ceramic bearings

[der_steuermann]

Well said Kevin.

Regardless of engine size I am convinced that within the next maybe ten years there will be major material and design improvements when talking about the absolute top range fraction of competition engines.

These refinements potentially can be considered:

Cylinder sleeve and crankcase deformation: Integral type cylinder sleeve meaning the “liner“ actually is part of the crankcase. Besides the absence of different coefficients of expansion supporting a proper long lasting piston-liner fit it is basically the REDUCTION of engine parts in this hottest engine area being beneficial to top end performance and reliability.

Coating of piston & sleeve: Special ‘exotic’ hard-coatings. For instance ceramic or high strength carbon particles .... to be applied to the piston and/or liner surface. Maybe in combination with chrome.

Overheating and prevention of detonation: Alternative, maybe non-aluminum based material of head button for quicker heat conduction.

Ball bearings: There should be the option to exchange the worn-out silicon nitride Si3 N4 balls. An interchange of single balls will easily be practicable without an inner ring being part of the crankshaft (groove). Thus again a reduction of engine parts favorable to engine life. Best material for the retainer would still be phenolic fiber (THB) IMHO.

Helge

 

[Don Ferrette]

"It’s like anything else: everyone in here has a computer and should take the time to educate themselves rather than Nod Their Head, Say Yes Master and blindly take another dose of bad advice."

Well Kev you & the couple others who've tried them & like them are lucky I guess. Since you seem to think those of use who won't run them have no experience with them well think again. I have personally seen premature failures, excessive & rather fast race wear, poor fit, ....well that's enough for now. Until a higher quality, longer lasting ceramic altenative is offered I simply can't or won't justify the expense. Not to mention there are plenty of us out there going just as fast without them. Do you know what bearings KP uses in his N/R 21's............. <_<

 

[izitbrokeyet?]

Hey Don.......did you read my post?

sometimes...I think we need to set up a Rock-em- Sock-em Robots area to just duke it out .........that post is in origional form (unedited)'

warning----I rule in blue corner

 

[Bob Kensill]

My own experience with the ceramic bearings has been good so far,so I will continue using them. As far as cost goes,how much is any engine improvement worth? I am going to make an educated guess here,but I would bet that the guys that had problems with the ceramics had their problems because of fuel. I hate to name names,but all the local guys that have had any bearing problems,have been using Redmax fuel. I am not badmouthing that brand of fuel,I just think that their oil is marginal in quality when you run too lean. A chemist friend of mine makes my oil and fuel for me. We spent many hours at the pond with his "chemistry set" until we got the combination that worked best. At 14% oil he says that I am running too much oil and he thinks that 6% or 8% would be fine. My engine is 10mph faster with this fuel and the ceramic bearings,than it was before. I don't think you can put a price on that kind of improvement. Not everyone can afford to do some of the things that some of us on this board do,but I listen to everyone's ideas and then choose what I want to try. I work at a hobby shop so I get things a little cheaper than most. Let me know if I can help anyone out with a better price on any parts or service. (cheap plug)

 

[Preston_Hall]

OK, so ceramics are still questionable to some extent.

The physics of the performance advantage comes from the lighter balls. The ceramic balls are 40-60% lighter than standard bearings

If this is true, which I agree, then just lighten your flywheel and use regular bearings. Right? Same thing?

I don't think ceramics will allow less oil since the P/S will be what fails.

Too many, if not all, steel bearings holding world records.

The only set I have seen lasted 10 minutes. The engine never worked correctly again. That goes with what Joe said.

So why use them? Any of the advantages stated here honestly don't seem to have bettered anybody's performance.

 

[Joe_Knesek]

It’s like anything else: everyone in here has a computer and should take the time to educate themselves rather than Nod Their Head, Say Yes Master and blindly take another dose of bad advice.

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Well Kevin, I haven't ever ran them but I am one of the few on this list that have ever made parts with silicon nitride like heart valves, artificial joints as well as semiconductor applications. One thing I think everyone is overlooking is that just like with steel balls, ceramic balls come in a multiude of grades. Obtaining the finish and accuracy needed for our application is not easy and is an expensive proposition. At the time I worked in this industry, ceramic balls of this quality cost over $50.00 per ball. I'm sure the price has come down in the past 7 years but I doubt any of the bearings we've ran have very high quality ratings.

