Ceramic Bearings

[Marty Davis]

Many years ago I tried to use ceramic bearings with VERY limited success. These were the early days when ceramic balls were being placed in stainless or chrome retainers. The balls were never exactly the same size and probably not the same material

I had a lot of failures at the most inopportune times. I lost some BIG races because of these failures.

With the new ceramic bearings that are available from several sources, I am thinking that I might re-visit this.

I have always done a lot of business with BocaBearings over the years and have used their stainless bearings with C3 fit and Plastic retainers. Have had fairly good success with them.

http://www.bocabearings.com/bearing-inventory/Radial-Bearings/14623/14-5x26x6-MX26145ET46C33AF2

I bought a few of the new 21 DD engines which have 1 ceramic bearing in them and 3 others that are chrome.

In looking at the current available Boca Ceramics I see that they have several choices in ceramic and hybrid ceramic bearings.

They have Bearings with chrome races with half Silicon Balls and half Chrome balls and plastic retainers. They have Bearings with chrome races with full ceramic Silicon balls.

They have full ceramic races (Zirconia) with Zirconia Balls and Peek retainers.

http://www.bocabearings.com/bearing-inventory/Radial-Full-Ceramic-Bearings/16521/14-5x26x6-26145MXTPC3ZS5AF2

They have full ceramic races (Silicon) with silicon ceramic balls.

http://www.bocabearings.com/bearing-inventory/Radial-Full-Ceramic-Bearings/16518/11-5x21x5-21115MXTPC3ZS5AF2

The full ceramics are expensive, but I would be wiling to pay for them if they were far superior and would last and last.

With ceramics I am sure that the lubrication package is SUPER IMPORTANT too. Do you use more or less lubrication? I don't know....

I am most interested to hear from others with knowledge about this subject. I am tired of having to replace bearings very often and have them "bit me" at the totally wrong time. Like this past weekend of testing !!!

 

[dwilfong]

Marty,

Albert has tested the full ceramics.

>>>>>>>>>>>>>>>THY DO NOT WORK>>>>>>>>>>>>>>>

The boat never even got on pipe and >>>>>KABOOO>>>>>>>>

DONT GO THERE>>>>>>>>>>>>>>>>>>>>>>>>>

 

[Samuel Hagan JR]

Great info as I was looking into this my self for next year.

 

[charles siler]

That's funny novarossi have ceramics and they run just fine.

The 46DD has a ceramic big bearing and a high speed small.

 

[Glenn Quarles]

Friends, the most critical part of any bearing is the fit! Most bearings we get, either from the manufacturers or aftermarket are way too tight! The secret to increased performance from your bearings is finding someone who can accurately measure and assemble then with the correct fit. My opinion is that a correct fit ceramic ball/steel race bearing is awesome! The Nova bearings are Very good but still not as good as a custom one.

GQ

 

[Elias Vazquez]

Friends, the most critical part of any bearing is the fit! Most bearings we get, either from the manufacturers or aftermarket are way too tight! The secret to increased performance from your bearings is finding someone who can accurately measure and assemble then with the correct fit. My opinion is that a correct fit ceramic ball/steel race bearing is awesome! The Nova bearings are Very good but still not as good as a custom one.

GQ

Hi Glenn,

Do you have a good source for customs that you could share with us.

Thanks in advance,

Elias

 

[Jim Allen]

Friends, the most critical part of any bearing is the fit! Most bearings we get, either from the manufacturers or aftermarket are way too tight! The secret to increased performance from your bearings is finding someone who can accurately measure and assemble then with the correct fit. My opinion is that a correct fit ceramic ball/steel race bearing is awesome! The Nova bearings are Very good but still not as good as a custom one.

GQ

This statement is 100% correct !! Accurate measurement of interference fit amounts & an in depth knowledge of what radial clearance amounts should be used, are critical for reliable bearing performance in model engines. This applies to all metal bearings or ceramic hybrids. There is no application in model engines for a full ceramic type bearing because of the very low thermal expansion rates of all ceramic materials when compared to steels. An understanding of which metallurgy type will be best also will be necessary when selecting a bearing. Most suppliers who are selling bearings, all metal or ceramic hybrids, will not have the necessary measuring tools or knowledge of the methods used to determine accurately the very important radial clearance amount before the bearing is mounted.

