-------------- Original message from "Paul" <sqpilot@bellsouth.net>: --------------

Well, after several mods to my airplane, which include installing firesleeve on all fuel lines, installing a vent for the sump tank (into the main wing tank) and bypassing the Facet fuel pump with a short length of clear tubing, I ran the engine until the water temp hit 230 degrees.  I shut it down and let the heat soaking proceed.  Then I restarted the engine and ran it up to 240 degrees. Still was able to go to full power with no signs of the engine stumbling or running rough.  Finally, temps hit 250 and I could hear the surge tank spitting out steam and liquid, but WOT was still smooth.  Previously it would stumble and quit by the time I hit 230.  I taxiied back in and temps only came down to around 220, so we placed the fan under the NACA scoop to cool it down.  There was evidence of small bubbles coming out of the top of the aluminum sump tank (which remained cool to the touch even at 250 degrees water temp), going into the left fuel strake. It was a small amount, but nevertheless, it was evident that the vent was working. There was no evidence of any bubbles coming out of the bottom of the surge tank and trying to work their way back up towards the fuel selector valve (through the line that the Facet pump normally resides).  I ran it again today, but just to normal 180 degree temps, and it still ran fine.  Paul Conner