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I am curious if AN363 are preferable over AN365 firewall forward?

peter

I used the AN363 where they're called for in the plans, which is basically everything structural (engine mount.) I have a lot of AN365 FWF on things like adel clamps, air filter and firewall-mounted accessories. I've never seen any signs of heat affecting/compromising them. The 2 downsides I see to AN363 are 1) they are harder to turn, and 2) I believe they may scratch the bolt a bit if moved/removed somewhat frequently, such as the air filter or prop hub.

AN363 nuts.............?

Don't use AN365 fiber lock nuts forward of the firewall. The heat will deteriorate the locking effect after a time.

All nuts in the engine compartment should be AN363 lock nuts OR AN310 castle nuts with a cotter pin.

In Canada the MD-RA inspector (final inspection before flight) will "snag" you for any AN365 nuts firewall fwd and make you change them to AN363's.

Gordon.......Hummel 2400......Onex #0024....C-IODB

I agree with Gordon - don't use any fiber-lock nuts in the engine compartment. It may not appear that they are being affected by the heat, but I have found that, over time they will ultimately lose their locking ability. Use all-metal locking nuts, or castle nuts with cotter pins, in the engine compartment. You'll be glad you did!

Sonerai13 wrote:I agree with Gordon - don't use any fiber-lock nuts in the engine compartment. It may not appear that they are being affected by the heat, but I have found that, over time they will ultimately lose their locking ability. Use all-metal locking nuts, or castle nuts with cotter pins, in the engine compartment. You'll be glad you did!

ok good info...

Would it also be a good idea to use loctite 242 (or other??) with the AN363s?

Thanks everybody...
peter

pfhoeycfi wrote:

Sonerai13 wrote:I agree with Gordon - don't use any fiber-lock nuts in the engine compartment. It may not appear that they are being affected by the heat, but I have found that, over time they will ultimately lose their locking ability. Use all-metal locking nuts, or castle nuts with cotter pins, in the engine compartment. You'll be glad you did!

Would it also be a good idea to use loctite 242 (or other??) with the AN363s?

No need for loctite. Besides, it is affected by heat as well, so wouldn't really do anything. Let the nuts do their job.

Sonerai13 wrote:
No need for loctite. Besides, it is affected by heat as well, so wouldn't really do anything. Let the nuts do their job.

ok thanks...

peter

The whole Aerovee engine case is held together with nylon locknuts, so how is that acceptable there but not on other components on the firewall, etc?

The nylocks on the engine are not there for locking. The idea of the nylock on a vw has been around for a long time. Regular threads have a helical shaped “leak” path that allows the studs on a vw case to leak oil over time. The nylock is there to seal the leak path and prevent oil leaks at the studs. Their locking ability is not intended to mean anything to engine function.

Ah, I wouldn't have guessed that! Thanks!