Add me to the list of failed alternators

Yesterday while driving to work in the early morning, I noticed my lights for my autometer water and oil temp. gauges were very faint. I didn't think anything of it so I continued on my way to work and as soon as I am backing into my parking space my radio shuts off. I am like wtf? My car was still running even though this happened. I then shut the car off and then try to start it again but all I get is click, click. Right away I knew it was my alternator because my battery was brand new.

Got a new alternator at Hollywood Ford for $217 with a pulley already installed. Luckily I had some of the tools in my car. The install was pain, but thanks to the instructions on here it made it easier. For me, taking off the alternator bracket is worth the agony. Oh yeah, my car has 50,000 miles with a Whipple 3.5 pulley, stock lower and stock alternator pulley.

Well that is good that you got it taken care of. I know I need to buy a new battery for my car. Right now it does not have one in it since it sits so much and do to the weather.

Well, you got 50,000 miles on the original. Not too shabby. Glad you bought the Ford alternator vs. a PA. Hopefully you'll be good for another 50K+ miles.

How long did it take you to install the new one?

I have heard that one of the reasons alternators fail so frequently on our cars is that they get exposed to water being mounted down so low. Anyone notice that cars driven in a dryer climate or rarely driven in the rain have less alternator failures? What about the eariler NA Cobras where the alternator is mounted up high near the intake? I wonder if they last longer. Just curious.

Mine has never been driven in the rain and the alternator went out in under 10K miles. I do have a lower pulley and the stock alt pulley was on the car until I recently replaced the alt and well as the alt pulley. It could be from me washing the car, and water getting under there when cleaning the wheel but who know. I just hope this Motorcraft alternator lasts.

Josh

51k is what I got here before the alternator went. Job sucks, but hey.

welcome to the club...

CobraBob said:

Well, you got 50,000 miles on the original. Not too shabby. Glad you bought the Ford alternator vs. a PA. Hopefully you'll be good for another 50K+ miles.

How long did it take you to install the new one?

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It took me about an hour or so because the lighting under my car was terrible due to a weak flash light I had. Next time I am buying a better flashlight.

I bought a PA long time ago, but I read of all the problems so I am using it as a paper weight.

I put one on at about 16k.

I believe heat and high revs are the #1 killers.

I was using a stock lower with a raised 7k redline. I believe revs killed mine.

I put a new Motorcraft on with a 3.2 Metco alt pulley to slow it down a bit.
I have a stock lower and I have no charging complications.

We will see how long this one lasts.:dw:

I'll cast my vote for using a smaller than stock upper pulley as being the culprit for why these alternators fail. I've come across on several posts on here and ModularFords where stock pulley Terminators have gotten 80k - 90k out of the alternator. A smaller upper is still causing the laternor to overspin based on the stock configuration. It just makes practical sense to me.

My alternator went out about a month ago, but thank God my warranty replaced it, and I still have my stock pullies.

01cobravortech said:

I'll cast my vote for using a smaller than stock upper pulley as being the culprit for why these alternators fail. I've come across on several posts on here and ModularFords where stock pulley Terminators have gotten 80k - 90k out of the alternator. A smaller upper is still causing the laternor to overspin based on the stock configuration. It just makes practical sense to me.

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Your sense of practicality is extremely altered.

The only way to change the rpm range of the alternator is by swapping the lower pulley or the alternator pulley itself. So, please explain to me how changing the upper pulley effect the rpm of the alternator??

MVD said:

Your sense of practicality is extremely altered.

The only way to change the rpm range of the alternator is by swapping the lower pulley or the alternator pulley itself. So, please explain to me how changing the upper pulley effect the rpm of the alternator??

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When you're replacing the upper stock pulley to a smaller one you are changing the size of the belt as well. The stock pulley is 3.65 in size and requires the use of a belt measuring 75.1". Lets use my application as an example. I only run a 2.80 upper and the belt I'm using measures 73.75". Its simple math my friend. The alternator pulley is not spinning at same rate with a smaller upper pulley, as opposed to the one using the stock size. :read:

01cobravortech said:

When you're replacing the upper stock pulley to a smaller one you are changing the size of the belt as well. The stock pulley is 3.65 in size and requires the use of a belt measuring 75.1". Lets use my application as an example. I only run a 2.80 upper and the belt I'm using measures 73.75". Its simple math my friend. The alternator pulley is not spinning at same rate with a smaller upper pulley, as opposed to the one using the stock size. :read:

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No, it is still spinning at the same rate because the lower pulley is the one that is spinning the others, your smaller belt has nothing to do with the pulley spinning faster it just allows the belt to make contact with all the pulleys and eliminate any slip that could occur. You could have a belt that is too tight and have some negative effect on the alternator, that may be an arguement you could make, but the smaller blower pulley or belt has no effect on the speed of the alt pulley.

