Guest Shadrach Posted June 1, 2011 Share Posted June 1, 2011 I just purchased a 1931 Plymouth and the owners manual which came with the car stated it had a NEGATIVE ground. I have read in a couple of different places that the car was orginally POSITIVE ground. Since the purchase the amp meter shows a discharge when sthe throttle is advanced. Can anyone help? Link to comment Share on other sites More sharing options...
keiser31 Posted June 1, 2011 Share Posted June 1, 2011 I just purchased a 1931 Plymouth and the owners manual which came with the car stated it had a NEGATIVE ground. I have read in a couple of different places that the car was orginally POSITIVE ground. Since the purchase the amp meter shows a discharge when sthe throttle is advanced. Can anyone help?Are you sure it said negative ground? All of the other 1931 Chrysler products are positive ground. Link to comment Share on other sites More sharing options...
ch1929 Posted June 1, 2011 Share Posted June 1, 2011 Reverse the cables and start it up. Should correct the amp meter to read positive.Roland Link to comment Share on other sites More sharing options...
Steve Braverman Posted June 1, 2011 Share Posted June 1, 2011 I have the manual right in front of me. It clearly shows a negative ground. It's possible that the ammeter is wired backwards, or the car is actually discharging. Link to comment Share on other sites More sharing options...
HarryJ Posted June 1, 2011 Share Posted June 1, 2011 (edited) Interesting point..............I have a '31 PA with a PB engine. In the PA's the ground is negative and in the PB's the ground is positive! Check your engine serial #. Edited June 1, 2011 by Harry J. (see edit history) Link to comment Share on other sites More sharing options...
keiser31 Posted June 1, 2011 Share Posted June 1, 2011 I have the manual right in front of me. It clearly shows a negative ground. It's possible that the ammeter is wired backwards, or the car is actually discharging.Well, I'll be dipped! Link to comment Share on other sites More sharing options...
Guest noncompos Posted June 1, 2011 Share Posted June 1, 2011 Is the battery going down???Like CH1929 sez, reverse the cables, it should then show charging; if the battery stays up, problem solved.If the battery goes down, back to the drawing board...(I've never heard of a 6V system being hurt by this problem, not unusual when some cars were pos grnd and some neg grnd)... Link to comment Share on other sites More sharing options...
ply33 Posted June 1, 2011 Share Posted June 1, 2011 Well, I'll be dipped!New to me too. I was sure that all the early Plymouths were positive ground. But I only have wiring diagrams for 33 and up... Link to comment Share on other sites More sharing options...
Rusty_OToole Posted June 1, 2011 Share Posted June 1, 2011 Normal is if the ammeter goes to slight - when you turn on the key. More - when the starter is turning. Then + when the engine is running especially if you rev it up a little.You might have to polarize the generator if it has been hooked up backwards or out of use for many years.A volt meter will tell you if the gen is charging or not. Connect it to the battery or to any live wire. It should show a certain voltage when stopped, not necessarily 6 volts but close. When you turn the starter it should dip. When the engine starts it should go higher than where it started from, especially if you rev the motor a little. Link to comment Share on other sites More sharing options...
impala Posted June 1, 2011 Share Posted June 1, 2011 A quick and dirty test lacking any diagnostic equipment is to disconnect one terminal of the battery with the car running. If the engine stalls the generator is not providing any or enough voltage to keep the engine running.Of course a volt meter will give a more accurate reading.impala Link to comment Share on other sites More sharing options...
broker-len Posted June 4, 2011 Share Posted June 4, 2011 I have had my 32 PA for 40 years It seemed to be a original car when I got it it has positive ground I looked in owner's manual and it states negitive ground I also have a repair manual covering 31 to 36 put out by nappa in 30s it shows positive ground for both my PA and 36 plymouth STRANGE -------- BR Link to comment Share on other sites More sharing options...
