alternator numbers

[fordman]

where are the numbers on the alternator that say what amp they are? i know what they should be amp wise but i need to find out for sure before i say it is this or that. i thought they were on the outer case but i couldn't find any numbers on any of the alts i have here.

[fordman]

now thats wierd.

[Dragon]

On original Autolite Alternators the ID plate color tells you the amperage!

Alternator data.jpg

[fordman]

is that plate on the back of it or something? maybe in the center of the bearing hub? they are autolites. i dont ever remember seeing any plates onthem the other day.

[Dragon]

By now there are no tags. They were on the back attached to the case bolts, they laid flat on the back. Aftermarket alternators that I have bought have 65A or 61A stamped in them. Rare though I have only replaced one Alternator in all the Fords I have owned and at the dealers I worked for.

[fordman]

great. no luck on any tags on the 3 i just looked at. one of them still ha the wires on it the other two didn't but the two that didnt had rebuild stickers on them that were different colored. i don't know if that meant anything. they had the auto parts store part number in the middle of the sticker. but they are all motorcraft. on sticker had red trim the other had black trim. the third one had nothing.

[SteveC]

mine had a sticker on it when i cleaned off alll the grease and grime during rebuild.
wanna say it said either 32 or 38amp

[Dragon]

What kind of truck? Stock almost all trucks were 65A

[SteveC]

67 f250 with a 352

[QC]

My '69 has a 35 amp. Even with AC they were only 55 amp.

[fordman]

What kind of truck? Stock almost all trucks were 65A

well its not any trucks anymore. it is a shelf full of them. they all came off of trucks before but i don't remember which one is which. one of them is also off of a galaxie or ltd from 68. its on the shelf with the others. i ha some one wanting to know what i had. i couldn't tell them for sure.

[Dragon]

67 f250 with a 352

Should be a 65 the real small amp ones were for 6 cylinder Falcon and Mustangs

[SteveC]

next time i have it off of there ill take a picture... i could be missing something but i swore it said 38amp

I know that with the truck idling the volt gauge jumps from 14.4 clear down to around 10-12 just with the turn signels.

Now just imaging having the wipers on high, lights on and the heater going full At idle that needle drops down to around 10 and stays there all the lights dim at this time as well.

This happened the last time it rained cats and dogs here... ill get a picture cause this is interesting, i also if i remember correctly it had a date code on it along with a motorcraft sticker

[fordman]

that would be cool to see a picture of cats and dogs.

[Dragon]

Someone might have switched it out. If you look at the numbers I posted the 38A start output at 400 rpm and is full output up in the 2000 range.

A 65A starts output at 360 and is at full output at 1640 rpm a distinct advantage.

When I do a search on Ford alternators (stock) I don't find any less than the 61A and the 65 was used into the 80s.

If you got a 38 no wonder it drops so bad. If it kicks in at 400 and is full at 2000 that is a 1600 rpm rise for a 38A rise and if you are at 700 at an idle you are only putting out 7.125 amps.

Voltage drop is 14.4 to 10 worse case. E/I=R so 4/7.125=.561 resistance which 4 1157 turn elements in parallel approximately comes to. That works out right for you having a 38 A alternator.