Gasket/seal/washer orientation references

[Let'sgoflying!]

Has anyone seen a reference for standard application of these?

I don’t mean your opinion, although I value that too, nor “I was taught” or “I heard” - I’m looking for FAA or manufacturer written instructions on which way the are applied:

-fibre gasket between an appliance and engine case
-spark plug copper gaskets
-exhaust gaskets - eg Spirotallic or Flexitallic (CMI)
-I did find one for split copper crush gaskets (open side to non rotating component)

It ‘feels right’ to put the flat surface against the largest or non-moving part (ie the exhaust gasket flat against the cylinder) but I’m not sure that’s valid.
Likewise, I can’t make myself put the curved surface of a metal washer against a part, it must go next to the nut or bolt head, in my mind.
An A+P friend told me he puts the gasket serial number out, at all times (but the SN on ex gaskets is on the flat surface which might be contradictory.

 

[Bell206]

Has anyone seen a reference for standard application of these?

Normally, if there is specific orientation of a part it will be noted in the items installation instruction or marked on the part. For example, on certain Lycoming exhaust gaskets the correct position is indicated:
https://www.lycoming.com/sites/default/files/Exhaust Flange Gaskets.pdf

Or, on spark plug gaskets there is no specific position noted, except to replace gasket after each use and not to use two gaskets:
http://www.championaerospace.com/wp-content/uploads/2015/06/AV6-R-Aug20141.pdf

As for the "curved surface of a washer" if you're talking about standard washers where one edge is smoother than the other, I've seen no particular orientation noted. However, there are some aviation washers that are designed with a bevel on one edge to reduce stress against the "bearing" side--but the required placement is usually indicated in the install docs.

 

[Raymo]

Agree with the above but on the curved vs flat (and sometimes rough) surface of a washer, a Sikorsky engineer said they specified that the curved/smooth surface go against the non-moving part to avoid damage. For example, steel washers against aluminum - you want the smooth surface against the aluminum; not the nut or bolt.

Gaskets? Doesn't matter, IMO. Same for copper washers but I still follow the Sikorsky engineer's advice here, even though the copper will likely do no harm.

 

[flyingron]

I agree with Bell206. Regular AN washers don't really have a side other than as a manufacturing byproduct. The Navion indeed has some that are intentionally beveled and you put the narrower side against the structural part (rather than the bolt head/nut side).