Bearing fit on OS50 Crankshaft

[Aviation addict]

Guys,

My OS 50 Hyper was a thing of great beauty for about 5 months until it sounded noisy and I replaced the bearings. After that I though I'd get another 6 to 12 months of happy flying out of it but sadly that wasn't to be. I ended up putting in another set the next month and a further set the month after that.

On inspecting every engine part in detail I have noticed that the front bearing seems to have been rotating on the shaft. Has this happened to anyone else? The shaft had a brown (heat) discoloration and I noticed a very slight ridge. I also noticed that I could just drop the front bearing into position using gravity rather than pushing it on.

I've ordered a new Crankshaft and although the last bearings were only in a month and seemed fine I'm going to put a new set (of ceramics this time) in and keep my fingers crossed.

Was also thinking of using some blue loctite to make sure the bearings do not slip on the shaft again.

Anyone had similar experiences?

[Janek]

The bearing in an OS50 (or any other IC engine I've used) are not a particularly tight fit on the crank when cold, having said that, they do require a slight tap on the crankshaft to get it out. In otherwords they should be tight enough so that the crank does NOT spin in bearing, but not much more than that.

Blue Loctite is pointless in this application, as the heat from the engine running will soften it, there is probably a compound for this type of application, but you'll have to seach their website. . . . there are many different Loctite's

[BarracudaHockey]

What kind of bearings are you using? If they are the stock bearings try a set of ceramics from http://www.rc-bearings.com

The owner is a member here and will talk your ears off about bearing problems/issues if you get him started :lol:

[RC-Bearings]

The crank should not be spinning inside the front bearing if you have your fan properly installed and tightened. The fan should lock the crank to the inner race of the front bearing.

Also, NEVER use locking compounds near bearings unless the part is designed to have it. There are just too may risks involved. BTW, the Blue threadlocker is good to 300 F. Your front bearing should NEVER see that temp.

[Aviation addict]

Thanks guys. I'm installing RC Ceramic bearings for the first time and have found that they fit the new Crankshaft better than the old one.

I always use the OS Cranklocking tool and tighten the Colet/fan tightly to the front bearing. When I took it all apart the last time the nut was still tight. I don't know how the discoloration occurred on the previous shaft but hopefully it won't happen again.