So engine rebuild time is still about 500 hours away but I am starting some pre-planning to have one assembled and ready when this one is done. My current 0-360 was rebuilt in '92. I was thinking about an IO-360 for round two. Looking for some opinions on this idea as well as anyone with knowledge of an STC to stick an injected in my 59'. Losing the carburetor looks like it will give me another 20-30 hp (depending on model) and save me a little fuel? Do I keep the same prop?

Hi Joshua,

Over the years there have been periodic discussions on this subject so you will want to do a search here and on the ACF as well. As I recall the discussions there is no STC to upgrade the O360 to an IO360. It may have been done on a field approval but as I recall I have not heard from an actual owner on the subject. Further the IO360 in question would be the 180 hp version which has the parallel valves, the same as yours. To get the 200 hp you need to go to the slanted valves and that engine is wider and the consensus of the conversation is it won't fit in an un modified Comanche cowl. It is for the same reason I can't just pop a 300hp IO540 in my plane. Isn't the FAA a wonderful thing?

My intent when the time comes is to send an engine to a shop to have its performance maximized within the bounds of the FAA guidelines.

Good Luck, Don

Don,

Food for thought. There was a GlasAir III that we raced against in a pilot skilled race where all planes were equalized with handicaps. One of his sponsors was Victor - they donated one of their top engine overhauls and promised super performance. Legal under race rules. We raced our Twin with completeely stock 200 hour old IO-320s new from Lycoming engines and won. So this is not apples and apples but given the GlasAir had won at Sun n 'Fun and OSH the year prior, we frankly expected to get beat - just sitting on the ground and looking at the two aircraft. It was his rookie race and we had combined 49 years of race experience - we oldies won overall and 12 of the 14 legs but as the RTW competition went along the GlasAir boys were learning. The point is, it is not always about the engine. Finding the good tailwinds and keeping everything else well maintained with good W&B can and has trumped super neat engine.

Just my 2 cents.

Hi Pat,

"Old age and treachery will always beat youth and exuberance."

Don

PS Experience is a great equalizer.

Really the best option would be the IO-390 if Lycoming was willing to play ball. So far they aren't and have said there aren't enough PA-24-180s to make the STC worthwhile. It would basically drop in with the change in fuel system and pumps being the only other change necessary. You won't get any extra power with injection on a parallel valve 360. You can however port and polish, as well as add electronic ignition. When I overhauled mine last time (for the second time with zero hrs flown, search my experience with Firewall Forward on this forum), they dynoed it at 195 hp at 2700 RPM and 800' elevation on a 85 degree day. That's 15 more than book at higher than standard density altitude. So you can get added performance with a bit of work. Yes the same prop works fine. The props on 180s all work for all applications in the 180 to 200hp ranges.

Zach

Hi Zach,

I admit to being ignorant on this but what would an STC cost Lycoming on something like this, or is there anyway of knowing?

Thanks, Don

Don,
I don't know but probably 200k would be a starting point. It still baffles me as they did Mooneys and Cardinals but won't do Comanches. Both have similar or less numbers than the Comanches.

Zach