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jchang10

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I have the factory lycoming io540, and it came with a couple of bags of hardware. I can't figure out what these Al self locking nuts for a 5/16 bolt would be for. Anyone have an idea? I called lycoming and nobody there knew either. clearly, i didn't get the right person or persons. Hopefully, someone here has a clue.

It is labelled as:

STD-2043 NUT-.3125-18 self locking

Thanks,
Jae
 
Some of the clamps are small diameter. however, the bag with the clamps includes nuts and lockwashers, too.

I forgot to mention that there was supposed to be 12 of the lock nuts, of course, i didn't receive that many. That may point to something with the exhaust mounts? However, I wouldn't think Al nuts would be good for that application. Vettermans come with their own stainless steel nuts anyway.

Oh well, just wanted to see if there was an explanation for all this. I sure hope lycoming remembered all the pistons.

Jae
 
Are you sure...

...those nuts really are aluminum?

Some of the high temp MS series nuts have different finishes on them that may look like aluminum (silver plate?).
 
Honestly, it is just a guess. All I did was place a strong magnet to it and got nothing. They are also very very light.

The only way to get a better idea would be if I were to cut it. I have lots of experience cutting Al. I'll sacrifice one of them when i get back to the shop.

I did get a bill of materials from Lycoming and this is how it is labelled:

STD-2043 NUT-.3125-18 SELF LOCKING count of 12

Here's another link to the part from googling it. Still no idea what it would be used for.

http://www.aeroperform.com/aicraft-parts-paint-catalog/STD-2043-buynow.htm

Jae
 
Exhaust flange nut?

The lock nuts look like MS21046C5. Which is a stainless steel silver plated high temp. (700 degree) lock nut. They are probably used for the exhaust flange attachment to the cylinder head. Other bag of hardware looks like it's for the mag harness.

Don
 
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