Author	[Modern View]
Stephenscity 08-07-2012 04:40:53 173.72.224.43 Report to Moderator	My new to me 8N has had the polarity switched to neg ground from positive grd. Know this was done on some of the old britsh cars but why would you do it on a tractor? Was there any advantage or disadvantages? [Reply]   [No Email]
JMOR 08-09-2012 08:00:58 99.29.98.186 Report to Moderator	Re: switched polarity in reply to JMOR, 08-07-2012 04:40:53   Tony C. said: (quoted from post at 10:31:43 08/09/12) If the 8N has a front distributor and the battery were reversed, would this cause the coil polarity to be backwards and output to be reduced? I assume if it were a side distributor you could reverse the coil connections along with the battery and all would be OK. But you can't easily do this with a front dist/coil, is that correct, I'm not sure? ACTUALLY, Tony, it would reverse the HV output polarity, but would NOT reduce the coil output voltage. HOWEVER, if he did reverse the coil connections (as you point out that he could if a side mt), then the HV output would be REDUCED (by the amount of voltage across the primary, an amunt equal to 1/100 th of the HV output for a 100:1 typical coil). Polarity is virtually insignificant (electrons leave a hot surface a bit easier than a coil surface). Most magneto ign engines have every other spark neg thus every alternating spark positive. Old Harleys used a single coil to fire both cylinders, thus sending a pos spark to one cylinder & neg to the other. Many modern engines (including some Fords) use a 'wasted spark' system & in those, half of the cylinders receive pos & half receive neg spark. If you install a pertronix EI on your otherwise stock N front mount, the HV output will be changed from neg to positive by this installation. Remember that both electrodes are cold/same temperature at startup when these old slow speed engines need a good spark the most. People will argue this forever, because of "what I've always heard", so do whatever you want, in the end it will make no difference in performance. With a side mount that you convert to neg ground, you could, if you absolutely must have a neg HV output, change the coil to one whose's windings are phased to produce BOTH the full voltage out AND a NEG HV output & have your cake & eat it too! But your tractor still won't perform better.........but you may be happy. :wink: This post was edited by JMOR at 08:11:03 08/09/12. [Reply]  [No Email]
36 coupe 08-07-2012 16:34:53 66.186.169.176 Report to Moderator	Re: switched polarity in reply to Stephenscity, 08-07-2012 04:40:53   Half the cars, trucks built in 1940 were positive ground.All 6v tractors Ive worked on were positive ground. [Reply]  [No Email]
1951 8N 08-07-2012 13:53:15 139.55.250.226 Report to Moderator	Re: switched polarity in reply to Stephenscity, 08-07-2012 04:40:53   Quoting Removed, click Modern View to see No, they did not come from the factory with negative ground. [Reply]  [No Email]
Stephenscity 08-07-2012 09:39:45 173.72.224.43 Report to Moderator	Re: switched polarity in reply to Stephenscity, 08-07-2012 04:40:53   Thanks everyone answered my question as always!!!!! [Reply]  [No Email]
Dell (WA) 08-07-2012 08:38:05 63.226.213.236 Report to Moderator	Re: switched polarity in reply to Stephenscity, 08-07-2012 04:40:53   Stephenscity........not only are old British cars positive earth, many early American cars were also. Some of it has to do with Lawyers and GM's Kettering patents. There are some obscure technical advantages of positive ground, mostly having to do with the "sparkies". Electrons (-) more easily jump from center post (-) to positive (+) ground bar. Modern sparkplug technology has eclipsed this problem. You do know Henry Ford and Thomas Edison were "buddies" don't you? ........Dell, yer self-appointed sparkie-meister [Reply]  [No Email]
Tony C. 08-09-2012 07:31:43 69.127.139.162 Report to Moderator	Re: switched polarity in reply to Dell (WA), 08-07-2012 08:38:05   If the 8N has a front distributor and the battery were reversed, would this cause the coil polarity to be backwards and output to be reduced? I assume if it were a side distributor you could reverse the coil connections along with the battery and all would be OK. But you can't easily do this with a front dist/coil, is that correct, I'm not sure? [Reply]  [No Email]
dhamps10 08-07-2012 05:47:14 50.103.149.161 Report to Moderator	Re: switched polarity in reply to Stephenscity, 08-07-2012 04:40:53   They came from the factory, that way, as did most 6 volt tractors. Dennis [Reply]  [No Email]
JMOR 08-07-2012 05:35:20 99.105.24.57 Report to Moderator	Re: switched polarity in reply to old-9, 08-07-2012 04:40:53   Quoting Removed, click Modern View to seeThose will work equally well either way, as long as the generator is re-polarized so as to have output voltage match the battery polarity. A smart man will not try to fix what is not broken, less he run the risk of ending up with it broken. My advice is leavre it be....it has & does function just fine as is. Why did someone do it? Guess is all anyone can do. Unintentional? Wanted it to be like all his other equipment (help keep from connecting jump box/cables up backwards)?, ???? [Reply]  [No Email]
TheOldHokie 08-07-2012 05:30:36 108.8.21.136 Report to Moderator	Re: switched polarity in reply to Jimmyjack, 08-07-2012 04:40:53   Stephenscity said: (quoted from post at 08:05:01 08/07/12) Sorry No it is all original with the 6volt system. Everything works great Genny is putting out battery is charging runs great. Guy I bought it from said it was that way when he got it, Other than on the old britsh cars I had just never seen it reversed on a tractor. Welcome neighbor - we're up north of you in Hagerstown. The tractor don't care which way it's wired. If it ain't broke don't "fix it". TOH This post was edited by TheOldHokie at 05:32:34 08/07/12. [Reply]  [No Email]
Stephenscity 08-07-2012 05:05:01 173.72.224.43 Report to Moderator	Re: switched polarity in reply to Stephenscity, 08-07-2012 04:40:53   Sorry No it is all original with the 6volt system. Everything works great Genny is putting out battery is charging runs great. Guy I bought it from said it was that way when he got it, Other than on the old britsh cars I had just never seen it reversed on a tractor. [Reply]  [No Email]
soundguy 08-07-2012 06:11:25 107.41.216.146 Report to Moderator	Re: switched polarity in reply to Stephenscity, 08-07-2012 05:05:01   idiot owners and mechanics that aren't aware that it was 6vpositive ground from the factor sometimes put the battery in to match their car in the driveway. that's how they get switched usually. if it's working.. why fix it... [Reply]  [No Email]
horsin around 08-07-2012 04:49:43 108.215.68.111 Report to Moderator	Re: switched polarity in reply to Stephenscity, 08-07-2012 04:40:53   Need a little bit more info. on tractor then that to be able to help. Was it converted to 12 Volts ?? [Reply]  [No Email]