Josh

About2bite said:

No, it is still spinning at the same rate because the lower pulley is the one that is spinning the others, your smaller belt has nothing to do with the pulley spinning faster it just allows the belt to make contact with all the pulleys and eliminate any slip that could occur. You could have a belt that is too tight and have some negative effect on the alternator, that may be an arguement you could make, but the smaller blower pulley or belt has no effect on the speed of the alt pulley.

Josh

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Josh I guarantee you that alternator speed is not identical in rpms to the stock configuration. Thats where people make the mistake. They take a smaller pulley and belt and equate that to the pulleys spinning at the same rpm with the stock configuration and that just isn't the case. Those few rpms that it over spins could very well be whats leading to a lower life. Its conjecture at this point but a hypothesis that makes sense nonetheless.

Look at what happens when you alter the size of the lower pulley? Belt size changes as well and so does the rpm speed on the alternator. The lower pulley is just another pulley being changed in diameter. Even when you add a bigger alternator pulley you aren't spinning the alternator at PRECISELY the same speed on the stock pulley setup. Thats the only point I'm trying to make here. :beer:

So if you run a bigger belt, let's say a 78 would that change the alternator RPMs?

01cobravortech said:

When you're replacing the upper stock pulley to a smaller one you are changing the size of the belt as well. The stock pulley is 3.65 in size and requires the use of a belt measuring 75.1". Lets use my application as an example. I only run a 2.80 upper and the belt I'm using measures 73.75". Its simple math my friend. The alternator pulley is not spinning at same rate with a smaller upper pulley, as opposed to the one using the stock size. :read:

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LMAO.......so you are saying because you use a shorter belt (with the smaller diameter upper) you are spinning the alternator faster :lol::lol:

Listen guy.......the diamter of the stock crank pulley is 8.5" and say the alternator pulley is 3" (I am not exactly sure). That is a ratio of 2.833. So if your max engine rpm is 6,500 rpms the max speed of the alternator is 18,415 rpms.

Now say you change the stock upper to a 2.76 and go to a shorter belt.......that ratio of the crank pulley to alternator pulley is still the same, which of course means the alternator rpms are the same.

It's simple math my friend :read:

01cobravortech said:

Josh I guarantee you that alternator speed is not identical in rpms to the stock configuration. Thats where people make the mistake. They take a smaller pulley and belt and equate that to the pulleys spinning at the same rpm with the stock configuration and that just isn't the case. Those few rpms that it over spins could very well be whats leading to a lower life. Its conjecture at this point but a hypothesis that makes sense nonetheless.

Look at what happens when you alter the size of the lower pulley? Belt size changes as well and so does the rpm speed on the alternator. The lower pulley is just another pulley being changed in diameter. Even when you add a bigger alternator pulley you aren't spinning the alternator at PRECISELY the same speed on the stock pulley setup. Thats the only point I'm trying to make here. :beer:

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I have so many points to make on why what you typed above is wrong but it is a waste of my time since you are convinced otheriwse.

I just wanted to quote this in case you edit, so everyone else can see how confused you are.

I hope you don't give much advise on this forum.

01cobravortech, you are completely wrong and just need to admit it. Belt length and pulley sizes other than the crank and alternator pulleys DO NOT change how fast the alternator spins at a given rpm. That's almost like saying a longer driveshaft changes your overall gear ratio or something.

Trick Pony said:

01cobravortech, you are completely wrong and just need to admit it. Belt length and pulley sizes other than the crank and alternator pulleys DO NOT change how fast the alternator spins at a given rpm. That's almost like saying a longer driveshaft changes your overall gear ratio or something.

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How is that even the same comparison when we're discussing the rate at which a pulley spins based on the size of other ones and belt sizes? That doesn't make any sense. The size of the driveshaft wouldn't change your gear ratio, no way no how. Thats just a rediculous analogy to use.