Jim Allen

 

[Glenn Quarles]

Friends, the most critical part of any bearing is the fit! Most bearings we get, either from the manufacturers or aftermarket are way too tight! The secret to increased performance from your bearings is finding someone who can accurately measure and assemble then with the correct fit. My opinion is that a correct fit ceramic ball/steel race bearing is awesome! The Nova bearings are Very good but still not as good as a custom one.

GQ

Hi Glenn,

Do you have a good source for customs that you could share with us.

Thanks in advance,

Elias

Hi Elias! Yes a gentleman named Greg Settle is the best bearing guy I have ever seen!!! sometimes he is kinda busy with other stuff so I you would like to get some bearings done send me a pm and I will check with him.

GQ

 

[dwilfong]

Gregs bearings are the snizel..........

That's all I use in my eng.

Full ceramic ball bearings with ceramic races DO NOT WORK..............................

I have full complement bearings I buy and are reballed by Greg and thy are set way looser than any C3 off the shelf.

Thy have run in my 1.01 for over 3 years with many gallons of fuel run threw the eng.

Thy are what I use in my 1.05 build up also. Ask any one running a VAC .91 how long there bearings last......I am running a heavy 1.01 billet piston and pin in this eng and have 10 gallons threw the eng no problems yet.

The oil is the same as I always ran. nothing special needed.

SS races will not hold up as thy are soft.

I buy $5 Enduro bearings then have Greg reball them.

Thy are very true and cryro treated races. Great bearing to use for reballing.

Greg dose not do many as it is a hobby to him.

If you look on line there is some info on bearings that have a stall grove in the race. thy stop the balls from bunching up reducing friction. I think that the groves in the full complement races to let you pop the balls in and out work like this with the light ceramic balls. This keeps the balls separated and reduces friction even more. All conjecture but this setup runs great. have not changed one out yet.

It is not just the clearance but quality of the balls used. You need good balls to get good results. Also the races used need to be true and of good quality. not all balls are created equal.......................

Measuring the clearance is not that hard BUT having the balls on hand in the different sizes to get it right is.

There are many different sizes of balls in the same range for one bearing. You don't know what you need till you measure them then disassemble and measure the balls. then you have to have the right balls to reload them and get the right clearance.

Takes lots of balls ...........

Well I ain't got that many balls...........................LOL

Also some races are to far out of speck from the production allowances and there is not a ball size to get it right or the run out is not in speck. So you need to buy extra bearings. Depend on what end of the tolerance thy came off the machine if thy can be reballed right.

Spent a few hours talking with Greg as you can tell..........LOL

He is a wealth of Knowledge when it comes to bearings.

Greg is the man when it comes to bearings....................................

Albert had Greg do some for his eng after the full ceramics did not pan out.

 

[Marty Davis]

OK, I got the info that all of you have offered.

I am going to order a hybrid kit for one of my 21 engines and also a regular chrome kit and see how each work. I will put one set in one engine and one set in the other. Back to back comparisons.

I spent some time with the owner of Boca Bearings and talked about the change in manufacturing process/fit/etc and decided that it is worth the effort to try these. There has been a great deal of advancement in quality since I used to sell the ceramics a long time ago.

I did learn something that I didn't know about their bearings. The have both stainless and also chrome races available. I have been ordering the stainless for years and years. They said that the chrome is harder and lasts longer and that we should only be using the chrome races. I will do that from now on. They are only slightly more expensive than the stainless version.

They also said that the full ceramics would only last a few seconds in our engines and should NEVER be used by nitro model boaters.

I will let you know when I see how these bearings act for me.

All of this makes me feel really dumb as I had been using the wrong bearings for many years. Maybe that is the reason that I haven't had good bearing life

 

[Glenn Quarles]

Hey Marty, just be careful about what conclusions you make on your back to back test...the clearance inside the bearings may/will impact the life and performance more than the material the balls are made of. If either the hybrid set or all steel set come tighter than the other then they won't perfom as they should.

GQ

 

[Jack ODonnell]

Marty, Glenn is 100% correct. J.

 

[dwilfong]

The bearings Greg did for me are lose..............................The crank side is set at .0008 to .0012 clearance.

The clearance is what makes them reduce the friction and last longer as thy do not heat up.

The crank moves in and out when thy are installed. If where production C3 bearings you would say thy where worn out.

It is a crap shoot buying bearings off the shelf........If thy are at the high side of the production tolerance thy will last longer.

If thy are on the low side thy will not last long.

