I thought I would post this thread here also because a lot of you guys probably have V-belt setup like I do.
My alternator keeps coming off.
I tried to move the alternator out a little more by inserting washers behind the bracket bolts.
The alternator pulley now seems lined up with the crank pulley but I'm still losing alternator belts for some reason.
Has any else had this problem or know how I can fix this problem?

 

I had a car that the belts was not lined up and it still stayed on. Could it be the belt? Also check and make sure the pulleys are lined up. That could be it to. Are you running the belt to lose or to tight?

 

Got a picture of the mount?

When you used washers to 'space it out' do you put them in equally on all mouting locations? If not you introduced a subtle twist into the equation which will help the belt to come off. Are any of the pulleys out of round? Do any of them have any dents in the track? Are you using the high RPM v belts or the cheap v-belts? Does the belt come of at idle or at 5500 RPM? Lastly, is the alternator mounted in the stock location or have you moved it for other power addders of some sort?

I used to have a belt slip problem with my first alt mount on my 408c. I remounted it exactly the same way the PO had it when I bought the car and the belt would come off. I did a little investigation and found out the alt was mounted in the incorrect place using the incorrect brackets. I examined it closely and it was 'slightly' out of line but not enough I thought to toss belts. After retrieving the correct alt mounts from a junk yard I have had no problems.

Before:


After (sorry its not from the same exact angle but you can see the brackets that changed).

 

DS may be on to something regarding the brackets. Have they ever been altered, or do you know? In addition to his pics, take a look at my 65 to see if your's is different.

 

I didn't know there was such a thing as "high rpm" belts. Where do you get them at? I always used the belts from autozone. It always comes off at higher rpms...like after 5K or so.
The alt. is mounted in the same position it always has been.
Before the engine was rebuilt last year, it always stayed on but ever since the engine went back in, I keep throwing belts. I'll look again to make sure none of the pulleys are bent or anything but I'm pretty sure they are ok.
Now, there is one thing to note here: After I added the spacers to realign the brackets, I put on of the old belts that I was able to recover after it flew off but it was twisted a little from not being lined up correctly from before.
I'm thinking maybe that's why......but who knows.
Sorry that I don't have a pic of the mount but it doesn't look anything like the ones posted here except maybe the lower bracket.
ROUNDMAN say Summit makes deep groove pulleys so maybe I'll try that after I find out for sure my alignment is correct.

 

yes they do there a race pulley..question....why haven't you replace those rusty *** bolts with stainless steel....they paint is to nice looking for those bolts..just my 3 cents worth

 

Just laziness...LOL

 

lol - all in due time....I put all my money into the drive train for now. I'll paint those bolts nice and blacks one of these days.

As for the belts...go to NAPA and ask for a better belt.

If you look really close at the pictures posted you will see:

1. in my first photo the fan belts has a smooth backside.

2. in soaring's photo the fan belts has a ribbed backside. The ribbed backside is the kind to get and is designed for higher RPM applications.

 

Yep...I've already tossed both kinds...smooth and ribbed.
I was thinking about making some kind of safety loop that loops around the belt so when it comes off, the loop will catch it and I can stick it back on......LOL

 

TY DS, yes the ribbed belts, although not a good pic, are preferable. Especially for high speed as they tend to flex. I would take out the alternator and take it to a parts place and see if they can replicate your problem. You may even have a bearing burned out in your alterntor which is causing a flopping. [:@]