Bearing damage

[Don Ferrette]

First off Boca is a bearing distributor not a bearing manufacturer. I stopped buying from Boca a long time ago after quality control issues cost me a couple motors and will never run them again. When I ran the VAC91s I too really liked them and yes they eat bearings. The go to bearing for me in them was the Swiss WIBs, lasted longer than anything else. Bearing fit and alignment is critical and I feel Jeff is correct about the VAC cases. And I'll agree with Mark in regard to synthetic oil, seemed best in those VAC motors at least for me. I used 18% Cool Power 2 cycle blue kart synthetic oil that Andy turned me on to years ago.

 

[Wasted wages]

Anyone know the ABEC rating on the bearings in question?

I’ve used ABEC 9 before in motors with good success. Just throwing this out there for discussion…

 

[Timbo Whalen]

Higher viscosity means bigger molecules, therefore more space between metal surfaces.

Klotz engineers recommend the KL-198 Lite Techniplate for our high nitro applications. They recommend it at 20%-25% without castor, but you can add castor if you want. KL-198 exceeds ALL of the physical properties of castor, according to Klotz.

We've been using it, but don't run as hard nor as frequently as you guy's do.
We'll stick with the science.

 

[RaceMechaniX]

Most of the large bearings in our nitro motors are a C3 fit, ABEC 5. ABEC rating does not necessarily translate into a better bearing. A very high quality WIB bearing with an ABEC 3 rating will likely perform better than a low quality ABEC 9 bearing.

The key here is to pick a high quality bearing. WIB, NMB, SKF, GRW, INA all produce good bearings, but you have to be willing to dive into the exact quality of these bearings to find the good combinations.

 

[John Beardslee]

Do any of you go through a bearing prep before you install? ie: clean and float in an assembly lube.

 

[Tom Foley]

Most of the large bearings in our nitro motors are a C3 fit, ABEC 5. ABEC rating does not necessarily translate into a better bearing. A very high quality WIB bearing with an ABEC 3 rating will likely perform better than a low quality ABEC 9 bearing.

The key here is to pick a high quality bearing. WIB, NMB, SKF, GRW, INA all produce good bearings, but you have to be willing to dive into the exact quality of these bearings to find the good combinations.

Well we are going to do a well documented test on the SKF beginning next week at Sowega., followed by Twin Shootout in Brandon in March then maybe Atlanta .

 

[Tom Foley]

Do any of you go through a bearing prep before you install? ie: clean and float in an assembly lube.

The bearings come pre packed . I have never blown the grease out and cleaned them assuming brand new from the factory will be good . Now the water we run in is filled with all kinds of funk so who knows what goes through them . The Voodoo water has suspended mud particles in it but what can you do . Here is the amount of unsupported bearing if you can see it. I can't imagine it flexing too much but maybe it does .

 

[Zimmerman]

Way back 40 years or so ago all our bearings were brass caged and they let go a lot. A major mfr claimed they start to skid around 16 thou RPM. About that time Skip Horstman taught me how to full complement bearings. Not only are they bullet proof, but last for ever if properly lubed.

 

[John Beardslee]

Tom, I pull the shields off both sides of the large bearing and the inner shield of the small bearing. I also always have lettering each other lie: the small bearing lettering faces in and the lettering on the large bearing faces out. I clean a new bearing with brake clean and use canned air to blow it out a couple of times. “ NEVER LET THE BEARING SPIN”!! Then I hand lube with an assembly lube. Sometimes I use Tri-flow other times I use Rislone Engine Oil Treatment, years ago Detroit Ball Bearing Co. had a bearing assembly lube. I was told that thick grease the bearing comes with was for slower applications.

 

[Tom Foley]

Way back 40 years or so ago all our bearings were brass caged and they let go a lot. A major mfr claimed they start to skid around 16 thou RPM. About that time Skip Horstman taught me how to full complement bearings. Not only are they bullet proof, but last for ever if properly lubed.

OK so I'm not going to employ full compliment bearings due to convenience time and cost . How often do you run the bearings that last forever ?

 

[Zimmerman]

I've slowed up the last few years, have 5 planned for this year. I used to make 8 to 10. It doesn't cost much to full complement a bearing just need a few extra balls.

 

[Chris Wood]

I am with Don. I have never ever had a Boca bearing that was any good.. There quality was horrible.

I had some go bad on the bank just braking motors in.. WIB was much much better. i never run the metal shields either.

 

[Jeff Lutz]

The bearings come pre packed . I have never blown the grease out and cleaned them assuming brand new from the factory will be good . Now the water we run in is filled with all kinds of funk so who knows what goes through them . The Voodoo water has suspend mud particles in it but what can you do . Here is the amount of unsupported bearing if you can see it. I can't imagine it flexing too much but maybe it does .

I haven’t seen anyone mention flexing. Me and a few others have talked about the bearing getting out of round. The 90/101 Evo’s in the past flex enough to break the crank pin, but the little 6001 bearings hold up fine. They are held properly. Cmb made the crank pin bigger to help. Now they have the Mline supported by a needle bearing in the front of the engine. The old Evolution and other older versions had needle bearings on the carb side and they never broke crank pins. That started when they made the RS series with ball bearings on both sides. This changed the fulcrum point and started the flexing. Now that they added a needle bearing on the front I suspect the crank pins will be fine, but that’s a different issue than the Vac. I run a Vac in my F hydro and you definitely should still run them. Ive been running SKF for years and like I mentioned Tom ,Im sure you will get better bearing life with them, but you will still change the big bearing a little more than most engines.

