Ways to fix vapor lock without a return line

[mquinn66]

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.

Caseys had it until last year now they say not enough demand so they took it out.

 

[C-440-300]

Exactly, i guess i may be drilling a hole in my new tank for a return line.

It worked for me. (The language is not for kids, but, this guy had an idea. This works. It's one of many videos. (14) No more vapor lock 62 impala - YouTube He made some newbie mistakes, but u get the idea. Here's the tube protection I used. (18) how to make a fuel vapor return line chevelle GM - YouTube I never needed to slit the plastic. Just buy the right parts that match. ) I used a softer, 100% (real) copper 20' 1/4" tube and ran parallel to my tank to pump feed steel line. First, I sleeved it in plastic piping/tubing with ID matching my new return line OD - lathered it up with Vasoline and kept at it. U can cut the plastic tubing in sections if it works better for you. With the plastic outside, no slitting required, it made handling and forming the turns way easier as I fed it from front to back. Zipped tied to the older line and ran it right up to the filler pipe. Took out the filler pipe and did nice, safe job on the barbed nipple (brass) 1/4" with screw/nut super tight(washer) by holding with long needle nose, the nut/washer inside the pipe as I turned the brass nipple. For extra seal, I used brass washers and I still added a bit of RTV, but, it's low pressure, and it has not leaked. Take the filler out. The key is getting the right three nipple filter. I used a WIX 33041 or '40 ? Uncle Tony likes 1/16" or thereabouts I forgot. Mine has the third nipple orthogonal to the filter axis. I know I'm writing this late - for the next guy. Good luck

 

[Bold & Old]

It worked for me. (The language is not for kids, but, this guy had an idea. This works. It's one of many videos. (14) No more vapor lock 62 impala - YouTube He made some newbie mistakes, but u get the idea. Here's the tube protection I used. (18) how to make a fuel vapor return line chevelle GM - YouTube I never needed to slit the plastic. Just buy the right parts that match. ) I used a softer, 100% (real) copper 20' 1/4" tube and ran parallel to my tank to pump feed steel line. First, I sleeved it in plastic piping/tubing with ID matching my new return line OD - lathered it up with Vasoline and kept at it. U can cut the plastic tubing in sections if it works better for you. With the plastic outside, no slitting required, it made handling and forming the turns way easier as I fed it from front to back. Zipped tied to the older line and ran it right up to the filler pipe. Took out the filler pipe and did nice, safe job on the barbed nipple (brass) 1/4" with screw/nut super tight(washer) by holding with long needle nose, the nut/washer inside the pipe as I turned the brass nipple. For extra seal, I used brass washers and I still added a bit of RTV, but, it's low pressure, and it has not leaked. Take the filler out. The key is getting the right three nipple filter. I used a WIX 33041 or '40 ? Uncle Tony likes 1/16" or thereabouts I forgot. Mine has the third nipple orthogonal to the filter axis. I know I'm writing this late - for the next guy. Good luck

@C-440-300
@ C-440-300

What size gas line are you using...3/8s?

Mike

 

[Sixpactogo]

Chrysler Corp dealt with this issue before I even heard of it. When I got out of the Navy in early 1968, I bought a new Charger R/T with a 440 four speed.
My brother bought a new Charger before me but his was a 383 four speed. The summer of 1968 while we were working in St. Louis, we took our cars to a drag strip on week-ends. His car would vapor lock after a run while mine would not. We found by accident what Mopar already knew. My car had a 3/8" fuel line with a 1/4" return from a separator bolted to one of the fuel pump bolts. We then found a wrecked Hemi Charger in a salvage yard and robbed the fuel sender, lines and separator for his car. He never had the problem again. That was in 1968 when premium gas was 103 octane.
Point being, Chrysler engineers figured out how to fix the problem before we knew it was a problem. I believe the gas was boiling in the fuel pump from heat radiating from the engine block causing the vapor lock. If I had a vapor lock problem, I would follow their fix.

 

[Bold & Old]

Chrysler Corp dealt with this issue before I even heard of it. When I got out of the Navy in early 1968, I bought a new Charger R/T with a 440 four speed.
My brother bought a new Charger before me but his was a 383 four speed. The summer of 1968 while we were working in St. Louis, we took our cars to a drag strip on week-ends. His car would vapor lock after a run while mine would not. We found by accident what Mopar already knew. My car had a 3/8" fuel line with a 1/4" return from a separator bolted to one of the fuel pump bolts. We then found a wrecked Hemi Charger in a salvage yard and robbed the fuel sender, lines and separator for his car. He never had the problem again. That was in 1968 when premium gas was 103 octane.
Point being, Chrysler engineers figured out how to fix the problem before we knew it was a problem. I believe the gas was boiling in the fuel pump from heat radiating from the engine block causing the vapor lock. If I had a vapor lock problem, I would follow their fix.

Thank you for the info....I have a after market setup I bought on eBay a couple years ago.

