Engines
 

What is the difference between an ABC Engin e and other engines? Are they powerful or havea long lasting life ?

Also what are ball bearing based engiens ? What is he difference betwen them and non - bearing engines ?

Engines
 

ABC Stands for Aluminum-Brass-Chrome. AAC Stands for Aluminum-Aluminum-Chrome. ABN Stands for Aluminum-brass-nickel. These all stand for the clyinder construction in a model engine. The first letter is the piston. The second letter is the sleeve or outer cylinder wall construction. And the third letter represents the wear surface of the sleeve that is next to the piston.

There are also ringed engines. These will have a ring on the piston to seal the combustion pressures. These vary some too. There are regular rings and there are Dykes type rings. A Dykes ring will exhibit very little sealing characteristic until combustion takes place. It is considered a low drag ring. Also in ringed engines the cylinder wall can vary. They can be plain steel, hardened steel, Chrome plated steel, Chrome plated aluminum, or Nickasil lined aluminum. Then there are the lapped fit piston assemblies whereby there is a cast iron piston riding inside a leaded steel cylinder with a tight fit. This engine would be in the non-ringed catagory. ABC engines generally last longer than the other types. However there is a trade-off in that the ring is a lot cheaper to replace than the whole piston -sleeve assembly.

There are also different designs of the induction systems in 2 cycle engines. The early model engines are loop scavenged. The intake charge comes around and over the piston on the left side and exits out the right side. These have a baffle on the piston that is about 2/3 over towards the intake side.

The Schnurle ported engines are of later design. They have intake ports front and rear of the cylinder with a smaller boost port on the left and the exhaust port on the right. They have a flat top piston. These engines respond better to throttle control and generally tolerate a little muffler pressure. (More-so than the looped scavenged engines.)

There is a combination engine that is a loop scavenged engine that is modified to have small Schnurle ports also. These are called PDP (Perry Directional Port engines). They have some characteristics of both the loop and Schnurle ported engines.

A ball bearing crankshaft engine is considered to be capable of developing more power at a higher rpm with less drag than a bushing type engine. But they cost more and are heavier.

Enjoy,

Jim

Engines
 

thanks that was great insight to the q ?