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Ways to fix vapor lock without a return line

mquinn66 said:
I dont have the factory steel lines out of the mechanical pump. I have rubber running up near the shock and over the valve cover and manifold. I do have the rubber wrapped with heat shield in that area though. I think i will plumb some ni-cop line in the factory path to see if that helps too.
Click to expand...
This could be the whole problem right here..
 
mquinn66 said:
I dont have the factory steel lines out of the mechanical pump. I have rubber running up near the shock and over the valve cover and manifold. I do have the rubber wrapped with heat shield in that area though. I think i will plumb some ni-cop line in the factory path to see if that helps too.
Click to expand...
I'm assuming your using non oxy gas?
 
mquinn66 said:
Hello b body folks, I have a 66 charger that im just getting back on the road after 20 plus years. I went out for the longest drive so far and i think I have a vapor lock issue. Is there a way to fix this without adding a return line to the tank. My tank is a new stainless steel without return line. So im wondering what my options are to fix this vapor lock situation. Should i only run non ethanol? Should i insulate the line where its close to heat? Should i just add an electric pump? I never had this problem back in the 90s when it was last on the road.
Click to expand...
DEI Fuel Line Insulating Wrap ...................WORKS!
 
mquinn66 said:
Hello b body folks, I have a 66 charger that im just getting back on the road after 20 plus years. I went out for the longest drive so far and i think I have a vapor lock issue. Is there a way to fix this without adding a return line to the tank. My tank is a new stainless steel without return line. So im wondering what my options are to fix this vapor lock situation. Should i only run non ethanol? Should i insulate the line where its close to heat? Should i just add an electric pump? I never had this problem back in the 90s when it was last on the road.
Click to expand...

Race fuel. The new stuff at the pump vaporizes alot easier than the old fuel. Not much of a problem on vehicles with EFI because of the high fuel pressures (and most have return lines too.)
 
Not sure if anyone cares or maybe can use my info to help themselves. I used a napa 3041 filter with a 1/4 inch return line then added a 1/4 hose barb into the sending unit in the tank. FYI the 3/8 fuel filters with 1/4 returns are discontinued by wix and nappa so get them if you can.
20210521_180346.jpg
Hope this helps someone.
 
I have been reading these return fuel line threads for a while now with interest, because I am getting ready to reinstall my tank and fuel lines, but I can't get my mind past something..... I am not disagreeing with the fact that a return line keeps the fuel cooler by keeping it moving,.....but really how effective is the stock set up? Let me explain why I ask this......the fuel travels from the tank to the pump, then to the fuel seperator (which is inches away from the pump). At this point, the return fuel travels back to the tank, and the fuel destined to the carb is in a now 'deadhead line' to the carb. Up until the fuel separator, the fuel lines are not near any heat source so they shouldn't be too hot anyways. It is the 'deadhead line' to the carb that collects the heat as it passes up along the engine, near the manifolds etc,....it seems like this is where circulating and moving the fuel would help cool it, but this fuel has not other route then to the carb. Would not at better system be having a fuel separator near the carb, where only a few inches of 'deadhead' carb fuel remain? Seems logical to me, am I missing something?
 
Kimodc said:
I have been reading these return fuel line threads for a while now with interest, because I am getting ready to reinstall my tank and fuel lines, but I can't get my mind past something..... I am not disagreeing with the fact that a return line keeps the fuel cooler by keeping it moving,.....but really how effective is the stock set up? Let me explain why I ask this......the fuel travels from the tank to the pump, then to the fuel seperator (which is inches away from the pump). At this point, the return fuel travels back to the tank, and the fuel destined to the carb is in a now 'deadhead line' to the carb. Up until the fuel separator, the fuel lines are not near any heat source so they shouldn't be too hot anyways. It is the 'deadhead line' to the carb that collects the heat as it passes up along the engine, near the manifolds etc,....it seems like this is where circulating and moving the fuel would help cool it, but this fuel has not other route then to the carb. Would not at better system be having a fuel separator near the carb, where only a few inches of 'deadhead' carb fuel remain? Seems logical to me, am I missing something?
Click to expand...
I agree with you and am remembering in utg's video he has his separator filter laying up on the intake. My setup is down low right now and havent tested it on a hot day yet. If it doesnt work as expected i will put the filter/ separator up close to the carb.
 
Update: vapor lock seems to be fixed. Now issue seems to be fuel pressure fluctuation. The guage bounces like crazy between 3.5 and 1. I added a piece of rod drilled with a 1/16" hole to restrict flow. It still bounces like crazy. If i pinch it off it is steady. I am running 3/8 sending unit and line from tank to carb with a napa 3041 filter with 1/4 return to the tank. Also running a mechanical pump that has great pressure when cold and return line pinched off then it has around 6 psi until warmed up then goes to 3.5 and bounces like crazy unless return is pinched off. Anyone have any experience like this and if so how'd you fix it?
Should i reduce my line out of the pump to 5/16?
 
mquinn66 said:
Update: vapor lock seems to be fixed. Now issue seems to be fuel pressure fluctuation. The guage bounces like crazy between 3.5 and 1. I added a piece of rod drilled with a 1/16" hole to restrict flow. It still bounces like crazy. If i pinch it off it is steady. I am running 3/8 sending unit and line from tank to carb with a napa 3041 filter with 1/4 return to the tank. Also running a mechanical pump that has great pressure when cold and return line pinched off then it has around 6 psi until warmed up then goes to 3.5 and bounces like crazy unless return is pinched off. Anyone have any experience like this and if so how'd you fix it?
Should i reduce my line out of the pump to 5/16?
Click to expand...
Is your pressure gauge oil filled they pressure flux less. I am ready to plumb my 440 charger and not going to do a return line. Sticking with 3/8 all the way to the holley. Makes sense if you restricted the flow that much the pump probly has an internal bypass that would even it out. From what I have see with a carb its all volume not steady pressure you can gravity feed a holley and it will work now will that do for a quartermile run nope. The trick is to keep the fuel level in the bowls. Have seen a bunch talking about vapor lock to me your fuel is boiling in the lines not giving liquid gas to the carb. Look at where the lines run easy trick aluminium foil wrapped around the line as a heat shield just to test looks like **** for permanent . Back in the day used to do a cool can lol A coffee can with 3/8 soft copper coiled in it fill it with ice and good to go.Hope some of that helps you .
 
451Mopar said:
Race fuel. The new stuff at the pump vaporizes alot easier than the old fuel. Not much of a problem on vehicles with EFI because of the high fuel pressures (and most have return lines too.)
Click to expand...
Very great thing to think about pressure raises boiling point. Guess I get to see next if pump gas will work at 11.3 to 1. Wish me luck.
 
I am having real good luck running a heat cross over block off valley tin, along with using a thermoquad carb.
Also zero ethanol blend fuel.
 
1967coronet said:
I am having real good luck running a heat cross over block off valley tin, along with using a thermoquad carb.
Also zero ethanol blend fuel.
Click to expand...
Hard to find ethanol free fuel in the corn belt of illinois.
 
mquinn66 said:
Hard to find ethanol free fuel in the corn belt of illinois.
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I live in iowa , mabey just lucky but all our stations , Casey's, QT, ect all have a ethanol free choice.
Costs a little more but well worth it.

One thing though, all the coop pumps do have only ethanol blend lol.
 
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