Alternator and fan belt slippage

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MOPARoldtimer

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I've got belt slippage bad on my '62 Valiant, into which I've stuffed a 360. It has single belt pulleys. I don't think there is room for two-belt pulleys.

It happens above about 2,500 engine RPM, as well as when the alternator is charging even modestly.

So far I've tried a new belt, cleaning the pulleys and belt dressing, but still have the slip. And how tight can you make the belt without ruining the alternator bearings, anyway? Maybe I should just tighten it up until it stops squealing and hope for the best?

Any suggestions would be appreciated.
 
Is the alternator the only thing hanging in this system? No a/c or p/s?
C
 
take some sand paper to the pulley and rough them up. the belt should have about a 1\4 of play in it as they say hope this helps
 
Assuming the mounts, adjustment, etc is OK, and you actually are getting the belt properly tightened, most probable is that the alternator pulley is worn. If you can find a little larger pulley will help. Of course a larger pulley will hurt your night time idle/ headlights
 
I cleaned the pulleys with lacquer thinner.

The v-belt I am using is, I think, a Gates No. 11A1155, but I bought it at AutoZone as a Duralast no. 15455.

No PS or A/C, and am using a large-ish flex fan.

Roughing the pulleys up sounds like a good idea. The aluminum crank pulley looks really smooth.
 
Slippage is why everyone went to serpentine belts. I don't know if there is a conversion kit for that but it would solve the problem.
 
Is it possible that something is wrong with the charging system/ regulator/ battery and that the thing is simply overcharging?
 
are the belts bottum'in out in the pullys,..belt needs to be tight to the flat V's an not rolling on the center of it...
 
dirty white boy said:
are the belts bottum'in out in the pullys,..belt needs to be tight to the flat V's an not rolling on the center of it...
Click to expand...

So true. The "bite" comes from the side of the "V" pulley. It made me think about the same problem I had years ago. I cured it by going to a wider V-belt.
 
Do aluminum pulleys wear out?? I found that the slippage is occurring at the aluminum drive pulley on the crank. I think its groove has gotten wider or something.

Where can I get a steel front pulley for a non-Magnum 360? Would anybody know the part number?
 
ANY pulley can wear out, cast, steel, or cardboard. They can also become glazed from slipping, IE nice and smooth, then they just slip worse.

What size are the pulleys compared to "stock?" Generally, smaller pulleys slip worse.

Is it possible you have "something else" going on, like overcharging, or a bearing going bad in the pump?
 
MOPARoldtimer said:
Do aluminum pulleys wear out?? I found that the slippage is occurring at the aluminum drive pulley on the crank. I think its groove has gotten wider or something.

Where can I get a steel front pulley for a non-Magnum 360? Would anybody know the part number?
Click to expand...
glad you figured it out,...salvage yard have some rusted up ones cheap,..or summit should have one that'll work,...new steel re-pro be as high as light weight aluminum ones id suppose...good luck...
 
The bigger the pulley the better Bit it has. the alu crank pulley is one of the largest of then all.

Get a ray tech temp gun(inferred temp gun)
Rev it up and let it squeal for a while, shut it of and check the temp of all the pulleys. The hot one is the problem:coffee2:
 
I solved the problem by going from a 7/16" wide belt to a 1/2" wide belt! I guess the smaller belt was bottoming out in the crank pulley.

Now it works great! No slip, no squeal.

I would never have thought of using a wider belt if it hadn't been for you guys helping me. Thanks very much!
 
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