68 Issues

When installing a new 100 amp 1-wire Powermaster alternator, I ran a new 8-gauge wire from the alternator to the starter with a fuse between the two. Right now, the original + wire from the alternator is not connected at the starter, just the new one. The original +wire and the new wire are connected at the alternator. Was the new wire supposed to replace the original wire coming from the alternator to the starter or be in addition to it?

The reason I am asking is when I started the car and let it fun for a while, (after running up the engine speed to "excite" it), the new alternator seems to be getting REALLY hot. Also, the ammeter in the car just barely moves at all when the Spal fans kick on and the bright headlights are on. The guy from Powermaster said that the ammeter would not really be accurate after I installed the 1-wire alternator but that I would at least be able to see if it was discharging or charging. As it is, I would wreck the car trying to see the ammeter needle move it is so subtle.

Any help would be appreciated.

7t9l82

the second wire is in addition to the existing, i suspect it isn't carrying the load and the alternator is getting hot. I'm sure our electrical experts will chime in.

MelWff

not clear on why you felt you had to run a new wire, why didnt you just connect the existing large red wire to the alternator output post. You werent specific as to which alternator you have but these are a sample instruction sheet from Powermasters site

http://www.powermastermotorsports.com/001___IS_ALT.pdf

DC3

The original wire needs to be connected for the ammeter to work. Either that or you need to relocate the leads of the ammeter from the original wire to the new wire but knowing where to connect them in order to properly calibrate the ammeter would be a tall order.

By running both wires, the ammeter will only read the portion of current flowing through the original wire so it won't be accurate but should work well enough for you to tell the direction of current flow.

I added an 8 gauge charging wire when I upgraded to a CS144 alternator and used the ammeter as is for awhile but later converted everything to Auto Meter gauges and replaced the ammeter with a volt meter.

DC

68 Issues

Thanks all. I really appreciate the information. Tomorrow I will reconnect the original power wire to the starter. Hopefully that is the cause of the excessive heat along with the ammeter not working. It will be great to get this straightened out before I fry the new alternator.

DC; does your aftermarket voltmeter actually replace the ammeter as in does it now reside in the same location that the ammeter once did or is it installed somewhere else?

DC3

Yes, my new volt meter is in the same location as the old ammeter. I replaced all gauges including the speedometer and tachometer with Auto Meter Sport Comp IIs.

Some have replaced the ammeter with a volt meter from a mid '80's Chevy pickup. Supposedly is a pretty close match looks wise.

Others have had a repair service convert their ammeters to volt meters. Search the forum as there was a recent thread about this.

DC

68 Issues

DC,

When I bought my car, it already had an MSD ignition system so it does not have a tach drive and therefore no working tachometer....which bites. Is your new tach cable driven or electronic? It would be really nice to bring the tach back to life without replacing the MSD system.


Kelly

DC3

My new Auto Meter tach is electronic. But, here's another option for you. The previous owner of my '73 converted the original mechanical tach to electronic by sourcing a '75 tach and then putting the face from the '73 tach on it.

DC

7t9l82

here is a question i have not seen, some say to upgrade the line from the alternator to the starter solenoid and others say go from the alternator to the horn relay would it hurt to do both?

toddalin

Would throw off the amps gauge. Needs to go to the horn relay for the amp gauge to function properly. And, you can't upgrade the wire between the battery and horn relay or that will throw off the gauge.

DC3

I did both. An alternator upgrade by itself doesn't really need the charging wire to the starter upgraded. It's all about the load the alternator and battery sees.

If you're upgrading the alternator to handle additional accessories such as dual Spal electric fans, adding AC, a new stereo, etc and you can take power for all new accessories directly from the back of the alternator, you don't need to upgrade the wire at all (assumes you won't need to power those accessories from the battery with the engine off). If you want to tap the horn relay for the new accessories, you should upgrade the wire from the alternator to that horn relay.

I did both so I could tap anywhere I wanted for my new electric loads and to allow the battery to have sufficient wire capacity to feed those extra loads when the engine is off and the ignition switch is in the accessory position.

As was said, adding a new charging wire will cause the ammeter to read low because it is now only metering the current flowing through the original wire and none of the current flowing through the new added wire.

DC