Hot Fuel Lines
My exhaust creates to much heat for these lines that it starts to vapor lock the fuel from feeding up the line. It doesnt start until after I go about 10 miles and then if the car sits it wont start back up until it cools off. Ive hit the fuel lines with my infra red and they get as high as 140+.
Fuel pressure starts at 6.5-7 when its first started up, but once it starts to do its what I think is a vapor lock its drop to about 5 psi.
Vapor can lock up fluid flow in a couple ways.
On the upstream, positive pressure side of a pump it will be a vapor pocket at higher pressure than the pump. That blocks most flow to the fuel inlet unless it can burp out. Early 60s Chrysler took extra measures to insure vapor could always excape the outlet of fuel filter to the carb bowl.
Hot restart vapor problems were from excess fuel in the bowls (ie flooding) after shutting down.
With your pusher pump setup I wouldn't expect exactly the same type of vapor issues, but knowing the characteristics may help you narrow it down.
Let me throw some ideas out.
The aluminum hard lines are not helping. Tarmack is easily 100*F in summertime Aluminum has very good heat transfer characteristics. So in this situation, insulation is almost certainly going to be a help. I'd use the insulated firesleeve for the entire length of the line. Then cover or shield in something reflective.
If that paint discoloration on the cross member is from heat, then do whatever you can to reduce the heat off the collectors. Wrap them in zircotec foil or something.
You might find my grilling experiment halfway down the link of some interest.
What to do about Winter Fuel in hot temperatures?
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