MFI drive belt

[inaminit]

First- Heart felt thanks to the MFI thread folks and the other MFI posters on this forum. My latest issue is that the newly installed drive belt for the injecton pump walks backward off the pump sprocket, rubbing a notch into the engine compartment gasket, and has become somewhat frayed in the process. Ok I said- put on a new sprocket. The old one had quite a taper from belt wear. But after installing a new sprocket-there is no change. There is no way this belt will last very long like this. Has this ever happened to anyone else? What is the fix? Thanks

[dtw]

Is the belt tension ok? Might need to adjust the position of the pump away from/toward the centerline of the engine.

[MBEngineering]

HI inaminit
you will need to remove the stacks of the engine, the L/H side injector lines and the injector lins on the pump for the R/H side only, you can then get to the injection pump mounting nuts, remove the nuts and washers from the pump on the L/H side only and check the gap on the stud to the slot in the pump, should be both the same, you will find on your pump the one near the flywheel end will have a larger gap, thay both need to be the same and the belt at a reasnable tension, not like a G string, when you have the pump in line and tightened and up turn the engine over and check the position of the belt on the pully, if OK refit the stacks.

regards mike

[356RS]

+ 1 with Mike's information. I will add that the tension of the belt must not be too tight. Most people over tighten the belt and that will cause the pulley to wear and the belt will want to walk off. With the correct tension set, you should be able to almost pinch the belts together, about a half inch from each other, in the area between the two pulleys.