Alternator pulley question
 

Anybody know of a deeper pulley for a Mando Alternator? I keep loosing the belt off mine over 5000 rpm and the belt tension and alignment is good but the belt doesnt bury into the pulley on the alternator like it does on the crank and water pump pulleys. Is it possible to convert a mark 4 set up to a serpentine belt? I really dont have the cash to put all the fancy colored billet pulleys on and dont have the time to build my own.

For what Merc would want for the pulleys , it would probably be cheaper to buy those expensive billet pulleys. And besides , you may get away with only buying one , for the alterator:cool:
I have also considered the surpentine route for mine , just for the simplicity and ease of changing the belt;)

If the belt is coming off then something isn't right. How tight do you have the belt? Check the alignment with a straight edge. An 1/8 inch off can throw the belt.

Its right on the money as far as alignment. I tension it so I have about 1/2" deflection on the long leg (without pushing too hard). It just seems that the alternator pulley isnt as deep as the others for the gaterback belt im using now.

They need to be pretty tight.

You can also get a thinner belt. You want the belt to sit just under the top of the pully at max!! Just make sure that the thinner belt is not sitting in the bottom of the other pulleys. Remember if you get a narrower belt you will need it to be a little bit shorter.

Jon

I use a 7480 Gates XL 11A1220 belt with no problems.
Gates belts have a lifetime warrenty.
I had a impellar belt snap on me and
my local parts dealer replaced the belt at no charge.
As said before the belt needs to be pretty tight on the
Mando alternator.
Hope this will help you.

I had snaped a Napa belt that fit into the pulley better but it nearly cost me the engine since it drives the circ pump too. I bought the gaterback because it is supposed to be stronger but now its throwing off at high rpm. Ill ty the gates A belt. Thanks for the suggestions.

Tom

One other thing to check is for rust on the pulleys and make sure that a pulley is not warped. both these things can cause that type of crap to happen