How do I tell if my crank bearings are bad?
04-18-2004, 10:22 PM
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How do I tell if my crank bearings are bad?
Is there a way to tell if your crankshaft bearings are bad without taking the whole shabang apart? Is is pretty obvious? Will it make any distinctive sounds when running?
I have a 4 year old OS .91 4-cycle that's had periods of heavy use and long periods on the shelf. Never crashed. Every time before I went away for a long time I put a bunch o' after-run in it.
Anyone?
I have a 4 year old OS .91 4-cycle that's had periods of heavy use and long periods on the shelf. Never crashed. Every time before I went away for a long time I put a bunch o' after-run in it.
Anyone?
04-18-2004, 10:40 PM
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RE: How do I tell if my crank bearings are bad?
The only sure way is that the bearings will whine when it is running. Sometimes you can feel it and sometimes you can't. Often when they feel rough, its just congealed castor oil. You can tell by excessive play, but unless it is really bad you would need the factory specs for the maximum play, they vary from model to model.
04-19-2004, 09:21 AM
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RE: How do I tell if my crank bearings are bad?
Thanks for the reply.
The reason I ask is that I had the rear bearing go bad on an OS .50 heli-engine, but I was using pure synthetic in it. I've been using a blend in the 4-stroke. Hopefully that'll protect the engine.
The other reason is that I've been getting a knocking sound at high throttle settings... I can't tell if it's the engine or airframe (occurs on the ground too). Last night, though, I bought a set of feelers and checked the valve clearances... they were way too wide. I'm no engine mechanic, but hopefully that'll fix the knocking.
Cheers
The reason I ask is that I had the rear bearing go bad on an OS .50 heli-engine, but I was using pure synthetic in it. I've been using a blend in the 4-stroke. Hopefully that'll protect the engine.
The other reason is that I've been getting a knocking sound at high throttle settings... I can't tell if it's the engine or airframe (occurs on the ground too). Last night, though, I bought a set of feelers and checked the valve clearances... they were way too wide. I'm no engine mechanic, but hopefully that'll fix the knocking.
Cheers
04-19-2004, 04:02 PM
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RE: How do I tell if my crank bearings are bad?
Put your ear right on the fuselage, (makes a great sound enhancer) and rock the prop back and forth. If they are bad you will hear a slight grinding sound as opposed to a smooth quietness.
Ernie
Ernie
04-19-2004, 07:22 PM
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RE: How do I tell if my crank bearings are bad?
With me it was quite obvious. Took my favorite plane out after sitting on the self for two months and tried to fire it up. When turing it over It felt a little rough and once she fired up it sounded like a geared motor. After two flights I quit as the vibration was getting bad. There was some play but not excessive. Rust did the rear bearings in. after replacing them there was no play at all and the engine's now back to normal.
Later.
Later.
