Hello,

I am looking for those with direct experience with these smaller O-470 variants. From the time I've invested so far these engines were known to be installed in Bonanza's and Navion's (?). I'm searching for a 6-cylinder that can operate well on fuels other than 100LL or 94UL that can handle a 2200 pound GW aircraft with floats being the biggest concern for added engine power. The IO-360 engines are lighter but all except the -AF require 100LL.

I think the only significant difference between these two engines from an operational perspective is the 225 makes that power at 2600 rpm and both make 185 hp at 2300 rpm.

No Millennium cylinders presently but Superior did tell me it is possible their product line will expand. However, they do carry a large amount of parts for these engines. J & J has complete cylinder assemblies in chrome or Nickel.

Thanks,

Rick

Have flown them in V tail bonanzas with pressure carbs and they’re fine but why one of those vs a more mainstream 470?

The mainstream O-470 is desirable but weighs at least 50 lbs more. To be more clear, I'm trying to get the engine weight down to 300 pounds if feasible. This would be about the weight of the TCM IO-360.

My "54" Cessna 180 came with an O470A that used the same cylinders as the E185 and E225. Mine was overhauled by Pacific Continental in 1972 and it took me a lot of places. There are heavy and light cylinders with the number ending in 727 being heavy and 454 being light. I did end up topping with 4 ring pistons instead of the 3 ring that came on it and even found Pacific had used a mix of heavy and light cylinders. I eventually put a 470K on

I'm also looking at the O470 engines that are known to possess a lighter dry weight such as the -A, -J, -K, -R, -S, -T, -U, and IO-470 in view of the splined prop shaft of the E185/E225. I just don't see a means of removing a sufficient amount of weight.

Edit - It looks the the splined prop shaft could kill this idea quickly.

You might look at an IO-470J or K if you want to keep it light, but go a little more modern. But from a weight to benefit ratio what you are probably actually looking for is an O-540 235 or 250HP variant with every lightweight mod in the book on them, or an Lyc IO-390. The E225 is a boat anchor on power to weight. Parts are hard to come by, and the props are practically unobtainable.