Matt Harwood Posted July 21, 2020 Share Posted July 21, 2020 You'd think this information would be readily available on the internet, but it is not. I sold a '47 Continental a few weeks ago and the new owner is yelling at me because he thinks the battery was installed backwards and that we're idiots. I'm pretty sure the cables are sized so you can't install them incorrectly but whatever. I sent all the manuals and diagrams with the car, so I don't have a reference on hand to check it myself and obviously the car is not here. For the record, is a '47 Lincoln Continental positive or negative ground? Link to comment Share on other sites More sharing options...
Brass is Best Posted July 21, 2020 Share Posted July 21, 2020 It should be positive ground. But when restored it could have been changed. The AMP gauge should let him know. 1 Link to comment Share on other sites More sharing options...
Matt Harwood Posted July 21, 2020 Author Share Posted July 21, 2020 Thanks, Andy. That's how we installed it, but he's insisting that it should be negative ground (because all cars are negative ground, don't you know) and I didn't have any proof. 1 Link to comment Share on other sites More sharing options...
Marty Roth Posted July 21, 2020 Share Posted July 21, 2020 Advise him that the 1941 Cadillac, and the 1930 Packard in my garage are also Positive Ground 2 Link to comment Share on other sites More sharing options...
Frank DuVal Posted July 21, 2020 Share Posted July 21, 2020 ANyone got a Motor's Manual from 1950 or so handy? They list this in the specification section of every make for the previous few years. Mine is not handy right now. 1 Link to comment Share on other sites More sharing options...
padgett Posted July 21, 2020 Share Posted July 21, 2020 Seems easy to Me, connect the battery and see which way the stater cranks the engine. Was an old trick with twin engine boats that one had a reverse ground cam and you just connected the starter in reverse (did need a few other special items like the sprag clutch). Link to comment Share on other sites More sharing options...
Bloo Posted July 21, 2020 Share Posted July 21, 2020 Positive ground was more common in the 6 volt days. GM cars (except some Cadillacs) were the odd ones for using negative ground. Link to comment Share on other sites More sharing options...
padgett Posted July 21, 2020 Share Posted July 21, 2020 and electrons flow from negative to positive so connecting the ground to negative means the device protects the fuse. Link to comment Share on other sites More sharing options...
F&J Posted July 21, 2020 Share Posted July 21, 2020 1 hour ago, padgett said: Seems easy to Me, connect the battery and see which way the stater cranks the engine. Hopefully you were joking, right? If not, wow, get out of the sun...and quickly please! A starter turns the same direction no matter what polarity you use on it. Try it and see. ( the heat is sure messing with my own abilities today working on my Nash...so I quit before causing even more damage. lol ) 2 1 Link to comment Share on other sites More sharing options...
Brass is Best Posted July 21, 2020 Share Posted July 21, 2020 6 volt and positive ground always tend to go together. Link to comment Share on other sites More sharing options...
Bloo Posted July 21, 2020 Share Posted July 21, 2020 (edited) I checked my 1947 Chilton/MotorAge and it does not say whether a 1947 Lincoln is positive or negative ground. Maybe Motor's would, but I don't have one handy. That was just the sort of thing every mechanic knew back then. EDIT: MoTor 12th Edition, 1949. 1947 Lincoln is Positive ground. Edited July 21, 2020 by Bloo (see edit history) 1 Link to comment Share on other sites More sharing options...
padgett Posted July 21, 2020 Share Posted July 21, 2020 Really ? Thought DC motors could spin either way. Memory was from working at Rybovich many years ago. ps XK150s was 12v positive ground: two 6v batteries, one in each wing. Link to comment Share on other sites More sharing options...
Matt Harwood Posted July 21, 2020 Author Share Posted July 21, 2020 The reason I stuttered without an immediate answer for him is because the Lincoln Ks are negative ground even though Fords were positive ground. I wasn't 100% sure if the later Continentals followed Ford practice or if they stayed with the K negative ground. 1 1 Link to comment Share on other sites More sharing options...
Bloo Posted July 21, 2020 Share Posted July 21, 2020 Oh really? Thats news to me. I corrected my post. Link to comment Share on other sites More sharing options...
Guest Posted July 21, 2020 Share Posted July 21, 2020 48 minutes ago, Brass is Best said: 6 volt and positive ground always tend to go together. Never on a Pontiac. Link to comment Share on other sites More sharing options...
Chris Bamford Posted July 21, 2020 Share Posted July 21, 2020 4 hours ago, Frank DuVal said: Anyone got a Motor's Manual from 1950 or so handy? By good fortune I had that exact book on the shelf... 2 3 Link to comment Share on other sites More sharing options...
Dave Henderson Posted July 21, 2020 Share Posted July 21, 2020 In the day a Motor 1 hour ago, Chris Bamford said: By good fortune I had that exact book on the shelf... I have some of these manuals from the '50's and later, earlier ones cover back through '35. In the day a Motor's Auto Repair Manual had about everything covered and was all you needed to know about fixing American cars. I'm thinning my library and will sell any one I have that will cover your car for $20 plus media mail postage.. Please pm me. Link to comment Share on other sites More sharing options...
