Hobbsy

My Feedback: (102)

I'm with Dave, I've been a happy BOCA customer for 15 years and will continue to be.

mike early

Dang, a lot of nerves (besides mine) have been touched.
I admit, I was frustrated when I disrespected on boca bearings. But damn: 89 dollars and there is 1/16" of axial play and oil being slung around inside my cowling? Maybe the axial play is not a big deal, I don't know. That's why I sent emails to boca, to ask them if this behavior is normal. The play is only present when the engine is warm. I dismantled the engine and was going to put my crashed-involved RC-bearings back in. When removing the rear bearings with heating the case, the bearings fell out. In the other times I've changed bearings in this engine, I've had to knock the case against a piece of wood after heating. Maybe these bearings are too loose, I don't know.

Upon comparisons of the bearings I noted the Boca bearings rotated much much more freely and made no noise whatsoever. The crashed bearings felt a little gritty. I presume I've chipped some stuff in there....

SO...until my new bearings arrive, I've reassembled the engine with boca bearings. It runs fine. The oil inside the cowling I can deal with. (I opted to spend more money on their optional better oil seal...) I still don't know if the axial play when warm is important. But that's the point. I am frustrated that Boca Bearings never even bothered to answer my emails. I consider that piss-poor form. They've lost a customer and if anyone asks me, I'll tell them my experience.


All they had to do is reply to my emails and told me the bearings were supposed to sling oil and move 1/16" when warm. Or, replaced the bearings. Even a go-to-hell is better than completely ignoring me.

mofosheee

My Feedback: (4)

Paul of RCBearings sells the same bearings that Boca does, but at 1/3 the price. They both distribute excellent Chinese bearings. Some people feel better when they pay more correlating paying money to obtain a better product.

Good luck.

P.S.

The ceramics worked great for me

togatoga

My Feedback: (42)

To each their own guys, however, thanks for the info. Most or all bearings that these 2 companies sell come from the far east so there's no question of brand loyalty, neither will any jobs be lost that has already been lost by choosing between the two.
In the end we make our own informed choice and leave it as that, its your own hard earned money and it is each individuals right to buy what he wants and where he wants it from.

Hobbsy

My Feedback: (102)

Confused terminology, axial is length wise along the crankshaft centerline and radial circular around the crank centerline. Sorry Mike.

mike early

now now. I'd be happy to take photos of my spinner/cowl relationship at each extreme. but you'd say I photoshopped it. BS. whatever.

Maybe the bearing housing is actually moving inside the block. I do not profess to explain how it is happening. I only know I don't like it.... and Boca Bearings could give a rat's ass about it.

Hobbsy, are you the owner of Boca Bearings? Why don't you send me some new bearings, that fit correctly, hell!

Hobbsy

My Feedback: (102)

Nope, I'm just a customer but I would have noticed 1/16th inch of slop before I put them in the engine and wouldn't have installed them.

mike early

I am presuming they do not fit correctly and they themselves slide back and forth inside the engine. But only when the engine is hot. Axial play, not radial play. Or vice versa, not really sure of the correct term...the crankshaft will slide in and out 1/16 of an inch. But not when the engine is cold. When cold it is tight.

Maybe...maybe the engine was damaged in the crash and can no longer hold the bearings in place as intended. I'll accurately measure the O.D. of both sets of bearings when my new ones arrive.

Hobbsy

My Feedback: (102)

In and out is no biggy, there are lots of engines where the crankshaft can move in and out more than one guy has asked about a knocking sound below 4,000 rpm on some two strokes. I'll have to see if I have any fourstroke that will do that.

mike early

Well then: if it's not a big deal, then maybe I shouldn't be calling anyone bad names....

But still a little disappointed that my extra $ for the better seal option yielded a very leaky front seal... that alone was an extra 20 dollars...

"Ceramic High Performance RC Engine Bearing Kits. Our Ceramic High Performance line of RC Engine bearings have a special heavy duty seal that is designed to cut down on leakage through the front"

Flyboy Dave

My Feedback: (21)

....yep, thanks Hobbsy. It looks like XJet just wants to name-call and pretend like
he's the only person that ever put a bearing in an engine.

He called me "ignorant"....twice. Imagine that.

FBD.

XJet

No, but it's very clear you don't understand the basics of bearing metalurgy and therefore aren't really in a position to be criticizing others for their choices or comments.

It wasn't name-calling, it was a statement of fact. The dictionary definition I've got here for "ignorant" is:

uneducated in the fundamentals of a given art or branch of learning; lacking knowledge of a specific field

In this case, that hat fits FBD. It's not intended as a personal insult or slight simply a statement of fact.

