Hi there. I have owned my 72 240Z since 1992 and have really enjoyed it. It gets driven about 150 miles per week (mostly back and forth to the golf course. I have recently installed the 240Z 60 amp alternator kit from MSA. I'm having a problem with the pulley on the new alternator in that its groove is about an 1/8 inch wider at the top of the groove than the stock pulley which causes the belt to ride about 3/16 inch down in the groove. No matter how I adjust the belt tension, the belt slips at engine start up, but is fine after the engine is running. The alternator, according to MSA is original equipment on an 81-83 280ZX Turbo. The pulley is of a 2 piece (split in the middle) construction. Has anyone else encountered this problem? Solutions?

When I got mine from MSA, it was a Bosch with what appears to be a one piece pulley (just looked). Belt appears to ride the same as yours, a little below the rim of the pulley.

Installed, tightened and took out for a spin. Everything fine.

After a few drives (alternately babying it and stomping on it), it would start to screech after getting warmed up.

Had to re-tighten and noise went away.

So far it hasn't come back but you may drive your Z more than I do.

Do know that there appears to be marks on inside of pulley where paint has worn away. Maybe yours hasn't worn that off yet?

If lengths are the same, maybe an 81-83 280zx belt?

Or something similar length with a 'fatter' profile.

New belts will stretch just a bit after initial tightening. Sounds like you're well past that phase, though.

MLC240Z suggested getting a "fatter" belt, but if you do, consider the other pulleys it has to fit as well.

You may wish to try some "belt ease" or some other type of belt conditioning spray.