on the 347 stroker in my 74 maverick. i have seem to come up with a problem and i can only guess it is the alternator. when i first start the car the amp gauge will read fine *reads at 14* i've noticed that the car "dies" however when my electric fan kicks on. the fan will kick in approx 200degrees.. today i decided to watch my car... what happened today was the car hit approx 200 degrees and the fan kicked on .. when the fan kicked on there was a noticable "surge" in the idle.. almost like it wanted to die, but not quite. normally this will happen to me while i'm in traffic. today the car was idling at 1000rpms where normally in traffic it idles about 800 and most of the time it dies there. i've also noticed that my amp gauge will drop when i pull my headlights on. so sometimes at night when i try to start the car if i turn the lights on it will die also. and recommendations on what to do about this situation?? should i go stock replacement or should i upgrade. money is a wee bit of a factor right now. basically if i dont spend the money upgrading my car, the money will go to help me pay off 2 debts i have. thanks guyz. jason
Alternator Problems Sounds like you may have too small amperage battery, or maybe even need to go to a larger capacity alternator. If you are running a bunch of electric powered equipt. such as MSD, fans, stereo etc. You are probably taxing the battery to the limit. Most stock batterys in your case probably were in the 550 amp range. Another thing to look at is a good ground to the engine and even a larger diameter cable on both positive and negative . Have found that 900-1000amp battery works best with afore mentioned equipt. Just sounds to me like the battery is the culprit, with a 347 and maybe a little more compression?, the larger batt. and alternator are probably needed anyway.
Take Old Guy's advice. There is just not enough capacity to handle the starting current draw of the fan motor. I would make sure the alternator to battery charge lead is at least # 8 wire. Also if you have under drive pullies on, that in it's self will cause a great deal of problems. You see in my sig. that I have Mark 7. This car is loaded with a lot of high current devices and has a 100 amp alternator and a 1000 amp battery to have enough spare capacity for reliability. There are many younger owner of these cars now and they get themselves into trouble with under drive pullies and a lot of audio equipment even on this car.
never thought that a new larger amp battery would be recommended. i will have to check that out.' on the larger alternator part..... isn't there a difference in mounting locations or something from my 74 alt, to say a newer 100+ alternator??? i thought i read that somewhere? input?
Depending on what unit you select, there can be some minor mounting spacers that would be needed. The late alternators need the pulley change from the flat serpintine to a V type belt of close to the same diameter. I have a 95 amp late Mustang internal regulated unit and a 750 battery on my Comet. With fuel injection it became manditory to make the change. The normal running current consumption is close to 15 amps powering the computer and the fuel pump so a reserve was needed for lights and heater etc. The stock alternator is rated at about 60 amps so the reserve wasn't there. If you want to stay with an external regulator, look at the Lincoln Mark 7, 100 amp alternator and it's regulator.
just a suggestion while you are resurching the altenator aspect you might check with a local rebuilder we have 1 here that can up the amps in your stock housing.......and alot of the time they will be cheaper than buying 1 at a parts house and it would eliminate the worries of a retrofit.......just a thought