It's not a good thing for you tell people that Bocca's bearings are "better" when that opinion is based on ignorance of the facts. People deserve to know the truth, and that is that Bocca's bearings are overpriced and some are actually inferior) when compared to alternatives.

As I said, it's a free world and I've got no problems if people want to waste their money on fancy branding but I think it fair that they do so in the understanding that they're not buying a better product.

Hobbsy

My Feedback: (102)

That may be what the dictionary says but in the real world it is an insult to call someone ignorant. It looks like a set of Boca chromium steel bearings with full contact seals are about 26 bucks. That's not out of line at all.
My guess is that if Mikes crankshaft didn't move in and out before, then one of his new ones is 7mm in width instead of 8mm.

TimC

It sounds like you have done some kind of scientific test using both sources of bearings. Or is this just an opinion? The fact is, since these generic ChiCom bearings lack manufacturer logos, and both vendors source from several bearings makers, any kind of test would be suspect.

liquid_TR

eerm, just to add a little taste to the flaming conversation here;

both OS, magnum, Saito engine mfgs use NSK (japan) brand bearing at the back, and NTN (japan) brand bearing at the front.

Now it doesnt necessarily mean they actually are made in japan but they have to be at the right quality.

Ive never bough stuff from "rc bearing" reseller company - never needed would be more accurate

as I've always ordered the actual original brand of bearing to my nearest hardware store, and used NSK and NTN bearings for a long time.

These little bearings in our small glow engines are used worldwide in thousands of machines so there's little chance they are "bad" to start with.

It usually boils down to harsh, nitro-rich, insufficient oiled environment they are in that starts to kill them.

And there is no cure for that if one doesnt use adequate amount or type of oil in their engines with high nitro percentages..

Flyboy Dave

My Feedback: (21)

.....for the reading comprehension impared....

XJet

Interestingly enough, replacement bearings (from RC-bearings anyway) seem to last a lot longer than the original bearings that come with OS and Saito.

Both my Saitos (82 and 100) needed new bearings within the first year of operation but have gone another two years on the replacements with no issues at all.

Likewise, ask any OS50SX user what they think of the stock OS bearings and you'll find out that just because it's Japanese doesn't mean it's good.

That's fine but I have saved myself a lot of money over the years buy purchasing on the basis of results rather than branding.

That's true but there are also a lot of variations on the basic (for example) 6902 bearing.

You can get then with bearing steel, stainless steel, with metal retainers, with polymer retainer, A-C spec, with or without shields, with or without seals, etc. And sometimes the best replacement isn't the exact same bearing. Polymer retainers are an excellent example of this. I've seen a number of engines that have been completely destroyed (scored liners/pistons and damaged con-rods/crankcases) after a metal retainer let-go, sending shards of shrapnel through the motor. That's one good reason *not* to use a genuine replacement part for those engines that still come with metal cages.

Poor fuel and poor practice will both shorten the life of bearings.

Bearings in many small 2-stroke engines (weedeaters, chainsaws, etc) are run with *much* lower oil percentages (as little as 1% in some cases) than we run with our engines and their bearings last almost forever so I'd venture to say that perhaps the quality of oil is more important than the quantity - and we're talking about wear, not corrosion here.

It's been my experience that corrosion is the biggest killer of the bearings in most "occasionally run" engines.

When people just hang up their planes at the end of a flying session, small amounts of corrosion *will* start to erode the bearings. This erosion may not even be visible to the naked eye but it will produce fine particles of rust that then act like grinding paste the next time the engine is run.

After not too long, the bearings wear out even though there's hardly any rust visible on them and that's because each "first run" of the session is actually producing a lot of wear.

By comparison, engines that are used often, run with a good oil package that provides a measure of corrosion protection and stored properly won't suffer the same issues anywhere near as much and can last many times longer.

It's silly but, if you're using a good bearing and good oil, your bearings will last a lot longer (in terms of hours flown) if you have less gap between flying sessions and fly more regularly.

My most-flown engine is a TT46Pro and it's now done almost 500 hours of very regular running. It's now just had its second bearing change and I expect to get at least a couple more years out of it (on these bearings) before I retire it. That's despite using those "cheap" RC-Bearings and using a fuel with just 12% oil.

XJet

So tell me again why they cost four times as much as others? [:-]

liquid_TR

XJet, I dont disagree with your views on bearing cage types.

All Im saying is if you get a replacement bearing, and run it in the bearings lubrication, load and max rev specs, there is no reason for it to blow open its cage.

also replacing the bearings of an active engine at 4-5 USD; regardless of their situation, once every year is not a very high load on my wallet. We spend 100 times more on glow fuel.
Spending 50 USD for 10+ engines per year is not that much. Not to mention Its fun!