 

[Tom Foley]

I haven’t seen anyone mention flexing. Me and a few others have talked about the bearing getting out of round. The 90/101 Evo’s in the past flex enough to break the crank pin, but the little 6001 bearings hold up fine. They are held properly. Cmb made the crank pin bigger to help. Now they have the Mline supported by a needle bearing in the front of the engine. The old Evolution and other older versions had needle bearings on the carb side and they never broke crank pins. That started when they made the RS series with ball bearings on both sides. This changed the fulcrum point and started the flexing. Now that they added a needle bearing on the front I suspect the crank pins will be fine, but that’s a different issue than the Vac. I run a Vac in my F hydro and you definitely should still run them. Ive been running SKF for years and like I mentioned Tom ,Im sure you will get better bearing life with them, but you will still change the big bearing a little more than most engines.

Yep , and I'm ok with changing them redundantly ahead of time
This one had little time on it and is the only bearing I actually ever had " go bad".in these engines since they came out whatever year that was . SKF installed now and logged .

 

[Terry Keeley]

First off Boca is a bearing distributor not a bearing manufacturer. I stopped buying from Boca a long time ago after quality control issues cost me a couple motors and will never run them again. When I ran the VAC91s I too really liked them and yes they eat bearings. The go to bearing for me in them was the Swiss WIBs, lasted longer than anything else. Bearing fit and alignment is critical and I feel Jeff is correct about the VAC cases. And I'll agree with Mark in regard to synthetic oil, seemed best in those VAC motors at least for me. I used 18% Cool Power 2 cycle blue kart synthetic oil that Andy turned me on to years ago.

I actually had a ball break in half from them years ago in a Picco 67 and haven't run them since either.

Most of the large bearings in our nitro motors are a C3 fit, ABEC 5. ABEC rating does not necessarily translate into a better bearing. A very high quality WIB bearing with an ABEC 3 rating will likely perform better than a low quality ABEC 9 bearing.

The key here is to pick a high quality bearing. WIB, NMB, SKF, GRW, INA all produce good bearings, but you have to be willing to dive into the exact quality of these bearings to find the good combinations.

I've found the stock SKF or WIB's worked very well and got about fifty runs before they needed replacing, that's for 6000, 6001 and 6002's in the 45's, 67's and my VAC 91's.

I was turning some races blue on the 6002's after just a few runs in my 67 SAW boat but I think it was due to the loose fit of the inner race on the crank, plus I was winding them up in the high 20K range. CMB has tightened up their tolerances and the bearing fits are excellent now.

Some bearings come through on the tight side of C3 and that's just too tight IMHO, it's 0.0004" - 0.001" for these sizes. Lately I've been re-balling WIB's with Cerbec balls and fitting them to the high side of C3, they run smooth for many, many gallons of fuel. I check them occasionally and it seems the balls don't wear at all, just the races.

I run 10% KL200 plus 5% Blendzall Green label with 60% nitro for heat racing.

 

[Al Hobbs]

A few years ago, I spent two days with Jim Allen in his shop. I learned more from him in those two days than all my time with other engine people.

He was very thorough with what he showed me and what he told me.

He only used Swiss Made WIB bearings in the Nelson engines he assembled. He would not use any other brand.

I think there are several good bearing brands, but after those two days with Jim Allen, I am sticking with WIB.

 

[Tim Kish]

WIB has always been my bearing of choice and I've had very good results with the stock bearings that come in the CMB engines.
Like a few others have mentioned I stay far far away from anything Boca sells.

 

[tnrcboatracer]

Greg Settle would buy the WIB bearings from me a reball them like Terry with ceramic balls for the exact fit he wanted for the tether car engines he set up. We had many coversations about bearings before he passed. Other than metallurgy and fit, the other key is concentricity of the ball race to the ID/OD. Race thickness and ball diameter also varies. In the GRW 6001 the balls are smaller and races thicker. Also keep in mind that the angular velocity varies greatly within one 360 degree rotation.

I still stock the WIB bearings for most motors. Though not many for the Nova Rossi. I don't advertise, those who know, know.

 

[Jeff Lutz]

A few years ago, I spent two days with Jim Allen in his shop. I learned more from him in those two days than all my time with other engine people.

He was very thorough with what he showed me and what he told me.

He only used Swiss Made WIB bearings in the Nelson engines he assembled. He would not use any other brand.

I think there are several good bearing brands, but after those two days with Jim Allen, I am sticking with WIB.

Hey Al, no doubt the WIB bearings are fantastic also. Jim Allen had a lot of education from Henry Nelson. He bought a large quantity of bearings from Henry because he knew Henry bought a very large quantity that helped assure the balls were the same size within +-.000010 and they had a slightly looser internal tolerance which he felt he could put more press fit on. If you dig deep with the high quality manufacturers they all hold those tolerances though and I don’t believe you really benefit from buying a “special lot” like Henry Nelson bought (and sold to Jim). Small quantities like many of us buy are fine in several high end brands. Jeff

 

[Mark Bullard]

After seeing the pictures that Tom posted I am in agreement that the case is what is causing the problem. With a small portion of the outer race in that kind of fit showing is why the motors are eating the bearings.
Use to be that the higher ABEC was better. It still is for some setups and I don't mean our motors. In todays standards ABEC 1 is as good as ABEC 3. Equipment making bearings has got better and able to hold better tolerances. The ABEC is the +/- tolerance of the outer, inter races, and the ball diameter. We use a lot of SKF and NTN bearings. Some of our customers want the SKF. And the others just want their motor repaired. But we go thru a lot of bearings and I work with fits by measure and repair all the time. Here is a picture of what is in my bearing cabinet right now. So as you can see I deal with a lot of bearings. Maybe a few dollars in that picture.