Alternator hot to touch

[mattt]

I have a T4 2056 that has been converted upright and has a T1 alternator. I have always noticed that the alternator is very hot to the touch after driving or after the engine has been running more than 10 minutes. Is the alternator body being too hot to touch considered normal?

A few years ago, I believe I checked it's orientation on the tin and it was positioned with the inlet/outlet(whichever it is) facing downward. The belt is not overly tight and the belt alignment is good. I am wondering if this hot alternator is why the engine oil temp is very touchy about going above 200*....with it preheating the air going in the fan.

Looking for suggestions or confirmation that a hot alternator body is normal.

[Bruce Amacker]

Heat is the result of the alt working too hard. Common reasons could be a shorted battery, too many electrical accessories, or an internal short in the alt. If it is not working too hard I doubt it would be hot to the touch even if the tins were installed wrong. Check output after it's run a while with a DC amp clamp. Typically after running a few minutes the amp output should be under 5-7 amps. This is assuming you have no unusual electrical load on the system like a monster amp or other appliance. If the number is elevated check the amperage at one of the battery cables, it's usually 3 amps or less on a happy battery. The difference in alt output and what's measured at the battery cable is what the ignition system pulls (usually 2-3 amps on a point system). If it's 10 amps or more at the cable, the battery is either low on charge or internally shorted.

I've seen shorted batteries many times when I had the shop causing hot alternators on trucks.
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'66 Deluxe Bus
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'65- http://leakoil.net/forum/viewtopic.php?f=23&t=4263

[mattt]

Thank you for the reply. This car has a light load, just the engine and a couple gauges. It has done this with a few different batteries. Is there a way to tell if the alternator has an internal short?

I guess I need to figure out what a DC amp clamp is.

Thank you.

[Bruce Amacker]

[slalombuggy]

Look carefully at your wires and cables they are at least 40 years old . Eventually they start to break down. Also if you have a multi meter, put it on the AC voltage scale and test the B+ wire coming out of the alternator. Any more than .5 of a volt and you could have a diode failing.

brad

[Pruneman99]

Backing plates installed correctly?

[Bruce Amacker]