Anderson Ed wrote:

 Looking at your schematic...  if you get an air/vapour pocket in your
header tank...  where does it go?  How do you get rid of it?

Neil

Good question Neil.  I had another fitting near the top (unused) that I
intended to put in somesort of check valve thinking that if vapor
pressure built up past 3 psi or so it would open and vent the vapor
overboard.  However, I had visions of the boost pump filling up the
header tank and pumping fuel overboard, so I finally decided just to
cap that fitting and rely on keeping the under the cowl temp down (which
the louvers seem to do a good job of and to have a blast due deliver
cool air to the header tank and fuel pumps/filters.  Since I added
lovers and started using Av gas I have had no indications of any
problems of vapor build up as I believe was occuring before I made those
two changes.

If anyone has a suggestion about how to vent the header tank for vapors
and not have the boost pump push fuel thru the vent, I would be
interested. But, so far have not had vapor build up problem since these
changes. I would most expect it on ground runup on a hot day so we will
see in August.

Ed Anderson

 
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