluminum inserts, those ones are junk. - If needed: New Borg-Warner or equivalent ignition module. Do not buy junk (i.e. Wells from AutoZone), the junk ones will fail on you.

1) Disconnect the negative battery cable from the battery. Wrap the end in a Scott Shop Towel or shop rag.
2) Disconnect the distributor connections at the distributor cap. There will be 3 if your distributor has the coil in the cap, and a one-plug wire connection if your distributor has an external ignition coil.
3) Mark the distributor location 'before' loosening the distributor hold-down clamp. As shown in my picture, you can use a grease pencil or crayon to mark a common location for a spark plug wire. On my engine, I marked #1 plug wire by drawing a line toward a reference point (in my case it was a bolt hole). I marked both the distributor cap AND the bolt hole.
4) Take a piece of tape about 3 inches long. Place a spark plug wire in the middle and then fold the tape over and join the tabs to make a label. Label that as 1, and move around the distributor cap. I started at number one spark plug wire (or you can use the reference point where you started, to make it easy) and move your way clockwise around the distributor cap, labelling each wire until all 8 have been labeled. I'm sure you're asking why you should do this. This is important because it will allow you to just plug each wire back onto the distributor cap later, rather than have to trace each wire down to the spark plug.
5) Lay the spark plug wires out of the way. Take your screwdriver with 5/16" socket end, or your 1/4" drive ratchet with long extension and 5/16" socket. Unscrew the distributor cap. There will be 4 screws holding the cap down. Remove the cap and set it aside.
6) You will now see the distributor rotor. It may not be in a spot that makes it easy to locate a reference point. Don't worry, just find anything that you can use to locate the rotor to later. In my case, the rotor was point directly at the top bolt for the windshield washer pump. I marked this with my grease pencil. 7) Remove the rotor with your Phillips screwdriver. Some distributor rotors may use a 5/16" screw, so use whatever required to remove the rotor.
8) Use your 3/8" ratchet and long extension with 9/16" flexible socket. Loosen the bolt underneath the distributor platter and unscrew the distributor hold-down bolt, then slide the hold-down back (it is slotted). Don't remove the hold-down bolt because you may end up dropping either the hold-down itself or the hold-down bolt down the distributor shaft. If you do this you will have to take off the oil pan to get them. Trust me, save yourself the trouble and leave the hold-down bolt in the intake manifold.
9) Grab the distributor platter and move it clockwise and counterclockwise. This will break the distributor gasket if it has become gummy. Next, grasp the center shaft that the distributor rotor bolts to. Rotate it counterclockwise while wiggling and pulling up. The distributor should start to work up while the center shaft turns counterclockwise. Don't worry if it doesn't want to come off, remember that the bottom gear of the distributor engages with the camshaft so there will be a little wear that may prevent it from sliding out easy. If it doesn't budge at all, make sure the hold-down clamp is out of the way. Try again, you'll get it after awhile. It took me about 10 minutes to work it out.
10) Once the distributor is loose, take a rag and get ready to wrap the distributor gear in it as soon as you pull it up and clear of the intake manifold. Quickly place a clean rag overtop the distributor hole so nothing falls into the engine. The distributor will also be dripping with oil so take it over to a work bench and wipe most of the oil off.
11) Examine the distributor for wear. Stand the distributor up as if it was installed in the engine. Wiggle the center shaft left and right and check for side-to-side wear. This will indicate a worn-out distributor and will require replacement. Also check for excessively worn or broken teeth on the distributor gear. Any major wear or broken teeth will require replacement of the distributor gear.
12) Lay the distributor on its side. Rotate the center shaft so that you can see the roll pin that holds the distributor gear on. Take your hammer and punch. Punch out the rollpin. Be careful not to hit the distributor housing, it is aluminum and will break if you hit it too hard. If you have a friend that can help, have him hold the distributor still because the center shaft tends to want to rotate when you hit it with the punch. If you have a vise, you can use it to perform this step. Place rags on the jaws so that the vise does not damage the distributor. Perform the steps above in the same fashion described.
13) Once the roll pin has been punched out, remove the distributor gear. From the bottom of the distributor towards the top there will be: distributor gear, protective gear washer, second protective washer/spacer with tabs on it that is 'inverted' with the tabs pointing toward the top of the distributor. Remove these and set them aside.
