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View Full Version : Changing a O-290 D to a O-320 Axx



Clayton Harper
07-21-2008, 09:59 AM
I have a pretty low time (35 TSOH) but not "fresh" (A&P overhauled in '98) O-290 D that is not legal for my Clipper. Without a lot of trouble, I can't get this engine approved for the Clipper. With the Stewart STC for the O-320 that seems to be the way to go, gets me 25 more HP and makes the airplane worth more at time of resale. A friend of mine found me a narrow deck case (like the one used in the STC), crank and logs for $800. I'm told that lots of the parts from the O-290 are the same as the ND O-320. I plan to buy a new ECI cam, have the case reworked by DIVCO, and buy new Lycoming Cylinders. I will have O-290 parts left over that may be valuable since many aren't being built any more. Anyone have thoughts.... other than buy someone else half time engine?

jay heil
08-03-2008, 11:27 PM
have a pretty low time (35 TSOH) but not "fresh" (A&P overhauled in '98) O-290 D that is not legal for my Clipper. Without a lot of trouble, I can't get this engine approved for the Clipper. With the Stewart STC for the O-320 that seems to be the way to go, gets me 25 more HP and makes the airplane worth more at time of resale. A friend of mine found me a narrow deck case (like the one used in the STC), crank and logs for $800. I'm told that lots of the parts from the O-290 are the same as the ND O-320. I plan to buy a new ECI cam, have the case reworked by DIVCO, and buy new Lycoming Cylinders. I will have O-290 parts left over that may be valuable since many aren't being built any more. Anyone have thoughts.... other than buy someone else half time engine?

I dont know what parts would fit from an O-290 and fit an O-320 but if you have the case and crank , your buying a cam and cylinders you dont have much left seems like you would be waaaaaaaaaay ahead to sell your O-290 as a complete engine and buy the rest of the stuff that you need for the O-320 with the possible exception of the mags , the carb is probably differant but I dont know that

Steve@StevesAircraft
08-06-2008, 06:43 PM
There is a world of difference between the 0290-D and the 0-320 ND. The 290 is a solid lifter engine where the 320 is a hydralic. All the parts there are not interchangable. If you had an 0290-D2, then you have a hydralic lift engine with a lot of more common parts. The accessory case is different also. The pan might fit, the intake system is doubtful, carbs are different , mags are the same, gear train gears might be ok.

I think the gentleman is right. Sell the 290 complete and use the money to put together a 320 with the right parts.

Steve

Frank Green
08-07-2008, 08:09 AM
There are some of us out here that think the 290 is a good engine and overly disrespected. The original 290 in our 1950 PA20 has been reliably motivating that plane for nearly 60 years! (Yes it has been majored once and topped once). If your 290 is in good running condition it would have value complete to someone building a homebuilt and that money could buy the proper parts to complete the 320.

Steve Pierce
08-09-2008, 03:38 PM
Clay, In your environment I would with the ECI Titan Nickel cylinders for corrosion prevention. I would compare the O-320 Parts Catalog PC-103 with the O-290 PC-102-1 and see what is interchangeable. I doubt it would be worth splitting the case. I think your O-290 could be installed on your Clipper via field approval because the 125 hp wouldn't be more than a 10% increase over the 115 hp O-235-C1. You can also check with parts overhaulers for used rods etc. I bought an overhauled crankcase from a guy in Hawaii who sold all the other O-320 parts from the engine to Aircraft Engine & Accessory in Dallas 800-808-5908. Buy a new cam, lifter and tappet set. I got a better price as a set on an O-540 I overhauled.

Here is the O-290 Parts Catalog.
[attachment=0:29kpizpd]PC-102-1.pdf[/attachment:29kpizpd]

I tried to download the O-320 Parts Catalog but the file is 15,861 KB and would not load. :x