3G Alternator Swap with Questions

[drdano]

I managed to get a 3G 130amp alternator from a 90's police Taurus (yea, that's a laugh in itself) that a fellow FE'er was parting out.  Right now, I've got just the alternator as it came off the car before it was squished and about half of the fat battery lead, no mega-fuse.  This model is the larger distance between the two mounting ears

My '62 Galaxie is currently running the OEM generator and the purpose of this swap is to open the door to more power electrics like fans, fuel pump, possibly water pump down the road, etc.  I have an alternator bracket set from a 60's FE, a crank pulley to add to my balancer that would give me dual belts if needed.

I'd like to know from others how is best to proceed regarding the pulley?  How many of you are successfully using a single belt and who's found they have to go to a dual belt?  In either case, what diameter pulley should I be looking for?  Larger is going to be better for the single belt in my mind, but perhaps the 3" units I've seen online are adequate if you use a good v-belt? 

Regarding the generator idiot light on the dash, I do want to keep this if possible.  Is this actually going to trigger the idiot light if the alternator stops working though?  The schematics I'm seeing show to bypass the bulb itself with a 500ohm resistor so that if the bulb burns out the alternator doesn't shut off. 

Thanks all.  I'll update this thread as I progress

[jayb]

I use Powermaster 3G style 200 amp alternators on my cars, like the one in the link below:

http://www.summitracing.com/parts/pwm-47760/overview/

They come with a 2 1/4" diameter 6 rib belt pulley, and I've usually replaced this with a dual groove 2 1/2" pulley.  I've found that the two groove pulley is an absolute minimum for turning one of these, and even with two belts I get a squeal out of the belts on startup, no matter how tight I make them.  The first time I tried one it was with the single groove pulley, and the belt squealed way, way too much.  Since yours is 130 amp I'd expect you to have less of an issue here, but I still think it would be best to run a dual groove pulley on that alternator.

On my Mach 1 last year I bit the bullet and installed a six groove crank pulley to turn the alternator.  With that setup there is no squealing at all on startup, and I can keep the belt tension to a reasonable level, rather than having to tighten the heck out of it. 

I don't know if you will be able to keep the generator light or not.  Do you have a schematic of the charging circuit for your car that you can post?  I'd be happy to take a look at it to see if it may be possible to keep the light in the circuit...

[afret]

You probably need a double pulley with that alternator.  PA performance told me to use a 95 amp unit for a single belt.   So I got a 95 amp 3G with a 4" single pulley.  It handles 3 electric fans, electric water pump, electric fuel pump, and MSD no problem.

[thatdarncat]

I switched my bracket race car to a Ford 130 amp 3G a few years ago. Initially I used a normal size ( about 2 3/4" ) single groove pulley and not only was it constant squeal, but it would actually melt the belt. I switched to a 4" pulley like they sell as the 289 hi-po/ Boss 302 reproduction and that works fine as long as it is adjusted tight. If you wanted the smaller diameter pulley you will need the double belt pulley or the 6 rib sepentine style like Jay mentioned. Watch too, since the 3G is designed for a serpentine style pulley the shaft doesn't stick out as far, some dual belt pulleys aren't machined deep enough where the nut goes. They could be machined deeper though. The 3G works great though, the swap is well worth it.

[drdano]

Thanks for the info folks.  Yesterday I go the alternator tested and it passed a-ok.  Belt wise, I only have a single belt right now just for the generator and no other accessories.  I do have a crank pulley that will bolt to the balancer and make it a dual belt and I could get a dual belt pulley for the alternator. 

thatdarncat, is this the pulley you are referring to? http://www.mustangsunlimited.com/itemdy01.asp?T1=AP11+01&Category=Ignition%2FElectronics&subCategory=Alternators+%26+Related&CatKey=EMUSTANG  I already have to adjust everything pretty tight as is, so this could be a way to go or at least try.

Jay, this is the schematic for the generator light circuit on my '62 Galaxie:


Here is the schematic out there for doing the 3G alternator swap that shows bypassing the GEN light with a resistor:


I've read the only other change to make to this 3G schematic is to wire the yellow A connection to the alternator side of the mega-fuse so it loses power if the fuse burns out too.  Thoughts on this?

Finally, regarding the squeal on start-up that some folks have.  Does this occur if the alternator is not powered on with ignition and powered after start up?  Say a toggle to power it after engine is started might be a workaround the issue?

[jayb]

Oops, forgot to respond to this.  I think the warning light circuit shown in your diagram will work fine - Jay