Fuel Vapor Separator - Filter Set for 1970-1971 MoPar E-Body w/426 Hemi & 440 | eBay

I like the idea of using copper line covered in plastic tubing for insulating the return.... because copper is easy to bend.

I had 3 new 68-69 factory high performance motors....... back then. Z28 & 2 427s.
I had to burn hi octane 260 Sunoco to prevent to per-detonation.... pinging sound sometimes i used 240 grade and still got pinging.

racing fuel no problem!

I read several magazines regarding the factory return lines.
Comeback 'Cuda Update: Fuel, Vent lines, and Gas Tank Installation - Mopar Connection Magazine | A comprehensive daily resource for Mopar enthusiast news, features and the latest Mopar tech

I also plan to insulate the engine fuel lines......

heat kills HP

A couple check valves to prevent pressurizing the tank in several locations.

 

[dsd1967]

I have a 67 sweptline pickup with a 400 that has the factory cast iron manifolds. After driving the truck, shutting it off and letting it heat soak for 10 minutes or more, it would vapor lock and not start until it was darn near cold again. Tried the return line plus the filter with the vapor separator line and it wouldn't work. I added an electric fuel pump and it starts every time. I think the cast iron exhaust manifold carried so much heat and is so close to the fuel pump that it boiled the fuel in the mechanical fuel pump.

 

[Bold & Old]

I have a 67 sweptline pickup with a 400 that has the factory cast iron manifolds. After driving the truck, shutting it off and letting it heat soak for 10 minutes or more, it would vapor lock and not start until it was darn near cold again. Tried the return line plus the filter with the vapor separator line and it wouldn't work. I added an electric fuel pump and it starts every time. I think the cast iron exhaust manifold carried so much heat and is so close to the fuel pump that it boiled the fuel in the mechanical fuel pump.

I am not sure but i think Chrysler was the only manufacturer to try to address the pre ignition. issue if there is such a word... but I stand to be corrected.

When i had my hot 60s GM cars the only thing we could do was retard the timing a bit... or bump up the octane.....either-way you lost power.

retard it in the summer and advance it in the cooler weather.

I am going to try to find a better solution this summer using the double line system.

 

[Kern Dog]

you should use a by-pass style fuel regulator too

This makes sense.

the constant movement of the fuel, helps/keeps it cooler,

I added a regulator that dumped all pressure over 6 psi to a return line that runs back to the tank.
This alone cured my vapor lock issue. I can drive in 110 degree heat and the car runs fine. Heck.,,, I could probably drive in hotter climates but I haven’t tried.
You might have to replace your sending unit to obtain the vent line nipple or maybe if you’re adventurous, you can add one yourself.

 

[diesel_lv]

I am not sure but i think Chrysler was the only manufacturer to try to address the pre-detonation issue if there is such a word... but I stand to be corrected.

When i had my hot 60s GM cars the only thing we could do was retard the timing a bit... or bump up the octane.....either-way you lost power.

retard it in the summer and advance it in the cooler weather.

I am going to try to find a better solution this summer using the double line system.

I don't think you have the gist of this. This thread is about vapor lock, and the fixes for it. Those fixes have nothing to do w "pre-detonation".

 

[Kern Dog]

I have not heard of “pre-detonation” but I am familiar with pre ignition.

 

[Bold & Old]

This makes sense.

I added a regulator that dumped all pressure over 6 psi to a return line that runs back to the tank.
This alone cured my vapor lock issue. I can drive in 110 degree heat and the car runs fine. Heck.,,, I could probably drive in hotter climates but I haven’t tried.
You might have to replace your sending unit to obtain the vent line nipple or maybe if you’re adventurous, you can add one yourself.

Thanks Greg for your input... and you are correct..
I am kicking around several ways to do this.

i have a couple ideas from building my steam pressure vessel days that may work.




.

 

[Bold & Old]

I have not heard of “pre-detonation” but I am familiar with pre ignition.

I corrected thank..... thank you.

 

[Sixpactogo]

I am not sure but i think Chrysler was the only manufacturer to try to address the pre ignition. issue if there is such a word... but I stand to be corrected.

When i had my hot 60s GM cars the only thing we could do was retard the timing a bit... or bump up the octane.....either-way you lost power.

retard it in the summer and advance it in the cooler weather.

I am going to try to find a better solution this summer using the double line system.

Pre-ignition, Pre-detonation, Pinging........All the same but have nothing to do with vapor lock.

 

[Kern Dog]

I corrected thank..... thank you.

Hey…. I didn’t know if it was a term that I didn’t know.

 

[Bold & Old]

Pre-ignition, Pre-detonation, Pinging........All the same but have nothing to do with vapor lock.

I am thinking of using two lines off the return line one near the gas tank allowing unimpeded fuel back to the tank.

The other will branch off the same return line near the tank... going up to the steel filler tube using gravity with a check valve............... and vented gas cap.

I have 3-4 months so things may change when it becomes hands on time.

Thank you all... I will update you here when the deed is done