Maybe Altenator issue?? Need help

[Automan]

65 amps alternator. early to mid sixties type

[jhv48]

There's the problem. Most cars have at least a 90-100 amp alternator. Yours can't keep up when all the accessories are on.
Fans alone can eat up 50 amps. Add the headlights and you're maxed out. Time to upgrade.

[Automan]

So i currently have a Remy 20155. Thats the part number. I have 3 leads going to it. I should probably get this one rebuilt to put out more amps.

[Automan]

My setup is very basic. 427cid with points distrubutor with a electronic module inside. Dual 650 holley carbs. No fuel injection. Mechanical fuel pump and no heater or radio.

[Automan]

This is the Fan shroud that i installed.

Branderale Cooling Products
Manufacturer's Part Number:16822
Part Type:Fans, Electric
Product Lineerale Performance High Output Single RAD Fan and Shroud Kits
Summit Racing Part NumberER-16822

UPC:083277168222
Maximum Fan CFM:2,400 cfm
Fan Quantity:Single
Fan Diameter (in):17.000 in.
Height (in):17.625 in.
Width (in):22.250 in.
Thickness (in):3.000 in.
Number of Blades:11 blades
Blade Material:Plastic
Blade Color:Black
Shroud Color:Natural
Shroud Material:Aluminum
Amp Draw:23.50 amps
Air Conditioning Relay Included:No
Mounting Brackets Included:Yes
Mounting Hardware Included:Yes
Quantity:Sold individually.
Notes:Two speed motor, 1,800 cfm at low speed drawing 17.4 amps.

[DanEC]

Well, the headlights probably pull up to 20 amps on high beam, less on low beam. That combined with the 23 amp fan and tail lights, parking lights, dash lights, etc would probably be marginal with a stock alternator at idle. It could also be that your alternator is a little on the weak side. It might be a good idea to pull the alternator and take it down to an auto parts store that can test it and see if it's putting out like it should. I would also check all your grounds to make sure they are good. And, I would check the temperature of your wiring to the fan when it's running. If it warms up considerably, possibly it's too small of gage for that fan load and pulling an excessive load on the alternator.

[RICK LAKE]

Automan Are you running March pulleys? Are they under driven? This is problem #1. Alt is not spinning fast enough to both recharge the battery and running the whole electrical system. 65 amp will run a basic cobra car without alot of extras. You need to take the ALT to a Autozone and have them check the MAX output of the ALT. If it's passing the test Want to see 60 amps min. This will work if you are at crusing speed, say over 1,500 rpms on the motor. Wouldn't run everything at 1 time.
Pulleys, if you are running any underdrive pulley setup on the crank shaft, this is another big problem. The Alt is spinning too slow and can't charge the system and the battery at the same time. You may be getting only 25-30 amps and need a 40-50 charge to keep everything with the correct voltage to system. You should have a 1-1 ratio on the crank pulley and waterpump pulley and about a 2-3" Alt pulley. Underdrives are for racing, 1/4 mile cars, or show cars. They work boardline when cruising( depending on rpm range).
Wiring last thing, Make sure you have a fusable link in the output cable of the Alt. I like a 150 amp fuse and #8 wire in copper.
I run 3 coolant fans, 3 blower fans for heat, 2 fuel pumps, ECU, fuel injection system, Lights, MSD igntion. I have gone to a PA preformance setup. They sell a kit that hooks up to your Orginial harness with voltage regulator box and heavyduty output cable. I went to a 95 amp setup and it powers everything. You CAN'T run a amp gauge with this setup. IT melts the insolators on both SW and Smith gauges over time. You get one hell of a fire too. You don't want to let out the smoke in this curcuit. Check into PA for their cobra kit. LIfe time warrantty on their system. Racing 5 years, no problems. Good luck. Rick L.

[Ron61]

I had much the same setup on my Cobra that Rick describes except I never had any under-drive or overdrive pulleys and I had a 100 Amp alternator built. When everything was on and I was racing the voltage would only drop to about 13 volts. It may drop to 12 for a second when I turned on more fans or something but it came right back up. Also you may want to check all of yur grounds.

Ron