Electrical questions 31 Deluxe Roadster

[old31]

1: Is the ammeter suppose to show negative when the key is turned on or when idling?

Mine shows zero, except when I turn on the parking lights, or high or low beam, then it registers different readings on the negative side.

2: Does the black wire go to the + or - side of the coil?

[Tom Wesenberg]

With a positive ground battery the black power wire should go to the negative coil terminal. The + coil terminal goes to the points.

The ammeter often times will show 0 or slightly minus when the engine is at idle. The generator should start putting out enough power to start charging the battery when the engine is running at 500 or more RPM.

[Rex_A_Lott]

Its pretty normal for it to show discharge when its idling with the lights on.

[Kurt in NJ]

If you were to read the owners instruction book you would find that it is normal to show a discharge both at idle and with the lights on

[old31]

Thanks, I did read the manual and that is why I am asking the question.

At idle I show 0 and not negative, so I thought there could be something wrong. I also thought that when the key is turned on it might show a quick negative, but it stays on 0.

Sorry, all dumb newbie questions.

[1ton]

Sponsored Links (Register now to hide all advertisements)

No such thing as a dumb question

[Mitch//pa]

Originally Posted by old31

Thanks, I did read the manual and that is why I am asking the question.

At idle I show 0 and not negative, so I thought there could be something wrong. I also thought that when the key is turned on it might show a quick negative, but it stays on 0.

Sorry, all dumb newbie questions.

If the points are closed the amp meter will show a slight negative when turning the key on...if the points are open it will stay at 0....

[100IH]

Shut the engine off and where it stops, no one knows. Will it come to rest with the points open or closed? Usually it comes to rest when the last piston, coming up on compression cant make it over the top. That's close to where the points are getting ready to open to end the dwell and make a spark. Also creates the situation where the same flywheel teeth always in the position to engage the Bendix on the starter. Most of the ring wear is at two spots 180 degrees across from one another on the flywheel.

[Tom Wesenberg]

Actually the coil wasn't wired into the circuit to show discharge when the points were closed, until late 1929. See Service Bulletins. I changed the coil feed wire from one terminal box post to the other so it would show on the ammeter, like the later Model A's.