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  #11  
Old 03-19-2020, 10:49 AM
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10builder 10builder is offline
 
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With a reman/OH crank hasnt the metallurgy been somewhat proven?
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  #12  
Old 03-19-2020, 11:51 AM
theduff theduff is offline
 
Join Date: Jan 2012
Location: Fallbrook Calif.
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Default Crankshaft Dilemma

Ive built a few engines and this choice has always been an interesting dilemma. Usually price wins out, but in the current market availability may be the primary driver. Try to find any good used 0-360 crank in the current market, (Superiors issues ) your talking 4K used, if you can find any. I would stay away from the PMAd world and go Lycoming factory new or used. At least Lycoming gave out crankshaft kits to replace their ADd cranks in their last episode.

My question though is what was the rpm of your overspeed that caused the counterweight ear to break ?
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  #13  
Old 03-19-2020, 01:07 PM
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Toobuilder Toobuilder is offline
 
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Default

I don't mean to imply that a new crank is "unsafe" - my main question really is: "What does the extra $4k buy me?" In my brain I can't come up with anything, and it seems this forum supports that.

Concerning the overspeed, it was in excess of 3800.
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  #14  
Old 03-20-2020, 06:59 AM
BillL BillL is offline
 
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Default Not that it means anything but . . .

Quote:
Originally Posted by Toobuilder View Post
I don't mean to imply that a new crank is "unsafe" - my main question really is: "What does the extra $4k buy me?" In my brain I can't come up with anything, and it seems this forum supports that.

Concerning the overspeed, it was in excess of 3800.
Assuming the factory cranks are made on modern machinery and managed with current best practices quality control (air gauges, SPC, etc).

I would say a high probability exists for a better dimensional consistency and surface finish of bearings and proper nitride hardness/depth (along with a 100 more details). Basically a more precision piece. This makes for (typically) more reliable part.

But as long as the "rebuilt" crank had only ground surfaces, and re-nitrided with good inspection procures on each crank, then it would be just as good for its original purpose. And both sourced parts are still bound by the same TBO requirements.

You might want a mag and eddy current inspection just to be sure for sub surface inclusions that might have grown in service. They are not detected by mag inspection.

I think it kinda is how much money you want to spend for a little better "insurance".
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