Niro engine MFG
 

I looks like all the nitro engine manufacturers are non existent. Does anyone know who is still making engines in to .46 to .53 range?

BTW, i have an OS 46 FX that needs a piston and sleeve. I cannot believe no one on earth has this part.!!!

OS is still active, and a few others, like SH, Force, and I am sure there are more. NGH also sells a .56 glow engine nowadays.

As for your FX: try to find an ASP or Magnum .46 twostroke that is still in good running condition. You should be able to pick these engines up cheap, for sure cheaper than the price of an original OS pison/liner replacement set.
The piston/liner set of those cheap chinese engines is not only a direct drop in replacement for those of the FX, it is even MUCH better, being true chrome (mine gained 1000 RPM, and my OEM set was still pristine, undamaged and not worn out...).

Out of an abundance of caution: Be aware that those piston/liner sets need to be replaced as a set, it is NOT possible to only exchange the piston or only the liner. It has to be the set, and also mark the orientation of the piston (which side is toward the exhaust) because mounting the piston 180 degrees rotated will ruin the fit if you try to run it.

Not cheap, but existent:

https://www.westonuk.co.uk/Engine-And-Pipe-Deals-/

Paolo

you can buy a K&B 48 hear in this link for $240. I believe they call this engine "the Screamer". I rather have it than any OS 40/46FX engine. just my opinion. you can buy other engines in this link too. but this 48 K&B seems to be the best buy. with mufflers the K&B should weigh close the same as your OS. they have the HP 40 too. but it's more money. both brands are super good engines, but old stuff I would have over a FX.
you can call them to see if they will build you a Webra. but I don't know if they have enough parts.

Model Engine Company Of America - America's largest producer of Model Engines for airplanes boats and cars (mecoa.com)

Jim

OO looky here looky here. even less money.

.K&B Scremin’ .48 Goldhead R/C ABC NIB #2 - RC Groups

Jim

.46 &.55 glow engines are still available
 

Chief Aircraft (https://www.chiefaircraft.com/radio-...s-glow-engines) carries OS 2 stroke engines in .35AX, .46AX, .55AX, .65AX, .75AX, .90AX and 1.20AX sizes. They also carry Saito 4-cycle glow engines in a variety of sizes. The Saito FA-62B would compare well to a typical .40-.46 two stroke glow engine, but would be a little heavier. However, it would drink less fuel. Still lots of good used engines available for near dirt at RC flea markets. Check your local model clubs. I bet somebody will probably still have some .46 size engines in a drawer they would be willing to sell cheap. Old does not necessarily mean its junk. Yesterday, I flew my Goldberg Cub powered with an Enya .53-4C that has been on it since 1995 and it still starts and runs like new. My Enya R120-4C has been on my Phaeton 90 biplane since 1988 and it too still runs like new 35 years later. If you can find a used, but not abused, Enya .40-45 .50CX in decent condition, it should last a really long time and become one of your favorite engines. I think Enya engines are still being made, but you will have to order them from Japan (https://www.enya-engine.com/ListAP2CYL_E.html). They show a 50CX twin needle valve model rated at 1.7 HP that should start your tractor.

Not quite true, you have O.S. and Force engines still available, plus some others.

Yes, Force and O.S. and DLE and Saito.

My advice is, due to exuberant part prices, one is better off buying a complete engine and either use as such or part it out to suite your needs.

FYI
The 46FX-H heli engine cylinder and piston will fit. Its a ringed setup vs the FX ABC/ABN. I've done the swap and it all fits and runs the exact same as the FX ABC parts. Same port timing. Same bore and stroke. All the same except the ringed setup in the heli version.

Personally, I favour "anything ringed from OS" over "anything ringless from OS"

For sport engines, I would agree. For me, a ringed setup lasts longer.

For racing, a properly fitted (expensive) ABC has been proven to run harder. Mainly, you can run massive ports without risk of the ring expanding into a port ajd hanging up.

More importantly is lack of worry about ring flutter in the ringless jobs. Ringed engines are cheaper to rebuild and renew, but true ABC and AAC spank ringed setups in every other aspect. I’ll gladly trade a ringed engine for an ABC/AAC any day. Properly treated from new, a quality true ABC/AAC can easily outlast a ringed engine though.

True, but I am more interested in durability, reliability and "refurbability". I don't care too much about balls-out all crushing power.
I don't mind having a GOOD non-ringed set-up, but when it's worn out, it's worn out and nothing I can do about it. It's a matter of principle because I've never really had too much issues with that, it's just the peace of mind in the back of my head that says, nah, I'll have the ringed one...

I'm the same way. I don't race or fly competitively. A ringed sport engine is my preference.

I don’t choose ABC/AAC for balls-out power. That’s never been the issue. I have had many ringed engines, and they ran fine. But the just weren’t as good as the ringless engines. Lapped included. I love the lapped engines just as much as ABC engines. Ringed diesels are not the best - and I have converted several engines to diesel. The ringless engines are far easier to start, and don’t suffer from stuck rings due to carbon. I’ll say this; I know who to turn to when I have ringed engines to dump. ;).

Joking aside - ringed engines have their place. In the displacement size I use, it makes little sense to have ringed engines (mostly <10cc with the exception of a few 4-strokes and an ST S90 that are used on airboats and a couple ancient Enya 2-strokes).

for the average flyer, or even a good pilot with a tuned muffler or even a tuned pipe you got to really scream a good ringed engine to mess-up a ring. when I was flying Helis I ran a constant 17,000 on my OS 50. and when I got the tuned muffler made in Europe I was running 18.000. today I still have that engine on a plane, with an oversize stock type muffler and it's tuned at 12.800 for flight the last time I checked it.

Jim

This, to me makes sense because with ringless ABC engines, the entire piston contact area forms the seal. Also, with rc ringed hobby engines usually only one ring is used surely a double ring engine would make a better seal?

It’s a catch-22. Two rings will seal better, but at the expense of higher friction. This is why engines that were originally fitted with two rings from the factory are often replaced with a single reproduction iron ring that are rewarded with better power (the better the piston seal the better the power).

Very true, agreed, it would increase the friction resulting in higher engine losses.