ddahlgren

What is it I have read it as 18000 at the alternator. I have a rebuilt alternator and taking off under drive crank pulley to install a stock one(L98) that is 7 1/8 diameter and the alternator one is 2 inch. Assuming the rev limit on a L98 is 5600 That comes out to 19950 at the alternator. Has anyone run this combination and made out ok? Doing air pump eliminator at the same time and sure seems a lot simpler than what I have seen done.

Patsgarage

Check to see if the internal cooling fan is metal or plastic. The plastic ones do not like high RPM, after one blew apart on me I had my rebuilder put a metal one in.

ddahlgren

There is an internal fan too? How do you see it from outside through the case?

Patsgarage

IIRC there should be holes in the front of the case.
I am assuming () that most of the late 80s early 90s GM alternators were built the same way, the one I had was off of a 1500 pickup.

ddahlgren

Big metal fan on the outside behind the pulley

C409

….. My set-up is as stock as far as pullies are concerned and this combo has been north of 8000 rpm with no ill consequences …..

ddahlgren

71/8 crank pulley and 2 inch alternator? Even if you have the 21/4 alternator one still well past anything I would do. With that combo you would still be over 25000 rpm at alternator. I get it I am worrying too much about it.

WVZR-1

Is the pulley on the alternator stock or actually measured as 2"? The CS130 stock for that car is 2.2 (56mm) so I thought maybe it was the way you took your dimensions.7 1/8 and 2.2+ is something right at the 18000 (18064 maybe). I did the math earlier in the day and best I recall.

ddahlgren

Measures to the top of the ribs on the pulley

383vett

I wouldn't worry about an alternator blowing up. I've seen hundreds of motors blow at the track and have never seen or heard of an alternator blowing.

JackDidley

First time I went to 6000 RPM my plastic fan exploded. Replace alternator. Second time at 6000 it exploded. Bought a new, not rebuilt alt at the Autozone with a steel fan and fixed the problem.

ddahlgren

Does it have an internal and external fan?

JackDidley

Internal fan blew apart.

ddahlgren

Found the internal fan, can see it through the last radial vent holes by electrical connectors, it is metal so screw it no worries there. Gave the pulley a spin and has a slight high pitched squeak. Is this car ever going to surrender?It it makes noise we have a local rebuilder that is real good and a friend will just have him put some bearings in it if needed.