“Stiff” O-rings.

Well, I found mine “stiff” too. But that wasn’t the problem. Even though the compression was very tight (hard to latch), the cap would still not seal, spin in the hole as it were. The two spreader plates were bottomed out on each other too.

OK … I found the cure -- at least for mine.

I had some “fuel lube” which is made for fuel selectors (et al) that are “stiff” --- hard to turn. It will not dissolve in gasoline meaning it could be a real problem if some got in the fine screen of the fuel filter or some such. Acetone does seem to make it “go away”.

Nevertheless, a tiny tiny amount on the nylon seals that squeeze the O-rings makes it so the O-rings can squeeze out to make a very good seal without much effort on the “handle”. Tight in the hole now. So it appears the O-ring could not “slide” or “squeeze out” on the nylon … but now slides nicely and the O-ring is no longer “stiff”.

If anyone wants the brand or name of this fuel lube stuff shoot me a note and I’ll get that to you.
Jim

 

From:

"Jim Nordin" <panelmaker@earthlink.net>

Sender: <marv@lancaironline.net>

Subject: LNC2 Fuel Caps

Date: Tue, 17 Aug 2010 13:09:44 -0400

To:lml@lancaironline.net

 

If the problem is the cap is now loose in the socket, the tension can be
adjusted on that cap. On the bottom of the cap is an AN365 nut. It can be
tightened slightly to make the O ring "fit better".
Jim

-----Original Message-----
From: Lancair Mailing List [mailto:lml@lancaironline.net] On Behalf Of
Greenbacks, UnLtd.
Sent: Tuesday, August 17, 2010 9:11 AM
To: lml@lancaironline.net
Subject: [LML] Re: LNC2 Fuel Caps

One of my three fuel caps appears to have an O-ring which is stiffer  
(header tank) than those on the wings. It closes ok but the tab no  
longer sits flush with the cap surface. I'm wondering whether the O-
rings which came with the original kit are now beyond their useful  
life. (not from flight time but build time)...
 From your experience, how frequently should they be swapped out in  
the field?

Angier Ames
N4ZQ