engine bearings

Is there a source for engine bearings? Can I just go to a general bearing store?
My ST G21-.35 needs a new set.
Nicolas

Boca Bearings 1-800-332-3256, www.bocabearings.com, fair prices and prompt shipping is my personal experience.

>Is there a source for engine bearings? Can I just go to a
>general bearing store?
>My ST G21-.35 needs a new set.
>Nicolas

Probably, yes. If your local supplier does not have it, (or can't get it, but I don't know why not) then try Bocca Bearings as mentioned in the other post.

I believe that the front bearing is a SKF-607-2RS1,
or Norma-Hoffman # EL7Z. I forget if one of these has a front shield.
I always remove shields on Tiger front bearings, some don't.

The rear bearing is a Delco Remy or Hyatt # 3LO1-6001SNR.

Should not be a problem at your local bearing store!!

If not I am sure someone will correct me!!!!!

Thank you everybody, I can't believe how fast I got some help. I can take the engine appart now. Nick.

When I used these things for Combat, the SKF bearings would fail because of the races. The races used bent over tabs to hold the balls - the same bent over tabs used to put together all those antique sheet metal toys from Japan, etc. The tabs would break from fatigue, and bye-bye bearing!

I can't remember anymore, but if there's a Fafnir equivalent, get it - their races are riveted. Go to your local bearing supplier and look at different brands they have for the same size, and get one without the bent over tabs.

The fellow at Dixie Bearings used to always argue with me and say, "They all meet Government Stds., there's no difference!" Well, it's not "Government Std." to put one in a model airplane engine with 20-30% nitro and 20,000 rpms.

"Thank you everybody, I can't believe how fast I got some help. "

That's because several of us spent a decade of our youth coddling this exact engine. We still have the part numbers memorized.

Don't forget the spacer between the crankshaft and front bearing when you reassemble it.

>"Thank you everybody, I can't believe how fast I got some
>help. "
>
>That's because several of us spent a decade of our youth
>coddling this exact engine. We still have the part numbers
>memorized.
>

Many of us also read and studied your recommendations at the time, too!

>Is there a source for engine bearings? Can I just go to a
>general bearing store?
>My ST G21-.35 needs a new set.

Probably no problem at all. I used to get bearings for my g21-46 at the local bearing shop. Just showed it to the kid at the desk, said, I need one of these, and literally 15 seconds later he had it and said $3.00. For stunt there is *no* wear or retainer issue no matter what bearing you get. The only thing I have seen kill them in older stunt or sport motors is corrosion.

Boca has good bearings as well, including ceramics, but I doubt that's going to be necessary, and they are quite expensive. I also note they have the previously "unobtainium" rear bearings and bearing sets for the 40/46VF ABC. Must have had them made to order, as they were originally a very oddball size.

I can't find bearings for EVERY engine, bu the ST 21 rear bearing was a pretty common commidity. I walk into Detroit Ball Bearing and let the clerk measue for me. Sometimes there are diffenent grades available.

ST 21 bearings are also used in power tools. Ask any millwright at your local car assembly plant.

as a professional millwright and current engineering student (65 days shy of the big 40!)i have to chip in my two cents worth. numbers tell the story with bearings. the first number is the type of bearing (6000 series-single row deep groove ball bearing...the most common in model engines), the second is the frame size of the bearing (6202-single row deep groove ball bearing frame size is two) and the last two numbers is the bore divided by five in mm (once again, 6202 bearing is a single row deep groove ball bearing, frame size two, and a 10mm bore....2*5=10. any bearing starting with the number 7 is an angular contact ball bearing, designed to take thrust as well as radial loads. NU style bearings are roller bearings....good for radial loads, NOT good for thrust loads! RS after the bearing number indicates Radial Seal (sealed bearings), Z indicates shielded bearings. NEVER NEVER EVER pound a bearing onto a crank! you run a good chance of brinelling the races and introducing runout to the crankshaft (bending it). if you must pound it on, make sure you apply force to the inner race only. you can heat the bearing by laying it upon a 100 watt light bulb (with the bulb lit, of course)for around 20 minutes. don't heat the bearing hotter than 250 degrees farenheit or you stand a good chance of changing the metallurgy of the bearing.
never accept a "max type" or "filling slot" type of bearing.....these are for slow speed applications only. my industrial experience with bearings (20 yrs.) has shown me that NSK make a pretty darn good bearing, but i'm unsure if they still make the small sizes. if you have spare bearings, lay them flat on the shelf and don't take them out of the package until you are ready to mount the bearing onto it's journal. i could go on and on, but my wife is hollering about using the phone! this is pretty elementary for a lot of 'youse guys' but i hope it helps someone.

