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CPI safety wire.

akschu

Well Known Member
Patron
I was looking at the CPI crank trigger setup and saw that two of the bolts have safety wires, and two don't:

Notice that the bolts holding it to the case have safety wires, but the bolts holding the hall effect pickup to the mount (Allen) aren't wired. Why is that? If either of those back out the fan will quit turning.

What am I missing?
 

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You could use a bit of Thread Locker on the Allen screws, they shouldn’t move.

The bolts don’t have a great deal of thread engagement in the thru nut & varies in washer stack thickness with each installation. A crush lock washer can’t be used as it would make sensor clearance difficult to set. Therefore the lock wire is required.
 
Yup 243 Locktite if you're concerned. Hundreds of thousands of hours on these. Nobody has reported any coming loose so far.
 
Can’t tell, but

If the socket head screws are engaged in a nut in the other side of the load/stack, (don’t know/can’t tell from the photo), no safetying is generally required. If they are installed in a blind hole, threadlocker, safety wire, something should be utilized. The OEM drawing technically overrides any standards but always lean towards the safe and conservative side.
 
Makes sense, lots of stuff depends on locktite. Just wanted to make sure I understood how this is locked.
 
If the socket cap bolt goes all the way thru, you could add a jam-nut (with locktite) too....

and drill the jam nut and bolt for a cotterpin
 
If the socket cap bolt goes all the way thru, you could add a jam-nut (with locktite) too....

and drill the jam nut and bolt for a cotterpin

I guess you could do that…. If addressing an issue that doesn’t exist in thousands of other installations.
 
Safety wire etc

When searching for a problem to apply a solution to it sometimes helps to remember that Lycoming connecting rod bolts are not safetied and have been that way for decades.
 
When searching for a problem to apply a solution to it sometimes helps to remember that Lycoming connecting rod bolts are not safetied and have been that way for decades.

They are a "through bolt"; not installed in a blind hole. No reason they would need safetying.
 
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