dyacht

Hello. I have a new OS 50 SXH in a raptor 50v2. Engine has not been started. i have read on a raptor site that you should not tighten the fan assembly down on to the engine bearing but allow the crankshaft nut to lock the fan into position. I have made a tool that would allow me to hold the fan hub while tightening the Cranknut. I first used that tool to firmly tighten the fan hub to the front engine bearing before putting the cranknut on Firmly. The engine rotates nicely. The site I am refering to suggests that this action would preload the engine bearings to fail early. I find it hard to believe that the fan is simply not sitting hard against the inner race of the front bearing which in turn is sitting hard against a shoulder on the crank. This would not allow any extra "preload" to be exerted on the bearings. I may of course be totally wrong!! Question is. What is the correct proceedure in this respect to ensure long life of the engine bearings. Much Appreciated
DYACHT

Bax

My Feedback: (11)

dyacht,

We're not sure about your difficulty. A fan would not be tightened any more than a propeller, which has the drive washer tight to the bearing when the prop's tighened on. If the engine spins freely when the fan is mounted, there are no problems with bearing loads.

If the bearings had an adverse load, you'd feel a roughness when you spin the engine.

dyacht

Thankyou for your reply. I had the same thoughts so I shall leave the engine as it is. Maybe some engines have this issue. I would say some have run bearings due to other issues but blamed the problem on "preload" during assembly. I also can't see that this is a problem due to the reason you have stated
Thanks
Dyacht