CJMay13

Well, according to RC Pro and ROAR Rules, it's illegal to run ceramic coated pistons and rods so........ Most forms of 1:1 racing ceramic pistons are illegal also.

dreaux

iTrader: (5)

this is one of my wacky ideas that i did not won't to tell anyone (like no one has thought of it before). I don't know why they do not do this already. Or hot rivet crank pins for that matter so you can replace them when they are worn out. You could do the same with rod bushings. Although they are a bit cheaper and can be replaced fairly easily.

how much would a titanium crank cost

dreaux

iTrader: (5)

that is so stupid. makes you wonder who makes up the board on ROAR. If someone would offer this service, i could give a rat's a$$ what roar thinks. I can run what ever i want in races at all my local tracks.


i don't want to get into R.O.A.R. rules and regulations. I know what purpose they serve, but as far as someone like me is concerned it means didly squat.

Davidka

iTrader: (86)

Hardeners and anti wear coatings will only drive the need for extrememly high precision manufacturing.

The reason I'm skeptical about the "matching" think is that break in is far more important and slow with ABC model engines than any other kind of engine I'm aware of. We're essensially cool forging the piston and sleeve into a match. There is obviously a tolerance range where it's either too tight to achieve a match at break in or too loose to arrive at a good seal. I don't believe it is at all difficult to manufacture within this tolerance. I would be interested in measuring a batch of piston/sleeve sets to compare them.

The hard-chrome coating in the sleeve is to prevent the piston wearing out the surface quickly.

martinh

The brass liner expands more than the piston when hot hence when breaking the piston and liner in you preheat the motor to free off the piston and liner fit other wise if the piston expanded more than the liner you would never turn the motor over when starting when new. The coeficient expansion of high silicon alloy (30%) is less than that of brass, Check material specs if you dont believe me. This is how motors rev so high because they free off when hot (turn a motor over when its hot and theirs much reduced compression and not more compression). Martin.

JAMMINKRAZY

iTrader: (17)

All true, but that has nothing to do with piston/sleeve wear. The aluminum piston wears much more than the chrome plated sleeve. It makes sense that you should be able to re-piston a sleeve with a new piston. I too believe that tolerances can be made tight enough that any piston should fit any sleeve(same make and model parts). I also don't buy the matched set BS. Unless you are buying an engine that has been hand matched, you aren't getting a matched set. You really believe factories take the time to match every P/S set they make? I can guarantee that is not the case. You get a piston from the piston bin and a sleeve from the sleeve bin. Nothing more, nothing less.

The true reason that they don't sell pistons separately is because chances are once the piston is completely worn out the sleeve will also have some scratches in it. They also can't take the risk that someone who doesn't know what they're doing(lots of those people around) puts a new piston into a sleeve that is shot as well. What happens when that fix fails, is that the person comes on here and bashes the brand. That doesn't do a lot of good for their reputation. Selling them as a complete new set cuts down on the risk that someone will do something wrong. It all really comes down to making money. They can sell a P/S set for more money than they could sell just a piston. And with a better reputation they will sell more engines to begin with.

martinh

I was making the point where somebody said the alloy piston expands more than the liner and compression increased when hot and nothing to do with why the piston wears. At Axe rossi they have a machine that automatically reads the diameter of the liner and then automatically grinds the piston to suit rather than just making lots of different size pistons and matching them. Pistons can be rematched/lapped to different liners something control line speed airplanes/ tether cars/ tether hydros, have done for years. We also make our own pistons to get a better fit or better suited piston material to used liners providing their still good. Most of the tether car motor makers supply as standard 2 pistons with each liner. Novarossi also use to sell just pistons part number 06000, Check parts list. I believe they stopped doing these now, The US importer of nova marine engines us to stock these for around $25. I think you sent him your old liner and providing it was good they had a series of different size pistons that they would fit to the relevent liner. Martin.

AlienModified

iTrader: (6)

I'd bet they aren't matched at all. It could be that they reach in a box on the left, grab a piston. Reach into a box on the right, grab a sleeve. If the piston fits in the sleeve, bingo, there's your matched set.

If you run off 100 sleeves from the same die, or 100 pistons from the same die, the tolerances may be different, but not by that much.

CJMay13

I could care less about ROAR also. Ceramic coated engine parts=big advantage. Start winning every weekend at your local track and see how long they let you run a motor with ceramic coated parts.

JAMMINKRAZY

iTrader: (17)

Yeah, cause we all know it's the engine that wins races.

CJMay13

Totally agree with you, but you know the first person that finds out they're gonna be cryin' and complainin' about it.

JAMMINKRAZY

iTrader: (17)

Yeah I kinda agree! People love to whine about those kind of things. But being the technology junkie that I am, I would love to see any advancements possible. I do believe SH makes an engine with a ceramic coated piston.

mudboger07

being the motor junky I am I too would like to see more advancement in these mills, I know some mills mainley for airplanes the motors have a kinda piston ring, I do not see why car motors cant do this also along with the coating yal are talking about, I think most of us would not mind paying a few more $$$$ for a motor that would last 10 or 20 + gallons and be able to rebuild it like a 1-1 by just droping new rings or just the piston in it...just my 2 cents...

dreaux

iTrader: (5)

Look. Just give me a crankpin i can replace. Double bushed. Heat the steel bushing up and tap it on the crank pin. Bushing wears out cut it off and put a new one. Hot riveting is nothing new AT ALL.

how about having the piston expand instead of the sleeve? When the engine is cold it will have zero compression, when it heats up the piston expands and has good compression. No more cold starts. THat alone will double the life of your motor. But this would defintley be close manufacturing tolerances.

Have to do something. electrics are getting bigger and bigger at my track it seems like every week. And alot are switching. It's either, they don't like tunning, tired of the price of engines and their parts, tired of the engines prices and how easy it is to ruin them.

Of course i think that is silly but if these manufacturers don't step up with longer lasting esier maintaing engines it could be a blow to the hobby.

bentgear

RC airplane engines last 10 to 100 times longer than RC car engines because of the RPM's turned and the constant load.

If you want a coated crank for your OS engine get one for the Speed. The hard coating used does reduce crank pin wear.

Judging from the way some folks can mess up an engine rebuild I am surprised manufacturers even offer internal parts for sale. As far as a replaceable crank pin, sounds like a lot of engines would be ready for grenade practice.

Rings don't work good on engine sizes we use turning the RPM's we like to turn them. Stay down under about 12,000 and they do OK.

And yes, I have been lucky enuff to find some used engine parts that will work together, but have found just as many or more that won't

Ed M.