[south65ss]

I just replaced all the wiring from the firewall to the front of my friend`s 71 Pontiac Lemans. Had to do it because the wiring was a real mess. Lots of dead wires and useless others everywhere. Now all works good but seems like the alternator gets really hot after few minutes of use. I connected the charging wire to the junction block next to the radiator, the number 1 wire to the dash light and the sensor wire to the junction block too. The alternator is the old external regulator Delco and the battery is in the trunk but with heavy gauge wire. There`s nothing in the car using much amps or volts so I`m a little lost here. Any clues?

[msilveira]

Hi,

Check the grounds (primaries) to the engine and chassis.

Check (or double check) the voltage regulator-- they are known to have lots of issues related to overloading alternators.

Check the grounds for the batteries in the trunk.

This link to Fluke's website is http://assets.fluke.com/appnotes/aut...e/beatbook.pdf

Good luck,

Matt

[DanielC]

Here is another good site for basic auto electrical:
http://www.vernco.com/Sparks/id606.htm

[ericnova72]

The old external regulator alternator needs to be wired with a external voltage regulator.

The way you have it wired will work for an internally regulater alternator but right now you have no voltage regulation on your external alternator, which is why it is overheating.

[south65ss]

Sorry, the alternator is an internal regulator. My fault!
The grounds between body-chassis-engine are new, several and of good gauge. Maybe the body of the alternator isolated from the engine with paint?
Will check the internals of the alt cause it was under the rain at least twice.

Thanks a lot!

[SSedan64]

This may help>> http://www.madelectrical.com/electri...evymain1.shtml
Other help>> http://www.madelectrical.com/electrical-tech.shtml

[lg1969]

The reason the alternator was not overheating it’s because the electrical wiring was inefficient. You had loses do to resistance in the wiring. Alternators will generate heat as high as 150°C or 300°F. If the battery is not fully charge it will draw large amount of current. It’s ohm’s law.(Watts = Volts X current). Watts is heat. The alternator is pulling more current. The halogen headlights, high-powered stereo sound system and air conditioner will cause a lot of heat to generate at the alternator. Be careful with the fuse panel connectors especially on older cars. Once they loose grip it will overheat and oxidize to the point of electrical failure.

[DanielC]

If the battery was not fully charged, because of the poor wiring, once you renewed the wiring, the battery would take a pretty good charge for a while. this would work the alternator, until the battery got fully charged, and then the alternator should run close to normal temperatures.