dravid Posted June 23, 2011 Share Posted June 23, 2011 Hi All I am a junior member from South Africa. I recently purchased my first 1931 Plymouth PA. This car has a 4 cylinder engine that was turning 180 degrees and then locking. I disassessembled the complete engine to find that 3 valves were stuck causing the problem. I dont blame the valves considering that the car was in a warehouse since 1973. I had the block honed, the shims between the conrod and caps removed and then the carnkshaft machined to suite in order to ensure the correct oil pressure. I am now at the stage to start assembling the motor but do not have a repair or owners manual. Where and how can I get my hands on these. if I do get my hands on a manual how will I know if it is the correct one for me. Link to comment Share on other sites More sharing options...
Guest De Soto Frank Posted June 23, 2011 Share Posted June 23, 2011 Back before 1935, ( not sure exactly when they changed ), Chrysler Corp used Delco-Remy electricals... at least my long-gone 1930 De Soto Eight had them...Is the Negative-ground Plymouth a Delco-equipped car ? Link to comment Share on other sites More sharing options...
ply33 Posted June 23, 2011 Share Posted June 23, 2011 Back before 1935, ( not sure exactly when they changed ), Chrysler Corp used Delco-Remy electricals... at least my long-gone 1930 De Soto Eight had them...Is the Negative-ground Plymouth a Delco-equipped car ?Delco-Remy was used from 1928 through 1934. Switched to Auto-Lite in 1935. Link to comment Share on other sites More sharing options...
Guest bofusmosby Posted June 24, 2011 Share Posted June 24, 2011 Hi All I am a junior member from South Africa. I recently purchased my first 1931 Plymouth PA. This car has a 4 cylinder engine that was turning 180 degrees and then locking. I disassessembled the complete engine to find that 3 valves were stuck causing the problem. I dont blame the valves considering that the car was in a warehouse since 1973. I had the block honed, the shims between the conrod and caps removed and then the carnkshaft machined to suite in order to ensure the correct oil pressure. I am now at the stage to start assembling the motor but do not have a repair or owners manual. Where and how can I get my hands on these. if I do get my hands on a manual how will I know if it is the correct one for me.I would suggest checking Ebay. Welcome to the forum! Link to comment Share on other sites More sharing options...
Guest De Soto Frank Posted June 24, 2011 Share Posted June 24, 2011 Delco-Remy was used from 1928 through 1934. Switched to Auto-Lite in 1935.Thanks - I didn't dealize they used Delco so late...I have a bit of a hole in my technical Library; none of my MoToR's Manuals go back before 1935, my Dyke's Manual is a 1918 edition, and my big ICC book on "Automotive Electrical Systems" covers 1925-1930....Nothing on 1931-34...Frank Link to comment Share on other sites More sharing options...
Steve Braverman Posted June 24, 2011 Share Posted June 24, 2011 I have a manual. I would be happy to scan and email you any part of it. Link to comment Share on other sites More sharing options...
dravid Posted June 27, 2011 Share Posted June 27, 2011 Hi Steve I enjoyed your pics on this site and really do appreciate your help. I actually need the entire manual as my intention is to get my car back to the original condition it was when it was first built. The engine assembly section will do for now as I am ready to begin assembling. I would be interested in the torque setting for the bolts and nuts as well as if there is any special procedures required like filing the ends of the ring to get the correct gap ect. ( I was not aware that must be done when assembling as most modern engines the ring gap is preset when yo u buy the set ) Im not sure if this site will display my email adress, so please let me know if so and will then try to determin a different method of getting it to you. my adress is dsha@toyota.co.za Link to comment Share on other sites More sharing options...
Guest Monaco Posted August 15, 2011 Share Posted August 15, 2011 Hi Steve,my Manual shows a positive ground. Seems there are two different Manuals out. All the same, just the terminals are changed (see attachment).By the way, my PA is on the street since a few weeks (wired positiv ground).I will also thank you for your help given to me! Link to comment Share on other sites More sharing options...
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