RE: Rossi .60 2 stroke
 

just an update , the engine had a bad rear bearing and I ahve already replaced the front and rear bearings. Tommorrow will be the first time I will run the engine after replacing the bearings.

RE: Rossi .60 2 stroke
 

Captain,


For your pocket's sake, I hope you did not buy "original" bearings, or those offered by an outlet that wants you to think they are inexpensive (...)...


[link=http://www.mcintoshcentral.com/rc-bearings/catalog/product_info.php?cPath=81_87_99&products_id=676&os Csid=7905128c17d496cae976a1abf43758c1]Paul of RC-Bearings[/link] sells this bearing set for just $7.97 and his rear bearings now all come with a phenolic/polyamide cage (to protect your engine's internal parts from metallic 'shrapnel')...

It would be a crime to pay more; and to get lesser bearings...
Paul's ceramic bearings are cheaper than the others' 'high-speed' steel sets...

RE: Rossi .60 2 stroke
 

As usual you are on top of things in on RCU . I did not buy cheap bearings, at least I don't think I did. The bearings I bought are sealed CERAMIC, from VXB bearings.


CAP.

RE: Rossi .60 2 stroke
 

Quote:

---

ORIGINAL: RC-Captain

...I did not buy cheap bearings, at least I don't think I did. The bearings I bought are sealed CERAMIC, from VXB bearings.


CAP.

---

They're definitely not cheap...

However, the general practice is to use original bearing configuration, when upgrading bearings...

I.e. if your engine, like most two-stroke glow engines, had an open rear bearing and a single-shield/seal front bearing (to allow lubricant flow to both), the rear bearing you should use should also be open.

Although the crankshaft theoretically floats in the bearings, some lubricant is needed in the front-rotor assembly; among other reasons, to create a better seal in this valve...

So, using a grease-packed, sealed bearing in the rear (that is also very expensive at [link=http://www.vxb.com/page/bearings/PROD/HybridCeramicBearings/Kit7664]$37.-[/link]), might not be a very good idea, especially with Paul's open ceramic bearing going for [link=http://www.mcintoshcentral.com/rc-bearings/catalog/product_info.php?cPath=80&products_id=262&osCsid=6 bf4ace0fe56100bb31c7fea840b4c74]less than half this sum[/link], as well as being more appropriate for the job.

Paul, however, does not carry a ceramic version of the [link=http://www.vxb.com/page/bearings/PROD/9mm/Kit7745]698ZZ front bearing[/link].

...Or did you install full (not hybrid) ceramic bearings in this engine???

RE: Rossi .60 2 stroke
 

You may be right , but I have to try it this way first. From my knowledge of ceramic bearings which is not alot, the ceramic bearings should run much cooler than metal which should eliminate the need for oil from the fuel to pass through the bearings. I am confident that the represrntitive from VXB new what he was talking about when he said I can use the bearings for RC engines, not to mention they were a perfect fit . Dar this might be a learning experience , using sealed bearings.

RE: Rossi .60 2 stroke
 

the bearings are hybrid, full ceramic bearings cost $70 or better.

Cap

RE: Rossi .60 2 stroke
 

OK, Catain.


Tell us how it runs.

I still think the oil in the front rotor in important for proper function.

RE: Rossi .60 2 stroke
 

well sorry to say I may not find out until next week do to my car needing repairs. When you say rotor , what exaxtly are you refering to ? If the bearings fail I have the email from VXB stating it will work, therefore allowing me to send them back for replacement bearings. Kit2065, and Kit7618 are the bearings I am using. they are rated for Limiting Speed: 34000 RPM and 100,000 rpm. which no rc engine in the world will produce.


Cap

RE: Rossi .60 2 stroke
 

Captain,


The large diameter journal of the crankshaft, which has a hole in its side and a passage through it leading to the crankcase, is referred to as the 'front rotor', or the rotary intake valve.

It controls when the carburettor will be exposed to the crankcase suction and when it will not.

This valve rotates within the front of the crankcase. Its seal is achieved due to good machining and matching, but the lubricant also contributes to it. I fear that if the rear bearing is sealed, an insufficient amount of lubricant will reach this part of the engine, to enhance the seal and to wash away ingested dirt and grit.

Neither bearing will need any extra lubrication from the engine's oil, because sealed bearings provide their own lubrication and ceramic bearings don't need very much lube anyway, but I don't think the rotary valve is designed to run dry...


I am certainly for installing ceramic hybrid bearings in high performance engines, but I would not dare deprive parts of the engine of the oil they need... So, as far as I can understand two-stroke glow engines, most of them are not designed to use a sealed rear bearing. Only those engines that come originally equipped with a sealed rear bearing, should use a sealed replacement bearing.


A company that specializes in skateboard and roller-skate bearings, does not necessarily know enough to recommend the type of bearings you should use in a glow engine.

RE: Rossi .60 2 stroke
 

Do you have a picture of the area of the engine you are talking about ? That was my main concern before installing the rear bearing, whether or not the bearings would reduce oil flow to the rest of the engine. As far as I can remember the sealed bearings would not change the fuel/oil flow . There is a notch between the rear bearing and the crank case which will allow oil to flow between the crank case and the part of the shart not surounded by the bearings . The piston and sleeve of course will get oil along with the piston arm connection to the piston . As I said you may be right , if so I beleive I can remove the seals . The original replacement bearing I received from AXE Rossi was the wrong size but it was sealed. Wish me luck DAR and if you have any pictures please post them. Thanks


CAP

RE: Rossi .60 2 stroke
 

Captain,


I don't have such a photo.

Most engines I disassembled have a lubrication channel in the crankcase, between the carburettor boss (exposed to the rotary valve) and the front bearing.

I don't remember any engine that had an open rear bearing, ever needing a channel from the crankcase chamber forward...
...After all, with an open rear bearing, oil can freely flow through the bearing and directly into the oil-gap between the crankshaft and the crankcase.

I seem to remember all crankcases I ever disassembled, had a circular socket for the rear bearing, with no such channel, or drilling.

If your Rossi does have such a lubrication channel, it just might be alright.

RE: Rossi .60 2 stroke
 

Hello DAR, I went to get my car and set everything up in the backyard. I am impressed with the throttle transition, absolutely no stuttering from idle to WOT. I had the needle set at 2 turns from open (rich). the idle I never touched from the last time I ran it but probably could be leaned out. Dar this is the greatest experience I have had with RC engines so far. Changing the bearings was not only challenging but very rewarding. I feel their are alot of people running their engines with bearing problems and don't know, because, all it takes to ruin them is moisture and a spec of dirt or metal.

This space I speak of is so obvious when the engine is apart. Picture you are looking through the top of the crank case in the piston and sleeve area with both parts not installed. You see the piston with the bearing but on the crank case there is a bevealed area which allows oil flow to the bearing. Also on the piston it self there is a tiny hole just before the front, of the rear bearing. The biggest mistake I made was not photographing the bearing replacement.

After I have ran the engine threw a few flights I will remove the bearing to inspect for any damge.


CAP

Rossi 60 Speed 10cc - RING Required
 

Can anyone point me to a source where I can buy a ring for my Rossi 60 Speed 10cc?
The engine is in as new condition except for a broken ring hence it's worth the saving.
Cheers

Contact Bjorn Baal at RMJMachineworx.com. He can set you up with a top notch quality ring. Bjorn took over for Frank Bowman.

Thank you for the contact. I have contacted him and he says he can help - HOORAH!