I certainly hope he is not using the G.21 .35 for stunt. It would be like seeing a thoroughbred pulling a plow. Hothandle and others above have recommended good replacements. For sure, don't use a rear bearing with a folded-tab retainer.

>I certainly hope he is not using the G.21 .35 for stunt. It
>would be like seeing a thoroughbred pulling a plow.
>Hothandle and others above have recommended good
>replacements.

Hey! Easy there! I used my G21/35 for stunt, and it worked pretty well.

I'll stick it in a VOO DOO !

Excellent application, Nicolas. Don't skimp on the nitromethane.

Considering how hard it is to find new cranks, you might back off a little on the Nitro. At Emerson Electric in St. Louis (1969),we were using a "New Departure" precision bearing in the ammo drum of a "Cobra Gunship" that fit the back bearing of a G21-35 exactly. I still have one narrow bypass G21-35 with that bearing installed.

>Considering how hard it is to find new cranks, you might
>back off a little on the Nitro. At Emerson Electric in St.
>Louis (1969),we were using a "New Departure" precision
>bearing in the ammo drum of a "Cobra Gunship" that fit the
>back bearing of a G21-35 exactly. I still have one narrow
>bypass G21-35 with that bearing installed.

"New Departure Hyatt!" That was the bearing name! New Departure Hyatt's for Supertigers, and Fafnir's for Foxes.

I did a little research: New Departure Hyatt was a bearing division of General Motors, and was sold to Hyatt Clark in 1981. Hyatt Clark was in turn sold to General Bearing Corporation in 1987. It appears that "The General" is still the name they are sold under now. Looking at their catalog on their web site, it appears that the races have not changed - they are riveted:

http://www.generalbearing.com/products/PDF/BallBrng.pdf

As Hothandle said earlier, a "6001" - 12mm crank, and 28mm OD. Limiting speed is listed at 28,000 rpms, which is ordinarily plenty, but as the catalog data notes, that speed is "... based on an open, oiled bearing." As Howard says, the riveted race makes a big difference. The G21-35 was pretty much bulletproof otherwise.

> The G21-35 was pretty much bulletproof otherwise. >

I had one that broke a crank, blew a bearing , and split the bottom of the case on the same weekend....

>
>> The G21-35 was pretty much bulletproof otherwise. >
>
>I had one that broke a crank, blew a bearing , and split the
>bottom of the case on the same weekend....

Well, one thing for sure - everyone has different experiences. I preferred the Fox's, but had both. Most people said the same thing about Fox's that you do about Supertigers.

When I got off G21-35s in 1979, I was only getting around six runs per crank shaft. I had 15 G21s and only two with good cranks in them.
I broke only one Fox MK III and found what was causing the breakage. I modidied the thrust washer and never broke another crank on MK IIIs. I only ran 35% nitreo though. My Tigres were breaking on 15 %. I never saw anyone get really strong runs that didn't break shafts on the Tigres. I did see quite a few Foxes break, but only one of mine.

Bigiron

Some runs of crankshafts were better than others. Bob Burch, who holds the record for all combat engine parts breakage, could identify them like a wine connoisseur tasting wine. I had a couple of shafts that lasted ten years. They broke on the same day.

LAST EDITED ON Oct-28-04 AT 08:53 PM (CDT)
 
"I only ran 35% nitro though."

That's because you're a wimp.

Marvin is a stunt flyer. He'd probably put flaps on a combat plane.

(edited to add second insult)

OOOOHHHHH That was a low blow. No fair Howard. If you keep that up, I may even call you a ---a---a----a---a polition!!!!

Bigiron

If you did not butcher the G21-35, try to change the timing by grinding on the crank, and ran nothing hotter than Missle Mist, (25 % Nitro). If you just polished stuff inside,tried to make the piston and liner fit well, and generally tried to free up the engine, the engine was not bullet proof but would give good service. Generally the only bearings I replaced were front bearings I burnelled while trying to take the engine apart,even the stock tabbed bearings gave good service.
I might give up 5mph but the engine would generally start and run reliably. Sheer speed is not necessarily a winner, who flies straight and level in a combat contest anyway?

"...and ran nothing hotter than Missle Mist, (25 % Nitro)."

You too.

I found a cross reference chart listing alot of engines.

http://www.minibearings.com.au/cgi-bin/product.pl?alpha=M&opencat=EX42#EX42