Adding a Fan Clutch to an M813?

[kubotaman]

Has anyone looked into adding adding an M939 fan clutch to an M809 series truck? I have an M939 parts truck and I am currently restoring an M813 and I would love to add a clutch to the fan to free up some power. Would the clutch fit without having to move the radiator and grille?

Thanks

 

[simp5782]

Upper plate for holding the clutch. Water pump for a 939. Shutterstat. Clutch. Fan. . You have to cut the fan shroud some as well. I believe the 939 fan is slightly larger.

You should not have to. The snub nose on the water pump allows for it to be closer to the block. The fan sits less than an inch in front of the accessory drive pulley

 

[kubotaman]

That is what I figured, I was just not sure if it had been done before. Will the original M809 fan bolt onto the M939 clutch so I could reuse the original fan and shroud?

 

[simp5782]

You can try it but the offset and curve of the blades may hit the accessory drive being that the snub nose 939 clutch sits closer to the motor.


Like on my big cam. I have to space big cam fan outwards on the 939 clutch to clear the accessory drive but the 939 fan is fine

 

[kubotaman]

Noted thanks