National Aeronca Association Bulletin Board

Anyone done the O-290 conversion on a 7EC or know anything about it? I'd like to talk to them.

Steve Jones

Steve,
I have a 7HC that uses the O290. Because the O290 is no longer supported by Lycoming, I plan on using an O320. I have a 337 that converts a 7GC to the O320 that I'll use as acceptable data.
In your case there is approved data for the conversion. Champion Service Letter 60 will cover it. Get a copy and see if that's what you want.
Paul

The O-320 is an excellent upgrade. I replaced the O-290 in my 7GC 3 years ago and wished I had done it long ago, instead of overhauling the O-290. I have not noticed any significant increase in fuel consumption, but there is a substantial increase in rate of climb.

Will it all fit under the stock cowl?
How about the motor mount?
Thanks,
Steve

Engine mounts were fine. Needed an inch or two more on upper cowl to nosebowl. Mags & lightweight starter switched over, as did exhaust. Needed new carb. I took the opportunity to add a lightweight alternator.

Steve,
If you still have the C90/O200 installed you will have to change everything FWF. Possibly the throttle cable and tach cable. Re mark the tach and make sure the oil pressure gauge has the correct range and marking.
Paul

Steve,

If you are not planning to use a Citabria cowl and nose bowl, I have a couple of Lycoming-style nose bowls built by Champion. They are not as nice looking as the Citabria stuff but they are correct look for the period.

Carl Prather

What dash model O-320 should I be looking at?

Thanks for all the replies.

Steve

Steve,
I would look for a Conical mount engine. A O320 with no suffix up to the A2B or B2B. The A's are 150HP the B's are 160. If you go looking get the serial number, a xxxxxxx-27 is a narrow deck and the -27A is the wide deck. There are also some differences in the narrow deck engines. Not all use the cylinder plates and round nuts, it depends on the compression ratio.
Using the conical mount will enable you to use a Lycoming powered Champ/Citabria mount.
Paul

Thanks, Paul.
Where's San Martin? I get to CA pretty often for work.

Steve

Steve,
I'm about 60 miles south of SFO and 25 miles south of SJC.
Paul