As for my comments regarding overheating, I'd suggest rereading it. I stated that the ceramic balls can withstand alot of heat. When they do reach their point of failure, it's a bad scene.

 

[gil sonsino]

Well I can speak by myself about my personal experience with ceramic bearings and can affirm that the problems with my engine were due to the bad tolerances of those bearings and not of my fuel that is the same for more than ten years and never had a single failure since that.

I agree about the high tec thecnical caractheristis of the ceramic matherial once I played with ceramic dental implants for almost twenty years(I retired from dentistry 6 years ago) and can testemony their incredible chemical resistance of the mouthfluids and their biocompatibility with human tissues. By the way all my dental turbines were equipped with ceramic bearings and here their superiority is something unquestionable!

Following advises of another site we bought some sets from Boca and with no exceptions all guys faced trouble with the fitting.The main influence here to buy them was the fact that my dental experience was awesome with the implants but on the hobby field not that good.I'm not saying that that site is responsible for that at all but how can I trust a supplier that sell three sets of bearings for the same engine,a Picco 80 EXR,one different from the other.

This is a topic to share different experiences and give advises to people that want to know more about this stuff so from good to bad ones every opinion is well respected and can help a lot.

Thanks

Gill

 

[izitbrokeyet?]

Yo Preston,

To some extent what you’re speaking of is correct with the lighter major axis of rotation in a bearing having a smaller moment of inertia. To a greater extent, the lighter balls will accelerate around their own axis with a significantly reduced moment of inertia.

Anyway:

I ‘ll restate that I would not recommend ceramics for a mono or tunnel. I don’t believe I ever went as far as stating that I would recommend them for a Hydro.

I get the feeling that some bad advice led to the purchase of a bunch Boca bearings that had ceramic balls and steel retainers in them. I’m convinced those bearings were crap and that they were sold to a bunch of customers that may or may not know if a good bearing hit them squarely in the A$$ after being fired from a slingshot. I'm not liking the idea that there are people basing their total ceramic experience on some POS boca bearing....doesnt seem fair to the decent bearings that are out there.

For me: Just having ceramic balls even come close to making the cut, when I made the decision to go ceramics in some of my motors. I can say without a doubt that all bearings are not created equal. That decision is an informed one based on the properties of ceramics, the C-fit and the ABEC rating on the set, along with the fact that I can pick up the telephone and call the guy that fit my bearings at any time. I guarantee there are only about 3 other people on this board who could own a set of these bearings if they wanted one.

In short:

Is there a performance advantage to running them in a hydro? I think there is some advantage.

Will the fastest boaters pay what it cost for that small advantage? I seriously doubt it

Do On-road racers pay the cost? Top racers absolutely live by them

Do buggy racers use them? nope

Do Dragster racers pay the cost? yep

DING!

GO BLUE!

 

[Bart Drieghe]

Don't be offended Kevin for my reply but :

Is there a performance advantage to running them in a hydro? I think there is some advantage.

I've seen many people thinking their boat went faster , having higher rpm , etc etc .

The only way to find out is to measure those things , by GPS , by RPM counter ( or in short , eagletreesystems : their data recorder )

I have no experience at all with Ceramics bearings but for me there is only 1 way i'll believe in it : By Real facts .

Don't get me wrong , im not saying they are worthless , its just that i haven't seen or heard anyone using them overhere . ( and i can't afford to risk my engine for testing a bearing )

Best regards ,

Bart

and one last statement , some people might think that they'll find the last miles or so in bearings , i think there is more to find in correct allignment , good fuel , how u work with your engine , prop, etc etc but i do know that every detail might help in breaking a record .

 

[Don Ferrette]

"Some 1/8 On-road guys use them and JP On-road motors come stock with them but they are expensive (around $100+) / set. Most of the .21 drag racing guys use them....I dont know many boat heat racing guys that use them.....I have thought about using them in a heat-race boat but haven’t due to the cost/ benefit"

"I can say without a doubt that all bearings are not created equal. That decision is an informed one based on the properties of ceramics, the C-fit and the ABEC rating on the set, along with the fact that I can pick up the telephone and call the guy that fit my bearings at any time. I guarantee there are only about 3 other people on this board who could own a set of these bearings if they wanted one."