Marty go look at the Enduro bearing web sight be for you buy. Thy may have what size you need in the zero series already made up.

There is a lot of good info on the New Hampshire Ball Bearings web sight. Go to the resource center and check it out.

Also a good source for balls..................

 

[Jim Allen]

Hey Marty, just be careful about what conclusions you make on your back to back test...the clearance inside the bearings may/will impact the life and performance more than the material the balls are made of. If either the hybrid set or all steel set come tighter than the other then they won't perfom as they should.

GQ

Very sound advice. The amount of radial clearance required for any deep groove ball bearing, before the bearing is mounted, will be determined by several things; 1) The amount of interference fit used in the housing to hold the outer race; 2) The metallurgy of the housing; 3) The tightness of the crankshaft in the inner race. The radial clearance that is left after the bearing is mounted in the housing & on the crankshaft will be reduced by both of these things. The radial clearance that is left after mounting will also determine the amount of axial play left. In an aluminum front end .005" to .006" axial play will be enough. In an all steel front end .002" to .003" axial play will be enough because the thermal expansion of the steel parts involved will be the same.

An increase in performance & reliability can be gained by "mechanically fastening" the inner races of both front bearings to the crankshaft.

Jim Allen

 

[michael faszcza]

Has anyone tried microblue bearings .full ceramic not just coated .been using them for years on dragbike crank with no failures .at more heat and pressure then you could imagine

 

[Terry Keeley]

I've found that if the inner race of the rear bearing slides on the crank both performance and bearing life will suffer.

Not very scientific but the crank needs to be pushed into the bearings firmly for the proper fit, if it's loose or a drop in fit it'll spin for sure. The front bearing is sandwiched between the step on the crank and the flywheel collet so doesn't have this problem. As Jim mentioned some of the best pylon engines think this is so important they make the bearing inner race part of the crank!

http://www.pylonentries.fsnet.co.uk/mb/cran%20dis.htm

You can easily tell by looking at the crank if the inner race has been spinning or not.

 

[dwilfong]

I have noticed that if the bearing radial clearance is set lose that the bearings do not spin even with a lets say looser fit to the crank than optimal.

Speculating that if the heat is not built up from friction with the loose clearance and top grade ceramic balls that the race will not expand and spin.

Only what I have noticed with what I have run.

 

[Jim Allen]

I've found that if the inner race of the rear bearing slides on the crank both performance and bearing life will suffer.

Not very scientific but the crank needs to be pushed into the bearings firmly for the proper fit, if it's loose or a drop in fit it'll spin for sure. The front bearing is sandwiched between the step on the crank and the flywheel collet so doesn't have this problem. As Jim mentioned some of the best pylon engines think this is so important they make the bearing inner race part of the crank!

http://www.pylonentries.fsnet.co.uk/mb/cran%20dis.htm

You can easily tell by looking at the crank if the inner race has been spinning or not.

Terry,

These basic facts about bearing inner race fitting & assembly are 100 % correct. I think that one of the problems with discussions pertaining to what works & what does not work is the absence of "NUMBERS" & how to measure correctly, with what instruments, to get those "NUMBERS". This applies to every aspect of any high performance engine!

Take for example the very common use of the registered trade name Cerbec*, which was purchased from Norton Advanced Ceramics by Saint-Gobain Advanced Ceramics in May, 2001. The ceramic ball bearing business owned by Staint-Gobain was purchased by Coors-Tek in 2012. In 1987 through 1989, the original Cerbec company, sold Noralide* NBD100 ceramic balls to the general public.

Some questions that should be asked about ceramic balls, which are critical to bearing performance, should be; 1) Can a visual inspection determine what ball material is being used? (NBD100, NBD-200 or SN-101C); What grade are the balls? (grade 3 or 5); What are the exact size of the balls & can they be measured? (L1, nominal dimension, M1, M2, M3, M4); What race metallurgy & finish is best for ceramic balls? (AISI-5200, 440C, M-50, BG42); What radial clearance amount is to tight or to loose & can it be determined by what feels good?; What temperature rise vs. crankshaft RPM can be expected; What rolling contact fatigue life compared to steel balls can be expected; Are different materials used for different size balls; etc.; etc.

Jim Allen

 

[Marty Davis]

Would attaching the bearing using 601 Loctite do the same thing as a tight fit?

 

[Jack ODonnell]

Marty; NO !!