Vapor Lock Woes

B

bullrunmotor

Senior Member
Headed out Sunday at 8:00 am with 80degree weather 59A runs like a champ-going 55 mph pulling strong. I've got upgraded pumps. haney coil. Modern condensor . Carb idles and pull great no pings etc. We leave at 3:00 and its 99 degrees with more traffic. Car starts surging and losing power. I switch on electric fuel pump-helper pump-and I limp another mile and pull over. Got it trailered home. Starts right up next day and I measure temp after 20 minute idle at top of manifold riser and have 135 degree. I measure base of carb and read 123 degree. so the stock gasket knocks off 12 degrees between carb and manifold. So I install a phenolic spacer today and let truck ide 40 minutes. I record 150 degree at top of manifold and 119 degrees at base of carb. Great 31 degrees drop with insulator-But-when i aim gun at the fuel pump and then the fuel bowl area of carb both read 140 degrees-not one degree difference.So- OK the plate has cooled down the bottom of the carb but you are still getting 140 degree gas delivered to fuel bowl area. Does anybody know temp where EBlend gas starts to vaporize. Truck doesnt not have a fuel bowl on the pump. My other fords do. Could that little storage amount in glass bowl help? Can anyone suggest how to lower the temp coming from the pump to carb? Fuel pump checks out AOK and was rebuilt 500 miles ago. No tin foil or bobby pins
 
Find some non-ethanol fuel. Living in Texas, when ambient temp is over 92, ethanol boils in the fuel bowl which creates vapor lock. Adding octane does not help. A cool can type solution works.
 
Agree with post #2. Elec. fuel pump should have overcome any vapor lock.

Both coil and condenser can fail when warm, then work fine again when cool. You were in very hot conditions. (99 degrees, traffic) Maybe that modern condenser started to fail under the heat? Condensers are fragile inside. Some are weak/bad new out of the box.

I have had confusing readings using a thermal gun. Asked about that on this forum and was told those guns will give different readings depending on the material/reflectivity of the item in sight. Can't think of anything else to explain reading 119 degrees on the carb base while 140 degrees on the float bowl.
 
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I dont think its the gun. I can go open the hood after the truck sits for 2 days and aim the gun at the radiator/carb/air filter/cylinder heads etc and get the same 84 degrees on all readings which is what is on the wall thermometer I'm going to get a metal in line filter placed between the fuel pump and carb with a rubber line and see if the temp goes down. This is only flathead I have without a glass bowl style fuel pump. I remember the same problem riding with my father in the 70's to National Meets. He would stall-pull over-put a rag in the cooler wad up some ice cubes in it and place it on the fuel pump. After 15 minutes we'd take off again. Anyway-I really wanted to hear if anyone knew the temp EBlend gas starts to vaporize
 
WOW, sorry for your breakdown. . Spoiled your whole day. I had something like that happen to me and was stuck under an overpass. Now, I have become afraid to take me car on an outing and only drive around my development. I am presently replacing my condenser and coil...Hope that solved the problem. You hate when these antiques break down because, you think if your leave it someone will strip or steal it.
 
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