How tight should a flywheel be?

[Ian McMillan]

Hello all,

I have an OS 50 that has only had about two gallons of fuel through it and
the rear bearing has failed. My question is, could it be due to the flywheel
being overtightened? If so, how tight should the nut on the crank be
tightened?
There does not seem to be any evidence of corrosion. The engine has never
had a lean run or been overheated and it has been running beatifully until
just now.

Thanks

Ian

[Ian McMillan]

Thanks again Kev. I think I'll be enquiring at Revolution and so will a few
others from our club I reckon :-). I must admit, we never had any trouble
years ago when all teh choice was model technics and that was that...

Ian

[Ian McMillan]

> Joe and Dave are going to LOVE you when you go in armed with an order for
> half a dozen gallons they've gorra mix:-))

Yes they said they can do it, very kind of em to get back to me so quickly,
all I have to do now is figure out how I can get it - they can't ship it
unfortunately so I'll have to see about fetching it somehow.

BTW, I removed the back bearing from my engine and the inner and outer race
were totally buggered. An engineer friend of mine took said bearing apart
and examined it. He said there was no sign of blueing or overheating, or
corrosion. All he could think of was maybe the bearing was a bad un from
the start or even more unlikely that some bits of metal swarf got in it and
buggered it.

Well, its now been replaced by a "good un" (for now at least). Bit of a
mystery but as my friend says, it doesn't appear to be my carelessness or
bad lubrication/overheating that caused it so...

Ian

[Beav]

"Ian McMillan" <ian.mcmillan63@virgin.net> wrote in message
news:oLA_a.11277$Kx1.163100@newsfep4-glfd.server.ntli.net...
>
> > Joe and Dave are going to LOVE you when you go in armed with an order
for
> > half a dozen gallons they've gorra mix:-))
>
> Yes they said they can do it, very kind of em to get back to me so
quickly,
> all I have to do now is figure out how I can get it - they can't ship it
> unfortunately so I'll have to see about fetching it somehow.
>
> BTW, I removed the back bearing from my engine and the inner and outer
race
> were totally buggered. An engineer friend of mine took said bearing apart
> and examined it. He said there was no sign of blueing or overheating, or
> corrosion. All he could think of was maybe the bearing was a bad un from
> the start or even more unlikely that some bits of metal swarf got in it
and
> buggered it.

It's unusual for engines to have loose bits of swarf in 'em these days. Some
bearings ARE crap though, so if that's all you've needed to change (apart
from your fuel) you got away lightly.
>
> Well, its now been replaced by a "good un" (for now at least). Bit of a
> mystery but as my friend says, it doesn't appear to be my carelessness or
> bad lubrication/overheating that caused it so...

It's hard to pin down why a bearing shags up, but it's usually lack of
lubrication, which is why I don't use less than 20% oil in my own stuff.
There aren't many advanced signs of a bearing packing up other than a few
rough runs and if you're quick, you realize before any serious damage
occurs, but mostly the bearings AREN'T suspected until the engine REALLY
lets you know it's ahgged by stopping dead and usually just when you don't
want it to die)

Al Rait's engine has still got it's origiinal bearing in btw, and his engine
is so old, it's son's called Methusela:-)



--
Beav


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