Ben Bruce aka First Born Posted July 22, 2020 Share Posted July 22, 2020 4 hours ago, F&J said: Hopefully you were joking, right? If not, wow, get out of the sun...and quickly please! A starter turns the same direction no matter what polarity you use on it. Try it and see. ( the heat is sure messing with my own abilities today working on my Nash...so I quit before causing even more damage. lol ) Go gitem, Frank. Ben Link to comment Share on other sites More sharing options...
Brass is Best Posted July 22, 2020 Share Posted July 22, 2020 3 hours ago, Tinindian said: Never on a Pontiac. That is why I said tend. Link to comment Share on other sites More sharing options...
Frank DuVal Posted July 22, 2020 Share Posted July 22, 2020 8 hours ago, padgett said: Seems easy to Me, connect the battery and see which way the stater cranks the engine. Nope, unless you rewire the connection from the armature to the field, the starter will turn the same way, as the relative magnetic field between the two stays the same. Are you saying one battery in a twin screw boat was positive ground and the other screw's battery was negative ground? Pernanent magnet motors are a different story, as the field is always magnetized one way, so reversing the armature reverses direction. Some modern starters ARE permanent magnet motors, so reversing batery polarity might work on those small high torque startes these days!🙃 http://what-when-how.com/automobile/permanent-magnet-starter-motor-automobile/ So, Padgett, just say your boat experience was last week.......😉 7 hours ago, padgett said: and electrons flow from negative to positive so connecting the ground to negative means the device protects the fuse. Another funny saying with no truth! Opening a circuit protects the device, does not matter which lead the fuse is in. There are however, safety reasons to put the fuse in the ungrounded lead to the device, but the device does not care. 6 hours ago, Brass is Best said: 6 volt and positive ground always tend to go together. Not in my world of GM cars (except Cadillac). Might just have been to be different than Henry F.😁 However, maybe it was Henry trying to be different than Charles "Boss" Kettering, who had electric starting first, for Cadillac, then the rest of what was to become General Motors. Most everyne had electric start before Henry.😄 My peronsal belief is the positive ground system came from people experimenting with spark plugs and discovering they fired better with positive ground back with magnetos. So, battery followed suit. Until they figured out the primary of an ignition coil can be negative ground and the seconday can be positive ground just fine!👍 MoTors Manuals are the only ones I have seen with the battery polarity in the specifications. Very valuable information. 1 Link to comment Share on other sites More sharing options...
8E45E Posted July 22, 2020 Share Posted July 22, 2020 15 hours ago, F&J said: A starter turns the same direction no matter what polarity you use on it. Try it and see. Just make sure the radio is turned OFF. (or better yet, the fuse removed as on some, the tube filaments remain lit, even it is switched off.). Reversing the polarity is vey damaging to radios. Craig Link to comment Share on other sites More sharing options...
padgett Posted July 22, 2020 Share Posted July 22, 2020 OK some DC motors will reverse if polarity is reversed. My boat working on experience was in the 60s and guarantee nothing from memory. Link to comment Share on other sites More sharing options...
SC38dls Posted July 22, 2020 Share Posted July 22, 2020 I've rebuilt the engines on 3 Chris Craft boats with twin engines each. This was in the 70's and 80's and all three had negative grounds on all the batteries. These were a 25 foot, a 32 foot and a 42 foot cabin crusiers that were all wood. The dry rot was harder to do than the engines. On the 42 foot Constelation I replaced 178 board feet of mahagony planking with a brass screw every 4 to 6 inches. Beautiful boats to look at but not a lot of fun to work on. dave s Link to comment Share on other sites More sharing options...
John_Mereness Posted July 22, 2020 Share Posted July 22, 2020 And, they bought a Lincoln Continental - that will be a recipe for disaster for them, but at least it will look nice in the garage Link to comment Share on other sites More sharing options...
JamesR Posted July 22, 2020 Share Posted July 22, 2020 (edited) My early 50's Ford was pos. ground from the factory, as I'm sure Matt knows. It would be hard to figure why FoMoCo would have one of their divisions with some neg. ground cars and the other two with pos. ground, but apparently they did according the the post above. An accessory consideration I guess. Edited July 22, 2020 by JamesR (see edit history) Link to comment Share on other sites More sharing options...
JACK M Posted July 22, 2020 Share Posted July 22, 2020 The 48 Jeepster was 6 volt NEGATIVE ground. 1 Link to comment Share on other sites More sharing options...
Larry Schramm Posted July 22, 2020 Share Posted July 22, 2020 On 7/21/2020 at 4:07 PM, Brass is Best said: 6 volt and positive ground always tend to go together. Except GM Link to comment Share on other sites More sharing options...
Brass is Best Posted July 23, 2020 Share Posted July 23, 2020 1 hour ago, Larry Schramm said: Except GM Right, we were talking about a FoMoCo product. Link to comment Share on other sites More sharing options...
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