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O-235, O-290, O-320 motor mount

azrv6

Well Known Member
Suppose you had a plane with an O-235 mounted on it. Would an O-290 and/or certain versions of the O-320 mount to the same motor mount?

Thanks,

Dave
 
It depends.

My -9 started life with an O-290d2. The O-235 and 290 share the same length engine mount (approximately 12" from the firewall to the back of the engine mount ring). However, I believe the the O-320 mount is 2" shorter, but check with Van's. The mount for my replacement O-360 is the same as the O-320's mount, which is approximately 10" from the firewall to the back of the engine mounting ring.. Scott, can you verify?

The other catch is the O-290 required a conical engine mount. I don't know if all O-235's are conical or not. O-320's came with three different style isolation dampeners.
 
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I had my O-290-D2 converted to Dynafocal, so it's possible.

Yes, you can have any engine case converted to a Dynafocal mount and it really doesn't cost that much. However, I believe it can't be done to an assembled engine, case halves only. I could be wrong here and would like to know if anyone will do it to an assembled engine.
 
Per Bill's post, the O-235 motor mount is extended approximately 2" further out than the O-320 mount. I have the Vans O-235 engine mount (Type I, dynafocal) and originally had a O-235 L2C on my RV-9A. When I upgraded to an O-320-D2A, I reused the mount. I also reused all of the engine cowlings without modification (physical difference in engine size is minimal). The only major change was that I had to replace the intake air box as the O-320 carb is not in the same location as the O-235 - it's approximately 4" further forward and offset to the left ~1". I used a lighter prop and EarthX battery to save weight, and ended up losing 1 lb in overall weight from the conversion. C of G worked out perfectly - empty C of G went from [email protected] to [email protected].
 
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