Here's a new for me. I used a GM alternator when converting my 47 flathead to 12 volts, had to buy the 5/8" pulley because the engine had big belts. At that time they only made them in aluminum so I didn't have any choices. The alt., was always noisy I tried different belts, belt dressing, even changed out the front bearing.... still very noisy, and got so it would out put about 12.5 volts. Got a new steel pulley from speedway today, presto thing works like new. Alum. pulleys are junk.
The crank pulley for the V belt that drives the water pump and alternator on the blown engine in my 55 has about 85k miles on it, it's aluminum. I guess aluminum pulleys are ok in some applications.
Some pulleys must be better than others. Mine are hard anodized and the v-belts are adjusted correctly and shimmed into alignment, never had a problem.
Had a similar problem with my 56 chevy. Put aluminium pulley on the front of alternator and worked great for like 4 or 5 years. Had Alternator rebuilt at one time with new bearings sounded good and the like 2 years later strange noise again. Replaced bearings again ( thought maybe chineese) no good replaced good Napa belt no change. Ran it with the belt really loose and no noise and slowly pryed the belt tight and here comes the noise. Put on old steel pulley and noise went away and hasn't come back Huh? Looked at old pulley and it had some minor wear grooves in it but nothing that seemed too serious. Guess I was wrong for the first time in my life.lol. Just kidding. Hope this helps.yruhot
You could get different switches put into your alternator to accommodate the drive change of the pulley.
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