Boiling my fuel.

[62 Dart Convertible]

Mate, I had massive problems with vapor lock. Tried insulating and still had trouble. Ended up putting in a 1/4" return line to tank from a 3 nipple filter just before carb to bleed off vapor and no more problems!! Cheap, easy and works!!

 

[themechanic]

Mate, I had massive problems with vapor lock. Tried insulating and still had trouble. Ended up putting in a 1/4" return line to tank from a 3 nipple filter just before carb to bleed off vapor and no more problems!! Cheap, easy and works!!

A lot of us would like to see that nipple.

 

[Dennis H]

Seems to work along with the 1/2 inch spacer.
Performance and reliability.

 

[62 Dart Convertible]

A lot of us would like to see that nipple.

Check out my 3rd nipple -



Is a OE filter for some Jeep models - Wix 33040 has 5/16" in/out, Wix 33041 has 3/8" in/out. Offset 1/4" nipple has in-built orifice to restrict return flow to tank and should be clocked to be highest point of filter to bleed off vapor (which floats). Best money I ever spent - my car was undriveable in warm weather yet has not stalled once since installing!

 

[ckessel]

I'll keep this info on the filters handy as I see more and more boiling issues happening. And since you are closer to the equator, you get hotter down there.

 

[bigmanjbmopar]

I considered that filter and a charcoal canister mounted under the car near the tank once. Decided to just upgrade the stock 5/16th lines to 3/8" insulate the line from the mech pump at the block to the top filter similar to what Dennis shows except black color. Its also insulated from mid way to pump. That along with a phenolic spacer and a QFT black diamond carb with the anti heat soak coating n it and unless it's 110+ ° outside its usually fine. I think with todays gas we all could use the fuel injected style gas tanks with a return line! Another thing to help is tuning. make sure your timing is right.

 

[furryfrog]

I added 1/4 return line as well, tied into each of my float bowls with a small orifice constantly recirculating fuel through my carb. Also drains the fuel in my carb when i shut the car off. Only fuel boiling off now is the fuel stored in my accel pump circuit.

 

[themechanic]

Check out my 3rd nipple -

View attachment 430894

Is a OE filter for some Jeep models - Wix 33040 has 5/16" in/out, Wix 33041 has 3/8" in/out. Offset 1/4" nipple has in-built orifice to restrict return flow to tank and should be clocked to be highest point of filter to bleed off vapor (which floats). Best money I ever spent - my car was undriveable in warm weather yet has not stalled once since installing!

$8.99 at Rock Auto but shipping would probably make it about the same as local parts stores charging $14 before tax.

 

[STREETREBEL]

UPDATE with pics. Seems to be working for now.

 

[STREETREBEL]

It's 92 today. Took her out for a test drive. Not to good.
The engine temp was at 195 at idle. I took off and within a
100 yards the A/F gauge showed 11-1. Better than before.
Before the changes the A/F would peg to 9-1, and the engine would die.

 

[ckessel]

I saw that one of the guys on this subject had mentioned that the boiling point of our pump fuel is 160* or so. You have 195 on the coolant plus the hot under hood air. I wonder if it might improve for you if you try and re-route that line as much as you can to cut down on some of the hot air exposure.

 

[Lionized]

It's 92 today. Took her out for a test drive. Not to good.
The engine temp was at 195 at idle. I took off and within a
100 yards the A/F gauge showed 11-1. Better than before.
Before the changes the A/F would peg to 9-1, and the engine would die.

190° is normal operating temperature.

 

[STREETREBEL]

190° is normal operating temperature.

The engine temp is fine. But the fuel is boiling at that temperature.
Fuel shoots out the vent tubes and floods the engine. It will kill the engine
if you don't open up the throttle.

 

[Dennis H]

Ethanol.

 

[Lionized]

Ethanol.

Pretty much as plain as this. I've had my car as high as 220° with no issues. Lotta sweating and really wouldn't want to go much higher than that though!

 

[Lionized]

Have you considered running a return line?
If your sending unit has the 1/4" nipple I would certainly consider it. I will also guarantee it will solve your issue.

 

[sputnik 440]

Personally I would swap that out to steel lines.

"...restoration shop ran metal tubing from tank to fuel filter under the passenger sill plate. From there they ran rubber fuel line to the mechanical fuel pump and from the pump to the pressure gauge, and, more rubber to the chrome tubing supplying fuel to each end of the Holley double pumper. Does this sound right? Does the rubber line provide the necessary insulation? Does it create other short or long term problems?"

Can you expound on that? One would think that fuel line rubber would be a much better insulator than steel or stainless. Is it not? Even if it is, I am still a little concerned about the long term effect of a hydrocarbon running through a line feeding a carb. Should I be, and why? I might add that the fuel lines run through the wheel well to give the shortest distance for the lines to be exposed to the engine compartment. The Hooker 2" headers through off a bunch of heat.

 

[Lionized]

"...restoration shop ran metal tubing from tank to fuel filter under the passenger sill plate. From there they ran rubber fuel line to the mechanical fuel pump and from the pump to the pressure gauge, and, more rubber to the chrome tubing supplying fuel to each end of the Holley double pumper. Does this sound right? Does the rubber line provide the necessary insulation? Does it create other short or long term problems?"

Can you expound on that? One would think that fuel line rubber would be a much better insulator than steel or stainless. Is it not? Even if it is, I am still a little concerned about the long term effect of a hydrocarbon running through a line feeding a carb. Should I be, and why? I might add that the fuel lines run through the wheel well to give the shortest distance for the lines to be exposed to the engine compartment. The Hooker 2" headers through off a bunch of heat.

Personally I would swap the rubber out for steel. I have steel lines to the (mechanical) pump and from there to the carb. Factory routing, factory HiPo manifolds. I only get into (heat) trouble when my temp climbs higher than about 210°. Which is rare.
Also, if you're running any percentage of Ethanol you're going to be very sorry running that much rubber line. It will it it like pigs at the trough.
Steel lines also will not trap the heat as rubber will.

 

[STREETREBEL]

A friend of mine reminded me that the factory use to pack insulation in the manifold, under the carb.

 

[Lionized]

A friend of mine reminded me that the factory use to pack insulation in the manifold, under the carb.

I've yet to see this mysterious "factory" insulation pack. I've gone as far as making one up myself. It trapped more heat than it dissipated. Plus, you'll have to pack two. One on either side of the heat crossover.