14) Slide the center shaft out of the distributor. Set this aside. Make 'sure' that you do not get any crud like metal shavings or lint onto the shaft. I wrapped mine in a clean towel. You will now have the distributor completely apart. To access the pick-up coil, remove the three screws. A small assembly will come off, leaving the pick-up coil underneath. Remove the coil and replace with your new one. Replace the small assembly in the same orientation as you removed. Tighten down the three screws.
15) Slide the center shaft back into the distributor. Put the collar with tabs back on, remember to have the tabs 'up' or inverted. Slide the distributor washer onto the shaft. Slide the distributor gear back onto the shaft (or the new one if you had to buy one). Rotate the shaft or gear until the roll pin hole is visible. I ended up having to punch the roll pin into the gear a bit before punching into the center shaft. Align the two and punch the rollpin completely through the center shaft. Make sure that the rollpin does not protrude out of the distributor gear. It must be flush!
16) Go back to your car. This is the hardest part of the whole distributor rebuild process. Place the new distributor gasket onto the distributor shaft. Now insert the distributor into the distributor hole. Rotate the distributor about 3/4" of an inch counterclockwise from the mark you made. Engage the distributor with the camshaft gear. Slide the distributor down the gear while rotating the center shaft clockwise. If you reach the bottom and the distributor is not seated you will be one tooth off. Raise the distributor back up and move it counter- or clockwise depending on where the center shaft ended up. Redo this process until the distributor seats correctly. If you are having problems, the oil pump may have rotated a bit when you pulled the distributor out. This generally happens when you 'yank' the distributor out the first time. The oil pump turns a bit and you must correct this. Take your screwdriver and rotate the pumpshaft either back or forward. If you look on the bottom of the distributor gear you will see it is slotted. The gear and the pump must engage each other correctly to allow complete distributor installation.
17) Once completely seated, place the hold-down clamp onto the flange on the distributor. Do not tighten fully yet, just tighten the bolt down fingertight so that you can adjust the timing later.
18) Install the rotor and make sure that your lines match up. If the rotor is slightly clockwise of your mark, your timing will be retarded. If the rotor is slightly counterclockwise of your mark, your ignition timing will be advanced. If the rotor is in perfect alignment with your mark, your timing will be correct as long as you replace your distributor cap in the correct place.
19) Replace the distributor cap. Tighten the 4 screws. Reconnect the distributor's connections (3 if it has an in-coil system, 1 if it has an external coil system). Reconnect all spark plug wires starting with the #1 wire you labeled and replace in a clockwise direction (or the same order you removed) until you have replaced all eight wires. If you have an external coil system, reinstall the coil wire to the distributor cap.
20) Rotate the distributor cap until your previously-marked distributor cap lines up with your mark on your car. In my case, #1 matched up with the bolt hole. Remember your distributor rotor? If it was counterclockwise or clockwise after install, correct for this by moving the distributor cap in the 'same' direction. (i.e. If it was counterclockwise a touch, rotate the distributor cap counterclockwise a touch.)
21) Tighten the distributor down a touch so that your timing does not change when you start your car. Take the rag off the negative battery cable and reinstall onto your battery. Now make sure all of your tools are out of your engine compartment. Connect the wires for your timing light now and make sure they are out of the way (i.e. out of the fan-blade area, not able to be caught or pulled into a pulley).
22) If your car electronically adjusts the timing (i.e.it is not vacuum advance) you must disconnect the EST (Electronic Spark Timing) wire. Generally, it is where the carpet meets the under side of the heater box in S trucks and is a brown wire with a black stripe. There is a quick disconnect to help identify it. Start your car and check your timing. If you are not sure how to correctly check your timing, see my tutorial on checking your timing. The link is here. If the motor has not been modified, the timing should be what the Emissions Sticker dictates. If the sticker is missing, most stock GM engines like around 6 degrees BTDC. If it is not, adjust it accordingly by rotating it. Make 'sure' you are wearing a rubber glove or you'll get a nice shock! If you don't have a glove, turn off the car and adjust the timing then restart and recheck your timing. Once the timing has been set, tighten the distributor the rest of the way. Recheck timing. If all is OK, you are done. Turn off the car, disconnect the timing light and clean up.

Submitted By: Colin Opseth
Edited By: custmguru
Edited By: 92SonomaST
Rev. 23AUG04 Dougofthenorth