Hi Guys,

I've been here before looking for help on this subject and I think I'm FINALLY narrowing it down, LOL

I have a 67 f100 with a 6 cyl 300 engine... I need to know what amp alternator belongs in this truck. It is NOT a 240 and it's bare bones, no options at all.

Also, I was sold a 40 amp alternator and I've been told I need a 60 amp. Are the inner workings of a 40 amp alot different than a 60?

 

hi man

i have a inline 6 cyl 300 and it is
not a 40 amp it is a 15v 60 amp
or that is what my is on my truck.

 

The 40 amper will probably run the truck, but when ya start adding accessories like extra lighting, music players, etc. they will require more juice than a 40 amper can produce. You will need an alt. sized to meet your requirements.

A radio wont have much draw, but a stereo putting out 60 watts per channel will. Start adding amps and other things and that adds up quickly.

hope this helps a little.

John

 

I know stock they ran about 35-40 amps, from working in parts departments. I was going to post the stats for the OEM, but, can't find it. I know from my 1990 spec book, the lowest rated alternator was 60 amps. I posted a curve chart from it earlier this month for the 140 amp alt.

The reason for 65 amps is it is about a bare minimum for using halogen headlamps, stereo, trailer lights, and A/C like many people do.

What jowilker mentions is the main reason noone offers lower amp alts any more. A radio does not have much draw, put a stereo running 60 watt speakers will make an stock sized 40 amp alternator run full out with lots of spikes.

Whatever was in my truck I am replacing with one I bought, 65 AMPS and $38 with lifetime replacement from Advance Auto Parts. I am already running heavy guage wire so I have no need to replace the factory wire. I have modest needs because I have no stereo or radio.

I put almost all my lamps on relays, except the headlamps, so the only weak lnks left in my truck where the low amp alternator and headlamp switch.

 

Thanks for all your input guys

I still can't figure out what's drawing my battery down though, if it sits over night the battery is dead in the morning and last week my batt, stank of sulphuric acid, a sign of overcharging. It's really weird.

 

Stuck voltage regulators have been known to cause this. It can cause the battery to boil over.

John

 

Can you get brand new, high quality voltage regs from ford? I've put 4 in already but I have no way to know if they're working or not...Anyone know how I can test one? I just bought a multimeter, itching to pretend to know how to use it :P

 

I would get a "one wire" alt. they have a built in reg. all you have to do is hook up one wire to the pos. side of the battery.