But as you say, the more active an engine is, the less servicing of bearings it needs. thats spot-on.

PS: I always use sealed bearings in the front and prefer to use sealed bearings at the back of all my engines.

Flyboy Dave

My Feedback: (21)

....this will be my final post in this thread. FBD.

togatoga

My Feedback: (42)

These chinese bearings do carry the manufacturers logo.They even have their own website. i have even contacted them for info. As for prices,it will shock if you only knew!!

chistech

I have flown RC for over 25+ years and have also been a machinery mechanic for longer. I have seen all brands of bearings have premature failures and it can run in cycles for manufacturers. My son races motorcross and he rides KTMs. The KTM 250 fourstroke motor is known to be the most bullet proof of all the racing fourstrokes. The japanese bikes can't even come close with the motor longetivity. In 06' the motor used all NTN bearings and had virtually no bearing failures. In 07' KTM switched to SKF and the bearing failures started with frequency. I know, both are Japanese bearings. So why do the Austrian bikes run longer? Better metalurgy in all areas. It leaves only the bearings as the weak spots and not the other areas such as rod, valves, head, crank, etc. We rebuilt his 07' with old stock NTNs and no more problems. I know this is not a motorcylce forum but just an experience with another bearing issue.
As far as machinery issues, I manage a large company that sells and repairs packaging machinery. In strapping equipment we use a lot of small bearings in the same sizes as some of our engines take. Some strappers are designed for the fishing industry so they are equipped with stainless bearings. I will tell you by experience that we end up replacing these bearings with standard steel bearings. They are by far stronger and if sheilded, will hold up to the tough envionment just fine. I have replaced bearings made in the following countries, Japan, Spain, Portugal, China, England, US, Indonesia, Israel, and I'm sure more that I have forgotten. They all break or fail!!
I have also bought the standard "cheap steel" bearings from RC Bearings for my engines and my machinery. When I buy bearings locally or from the machine manufacturer I end up paying too much and they don't last any longer than Paul's. I have rebuilt many OS, ASP, and Saitos with the plain steel bearings and have had zero problems with any of the motors. As a matter of fact, all my friends comment on how well my motors idle and run. I think a lot has to do with how lean you run your motor. If you run your motor too hot it will cause all aspects of problems. When dimensions change because of heat, stress occurs. I know motors are designed to get hot but not overheat. Overheating in any motor regardless of what type of motor it is will eventually cause problems. You can overheat a Toyota just a little and think you're fine. Then a week later your head gasket will start leaking because damage was started and took some time to show. Same thing can occur with our small engines. Another problems with bearing failure is improper assembly. If people have replaced their bearings but haven't got them completely seated it can cause premature failure. You can also not rule out improper component manufacture. It is not impossible for a engine case to be made out of spec or a bad crank. A engine with a previous bearing failure could have also spun the outside race in the case causing the new bearing to now also spin in the case. Rebuilding model engines is fun but it is not for everyone. People need to know what to look for and need to pay attention when they disassemble and reassemble.
This day and age I have to agree that most bearings are decent and comparable. I will always look for the cheaper cost from a reliable supplier who will stand behind his product. I can't see paying more for getting the same.

FlyingPilgrim

My Feedback: (26)

Christech, thank you for you post. I found it very informative, and based on real life experience that has no emotion interjected.

the pope

Holy smoke ,I got a thread locked and was accused of being in a pi##ing contest on another rc site by a dude by the name of ITobor or some such name. Gee I'm glade hes not involve in this thread or he would have a heart attack[:-] over the goings on here.I think its time to calm down or get the boxing gloves out. Just between you and me there must be a full moon or someones hid the moonshine and everyone's getting cranky.As someone who comes to these sites looking for friendship and a quest for knowledge I find these goings on very disappointing and extremely entertaining. Keep up the good work cheers the pope PS this is the mutha of all pi$$ing contests.

Hobbsy

My Feedback: (102)

I will continue to buy my bearings from BOCA, they sponsor and support this site, RCBearings does not. That might make me ignorant, hard headed or maybe just Brand Loyal but I can live with all that just to keep on being me. So far, in 18 years of using ballbearing equipped engines I have not had to replace bearings in any engine I bought new, only in used ones. My 1990 Enya .46 MKII is a little rattly so what I just said may not be true for much longer. So, did we settle anything here, not a chance. I'm going out and build an ACE Big Bingo for a Tartan 1.34 Diesel.[8D]