fan belt

blackstack · Post by **blackstack** » Sat Jan 30, 2010 7:11 am

I have a napa belt on now. New it has to be run with no adjusting washers or it slips. Is this typical when using replacement part rather than original? Is there a replacement thta works better?
thanks

undysworld · Post by **undysworld** » Sat Jan 30, 2010 8:22 am

I've also got the NAPA 4L41W belt which was listed on the replacement parts list. Mine works fine.

Are you saying you've got no washers between the shives and all the washers on the outside? IIRC, that would adjust for max. tightness of belt. If you're still loose then, I'd have to assume you needed a shorter belt. Not sure why that might be. It does not sound typical.

Putting all the shim washers between the shives, and none on the outside would make the belt looser still.

blackstack · Post by **blackstack** » Sat Jan 30, 2010 10:00 am

that is the belt I have on...and yes no washers between the cheeks of the sheave. I will try one of the other replacement belts

Jimm391730 · Post by **Jimm391730** » Sat Jan 30, 2010 10:54 am

If it doesn't slip without any washers between the sheaves then you are OK. The adjusting washers are for just that - ajusting. If it still slipped then I would agree that you need a shorter belt.

Jim M.
712W and 710M

David Dunn · Post by **David Dunn** » Sat Jan 30, 2010 12:23 pm

There needs to be some deflection in the belt. If it doesn't, you'll overstress the alternator's bearings. With proper belt tension, and you have the belt slip, it could be the bearings are going bad ( not allowing the alternator to spin up as quickly as the engine).
Also, if the aftermarket belt is different than the original, it may not be making proper contact with the pulleys. I had this with a Supacat, where a replacement belt had a slightly different pitch and thickness where I couldn't get a proper adjustment. And oddly enough, it too has a split pulley .