Hey Kev, you've just exerted a ton of energy making a case for people to try them then say you can't justify the expense? :blink:

On this I will agree, the cost vs. quality is not justifiable, they need to become more reasonably priced & higher quality before I risk $600 engines on them. This is based on what I have personally seen (& the associated failures that went with them) that is available to the majority of people here & that's junk. And you're making you case based on stuff only you can get. I don't think this is a remotely fair comparison. :unsure:

"At 14% oil he says that I am running too much oil and he thinks that 6% or 8% would be fine. My engine is 10mph faster with this fuel and the ceramic bearings, than it was before. I don't think you can put a price on that kind of improvement."

Bob your gain was from the dropping of oil content, been there done that, got the records. The increase I experienced dropping oil content in my record trials motors was significant, more than yours actually & with WIB bearings. I'd be willing to bet if you had 2 IDENTICAL motors except for the bearings they'd probably both be as fast as each other on the lower oil content

Until I see a DRAMATIC improvement in quality, PROVEN race winning advantages in a broad spectrum of BOAT motors (not roller skates or Kawasaki's) in what any of us can go out & buy & they are more AFFORDABLE to the average boater for the QUALITY that the Bull is lucky enough to get his hands on then will I step up & try them. Anyone who knows me well can tell you I'll got to the outer limits in search of another mph or tenth (but I won't be foolish about it). B)

And on a closing note this is the best statement so far--

"...some people might think that they'll find the last miles or so in bearings , i think there is more to find in correct allignment , good fuel , how u work with your engine , prop, etc etc..."

DING! DING! This round goes to the RED corner! :lol: :lol: :lol: :lol:

 

[izitbrokeyet?]

I have the ability to build two identical Rx21r1wc Novarossi Motors. One without ceramics and one with...the new one without ceramics will need to be run in......I'll bolt up both motors in my rigger and and let Judge Judy decide

the specs of the motors will be using EAP;16.5 0.497 184 0.642 128 0.639 130 0.007 0.18 10.6 0.742 216 0.375 68 211

Hopefully Preston will lend the stalker or shoot it himself for verification:

That type of info is objective enough for me....anyone else?

 

[Don Ferrette]

I have the ability to build two identical Rx21r1wc Novarossi Motors. One without ceramics and one with...the new one without ceramics will need to be run in......I'll bolt up both motors in my boat and and let Judge Judy decide
the specs of the motors will be  using EAP;16.5 0.497 184 0.642 128 0.639 130 0.007 0.18 10.6 0.742 216 0.375 68 211

Hopefully Preston will lend the stalker or shoot it himself for verification:

That type of info is objective enough for me....anyone else?

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Good for starters BUT you're still doing this with bearings others can't obtain..... :unsure:

 

[izitbrokeyet?]

Only to make the point that I think there is a difference that is measureable in the Hydros. I dont know about a mono or a tunnel.

all along I thought My point has been that ceramics can excell at some apps....but probably not well suited for recreational boat apps.

 

[RaceCraftBearings]

Guys did my post not get read or if read did it not sink in? We are testing that same bearings that Kevin is speaking of from the same source and I am part of that source. They have proven to do well in TUNNELS as we were able to capture US-1 in 3.5 and as I said running away from the competition. Anyone that was at the Nats knows Ron Drakes 3.5 was haulin. We have been unable to break any records due to radio problems or flat water. We are planning some comparisons between traditional and ceramics but have yet to do so. I think they are a benifit but for the price I am not sure that they are cost effective for everyday heat racing. We are still running that set and if they live for an extended amount of time then yes they might be a viable alternative. With that being said I pay x amount for a set of traditional bearings per year with 12 months racing on them and I buy a set of ceramics for 3 times that but they only last for 6 months then no its not worth it to me but if they were to last 5 years and run well the entire 5 years then yes they would be worth it. So far our test set has been on the water racing and testing around 7 months now.

I am still running traditional bearings in all my motors and I do bring home plenty of hardware for my efforts. Driving and setup are the things to key on for success. If you cant drive or setup a boat then not even a turbine engine will get you to the winners circle.

Ron

 

[izitbrokeyet?]

Good for starters BUT you're still doing this with bearings others can't obtain.....

cant obtain yet....

