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Aircraft guy’s I need your help!


Well-known member
I know somebody selling a Lycoming 4 banger it has standard nut’s on the jug’s with no plates so I know it’s not a narrow deck it has parallel valve heads and a carb it’s a dual mag aircraft motor and the tag reads 130HP and 140@ take off. Is this a 290 cubic inch 125HP motor or something else. He want’s $1,000 for it and I’m thinking about buying it to build a boat for my wife I would also enjoy building another aircraft motor It has been at least 5 years since I built one. Can any of you tell me what this is and about how much it’s worth it’s in a garage for 10 years and turns easily by hand.
Thunder I found this on line in a paper at


Fortunately this engine exists, in the form of the
Lycoming O-290-D2. This 140 horse powerplant (135 continuous hp) is the bigger,
older brother of the 108 hp O-235. It is smaller, lighter, and thriftier than
the big O-320, but still gives great performance. Best of all, it shares a lot
of parts in common with the O-235 and so is fairly easy to install in your
Yankee, especially if you have the right bird.

Overhaul plus Parts and operation manuals are available at:

http://www.chiefaircraft.com/cgi-bin/ai ... oming.html

Aircraft Spruce may have a little better prices on some of the manuals at:

http://www.aircraftspruce.com/menus/bv/ ... ngine.html

These things were dogs even in new planes. I have flown in Tri Pacers with the 125 0-290 and they are under powered. I had that same engine in my first airboat, it was , thankfully, underpowered as well. Was a great learner though. Fine on the water but can't cruise with the big boats, I burned mine up just trying to cruise with the 455s we built.

I would say no runout engine has any or much real value. Maybe as a core or something and that's about it. Airboaters pay horrendous premiums for junk just because they will do it. Whatever the scrap price for aluminum and steel is by weight is its real value. Outside that, value is in the eyes of the BEER HOLDER.

I don't know if they are getting it, but theres a couple O-290s on airboat trader in parts for sale for more than the grand they want for that one. I guess the grand they want is well, its mind over matter. if you don't mind----it don't matter.
Hope it helps man.

The 0-290 is a good little motor.....the only thing ive ever heard bad, is the crank flange is kinda thin, if you get a 0-320 crank (150hp) and swap them out, it makes it stronger,,,,as far as value, if its an aircraft, not a g/power,,,,its worth 1k as a core for sure. I would rebuild the mags and carb, checking coil output. If you have a dial indicator you can run down the cylinder boar, it will tell you if the cylinders are any good
I believe this is it a O-290-D 130 with 6.50:1 compression and Solid tappets with adjustable valve train this is cool, Hydro control. If my back calculations are correct an O360 has a 5.125" bore with a 4.375 stroke. So I would assume that a O320 has a 5.125 bore with a 3.875 stroke these numbers come up to 320 so does a O290 have a 4.875 bore with a 3.875 stroke this is the only combo I could find that comes up with a 290 Cubic inches. First question if the Continental bores are 5.250 how come we don't see people installing Continental jugs on Lycomings?
Cool the same calculations work for an aircraft engine that work on car motor see we ain't all that different.
Most folks dont put the continental jugs on Lycomings, because the on the continentals, the cam is below the crank. On lycomings, the cam is above the crank, so the valve actuation does not make for an easy swap.

I know some folks who have done it though, and they swear a lycoming with continental jugs mounted upsidedown work very well.

I have not see one run though, and those folks swear alot... about alot of things.
Hey thunder, was at the milk bus sat afternoon and thought i saw a passenger fall out of your back seat , hope everyone was ok. Also your boat was so quiet i could hear a warp drive drowning out your boat and he must have been 3-400 yards beyond you to the north, that rig is impressive, especially when you stopped in the middle of that sticky mud where people were having problems, and took off with little effort.
Yep that was me, my wife lost her hat and let go to catch it and ended up on her but but everyone was fine and we all got a laugh once we knew everybody was fine. I had a few people comment on how it run thru that bad spot, I guess thats why everyone avoided it. I went that way to prevent blasting anyone because three boats parked around me and one behind me. No big deal but thanks for asking? Why wife swears she will get me back I'm scared now!
Thunder your wife did one hell of a job with protecting your child, good to know every ones OK Thank god for a deckover
Big Johnson or SRE how come you didn't drop by and say hello I had no idea you guy's were at the bus. I saw an opening in the rain and was in a rush to get thru it.
We had pulled up a little before and had just started mingling with every one will meet up one day and hang out,
sorry, i was parked by the myrtles south of you and did not recognize your boat till you were leavin, recognized it from the rudder art, it was neat watching everyone hit the mud holes, some made it, some did not.
Davie said ....if its an aircraft, not a g/power,,,,its worth 1k as a core for sure.

That may be true, but it presumes the entire engine can be reworked to aircraft standards. Including the crank and jugs. If the jugs can't be honed and trued up they are worthless, if the crank has to be cut .060 its worthless. If the cases have bulges or warps they are worthless. All of these are possibilities in ANY runout engine.

I still maintain runouts are junk until rebuilt to aircraft standard. Few folks realize what RUNOUT means anyway. Most private pilots these days use a progressive maintenance plan which as long as they show good compression is independent of actual hours on the engine. You can find 4,000 hour engines still flying and never rebuilt. More realistically theres lots of 1,800 hour engines running at 2,400 hours etc. Commercial ops are a different story though. They aren't allowed to do progressive maintenence plans. Private planes can have the pistons swapping holes and as long as the owner says he will fly it he can get away with it. Hes allowed to do his own inspections and just get his signoff once a year, generally by an IA buddy in the next hanger that does nothing more than review his log entries over the year and sign the log book....Used airplanes are every bit as much of a crap shoot as used cars are. Maybe more.

I'm not saying any of this is bad, just that it isn't common knowledge.

My point is still that for an airboater the value is a perceived value not an actual value.

I remember some years ago Billy Willard ran a hybrid engine that was BAS Arse...not sure how many runs he got out of it, but he went fast.
What's funny is I have seen motors fresh out of a plane that had some real shoty work done by FAA certified techs. A buddy of mine owns a new Sirius on his first oil change by a certified FAA mechanic the moron put the wrong dip stick in his plane. Fortunately after landing and checking his oil level he found it was to high and realized the mechanic installed a different dip stick lucky for him it wasn't the other way around so my buddy called the aircraft mechanic told them what happened and asked who's plane is my dip stick in because they are low on oil. Terry told me the mechanic paused then asked how do you know? So Terry proceeded to explain it to him?
Thunder, Brad Hendry ran a hopped up lycoming with cont, jugs. Lacy Everett built the motor. You may remember it, it blew the jugs off the case at the St Cloud race about four years ago. They just turn the jugs upside down. If built right, im sure they can be good motors.
I have seen a couple of lyconentals around, 4 and 6 cylinders. Usine the standard continental angle valve jugs you have the intake and exhaust on top and when you use gitsu cylinders you get a bottom intake with an upstack exhaust. With that 290 there, if it is a d2 with hydraulic lifters you can put gs0435 cylinders on it with high comp. pistons and have a real strong running motor, have seen a couple of those push close to 200hp and they are about 60lbs. lighter then a 360 200hp. You can convert the solid lifter motors to hydraulic to run the angle valve cylinders, it's just a little more work.

Here are a couple pics of some hybrids