Engine bearing change

[gorber]

I changed the engine bearings for the first time last night on my OS55.

It is the first time I have changed the bearings in any engine, not just this one.

Looking at the old bearings, it was clear that the larger one (rear?) was in a poor state, quite rusty and it felt notchy when turning it. However the smaller bearing still looked perfectly fine (although I damaged it slightly when pusing it out).

Is it normal practice to change both bearings at the same time? Or does anybody just change the bearing that needs changing?

I did change both. I ordered ceramic bearings shortly after buying the engine because I was advised that the original bearings supplied with OS's fail pretty quickly. As it happens, this engine has had about 5 gallons through it.

Cheers,

Andrew

[waveydavey]

Normally just the rear one.

[Andy from Sandy]

I ordered ceramic bearings shortly after buying the engine because I was advised that the original bearings supplied with OS's fail pretty quickly.

As the saying goes, "your mileage may vary." Ceramics have been tried in the past and the expense compared to how much longer they may or may not last does not warrant the high price tag, imo. If you are not careful the bearings can break up with desasterous results.

By purchasing cheap bearings circa £3 or £4 and treating them as consumables has been a well trodden path for those that have gone before you.

[vanman]

i usually only change the rear bearing and check the front bearing usually 2 rear bearings to 1 front

[Steve]

I changed the engine bearings for the first time last night on my OS55.

It is the first time I have changed the bearings in any engine, not just this one.

Looking at the old bearings, it was clear that the larger one (rear?) was in a poor state, quite rusty and it felt notchy when turning it. However the smaller bearing still looked perfectly fine (although I damaged it slightly when pusing it out).

Is it normal practice to change both bearings at the same time? Or does anybody just change the bearing that needs changing?

I did change both. I ordered ceramic bearings shortly after buying the engine because I was advised that the original bearings supplied with OS's fail pretty quickly. As it happens, this engine has had about 5 gallons through it.

Cheers,

Andrew

Ceramic bearings have a tendency to shatter and destroy the engine in the process, so I'm led to believe.

Secret to longevity of bearing live is in how you run the engine and the fuel you use. Dropping down from 30 to 20% nitro will increase your bearing life, and running the tank dry at the end of each flight also helps loads. These two things could increase your bearing life almost indefinitely.

[Dedcalm]

Ceramic bearings have a tendency to shatter and destroy the engine in the process, so I'm led to believe.

Secret to longevity of bearing live is in how you run the engine and the fuel you use. Dropping down from 30 to 20% nitro will increase your bearing life, and running the tank dry at the end of each flight also helps loads. These two things could increase your bearing life almost indefinitely.

I suspect the conditions the heli is stored in also plays a part, i.e. kept in an unheated shed is more likely to allow water to enter the engine and rust the bearings...

I check the front every couple of times the rear is replaced but I have only had to replace it once as it was very slightly notchy. I would not use ceramic due to the risk to the liner if (when) it breaks up.

[gorber]

After seeing the front bearing, the 2 or more rear to 1 front change makes sense.

I'm a bit worried about the ceramics breaking up now. Are there any signs that they are nearing the end of their life?

[Andy from Sandy]

If you don't recognise the bearing death rattle then there could be no warning. I have seen an OS 32 or 37 destroyed when the ceramic bearing fell apart. The ceramic balls went through the combustion chamber with spectacular results!