Matt:

Sorry, the jargon does tend to accumulate.

ringed engines? A piston either has a lapped fit in the bore for sealing, or a mteal expanding ring around the piston to seal it against compression. Most small two strokes are lapped piston, I don't know of any four stroke engines that are not ringed.

Three of your next are methods of making a cylinder sleeve and piston set.

ABC? Aluminum/Brass/Chrome.
AAC? Aluminum/Aluminum/Chrome
ABN? Aluminum/Brass/Nickel

The first is the material ofthe piston. then the sleeve itself, finally the plating material the piston rides against. The ABC was the first, and is still good, but it makes a heavier engine than the AAC. ABC is still common, currently used by Magnum and others.

AAC is a later process, machining and finish is more expensive that ABC, but the material cost is lower. The late Saito engines, and the K&B Sportsters are two examples using AAC.

ABN is the least expensive of the three. The nickel being softer than chrome they are less wear resistant than either ABC or AAC. OS, current Webra, and Thunder Tiger are ABN engines.

These aren't the only ways to make an engine, the K&B ringed engines have chrome plated steel liners, some of the Fox engines still use plain steel sleeves with iron pistons. Don't laugh. I have some steel/iron engines more than 40 years old, still run well, but you must use castor oil with them.

ASP? This is the odd ball. What we get in the USA with the brand name "Magnum" is sold elsewhere in the world under the ASP brand.

Some others you might see. C/G, c/g, cg. and sometimes cog all mean center of gravity. CHT is cylinder head temperature, MAC - Median (or Mean) aerodynamic chord is the geometric center of the wing in the fore and aft direction. Used for relating cg position.

You will also see "Bushing Engine" which should be called a "Plain Bearing Engine" as many do not have a bushing, the crank runs directly in the material of the crankcase. All the Cox engines you will see are plain bearing, with no bushing. And like the steel/iron engines, long life requires castor oil.

That's enough for now. See another come on back. But to assure an answer, call with a PM or email.

Bill.