crank end float os engines

[dogbiscuit]

This ones about end float on os 50/55 engines......

I have now just read conflicting advise so just wondered what people think......

The fan came loose on my 50, and as a result the end float was then quite significant (also would not stay running). When I tightened the fan, there is still a touch of endfloat that cannot be removed. should all of this float be removed when the fan is done up or is a touch of float ok? (this is with the std washer in place)

I notice on the 55 I recently bought, there is no endfloat on the crank at all without any fan fitted.

[jwatts007]

Just use the washer that comes with the engine under the fan housing...do not try using 2 washers and pulling the crank tight...ask me how I know...LOL...

[pgkevet]

600? Just make sure the fan hub is fully seated with single washer

[dogbiscuit]

when the fan is fully seated with a washer..... should there be any discernable end float in the crank or none at all?????

[jwatts007]

Take the back off the engine off and have a look whilst turning the engine over...if you think there is a problem....

[dogbiscuit]

looking in the back, the con rod has touched the backplate and caused some scoring on the backplate ( caused when the fan came loose...) nothing terrible though...

same question though..... when I do the fan up should this remove ALL the end float in the crank????? If it should.... then i have an issue with the bearings I guess and I should be changing them. If a really small degree of end float is not an issue, then I assume I dont need to change the bearings and can just put it back together and fly it.... hence the end float question

[Nitro Head]

A TINY amount of end float is not necessarily a sign of failed bearings as there is a tolerance variation from engine to engine. However if you have the engine out I would remove the piston and liner and rotate the crank and feel for any roughness in the bearings. Also if i have the engine out and the bearings are more than 12 months old I would replace at least the rear bearing as a matter or course.

There will always be end float in a crank with no fan or nut fitted however in the case of your 55 it's probably that the crank is still a very tight fit in the bearing inner that it does not slide in and out easily but the fan is the only thing that stops the crank moving back until it contacts the back plate.

Paul.

[Rotorhead]

All OS engines I've had all had a tiny bit of end float in them, and they all mark the backplate, they kind of gradually polish it where the con-rod moves against it, no problems.