Toysrme

Now you would probably figure that of everyone on here Id probably be the ****** lover that would know this.
Why do we use rings in engines? In nearly all 2 and 4-stroke glow performance we use in R/C up to around 1ci in displacement you use a tapered cylinder wall.
ABC or ABN. Aluminum block with a Brass cylinder liner that is Chrome or Nickle plated. (ABN is the el-cheapo version) The cylinder wall tapers bottom to top, snug at the top. The piston will somewhat score into the chrome/nickle liner. At the same time the brass liner expands quickly with the heat input and you wind up with a seal youd never see any other way in our lifetime.

Google it for 2 min will tell you why it's replaced ringed engines.
They break in 100% within an hour of first run, most of that in the first 15-20 minutes. The friction is DRAMATICALLY reduced VS what just one ring drags (no 3-4 rings in this size engine) and the seal is FAR tighter than youd ever get with a ring. They are NOT tolerant of rich conditions, if they run rich, they run too cool and hence the brass liner wont expand. They are VERY tolerant of lean conditions. There is no ringland weakspot to microweld & crack off with detonation... Piston face sure, but lets face it this is HMT. Everyone that's been here for any time will probably throw up you're more likely to crack a ring-land before the face. Overheating the engine... Not a problem. Aslong as the bearings get their oil you're moist vagina. You get a more reliable running engine (in the glow case), and a longer running one. The downside being instead of replacing a ring and honing the cylinder you replace the sleeve with a matched piston. (cost)

Personally... Having dozens of ABC engines (not 6, or 8 or one dozen, dozens, nearly 30), and having flown between multiple times a week to a semi monthly basis for the last 14 years. Ive never had an ABC engine wear out, let alone need any form of factory servicing. Never met anyone in real life that had one with a new piston & sleeve, provided they didn't run one sick rich (the big no-no).



So anyone know why we don't see it on larger engines? Itd be ------- **** for FI. Ive heard manufacturing problems. I refuse to believe manufacturing problems... It's 2008 you can machine any------- thing ya want!



Edits because its 10:17am and Im already drunk. College football WOOOO LoL

Toysrme

Piston itself runs a hell of alot cooler too. You transfer alot more heat with the piston riding a brass sleeve than a pissy ferrite ring riding a normal liner.

Slo_crx1

They probably won't do it just for emissions reasons, and I'm sure positive crankcase pressure would tend to be high, more oil changes due to carbon building up in the oil, etc.

ghettoturbo

seems like you would be losing a lot of energy as well, since it only really seals near the top right?

Adam Hopkins

These engines are terribly inefficient compared to the standard combustion engine. A lot of fuel goes through the engine that is unburnt and ends up in the exhaust.

Toysrme

Yet they make 30%+ power that a gas engine in that size do and 50% over a diesel.
Stupid dip-****** the fuel is your oil, its the oil flying out of your combustion chamber.

Hitchhikkr

+1

Burning oil in your combustion chamber makes the NOx levels go thru the roof. No cat would survive long under those conditions.

Toysrme

That's for diesel / alcohol fuels where the oil is IN the fuel.
Remember the CC seal is far higher than that of a ring. There would be even less oil in the chamber than with rings.

N1ghtM0nkey

You've honestly never heard of people putting new pistons and sleeves in ABC engines? Give me your address and I'll send you 2-3 that need a piston/sleeve from my own collection. After you run probably 4-5 gallons through an RC Car engine, it's normally in need of a rebuild.

You can tell this because the engine will still start up and run when it's cold, but after it heats up - the engine just shuts off.

I'm under the impression you're talking about RC airplane engines and not RC cars. The reason you've probably never seen one need a rebuild as fast as anybody that has a glow fuel powered RC car is because the engine is under a lot less stress. It's like the difference between driving a car on the highway it's entire life or driving it in busy traffic in town.

So the reason I see that we don't use them in cars is because they wear out entirely too fast, and they're way too fragile. If you suck in some dirt on a ringed engine it's not that big of a deal as long as there aren't any chunks. If you suck dirt into a non-ringed engine you're either going to see engine failure (no compression) or a reduction in engine life. Also 2 stroke engines are not very popular with the emissions control crowd, there's been rumors for awhile now that 2 stroke vehicles/boats are going to be banned from certain recreational areas.

The last thing we need right now is vehicles that consume oil more than the ones we already have.

Toysrme

I sure have, but Ive NEVER had one that needed it because mine are NEVER run rich.
Car people are god damned morons so STFU. Not only are cars gay, but there is almost no group of car people in anywhere in the world that know anything about anything. They destroy their engine and motors, they can't setup anything, they ruin battery systems because they don't know ------- ----.




Get a large pink ***** and hang yourself around the neck.