I may be wrong but I heard a rummor they may become available

 

[Don Ferrette]

"We are planning some comparisons between traditional and ceramics but have yet to do so. I think they are a benifit but for the price I am not sure that they are cost effective for everyday heat racing. We are still running that set and if they live for an extended amount of time then yes they might be a viable alternative. With that being said I pay x amount for a set of traditional bearings per year with 12 months racing on them and I buy a set of ceramics for 3 times that but they only last for 6 months then no its not worth it to me but if they were to last 5 years and run well the entire 5 years then yes they would be worth it."

Very cool. That is kinda what I was gettin' at, make the arguement when we have a proven viable alternative. As of right now we, as in the general boating community, do not.

 

[TimD]

Here's a slightly different spin on the subject and some food for thought.

We are talking about a difference in low friction bearings but we still run a flex shaft fixed to the crankshaft that runs almost completely unsupported in a brass tube....... and a lot of struts use a BUSHING or BUSHINGS!

Not meaning to distort the thread - but it seems that there is an argument based on performance increases due to less rotational weight and drag, but it seems to neglect the whole story. I could change my opinions based on KB's posts and tests, but would like to see the other things I've mentioned addressed before hand.

I hope we can keep this thread going in a manner where (1) we can avoid people spending hard earned $$$ on areas with minimal gains, and (2) improve the driveline systems to better capitalise on the improvements to bearings.

Tim.

 

[Mark]

My thoughts exactly TimD. I know the flexdrive and bushed strut has been around for a long time but I believe that it's not very efficient. A lot of drag. Does anyone run teflon bushes in the strut or are they no good? Someone here suggested running a long straight shaft and a short flexdrive shaft to the prop shaft and strut.

On that note does anyone weld their own flex drives to the prop stub. Do you just machine the stub so that the flex fits over it in a snug manner and then bronze it?

Will this guarantee a shaft that runs true?

 

[EatMyShortsRacing]

Anyone who says that Boat Engines are a different animal will only convince me by providing me with the new set of Physics laws that their special boat motors obey. 

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I agree you cant change the laws of physics but boat engines are different in their application. Components that will last all day every day in the same engine in say an aircraft can blow apart in a boat. Different applications can require different solutions and potentially different technologies.

The physics of the performance advantage comes from the lighter balls.  The ceramic balls are 40-60% lighter than standard bearings.  This is simply a direct reduction of rotational mass that will spin up.   

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In general I understand that there must be gains (assuming tolerances and hardnesses and lubrication are matched)... my interest is how much of a gain???

I suspect lots of sets will be sold / have been sold to people who don’t have the wherewithal to figure out if they have a good set of bearings or an expensive piece of junk……It’s like anything else: everyone in here has a computer and should take the time to educate themselves rather than Nod Their Head, Say Yes Master and blindly take another dose of bad advice.

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Yes and this is the point of my questions / comments.

On paper ceramics (and other exotic substances) are the way to go....

But there has also been problems with ceramic bearings as statet by others. Now these may have just been crap bearings or wrong tolerances or wrong materials...

My point is there is little information on successfully running ceramic bearings in boat engines and the potential gains (in real terms) have not been specified. These are the questions needed to be answered by the general boaters before they jump into ceramics. You may be having success with ceramics because of your knowledge combined with the technical advantages. What everyone else needs is to have the same knowledge and comfort level to allow them to consider ceramics as a viable and worth while alternative.

I am definitely not arguing that ceramics are bad or anything. I do believe that applied correctly there MUST be a performance and longevity advantage.

 

[EatMyShortsRacing]

My thoughts exactly TimD. I know the flexdrive and bushed strut has been around for a long time but I believe that it's not very efficient. A lot of drag. Does anyone run teflon bushes in the strut or are they no good? Someone here suggested running a long straight shaft and a short flexdrive shaft to the prop shaft and strut.On that note does anyone weld their own flex drives to the prop stub. Do you just machine the stub so that the flex fits over it in a snug manner and then bronze it?

Will this guarantee a shaft that runs true?

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I have been using lead teflon bushes in struts for years. Correctly maintained they seem to be fine. The longer the strut the better though. Allows less leverage on the stub shaft. Bearings will last longer.

Longer straight shaft and shorter flex??? You been looking at my .21 rigger? It has a 12" stub shaft and 7" flex drive..... and the next one will have even more solid shaft in it. Technically has to provide better power transfer. How do you do the mechanics of that in an RC boat???? Thats up to your ingenuity.

I prefer using ferrule setups rather than the stub connected directly to the flex shaft. Allows you to use square drive connections to your engine and you will lose far fewer props.