which flywheel do I need?

[IowaRV9Dreamer]

I just bought an O-3200-E2A (partially rebuilt)... I don't like the flywheel and will be replacing it. There seem to be a lot of choices (belt size, # of teeth) - what is best? I'll be using the Vans/Plane Power alternator and some sort of light weight starter?

Thanks for any info - I'd like to know what to look for in case I see one at OSH.

[breister]

There are two types of teeth on the flywheel - 122 tooth and 149 tooth. An O-320 is at the top end of engines which can use the 122 tooth flywheel, but it seems fairly rare that people do so. I believe the 149 tooth is also somewhat larger in diameter, meaning your starter doesn't have to work as hard.

Check your current flywheel - if you go with a different number of teeth, you will also have to change your starter (or at least change the gear, if that is possible on your model).

On the other hand, I have a spare Skytec starter for a 122 tooth flywheel for less than a new one...



As for the belt, that decision may change the total depth of the flywheel and thus move your prop out or in - but I'm not certain of that.

Good luck!

[ddurakovich]

Piper used to offer air conditioning on some Cherokees back in the early 70's. THey used a dual belt arrangement, with the standard size belt driving the AC, and a very small belt driving the alternator.

UNDER NO CIRCUMSTANCES TRY TO USE THE SMALL BELT PULLEY TO DRIVE THE ALTERNATOR ON YOUR RV, OR ANY OTHER APPLICATION!

If you have the dual groove flywheel, immediately convert it into a potted plant holder. I'm sure it will work better for that than it did as a flywheel

[IowaRV9Dreamer]

I have a single belt groove on the flywheel (not dual) - I was under the impression that there were different sizes of single belt grooves available. I'll measure it and post the size.

I'll also check the diameter and # of teeth on the ring gear. The gear looks pitted, like it was once corroded heavily, then it was sandblasted and then painted. Not good. I understand the ring gear can be changed, but I wanted to see if it was better to replace the whole thing.

Thanks for the info - I'll post some measurements this weekend.

dave