The 150hp O320s for fixed pitch only may have a 4 piece front bearing setup and if so they might not have the hole drilled for the prop control oil feed.
As we’ve previously ascertained, O320 *solid* cranks don’t exist
but what DOES exist is hollow cranks without the hole in the front section for the oil feed tube.
What I don't know is whether the front bearing area of the case is the same whether you use a 2 or 4 piece bearing. My engine was a 150hp and was then rebuilt as a 160, but I am pretty certain the guy who did the "overhaul" (if you can call it that) didn't send the cases off for any work of this nature.
By my understanding the things an O320 needs for constant speed use is:
- Oil hole drilled in the front of the case
- 2 piece front bearing
- No drain hole on the left side of the main bearing (or this needs to be plugged if present)
- A crank with the oil feed tube, with the front plug removed and rear installed
- Governor drive pad on the accessory case
That's it. Some of those things you can't find out without dismantling the engine unless the engine builder kept diligent records. If the case doesn't have the hole drilled, Divco can add that for you. There may also be a hole in the front bearing area on the left side of those cases for fixed pitch only engines but this can be plugged. That's been documented here on VAF I think.
FWIW my 1975 wide deck O320 was originally fitted in a Rallye, and despite being fixed pitch 150hp it had the 2 piece front bearing and accessory pad for the governor. It had the hole for the oil feed too so it was easy to convert.
