screeching pulley - how to fix?

Hi all,

got a '55 Studebaker coupe into which I've dropped a '63-64 spec R1 (Avanti, high compression) engine. As a part of the engine swap and just general underhood detailing I electrolytically derusted and painted the pulleys. Now I find that with the new engine (which has an aluminum flywheel, which doesn't help) when you rev the engine in neutral the alternator belt slips, and makes an embarassing sscreeching noise. Closely inspecting the pulleys shows that the belt hasn't worn through the paint on the pulleys, but the paint is very smooth, almost polished. Belt doesn't have many miles on it and is as tight as I feel comfortable tensioning it. (don't want to trash the alternator or water pump.) I haven't hooked up the power steering yet, but am fesring that I might run into a similar situation there.

Did I screw up? Would sanding the paint off the belt grooves help? Carefully taking it off with a rag and lacquer thinner? Masking and media blasting? (I would bet that would work well, but is not my favorite option as the only blast cabinet I have access to is my friend's, and it's an exercise in frustration trying to get it to work.) Any other thoughts?

New pulleys are not an option, as the WP pulley is NLA and the crank pulley is built into the harmonic balancer which is also rare and expensive.

thanks,

nate

Reply to
Nate Nagel
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The paint is the problem...

Perhaps just roughing it up with some emery cloth will solve your troubles.

Reply to
anumber1

If you have good hand-eye coordination you may be able to shave off the paint with an exacto knife while the motor is running. OTOH, if you don't have the skill or luck you might lose a finger or eyeball :}

-jim

Reply to
jim

I have been through 3 of the same GM alternators over the years and 'all' of them will screech the belt just after being started while the alternator is under max load trying to top the battery back up. Once warmed up no problems.

Old alternator, old pulley, old or new belt, new alternator new pulley, new or old belt, no matter.

If I tighten them more, the noise will stop, but I, like you am uncomfortable with the belt too tight. I figure the belt is the right tightness when I can't take the pulley and spin it by hand on a cold off engine. It then will just do the screech for a second or two and only on the first start in the morning.

I get about 2 years out of a belt, less if I am mud running, then I eat

3 or more belts a year.

Mike

86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail >
Reply to
Mike Romain

One more thing to check: the charging voltage. Should be no more than 14.5 volts or so. Excessive voltage means excessive alternator load, and that belt will screech. Won't do the battery any good, either.

Dan

Reply to
Dan_Thomas_nospam

That may be it; I think you're alluding to an earlier thread where i was swapping to a 10SI... it is in the car now and yes, when I hear the screech is right after startup. if I really gun it in neutral I can get it to slip any time, but then again, it does rev up pretty darn fast. (which was purely intentional)

nate

Reply to
N8N

Yup, we were comparing pulley sizes a while back.

I think once you drive it and the battery gets fully charged it will not be as bad. I can make mine squawk if I drop the battery down while winching. I then just let it run on fast idle for a while to bring the battery back up and have no issues.

I have a hand throttle in mine for winching because those alternators don't seem to put out full power until it hits over 1000 rpm. I winch at 1250 and usually have no issues. Mine is a 65A I believe.

I use the cold off hand slip on the pulley to test my tightness. If I can hand slip it, I tighten it just a 'little' more.

Mike

Reply to
Mike Romain

Nate Nagel wrote: ('55 Studebaker coupe)

I installed a '63-64 spec R1 Avanti engine and electrolytically derusted and painted the pulleys. When you rev the engine in neutral the alternator belt slips and makes a screeching noise. The belt hasn't worn through the paint on the pulleys, but the paint is very smooth, almost polished. The belt doesn't have many miles on it and is as tight as I feel comfortable tensioning it. I haven't hooked up the power steering yet.

Would sanding the paint off the belt grooves help? Taking it off with a rag and lacquer thinner? Masking and blasting? New pulleys are not an option - the WP pulley is NLA and the crank pulley is built into the harmonic balancer which is also rare and expensive. Any other thoughts? __________________________________________________

The belt may be so narrow it touches the bottom of the vee-groove, preventing a firm grip on the pulley walls.

If so, find the next size wider belt, which will ride higher and make good contact.

Also, there are a few different belt vee-angles. The best angle is the one which most closely matches the pulley vee.

Good luck.

Rodan. ________________________________________________

Reply to
Rodan

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