Re: Ford vs Chevy Build-up
 

This one Sean... http://www.jegs.com/i/JEGS-Performan...oductId=752892

The set-up as run...

http://i434.photobucket.com/albums/q...psgai39o0o.jpg

Just grasping at straws here. I did not have any 10 gauge wire on hand so I paralleled two 12 gauge wires to the battery positive and a short 10 gauge ground from the alternator case to a head.

Edit: Just re-read the instructions and it states no Jegs alternators are designed to to be spun beyond 15,000rpm (6000 engine rpm). :rolleyes: I can try it one more time with a large crank pulley or purchase another brand alternator. At this juncture I just want one that works without worry.

Re: Ford vs Chevy Build-up
 

Just a heads up....

I think that you have it backwards....

Big crank pulley & small alternator pulley = overdrive

Small crank pulley & large alternator pulley = under-drive

4" crank pulley with 2" alt pulley at 7,000 rpm engine RPM = 14,000 alternator RPM

2" crank pulley with 4" alt pulley at 7,000 rpm engine RPM = 3,500 alternator RPM

Hope this makes sense to you and helps......

Bob

Re: Ford vs Chevy Build-up
 

As stated above, the small crank pulley slows it down.

Re: Ford vs Chevy Build-up
 

You know, that is what I thought as well but I let someone talk me into that one lol. With that out of the way I can see no reason for two failures in a row other than these alternators are junk.

Re: Ford vs Chevy Build-up
 

This may be true. I had a Powermaster that wouldn't charge my Optima so I replaced it with a 140 amp Tuff Stuff connected as a one wire. It worked fine then went haywire and put out 44 volts to the battery. I popped the cover to the two terminals for a three wire hookup and jumped one to the battery output on the alternator based on something I read on the Internet. Makes little sense to me but it works now. Whatever internally activates the regulator crapped out, I guess.

Dale

Re: Ford vs Chevy Build-up
 

Rich a one wire alt. has to turn around 2000 rpm to excite it for it to start charging. Once it starts charging it stays until you shut off the engine


Joe

Re: Ford vs Chevy Build-up
 

This one excites at 880rpm...when its working. http://www.jegs.com/i/JEGS-Performan...oductId=752892

Re: Ford vs Chevy Build-up
 

Bob is right on. That crank pulley has to be close to 3.5", if the alt pulley is 2", that calculates to 12,250 at 7000 RPM. At 1000 RPM the alt is only at 1750 RPM.
Will the alt produce any voltage if you increase the engine RPM to 2000 or 3000?

Sean

Re: Ford vs Chevy Build-up
 

From the beginning both alternators worked fine, even at idle. I guess they lasted part of one stint each at the track when I realized they were no longer charging. You can wing it to six grand if you like...it aint happening. Something inside the alternator is just not holding up it's end of the bargain.

Re: Ford vs Chevy Build-up
 

Just went through a similar issue. The one wire alternator didn't excite until 2500 alternator rpm. With the combination of a large alternator pulley and small crank pulley, there wasn't a lot of time that the alternator was putting anything back into the battery. To make things worse, the alternator had a bad diode and rectifier so it was only putting out 15 amps when it was charging. :( Had it rebuilt and now it works fine.

Changed the charging system to a larger 74 amp constant output alternator with a 6" crank pulley. The excite power wire runs through a heavy duty toggle switch on the dash so the alternator can be turned off during a run. -Al