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Lycoming O 290 Conversion
Posted: Thu Mar 13, 2025 3:32 pm
by 6555
Does anyone have experience with the conversion, what's involved, cost etc on a 140?...Thanks
Re: Lycoming O 290 Conversion
Posted: Thu Mar 13, 2025 3:59 pm
by 6597
fellow local flier had this on his 120.
Gross weight remains the same, you are basically a solo flier due to increased weight.
Need wheel extenders or swept forward gears due to the increased weight in front.
Pretty tight in the cowling area inside.
Cylinders for 0-290's hard to find.
Climbs like a bat out of hell.
Our member Gus Warren now holds the STC's, you can find his contact on the latest newsletter.
Re: Lycoming O 290 Conversion
Posted: Thu Mar 13, 2025 6:49 pm
by 6183
Email Reddoch Williams at:
reddoch@aol.com
He has a Cessna 140 that had the 0-290 conversion, which I now believe has been replaced with an 0-235. He mentioned that parts for the 0-290 were becoming scarce, and he decided to switch over to the newer engine when the installed 0-290 needed an overhaul. He can give you the costs, advantages, and disadvantages.
I’ve flown his aircraft when it was equipped with the 0-290, and as you would expect, takeoff distance is better than with a C-85 or C-90, additionally the climb rate is better. If I remember correctly fuel burn is around 6.5 - 7.0 gallons per hour depending on the cruise configuration of power. Lycoming 0-290 series weighs somewhere between 235-245 pounds while the 0-235 can go up to 240-250 pounds.
Re: Lycoming O 290 Conversion
Posted: Fri Apr 04, 2025 5:16 pm
by drbob
That originally was the McKenzie STC. He also had an STC to put an '0320 under the hood. I saw one in action in New Hampshire at a fly-in. There are two of them flying today. He made a total of five of them before the FAA pulled the STC. It did rather well on takeoff.
Re: Lycoming O 290 Conversion
Posted: Fri Apr 04, 2025 9:21 pm
by 6597
We had a 140 at 59S Evergreen about 20 years ago with the 0-320. Never could get him to show us the paperwork. Black with wheelpants and a skull/crossbones decor. McKenzie's was just a stones throw away from here at Vancouver. Climb was phenomenal.
Re: Lycoming O 290 Conversion
Posted: Sat Apr 05, 2025 5:31 am
by 8342
Just a suggestion for you to get more horsepower for the least amount of money is to make your current C-85 (I assume that is what you have) a Stroker C-85.
There is an STC to put an O-200 crankshaft and connecting rods in the C-85 case. They do not advertise the horsepower increase but it is substantial.
You do not have to do anything else to the engine compartment. No change of engine mount or connections. It is much less complicated.
I did it on mine and highly recommend it.
Rick
Re: Lycoming O 290 Conversion
Posted: Tue Apr 15, 2025 1:39 pm
by walker aviation 2
Does anybody have stc for the 0-320.
The 0 290 parts are getting hard to find
Thank you
Re: Lycoming O 290 Conversion
Posted: Tue Apr 15, 2025 2:13 pm
by dcannon
See Dr.Bob's post above. Looks like it was pulled.
Re: Lycoming O 290 Conversion
Posted: Wed Apr 16, 2025 8:42 pm
by V529
walker aviation 2 wrote: ↑Tue Apr 15, 2025 1:39 pm
Does anybody have stc for the 0-320.
The 0 290 parts are getting hard to find
Thank you
Sorry, there is no "known" STC to install an O-320 in the C-120/140 aircraft.
Re: Lycoming O 290 Conversion
Posted: Thu Apr 17, 2025 8:26 am
by 6643
If anyone has a copy of Aircraft Specification A-768 dated prior to 2003 (the only one I can lay my hands on right now) you might find it there.
I know I saw a plane at a convention in MD back in the 1990s with a 320 in it. We had a seminar on weighing aircraft. After his plane was weighed, I recall he was looking for a ride home for his wife...