Learned a bit of an expensive lesson today, that I thought I would share, to hopefully save someone any grief. I decided to use a 67 GT 500 pre-bent fuel line from fuel pump up to a 45 degree inverted flair that attaches to a Summit fuel line and pressure gauge. This makes a very clean installation for a double pumper carburetor. I then decide to upgrade to a liquid filled fuel pressure gauge. The issue started when I started up the car cold and the gauge would read
5 1/2 psi so everything was good until the car started to get warm. As the car came up to temperature, the gauge started to read lower and lower until it would read about 2 psi! To make a long story short, changed the fuel filter, installed a new tank and sender as well as cleaned and flushed the lines. Started the car up and the same scenario, as the car came up to temperature the fuel pressure was dropping until it would be 2 psi on the liquid filled gauge. Thought maybe the 10% ethanol pump fuel sold here in Florida was vaporizing as the fuel lines got hot Insulate the lines. Same result. Googled liquid filled fuel pressure gauge and guess what? A liquid filled fuel pressure gauge will change readings as temperatures change. Attached is a Summit Racing bulletin regarding this phenomena. Hope this helps someone in the future.
Don
gt350bp