K

KRAUSEGB

Well Known Member
I am starting the fuel window install.
Question-page 37-05, as I read it, calls for 4X NAS1149FN632P washers per screw. Does this really mean 4 washers per screw?

I sure don't want to screw this up after all the troubles many are having with this assembly.

Thanks,

Gary
 
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The 4 washers serve as a stand off so fuel can enter between the site glass & back plate. Study the plans a little more.
 
Hmmm - Not so sure.....

Larry,

I'm not sure you are right about this. I hestiate to question your judgement, after all that time I spent drooling over your workmanship at the ROTAX booth - however....

Page 37-05 shows the washers in question on the OUTSIDE of the backing plate. That would not provide any spacing to allow fuel inside the gauge. Then there is this post: http://www.vansairforce.com/community/showthread.php?t=55507&highlight=37-05 that seems to say one washer is sufficient. That is the way I built my tank, and I sure hope it is OK! It seems to me that the fuel will enter and exit the gauge at the top and bottom where there are gaps - no other spacing required. Plus I would think the intent is to have the backing plate up firmly against the plastic material, so that stress is evenly distributed.

I think some changes were made here, and this page is on Revision 3. That possibly explains some confusion here about the washers.

Your thoughts? And maybe Scott M's too?
 
The TRUE original instructions said - - -

The 4 washers go between the 'glass', and the backing plate. This time Larry WAS correct - ( bet you didn't expect that Larry, did ya ? ).

John Bender
 
Just for clarity...

The revised drawing (Rev 3, 9/30/09) for the new window does not show four washers although the callout says 4X (which has been identified in previous posts as a typo left from the original drawings for the old window).

The new window backing plate is a channel shape so fuel gets behind the window and does not need washers for stand off. That shape also makes the backing plate rigid to better support the window.

I think BigJohn built his tank correctly, using one washer per nut and that is the way I built mine (still leak free at 24 hours).

I generally like the window. It is simple, no moving parts, and you see the fuel level directly, like dipping the tank, not a bad thing. If it fails, I guess I will go to the Moller gauge, like the others.

Tony
 
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Everyone is correct

Everyone is correct. There is confusion because Van's changed the plans. The original flat plate required stand-off washers, the new channel plate does not because fuel can flow through the channel at top and bottom. Extra washers under the nuts will only add weight and necessitate ordering more. Use plenty of sealant around the screws and fill the slots in the glass too.
Joe
 
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