Andrew93 Posted July 12, 2022 Share Posted July 12, 2022 (edited) I am working on our fire department associations 1951 Mack with a continental 331 flat head 6. I tried to see if it would start today and I have power to the ignition coil, but no spark, it has dual ignition and both had no spark. I was jump starting it, the battery int he truck is very dead. I am thinking maybe bad coils? The was visible wear on the inside of the cap, and one of the rotors was slightly corroded, points contacts looked ok, everything was dry. Last time the truck ran was at least 10 years ago. Is there a way to cross reference the parts numbers to NAPA parts? The plate on the distributor say model/serial number 1112290 OK14, all I could find online with this number was for an 8 cylinder Pontiac. I figured replacing the cap, rotor, points, condenser, and coil are probably in order. The truck is going out soon for professional mechanical work, but I would like to see if I can get it at least moving on its own power first. Edited July 17, 2022 by Andrew93 Quote Link to comment Share on other sites More sharing options...
609albert Posted July 13, 2022 Share Posted July 13, 2022 are the rotors moving when you turn the engine over ? I think actual any coil might work to start temporary . also Macks work on a positive ground system 1 Quote Link to comment Share on other sites More sharing options...
Andrew93 Posted July 13, 2022 Author Share Posted July 13, 2022 2 minutes ago, 609albert said: are the rotors moving when you turn the engine over ? I think actual any coil might work to start temporary . also Macks work on a positive ground system I agree any 12v coil will be fine. Shame on me I did not spin engine with caps off. The truck was parked running, I would like to think the distributor itself is ok, but I will check next time I am at the truck. I figured a new cap/rotor/points/condenser can't hurt either, but not sure the parts numbers. I was jump starting the truck but I do not think I was jumping it positive ground, the battery was still in the truck, just very dead. I will have to look and see and how that battery was hooked up, all the accessory light were working etc and I had 12v on the positive side of the coil that was working with the ignition switch. A 1928 Maxim I help maintain is positive ground, I should have looked closer on this one Quote Link to comment Share on other sites More sharing options...
yarnall Posted July 13, 2022 Share Posted July 13, 2022 My 1951 405A is 6 volt. Also positive ground. It should not matter if it is positive or negative ground. Just hook positive to positive and negative to negative to jump it. I don’t remember if we did a tune up in my 405A. We might have just cleaned everything up and ran it. I think we replaced the coils but if we did we just went to NAPA and asked for a 6 volt coil. They always ask what I am working on. I tell them but them tell them what parts I want. Let’s see a photo. Good luck. Mike 1 Quote Link to comment Share on other sites More sharing options...
Andrew93 Posted July 13, 2022 Author Share Posted July 13, 2022 (edited) If I have the polarity wrong would jump starting the truck cause a no spark situation? The truck is dual ignition and I found it odd I had zero spark on either. I used a known good plug to test also. I did read the starter should spin the right direction no matter what, but maybe the ignition system will not work right? The fire department I work for full time started working on a 1928 Maxim, with that project going well I brought up to the department I still serve as a call FF with to start working on their 1951 Mack 45A. The Maxim got sent to Gaspers Automotive Restoration in Manchester, CT and he did a great job, we have been fundraising and are on his wait list for the '51 Mack. Under all the dust the body is in great shape. My goal is to have the truck moving under its own power when we send it to Gasper's hopefully in the fall. The Mack originally served with Collingdale, PA and has been in Ashland, MA since the late 60's. Attached are photos of both projects, the Mack and Maxim Edited July 13, 2022 by Andrew93 2 Quote Link to comment Share on other sites More sharing options...
mechohaulic Posted July 13, 2022 Share Posted July 13, 2022 as a thought; if the battery is stone dead, did you try another good battery for start up? a low battery can improve with a boost; stone dead ;; you might not have enough for start up. 1 Quote Link to comment Share on other sites More sharing options...
Brocky Posted July 13, 2022 Share Posted July 13, 2022 When jumping a totally dead battery the battery will absorb mot of the juice coming to it and therefore you have limited energy going to the rest of the vehicle.. Try unhooking the battery cables and jump directly to them??? 2 Quote Brocky Link to comment Share on other sites More sharing options...
h67st Posted July 13, 2022 Share Posted July 13, 2022 I'm with mechohaulic...try a good battery. Clean up the contacts on the rotors and caps; if you have spark from the coil and good condenser then old cap/rotor will work. 1 Quote Link to comment Share on other sites More sharing options...
Popular Post Andrew93 Posted July 17, 2022 Author Popular Post Share Posted July 17, 2022 For the $35 in parts I put in a new cap, rotor, condenser, points, and coil. I put in a better not very good battery I had and jumped that, cranked slow and needed a squirt of carb cleaner and then it stayed running on its own with the clean carburetor I put on it. Running off a boat fuel tank and a primer bulb for now, but I'll take it! 1489910634_MackIdeling.mov 900957314_MackRunning.mov 3 Quote Link to comment Share on other sites More sharing options...
mattb73lt Posted July 17, 2022 Share Posted July 17, 2022 It’s alive!!! Congratulations!!! 1 Quote Link to comment Share on other sites More sharing options...
yarnall Posted July 18, 2022 Share Posted July 18, 2022 Way to go. Quote Link to comment Share on other sites More sharing options...
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