Can You Upgrade A 37amp Alternator?

[6T5RUSH]

Hello,

Seriously thinking of installing a Vintage Air or Classic Air setup on my small block. I know I'll need to upgrade my copper/brass radiator...maybe a DeWitt's (he's got a group purchase going at the other site). Got to thinking about the electrical demand of these units. My '5 is a base car...only power is to the antenna.. and has the stock 37 amp alternator. I'm sure I'll need to upgrade it. Just curous, can these be rebuilt so they'll handle the added load? Would I be overloading the stock wiring harness in doing so? There's a local shop that's been around the metro Detroit area for years, Suburban Electric on Gratiot near 13 Mile. I know they'll do a rebuild of your unit. Just curious if anyone has gone this route and addressed the added electrical needs.

Appreciate any and all responses.

Thanks!

Jim (6T5RUSH)

 

[IH2LOSE]

Jim

A quaility rebuilding can build the alternator to practicly any resonable size you want. I have owned a pick up with a plow on it since I been driving.And normally the first thing modification is having the alternator built up to 100 amps,and dual batteries installed.(the 03 chevy plow truck I own now all ready came with a beefed up electrical system so NO MODS were needed)

As for the wiring just make sure its in good stable condition with clean connectors.The alternator will only produce what you draw off it.I have an older cadillac with a elaborate stero system in it with a high output alternator that I had built I had to install some heaver wires to handel the draw of the amplifiers.(its like a secound wireing harness that can be removed if the next owner of the car doesnt want it) In your case if your just adding a/c I would not be concerned with it.

If I was you I would go thru the option list for your year car and see what alternator the general suggested with a/c and built it to that.Or if your not concerned with originality go the the local auto parts store and purchase a rebuilt alternator and just pop it on and forfit the core charge to keep the one you have with the car.

Good luck and enjoy your New A/C system

 

[ctjackster]

you are gonna want the twin electric fans, wired up so they only come on when car is in "run", they can be installed right up against the rear of the rad with no interference with the enigne fan - point is that the elec fan kit (VA sells one) will draw the kind of amps that will require an alt upgrade - my advice - if you have the correct for your car, dated, etc. alt on there now, take it off and store it, and buy a new GM alt in the proper amp range and put that on - the case looks the same, 'cept it ain't pn and date stamped in the old spot.

 

[magicv8]

135 amp alternator 1 800 607-0016 $70 at Alterstart 4alterstartcom.verizonsupersite.com

I put one of those in my 66. I added 2 60amp stinger fuse holders to protect the harness without ANY mods to the harness or body.

You can see the bracket for the Stingers at the Details page, linked off my homepage (shown below).

 

[ArkShark]

I just recently purchased the 135 amp from alterstart...got the Chrome version.

They suggest you upgrade your wiring from the battery to the alternator, since you will be drawing more amps.

The only problem I have now is that this alternator charges at a lower RPM then what I currently have set. So, the "GEN" light comes on all the freakin' time. (at stop lights, or when I just warming the vette up).

I can up the idle, and they should help, but I guess it doesn't bother me that much...

And, I believe that 135 amp alternator charges at 650-700 RPM. Mine idle is set at 500.

 

[ctjackster]

thankfully 6T5Rush has only two "early design" idiot lights - the flashing "Lights" for when his lights are on and his lights are not fully up, and the flashing "Brake" for when his handbrake is on and the key is in "run" - nice round faced gauges otherwise

plus I have yet to see the C2 SB that can idle at 500 . . . . ! One smooth engine there, ArkShark!

 

[6T5RUSH]

Hey Guys,

Thanks for the responses. Appears the best approach w/b to mothball the stock 37 amp alternator, (it's the original I had rebuilt years ago) and buy that 135 amp alternator magicv8 & arshark did. For that kind of money it makes sense.

So, the fact that all my wiring harnesses were replaced with brand new ones many moons ago should eliminate the detioration/time issue. My only concern now is is there a difference in harness "strength" for the non-air harness vs air harness? In other words, can I use the existing non-air harness and just go the route magicv8 did by installing these Stinger fuses? Magicv8, I may ask you to "walk me through" how you did this without disturbing your original harness. Didn't I read somewhere on your site that your car was originally an air car? Would your harness then be different, read this, able to handle the load better?

Thanks again IH2LOSE, CTJACKSTER. and ArkShark!

 

[wallyknoch]

A 63 amp GM alternator was available for the AC cars and is a direct fit. Simplest way.

 

[VAroute66]

Your AC conversion sounds great. When I was looking at electric fans and water pumps for my car I stumbled across this website: http://www.madelectrical.com/index.shtml. They discuss how to integrate a high output alternator into 60's cars electrical systems and essentially bypass the weak stock wiring with a special junction block that safely ( uses fuseable links) distributes power more directly and with less voltage drop. It also discusses one vs. three wire systems and amp vs. volt gages. An alternator will only supply what the system demands, but if your battery is low, the demand could be very high. You might also consider the 140 amp PowerMaster unit that can be used with either one or three wires. It seems like the best thing is to go with the better regulation of the three wire system and a voltmeter. Best of luck!


Dan

 

[magicv8]

" Didn't I read somewhere on your site that your car was originally an air car? Would your harness then be different, read this, able to handle the load better?"

The engine harness is the same. A-C gets an added harness that replaces the fan and blower control connectors, and provides power and compressor connections. I used a 1 inch wide piece of aluminum to hang 2 stinger 60 amp fuse holders from the regulator mount bolts. I dropped a line to each 60 amp fuse, and stuck an alternator electrical post in the other end of the fuse holder - in place of a wire (see my web Details page). The alternator connector lets me bolt my original harness connector to the fuse holder with no harness mods - even the rubber boot fits on the holder. If the battery needs more than 60 amps, the fuse will blow, but it beats losing the harness (that's why I installed it). The other 60 amp fuse powers all the rest of the nonstock electrical stuff in the car.

 

[6T5RUSH]

wallyknoch: Thanks! I'll be sure to check the "general" against the aftermarket competition.

VAroute66: Well, I ain't close to installing the A/C but I'm well on the way to converting my hydraulic setup to solids (going the LT1 cam and GM edge orifice lifters route). Spent this past week taking things off the motor. Hood off, battery disconnect, alternator, fan and fan clutch, radiator drain, hoses, shroud and radiator out. It's a laundry list so I'll stop here. I really enjoy wrenchin' on her. Hope to have the carb and intake off then it's on to the front of the motor tomorrow. When I'm done I'll start a thread comparing overall driveability and performance...before and after. Hey, thanks for the electrical site tip. This may do the trick.

magiv8: Thanks for that insight on the engine harness. Having your pics saves a lot of words!

This is one topic I'm printing off for my library/reference.

Thanks again!

Jim (6T5RUSH)