PaulS makes a good point that I see everyday...people using a too small of wire on a big output alternator. I'm using 4 ga battery cable on a 100 amp alt. Now is a good time to ditch the ammeter and go to a volt meter
I think the cables I have will be sufficient, considering they are bigger then the cables that were on the Taurus I removed the alternator from.. I ditched the ammeter 3 years ago when it nearly caught my car on fire.
So I spent three unsuccessful hours this morning trying to get the pulley off the 3G without an impact wrench. Came in to take a break, got on Pull-A-Part's site and noticed they had a '75 Comet at the Atlanta south location, which happens to be not far from Hawkco's house. Gave him a call to see if he had an impact wrench, and sure 'nuff he did. So I jumped in the beater '92 Nissan and drove down there. What I struggled with for 3 hours, literally took him less then 10 seconds to remove with his impact (thanks again Terry). Went onto Pull-A-Part, the Comet was rusted out, puke green, and mostly stripped with an old 250 in it. Nothing special there. Got home and started to remove the Chevy alternator when I noticed that the belt was eaten up again, and there was rubber dust all over the place, the belt didn't have much tension on it. It was worn to the point where it was bottoming out on the bottom of the V belt pulleys. This belt is almost brand new, something is definitely not right. It didn't take long to see the problem, the alternator was turned slightly outwards, so that the pulley didn't line up right with the water pump and damper. I hadn't given much thought to it before, but the part on the Chevy alternator that mounts to the bottom bracket on the engine is not as long as the Ford. So when I tightened the lower bolt down, it caused the bracket to fold in on itself, causing the alternator to turn outwards. I straightened the bracket back out, and made a 1 inch spacer to take up the extra room. Now the alternator is sitting perfectly in line like it should be. Went and got another new belt. I then drove around town a little, everything seemed great. So I drove over to Dan Hines' house in Cumming to drop off a fuel gauge. Going to his house involves driving a few miles up GA400, which I ran about 80 mph for those few miles. Got to his house, everything still was working great. So I drove on up here to NC from his house. I have put just over 120 miles on the car today, everything from idling in traffic with the headlights, electric fan and CD player going, to driving 75 mph up the interstate, to running 60 mph across a 2 lane road, and haven't had any charging problems yet, and the belt still looks just as good as when I put it on. Best of all, all the lights are BRIGHT, brighter then they have ever been, and the headlights no longer dim with each flash of turn signals like they used to. So I may not use the 3G unless the problem returns. I'll put about another 150 miles on it tomorrow, if all goes well then I will drive it back and forth to work (32 miles interstate each way) next week and see how it does. Keeping my fingers crossed.
Good to hear you have it ironed out. I have an aftermarket chromed 100 amp 10 SI that works very well. Yes, you have to cut the correct spacer and drill out the mounting hole to fit the Ford bolt, but that is fairly straightforward. The 3G is a good choice also. I just like the simplicity of the GM alternator. I have the dash light and voltage sensing wires hooked up so it charges as designed. You could even get a parts store 12 SI at 94 amps for a reasonable price and have a fine unit that will charge amply at low rpm.
Mine is 83 amps, IIRC. It is remanufactured, from Advance Auto, which I did wonder more then once if that was the problem in and of itself..
The problem has returned. Now, as long as you keep it under 65 mph, it charges fine. If you run 70+, it quits charging. 3G going in this weekend.
i know this is going to sound like a dumb a$$ thing to say but this has happened to me, have you tried to check your terminals to see if they're corroded inside or if they're fitting tightly? some times the most dumbest things are the ones that will give you the most problems.
Almost sounds like the belt is slipping at higher rpm. Check tension and/or consider some Gas-ga-cinch (sp) on the belts/pullies. ------------------------ P.S. I know what you mean about the altenator nut. It's almost impossible to remove with hand tools. I picked up a cheap Harbor Freight electric impact (240lbs torque) and it's been working fine. Stubborn lug nuts, altie nuts, etc. busts 'em loose no prob.
I don't remember if you mentioned what your rear gears are but it sounds like you are turning the alternator too fast - or trying to. The belts are probably jumping all over the place. check your pulleys for wear and concentricity (rotating without an oblong motion). How do you know that the alternator stops charging at 70 mph?
i saw Jamie going down I-85 at 70 MPH with Tyler running along beside the car with a voltmeter. i was thinking he was checking the voltage.. ......
Rear gears are 2.79. Don't remember the exact RPM's at 70, but I know it rarely turns much over 3,000 RPM. There dosen't seem to be anything abnormal about any of the pulleys, the belt is new and tight. With everything in the car on (heater fan, dome lights, headlights, CD player, electric fan), you can drive along all day at 65 mph with no problems. The turn signals flash at a normal pace and they are bright. You speed up to 70, and within a couple of minutes, the radio starts turning on and off. Then all the lights start going dim. The turn signals flash very fast, and they are dim. If you keep going, the lights get very dim and the car starts misfiring. Slow back down, and it's like someone hit a light switch, radio comes back on, lights get back bright. Even just driving with nothing but the radio on in the middle of the day, you speed up to 70 for a few minutes, turn on the blower motor, and the radio turns off. Haven't drove with a volt meter hooked up, because it's obvious what's happening. I'll see tomorrow about getting some voltage readings. Seems to me I should be able to replicate the problem just revving the car in the driveway..
The battery should have enough juice that even with total alternator failure, you shouldn't notice such weird symptoms that quickly. Something else might also be going on. Odd that every alternator you've tried has done this. I'll give it a good 8 for a Twilight Zone rating. Yeah, try the driveway test. Run some long extension leads into the cockpit so you can monitor the voltage (use a digital meter if possible).
