General MG elect. prob.

[Mickey Richaud]

May not be relevant, but IF you're distributor has been converted to electronic and points were done away with, it won't like positive ground. If you still have points and condenser, no worries.

 

[Louis 52MGTD]

Thanks Mickey,
I did copy an article here on how to change from a pos. ground to a neg. ground and thought about just reversing it, but I'm very weak on anything elect. I will ck to see if it's still points or elect. if it is still points I guess I could remove the radio and follow the artical in rev. it does mention changing a wire on the gen. and on the coil and rev. the wires on the amp.meter and of course the two batt. cables. does that sound ok ?

 

[NutmegCT]

Hi Lou - just so we're talking the same language, is any voltage being produced by the generator? Have you actually measured the generator output, directly from the generator? or are you just referring to the ammeter not showing any changes in current?

Thanks.

 

[Louis 52MGTD]

Tom,
I tried to get a reading off of the gen. it was bouncing all over the place from 1.5 to 13.00 but mostly on the very low side, 1.5 to 4.4.
I did do a 30 minute drive today, the amp meter stayed on neg. charge, I just checked the batt. voltage, it was 12.30V, this is after two other 20-30 min drives without a trickle charger in between. I did swap the post on the gen. same results. all over, would not settle down.
I did turn the head lights with engine running and with the engine off, same thing neg. charge even more, but the amp meter did move a lot.

 

[NutmegCT]

Thanks Lou. Right now, I'm betting the generator brushes need replacing. Brushes are on page 55 of your operation manual. Not a difficult job -

You can get new brushes from Moss Motors, or many other online sources. And you've probably got a "electrical starter and generator" repair shop within fifty miles of where you live.

When you say the ammeter did move a lot when you tried the lights on/off thing, it's probably ok, but may be wired for positive, not negative ground.

Hope this helps.
Tom M.

 

[YakkoWarner]

I never had a car old enough to worry about positive ground, but my practical inclination would be to stay negitive ground if it has already been switched over, for no other reason than consistancy with the rest of the automotive world. A true show-grade restoration would want to have the car in perfect original form, but with positive ground being so uncommon these days the risk of confusion if anyone other than yourself does anything with the car seems really high and there isn't any advantage to positive ground (unless its a show-level restoration where having it correct means earning points in judging). Any kind of radio, aftermarket gauge (even just for testing purposes), diagnostic tools. etc will normally expect a negative ground.

 

[Louis 52MGTD]

Thanks Lou. Right now, I'm betting the generator brushes need replacing. Brushes are on page 55 of your operation manual. Not a difficult job -

View attachment 89764

You can get new brushes from Moss Motors, or many other online sources. And you've probably got a "electrical starter and generator" repair shop within fifty miles of where you live.

When you say the ammeter did move a lot when you tried the lights on/off thing, it's probably ok, but may be wired for positive, not negative ground.

Hope this helps.
Tom M.

Thanks Tom,
I will try that in the morning, I don't know when or if the brushes were ever checked like the book says, I hope it is something simple like that, I will let you know tomorrow.

 

[Louis 52MGTD]

Tom,
I removed the insp. clamp to check the brushes, no insp. hole ? maybe a more modern gen ? I guess the clamp was left on for looks ?
Here's a few pic's, but it does take the tach. hook up.
I guess I'll just have to pull it off and take it to a gen. repair shop.

 

[NutmegCT]

If you've not opened up a generator before, I think a trip to the generator shop would be the next step. At least then you'd know if it has a problem, and you'd have someone to fix it while you wait if needed.

Tom M.

 

[Louis 52MGTD]

Thanks Tom, That's what I'll do. I'll get back.

 

[Louis 52MGTD]

I just gave up on getting my bad gen. fixed, the gen. shop could not find the right parts so I ordered a gen. from Moss.
The told me I would have to polarize the new gen. anyone know which of these post on the reg. I need to jump for a second ? the car is a neg. ground. thanks for any help. Louis.

 

[NutmegCT]

Seek and ye shall find!

 

[Louis 52MGTD]

Tom,
Thanks for the video, that makes it simple.
That is good for a pos. or neg. ground right ? some one changed this car to a neg. ground.

 

[Louis 52MGTD]

If I'm rambling on to much, please let me know.
I got my new generator from Moss this morning, after around two hour's of work and mostly hunting the right tool's I got it installed and polarized.
I took it for a test drive and I guess I'm happy ??? It is the 1st time I have seen the amp. needle go to the plus side of "0"
It takes around 3500 RPM to get it past the "0" to charge, and when I'm driving at aprox. 4000 RPM it stay's in the charging side all the time, and when I stop for stop sign the amp. meter shows a slight discharge until I get it back to around 3500-4000 RPM.

Even if it's not right at least I get to drive in without staring at the amp. meter reading discharge all the time.
Thank everyone for the great advice.

Now I can start on why my brake lights stay on after a drive with the ign.sw on and engine off, but it's gone out in the morning when I cut the sw. back on.

I knew it had a few minor prob's. when I bought it, but I wanted something to do, And it's doing an outstanding job.

 

[NutmegCT]

I'd doubt that many BCFrs bought a car without problems, so you're fitting right in.

The 3500-4000 rpm should give you more than a slight positive on the ammeter. But a slight negative at idle is perfectly normal. Could be your voltage regulator, or your fan belt tension, needs some adjusting.

Tom M.

 

[Louis 52MGTD]

When driving at about 4000 RPM [about the speed limit] and cut the head lights on the amp meter does jump even more to the pos. side of "0".
The needle does bounce around a lot, thinking some the prob. might in the meter ??
I'll watch it for a few days, at least it does show a + some of the time

 

[NutmegCT]

Whoa - you say the ammeter jumps more to the positive side *when you turn on the headlamps"?

Should go toward negative, not more positive.

So we're back to the ammeter wiring situation. Was it ever rewired for negative ground, etc.

 

[Louis 52MGTD]

Tom,
Let me reword that, while driving at 4000 rpm the amp. meter shows that the generator is charging, when I turn the head lights on the amp meter shows a fast drop then pick's up the charging again, slightly more then before, I figure the Voltage reg. read the new load from the head lights and adjusted for it?? don't know ? electrics is my weak area. but the batt. is staying charged, and with the engine off and just the sw on and turning on the head lights the amp. meter does jump to the far neg. discharge, when I cut the head lights off, the amp meter goes back to "0" again, so I feel pretty sure the amp meter wires are right.
Any way it seems to be charging for now, I will just keep an eye on it for a few day's. The amp meter look's to be org. [71 years old] it might be the prob. every thing wear's out at some point. it does bounce around a lot.....But, I'm happy for now.

 

[NutmegCT]

" ... amp meter shows a fast drop then pick's up the charging again ..."

OK - that's the clue. This sounds completely normal.

So crank it up and go enjoy some rural Georgia driving!

Tom M.