Bushings....
I have a Hartzell constant speed prop with a Superior IO-360 Engine.
The prop bolt nuts (bushings) only stick out of the starter ring by 1/8". My A&P is concerned about this as the prop hub would allow a 7/16" nut bushing penetration. He is concerned that the prop hub could slip over the 1/8" bushing nut.
I called Superior and they said that is the nut bushings used to be longer and still are in O-320's but this is the new way of doing this.
What say you????
Carl... all of the info. on prop bushings is here...
http://www.lycoming.com/support/publications/service-instructions/pdfs/SI1098G.pdf
The bushings on a O-360-A1A (and most other late model O-360s) are 76656-S which are 0.84 inches long. The later crankshaft flanges are 0.44 thick and the flywheel is around 0.25 inches thick. As you noticed, this leaves 0.15 left to drive the prop, and some of that is not available due to the small bevel on the end of the bushing.
One option would be to replace two opposing bushings with longer ones - 74249-S in your case. This can be done quite easily - and if you call your local engine rebuild shop, they should have lots of bushings lying around taken from rejected cranks.
I just did this on my Tiger (STC option with a new Sensenich prop) and it was quite easy to push the old ones out, and press the new ones in, with a C-clamp and some tubular jigs.
Note that one of your short bushings is fatter than the others (in the hole marked "O") and is listed that way. In the case of the Tiger, the STC option called for the two short bushings to be lengthened to about 0.150 inches longer than the other four.
If you lengthened your short ones, it would be a 74249-S and a 74248-S as part numbers.
Sometimes oversize bushings are installed, and they should be marked with a number on the rear P05 to P20. Of course, a oversized one should be replaced with a similar oversize. In my case, they were all standard, and the crank was a Lycoming factory overhaul.
gil A
