Text by Sterling Vaden, photos by Scott Douglas
If you want to remove the generator, it is not necessary to remove the fan first.
The procedure is as follows (photos show a 1969 912 engine):
- Disconnect the battery.
- Remove the pulleys and fan belt.
- Remove the coil, then the oil filter. The nuts that hold the coil are on the front side of the fan shroud. Don't drop them, or their big flat washers. Now remove the bracket that holds the oil filter. Again, the nuts are on the front of the fan shroud. In the photo you can see that the coil has not been completely removed, just the right hand mount bolt loosened so that the oil filter mounting bracket can be moved out of the way of the generator.
- Remove the four screws holding the generator pan to the fan housing. Loosen the strap holding the generator. Remove the generator wires from the generator. Slide it back part way.
- Remove the two bolts and two nuts holding the generator stand to the case. Now you can slide the generator and stand rearward and out. You may have to fiddle to make sure the fan clears the fan housing. Once the generator is out, you can peer into the fan housing and see if there is any crud clogging up the oil cooler.
- With the generator/fan assembly on the bench, you can remove the big nut with an air wrench. (the recommended way) Or use a strap to hold the outside of the fan and muscle it off. Careful not to bend the fan while doing this.
- Take notes and pictures of the order of assembly of washers and shims behind the fan and also of the fan belt pulley assembly. This will save much head scratching on re-assembly. Torque the fan nut to 72 lb-ft. There is a large cardboard gasket that goes between the generator cover plate and the fan housing. This is a spacer, and it is used to set the clearance between the fan and the housing. The clearance between the fan impeller and the front of the housing should be about 3mm. Also check the alignment of the generator pulley and the crankshaft pulley before tightening the generator strap, but realize that there should be no stress placed on the fan housing by the generator alignment. Check that the fan does not scrape against the fan housing.