I recently rebuilt my O-320 and hung it on the RV-6. I was working on fitting the cowl and while turning the prop, I heard a metallic click. Upon further investigation, I found an odd and disturbing situation.
When rotating the engine in the standard direction, a click can be heard when either prop blade reaches the 1:30 position (one prop tip is indexed to TDC on #1) . In other words it happens in 180* repetition in exactly the same spot. I can back up a few degrees and repeat it, but if I only back up slightly, it won't repeat. It is very consistent. I can also swing the blade in the opposite direction and will get the click with either blade at the 10:30 position.
The click sounds like tension is built and is released at the point the click is heard. You can feel it in the prop blade. It is very light, but can be felt.
It is difficult to locate exactly where the sound is coming from but my best guess is in the case behind the #4 cylinder.
When I assembled the oil pump, there was a spot that was just a bit tighter than the rest of the rotation, but it certainly didn't seem significant and assumed the gears needed to be run in to mate properly. My first step will be to pull the accessory case to eliminate this as the cause.
I am baffled by this. I just can't visualize what could be causing this. I am hoping some of the more experienced members will have some ideas.
Thanks in advance for your assistance here.
Larry
EDIT: Failed to mention that the engine is bare of accessories. No mags, fuel pump, etc.
When rotating the engine in the standard direction, a click can be heard when either prop blade reaches the 1:30 position (one prop tip is indexed to TDC on #1) . In other words it happens in 180* repetition in exactly the same spot. I can back up a few degrees and repeat it, but if I only back up slightly, it won't repeat. It is very consistent. I can also swing the blade in the opposite direction and will get the click with either blade at the 10:30 position.
The click sounds like tension is built and is released at the point the click is heard. You can feel it in the prop blade. It is very light, but can be felt.
It is difficult to locate exactly where the sound is coming from but my best guess is in the case behind the #4 cylinder.
When I assembled the oil pump, there was a spot that was just a bit tighter than the rest of the rotation, but it certainly didn't seem significant and assumed the gears needed to be run in to mate properly. My first step will be to pull the accessory case to eliminate this as the cause.
I am baffled by this. I just can't visualize what could be causing this. I am hoping some of the more experienced members will have some ideas.
Thanks in advance for your assistance here.
Larry
EDIT: Failed to mention that the engine is bare of accessories. No mags, fuel pump, etc.
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