The Ford Barn

BFD · 07-11-2010, 08:56 PM

My Dads 1929 A We are putting it back together . When trying to get it to start the ammeter was very hot The wire caps would burn you. the car has a new wiring harness. starter and generator and ammeter are all on the car originals from before the restoration double checked the wireing Would the ammeter be bad or some other problem THANKS

MAG · 07-11-2010, 09:18 PM

Remove the wires from the meter and tighten the nuts on the two posts. Re-instal the wires. It's a common problem. The heat is caused by current flow in the loose connections

PC/SR · 07-11-2010, 09:56 PM

Current will flow when the points are closed, and Ford later changed the wiring so the flow would show on the ammeter. (Service Bulletins, pg 390.) It should only be a few amps. If you have more that this you have a problem somewhere. The terminals should not be hot if tight as Mag mentioned. I changed the wiring to put the ignition switch in the circuit before the coil. It does not change the current flow but reduces the possibility of a short across the terminal box or elsewhere while you are sleeping, because otherwise the primary system, through the coil, up to the switch, is hot all the time. I also separately fuse the lights wire harness. That way not everything will blow at the same time.

BFD · 07-14-2010, 08:25 AM

Thanks for the replies. The posts on the ammeter are tight it still gets hot . Should the meter go to discharge as soon as you turn on the key The cut off switch has been replaced aslo no change.

Tom Wesenberg · 07-14-2010, 08:49 AM

No, the amp guage should not go to discharge as soon as the key is turned on.

If the points are closed the amp guage should go to -4 to show the current going through the coil and points to ground.

It sounds like the ignition switch is shorting to the gas tank if it's a repro switch, or the wire inside the cable may be shorting to ground if it's an original popout switch and cable.

Disconnect the power wire from the coil and see what the amp guage reads. IF it still goes to discharge, you know it's the switch or wire comming from the switch.

steve s · 07-14-2010, 08:58 AM

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Quote:

Originally Posted by BFD

Thanks for the replies. The posts on the ammeter are tight it still gets hot . Should the meter go to discharge as soon as you turn on the key The cut off switch has been replaced aslo no change.

The ammeter should show a few amps discharge as soon as the key is turned on IF the points are closed (as PC/SR said). Most of the time that will be the case.

Are you sure that you checked for tightness of the bare post; not just the nut that holds the connecting wire? If so, it sounds like something is loose inside the meter. I would order a new meter. You can still drive the car without the meter, if you want to. Just clamp the two meter wires together with a wire nut. If you're worried about maybe burning something up, you could wire a fuse in the place of the meter.

Steve

07-11-2010, 08:56 PM	#1
BFD Junior Member Join Date: May 2010 Posts: 17	Ammeter My Dads 1929 A We are putting it back together . When trying to get it to start the ammeter was very hot The wire caps would burn you. the car has a new wiring harness. starter and generator and ammeter are all on the car originals from before the restoration double checked the wireing Would the ammeter be bad or some other problem THANKS

07-11-2010, 09:18 PM	#2
MAG Senior Member Join Date: May 2010 Location: Austin, Texas Posts: 925	Re: Ammeter Remove the wires from the meter and tighten the nuts on the two posts. Re-instal the wires. It's a common problem. The heat is caused by current flow in the loose connections __________________ I noticed the harder I work the luckier I get!

07-11-2010, 09:56 PM	#3
PC/SR Senior Member Join Date: May 2010 Location: Santa Rosa, CA Posts: 1,279	Re: Ammeter Current will flow when the points are closed, and Ford later changed the wiring so the flow would show on the ammeter. (Service Bulletins, pg 390.) It should only be a few amps. If you have more that this you have a problem somewhere. The terminals should not be hot if tight as Mag mentioned. I changed the wiring to put the ignition switch in the circuit before the coil. It does not change the current flow but reduces the possibility of a short across the terminal box or elsewhere while you are sleeping, because otherwise the primary system, through the coil, up to the switch, is hot all the time. I also separately fuse the lights wire harness. That way not everything will blow at the same time.

07-14-2010, 08:25 AM	#4
BFD Junior Member Join Date: May 2010 Posts: 17	Re: Ammeter Thanks for the replies. The posts on the ammeter are tight it still gets hot . Should the meter go to discharge as soon as you turn on the key The cut off switch has been replaced aslo no change.

07-14-2010, 08:49 AM	#5
Tom Wesenberg Senior Member Join Date: May 2010 Location: Mpls, MN Posts: 27,582	Re: Ammeter No, the amp guage should not go to discharge as soon as the key is turned on. If the points are closed the amp guage should go to -4 to show the current going through the coil and points to ground. It sounds like the ignition switch is shorting to the gas tank if it's a repro switch, or the wire inside the cable may be shorting to ground if it's an original popout switch and cable. Disconnect the power wire from the coil and see what the amp guage reads. IF it still goes to discharge, you know it's the switch or wire comming from the switch.