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| | | | Joined: Jul 2012 Posts: 10 New Guy | | New Guy Joined: Jul 2012 Posts: 10 | New here and just starting on my '51 GMC 150. A couple issues: mainly, the guy who installed the rebuilt engine hooked it up as negative ground. It's all original 6V. Any damage from him doing that? I've noticed a couple things. Real hard to start, won't idle well, ammeter shows negative charge. From what i've read in the threads, the coil being wired backwards reduces its effectiveness but other than that, not much harm comes from the negative ground. I'm inclined to switch it back to pos. ground by swapping battery hookup. Anything else i should look for or switch around? (besides improving the grounding system and upsizing cables.) Would the reverse polarity have any effect on rough idle? (plus it bucks and surges a lot in 2nd gear) | | | | | Joined: Mar 2012 Posts: 240 'Bolter | | 'Bolter Joined: Mar 2012 Posts: 240 | Welcome to Stovebolt! Here's a good tech tip on 6V to 12V conversion; it helped me. It also covers pos to neg ground conversion. It might be helpful in figuring out what's going on with your truck, at least the ammeter reading. http://www.stovebolt.com/techtips/12_volt_conversion.html As far as the coil wired backwards, I don't know for certain. But if you're going to go to neg ground, just hook it up properly all the way through the system to remove doubt. Best regards, Bill
1947 3100 Advanced Design
Never, never, never, never give up. - Churchill
| | | | | Joined: Feb 2004 Posts: 29,819 Kettle Custodian (pot stirrer) | | Kettle Custodian (pot stirrer) Joined: Feb 2004 Posts: 29,819 | Yes, reversed polarity will make it run rough. it takes about 20% more voltage to fire the spark plugs from the "cold" side(the ground electrode) and most 6V systems don't have a lot of spark voltage to spare. Just change the battery cables around, and re-polarize the generator by touching a short jumper wire from the Bat. terminal of the regulator to the Arm. terminal for about 1/2 second. You'll get a moderate flash- - - -that's normal, not a short circuit. Crank up and drive on!
Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!
| | | | | Joined: Jul 2012 Posts: 10 New Guy | | New Guy Joined: Jul 2012 Posts: 10 | Thanks for the help. one piece at a time. | | | | | Joined: Apr 2001 Posts: 268 Shop Shark | | Shop Shark Joined: Apr 2001 Posts: 268 | Hotrod Lincoln is right about the generator/voltage regulator. For 6V Positive Ground.
Dance like no one is watching,
Sing like no one is listening,
Love like you've never been hurt.
1948 GMC FC101 1/2t Pickup w/270 and SM420
1948 GMC FC253 1t Factory 80"x9' Flatbed Dually
1948 Chevy COE 2 Ton 8'x15' Flatbed
1950 GMC 354-24 2 Ton 8'X12' Flatbed w/Dump Hoist
1953 GMC 454-30 3 Ton 8'x14' Flatbed w/Dump Hoist
1953 GMC 454-30 3 Ton Cab and Chassis
1942 Clarkator 6 MILL-44 Heavy Aircraft Tug
1942 Ford (9N) Moto Tug with 1/2 yard Loader
1947 Oliver OC3 HG-42 Tract-Crawler Bull Dozier w/6' Blade
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