'Compatible' engines in a -9?

Now that I have my fuse ordered I'm starting to keep an eye out for engines. Looking for a used (I)O-320 but unsure about all the dash designations.

Can someone point to a good doc on which ones work well in an rv-9a? My only requirements are that it fit with no/minimal extra work, accept MoGas, and be easily convertible to c/s in the future.

Any pointers or thoughts greatly appreciated!

http://www.pilotfriend.com/aero_engines/engine_specs/Lycoming 0 320.htm

Try this.
Dave

So really anything with the right mount should work?
I don't see any stock o-320 with the 9:1 pistons so mogas should work in all of them?
Looks like the -*1* are c/s and the -*2* are fp?

Any gotchas I should watch out for?

A few O-320 engines have the carb mounted toward the rear of the sump. These do not play well with "A" type aircraft. The carb interferes with the nose gear.

Thanks Mel. Is this a designation or model number I should look out for?

I don't have that information right at hand, but these engines were primarily used on the Grumman aircraft. I believe that the suffix is -xxG, as in E3G, etc.

Additional resources and choices

From Matronics archive http://www.matronics.com/rv-list/hovan/Vans/engine.html:
"...Not every O-320 or 0-360 will fit... Carburetors, fuel injectors, induction tubes, governors and other items have all been mounted in different places to satisfy the needs of aircraft designers..."

[support for Mel's response:]
"...Engine configurations that cause problems on RVs include HORIZONTAL DRAFT CARBURETORS or INJECTOR BODIES, that are mounted on the rear of the oil sump... Another problem area is the "H" engine. Lycoming produced an entirely different O-320 for the 76-77 Cessna 172. The fuel pump was mounted over the front left cylinder, the accessory case at the rear is integral and a different shape. As supplied, the RV mount will not fit with this engine, but modifying the mount is not difficult, and several RVs have been flown with this engine. In general if the induction system faces forward or is mounted toward the front of the oil sump then interference with the mount itself is not very likely...

Lycomings also come with three different engine mounting systems. The most common and modern is the DYNAFOCAL TYPE I which has a bolt attach angle of 30 degrees to a line that would parallel the crankshaft. The second most common is the CONICAL which has bolts which directly parallel the crankshaft. The third and least common is the DYNAFOCAL TYPE II which has a bolt angle of only 14 degrees to the crankshaft. Van's can supply mounts to accomodate any one of these engines. Another major consideration would also be that the engine have a mechanical fuel pump on the accessory housing. Many high wing aircraft do not use engine driven fuel pumps. If one of these engines is to be used on an RV then either a machining job is in order or a new accessory case must be located.

... A nearly complete list of these engines is included in the engine section (chapter 11) of the RV construction manual..."


I don't have my construction manual to hand, but you might.

Google is your friend...

Engines

Mel said:

A few O-320 engines have the carb mounted toward the rear of the sump. These do not play well with "A" type aircraft. The carb interferes with the nose gear.

Click to expand...

The engines with the carb mounted toward the bottom rear of the sump are easily converted by changing the sump and intake pipes. Don't pass on a good deal on an engine because of the sump configuration.
Virtually all of the Type II mount IO 320 engines were used on Twin Commanches. If you are dealing with a core engine for overhaul, the type II mount can be converted to type I by the shops that overhaul crankcases.
The type II IO 320's all have the rear mount fuel injection, so that will likely need to be changed.