KJL

I have had intermittent issues with the alternator. I decided to replace after and second episode with a near dead battery. I discovered the pully on the existing unit is quite large and it is very difficult to install and replace the serpentine belt. I had to use pliers to walk the belt off of the pulley. I purchased a new 140 amp Powermaster (I have heard good things about these) unit from Summit. The pulley on the new unit is smaller. It will probably still work but need to do a test fit. Should I swap pulleys? I am concern that the new unit will not behave properly if I use a larger size pulley.

Any thoughts?

WVZR-1

Use the correct pulley for the application (the original pulley). You need to confirm the fan and the pulley are a match to one another. What was the PowerMaster number you bought?

KJL

It is a PWM 17864 CS144 from summit. Looking at the units I cant see why the fan that is on the new unit wouldn't work. I still am concerned over reducing the speed. Powermaster web site recommends a driven to drive pulley ration of 3:1. The crank pulley outside to outside is approx. 7.125" and the stock pulley is 2.875", this yields about a 2.5 ratio. The new pulley measures in at approx 2.125" which yields 3.35 ratio. Powermaster says you can't overdrive an alternator but you can underdrive. They recommend staying above 2400 rotor rpm at idle speed. If I idle at 900 rpm that will put me at 2250 rotor speed. I may test fit the existing pulley to see if there is enough tension in the belt. Plus I am not 100% sure if the alternator that is in the car is the stock unit. Anyone know what the stock pulley diameter should be?

It is interesting that Powermaster and others do not list pulley diameter in the details section. I would think this would be critical information...