Aligning alternators and engine pulleys, general principles

[Kit_L]

A question to the tech gurus here, re. aligning or realigning alternators—how is any needed correction done? Shims? A judicious whack with a lump hammer? I do have straight edges. If there is a definitive thread on this process, please link!

The back story is that I lost an alternator belt of the starboard Volvo Penta KAD-300 while offshore in rough conditions. I have researched how to change the two serpentine belts, and how to torque the adjusters. The top pulley has to be removed to access the alternator belt, but I decided to replace all three (two serpentine, one alternator) as I had the spares.

I have noticed alternator belt dust before, so suspect misalignment is part of the problem. All responses gratefully received.

 

[O C Diver]

Before solving the problem, determine one exists. The 2 serpentine belts on my JD gave off some dust, regardless of the alignment being perfect. The two original belts were still on the engine after 6,000 hours. They were both 8 groove belts running well below half of the allowed load. Belt failures are sometimes alignment, but often loading close to the limit.

After checking the alignment, post some pictures of the offending accessories to better answer how to correct them. Also it's important to understand whether the pulley is in a different but parallel plane or the pulleys plane isn't parallel to the crankshaft pulleys plane. Hope I made that clear.

Ted

 

[Kit_L]

Ted, thanks, and perfectly clear. I wasn't clear—the serpentine belts are fine, and no dust, but because the outermost one and its pulley has to come off anyway (to get to the alternator belt) I decided to replace both. The ordinary fan-belt type of belt that spins the alternator is the one that's throwing dust. Because of the confined nature of these large engines in catamaran hulls, it's very difficult to get a clear view to check the alignment of the alternator pulley with the crankshaft pulley.