I went out to a new place I found to try out a carb. I just rebuilt and changed the jets on.
I went from 74-84 to 72-76, wow what a difference.
Anyway I seen 7000 rpm on the tach. witch is strange cause it was on the rev limiter that I have set at 5500? (maybe it bounced up there)
Anyway after I let off the gas and things settled down I looked at my volt meter and I had 10v?
I thought I slung a belt, but that wasn't the case.
When I got home I took the alt. off and it had stuff rattling around inside, black plastic and cream colored stuff was falling out of it.
BUMMER !
Anyone know how many RPM an Alt. can take?
T.C.

I believe a stock alternator can take about 6,000 rpm's. If you plan on going higher they say to swap the pulley for a bigger one. "They" being powermaster (I just bought an alternator, and they had the warnings in the box).

less than 7000 revs, sorry I could not help it.

Most alternators are quite a bit overdriven. Just at a glance, I would think that is is in excess of 2-1. That translates into some pretty high rpms. L78s and 302s got much larger pulley's to reduce the alternator rpm. The alternator on our car is just a standard 37 amp unit. Nothing special except for the pulley and the stamped numbers.

That may be the problem, I have a March pully set that has a 6 3/4" crank pully and I bought a special 1 1/6" Alt. pully.
Now that I think about it "thats alot" almost 7-1 ?
So that would be 5500 x 7= 38500 ?
Is that correct?
T.C.

Sure thats not 2 1/16? They can take 20k rpms for short periods.

Thanks for the replies guy's
Actually I looked on the March web site and I was wrong, the crank is 7" and the Alt. is 1-11/16" .
That does change the ratio, but it's still over 3-1witch puts it over 16000 at 5500 rpm.
I think the Alt. was going bad anyway because I was getting radio noise that would come and go?
Don't know if that was a sign it was going out or not?
T.C.

That does change the ratio, but it's still over 3-1witch puts it over 16000 at 5500 rpm.
That should not cause a problem. Its well below the max alt rpm limit.
I think the Alt. was going bad anyway because I was getting radio noise that would come and go?
Don't know if that was a sign it was going out or not?
T.C.
If a bearing went bad, make sure not to have belt to tight. To tight of a belt shortens alt bearing life.

I had the Alt. rebuilt and the guy showed me where the "plastic" fan had come apart taking the armature wires and brushes with it.
He rebuilt it with a new armature that has metal blades, said it's good to 10,000 RPM?
I also had a radio noise I though was the Alt. diodes going out, hoped it would be gone after the rebuild................It's still there, bummer!
T.C.

I had the Alt. rebuilt and the guy showed me where the "plastic" fan had come apart taking the armature wires and brushes with it.
He rebuilt it with a new armature that has metal blades, said it's good to 10,000 RPM?Don't know what he meant by that. You can't go by engine rpm without taking into account the crank to pulley ratio. Alts can take 20k alt shaft rpms for short periods. See link (http://www.powermastermotorsports.com/power_pulleys.html)

Thanks for the replies guy's
Actually I looked on the March web site and I was wrong, the crank is 7" and the Alt. is 1-11/16" .
That does change the ratio, but it's still over 3-1witch puts it over 16000 at 5500 rpm.1-11/16= 1.6875. 7 divided by 1.6875 = 4.148 pulley ratio. 5500 x 4.148 = 22814. Consider changing the alt pulley.

I also had a radio noise I though was the Alt. diodes going out, hoped it would be gone after the rebuild................It's still there, bummer!
T.C.
Is the noise still there if the alt is disconnected?

Thanks for the reply,
I am thinking of changing the pulley .
The noise I think is in the radio itself, I say that because I can turn it on and off quickly and sometimes it will make the noise and sometimes it wont?
I think the tuner is going bad, if it was the Alt. seems like it would make the noise all the time?
T.C.

The noise I think is in the radio itself, I say that because I can turn it on and off quickly and sometimes it will make the noise and sometimes it wont?
I think the tuner is going bad, if it was the Alt. seems like it would make the noise all the time?
T.C.Does it ever make the noise with the engine not running? Could be the tuner or something else (fans, pumps, ect...) Testing would be the only way to find out for sure.

I think it's the 100.00 radio I have, Im going to do some testing this weekend ,
I'll post the results as I get them .
Thanks T.C.

There is a cheap noise filter i used to buy at radioshack yrs ago that in nstal in the hot wire t the stereo/radio that totally elimintaes the alt noise,cost 5 buck yrs back so its likely 10-15 buck now.

Scott

Thanks for the reply:
I didn't get a chance to do any testing yet, I do have one on the hot lead to the radio, one on the hot lead to the CD player and one made by MSD on the ignition box.
I think it's the radio because it used to play just fine and as I said I can mess with the tuner and the noise will go away?
T.C.

I found the radio noise, after I plugged the ant. directly into the radio It played perfect.
That meant the CD changer was the problem, so I checked the plug inside the car and it was good.
I then went to the trunk and started wiggling wires, after three months of fighting this problem I found it.
A stinking loose ground wire!
DUH....boy am I stupid.
T.C.

Delco Remy lists 10,000 RPM Continuous service limit for a 10SI alternator, with a 12,000 Intermittent limit. That is at the alternator so you have to take your pulley ratio into account.

I found the radio noise, after I plugged the ant. directly into the radio It played perfect.
That meant the CD changer was the problem, so I checked the plug inside the car and it was good.
I then went to the trunk and started wiggling wires, after three months of fighting this problem I found it.
A stinking loose ground wire!
T.C.

:D Testing/checking narrows the possibilites of problems till it is found.

DUH....boy am I stupid.

No, it happens to everyone at times. You had 2 different problems that happened around the same time and they wern't even related, although they seemed to be. Testing/checking narrows the possibilites of problems till it/they are found. Now you have learned something, and others who read this thread.

Thanks Guy's
T.C.