241 Dodge Hemi Distributor Rebuild
I made the plunge and decided on a 241 Dodge Red Ram Hemi engine for my little hot rod. While the machine shop finishes up the detail work on the block and heads I have turned my attention to the bolt on components to make her run! It is important to me that the engine appear as though it was pulled out of a Coronet back in the fifties and transplanted into a hot rod. Because of this I am running many of the stock components on my engine. Fancy parts are tempting, and believe it or not these days there are a vast array of modern amenities to satisfy anyone’s’ hunger for billet aluminum, fins, or chrome! In the distributor department things are no different. Many adapt later small block Mopar distributors for use on these “baby” Hemi’s, and if you want to go all out you can purchase a magneto, or magneto-look distributor. I am keeping it simple, so to stick with my ‘50’s theme I will rebuild the stock distributor to give me the right look. By choosing to run a stock distributor you are not stuck with old school technology of points. Tucked under the cap (where no one can see) I will have a trick electronic conversion making my distributor work like new without the need for an external ignition box.
First I selected a distributor to restore and luckily I had two from which to choose. One was the original distributor to the engine I have in the machine shop, and another bolted to a second engine I have been using for mock up on my chassis.
These distributors have brass bushings inside supporting the shaft. You should give yours a feel to decide if those bushings require replacement. I popped off the caps of both of my distributors and it didn’t take long to notice which distributor was in better shape. Feeling the side to side movement on the shaft can tell you how much wear the bushings have. The distributor off of my mock up engine was obviously a much lower mile example with no play at all. The other would require some serious work so I’ll put that one back on the shelf for another day. If you have an old distributor that needs to be re-bushed it should be a fairly straight forward operation for any machine shop. A sloppy shaft can lead to timing issues so give yours a look!
I stopped by Speedway Motors to purchase what would be the heart of my rebuilt distributor. The folks at Pertronix Performance Products have been producing electronic ignition conversions for a wide array of vehicles for many years. They have proven themselves as a reliable and superior alternative to points. Part number 447-1383 (1383) is the Pertronix “Ignitor” electronic ignition conversion kit for my little 241 Dodge. According to Pertronix this unit will cover all ‘51-‘58 Mopar distributors set up for dual points. I’ll talk more about the specifics of installation in just a moment. Chances are if you have an old engine with points, Pertronix produces a kit to convert you over, and Speedway Motors has it on their shelf ready for you!
I also was in need of a new cap and rotor to make things fresh. If your cap and rotor are in good shape you do not need to change them to run the Pertronix conversion, but mine were petrified from age so they needed to be swapped out.
Once I had all of the new parts purchased I began fixing things up. I took my distributor apart to thoroughly clean it. Even being the best unit I had to choose from, it was rusty, dirty, full of dead bugs, and in need of serious attention!
The first order of business was to set aside all of the old stuff that wouldn’t be needed after the electronic conversion was made. See you later points!
Once disassembled, I cleaned the parts to remove years of grunge and baked on grease. It took some elbow grease but slowly I was left with a clean casting ready for a fresh coat of paint.
Once the shaft was reinstalled, I heated the casting so the paint would stick well. After a quick shot of high heat engine enamel it was looking new again! When installing the ignitor plate you will notice three holes on one end. The middle of the three holes will line up with the threaded hole for the condenser and the hole on the opposite side will line up with the point screw hole on the breaker plate.
After test fitting the ignitor, I cleaned up the breaker plate and lubed up the bearing to free it thereby allowing the vacuum advance to work properly. When you install your Pertronix unit you will want to check your ground wire. Mine was in horrible shape, so I removed it and installed a new one. With a piece of scotch-brite and some oil I was able to clean up the vacuum advance mechanism too.
Next I fastened the ignitor plate using the new screws provided in the kit. I then routed the wires through the hole in the distributor housing and pulled the provided wire grommet into place. Be careful here as it is easy to pull it straight through the hole having to do it again! After a couple tries I got it!
It is important when doing this step to also allow enough wire inside the distributor to allow the vacuum advance to move freely. Also make sure the ignitor wires do not interfere with any moving parts.
It is important to note that the Ignitor I am using from Pertronix is designed to be used with a 12-volt negative ground system. I am using the matching Pertronix “Flame Thrower” coil (p/n 447-45011). By doing this I do not need to run an additional ballast resistor. If you are running a coil with less than 1.5 ohms of resistance you will need to run a ballast resistor.
Wiring the distributor back to the car is easy. The black wire goes to the negative side of the coil. If you are like me and are not running a ballast resistor you simply attach the red wire to the positive side of the coil and you are all set! With everything installed I finished the job by adding a new cap and rotor. What was once a crusty old fashioned distributor now looks new and is sporting some great technology!