Vapor lock revamp thread, any interest?

[747mopar]

The parts are ordered so work will commence soon just looking to see if there's any interest in me doing a thread on the matter. I've put 19,000 miles on the car starting with basically the plain ordinary parts then added a phenolic spacer, insulated the fuel line and now will do a full fuel delivery revamp and pass on the results. There never seems to be a shortage of vapor lock threads and questions so.. let me know and I'll share.

 

[Skatpak]

Yes I would be interested in what you found/find out, Todds Restorations., Todd

 

[toolmanmike]

The parts are ordered so work will commence soon just looking to see if there's any interest in me doing a thread on the matter. I've put 19,000 miles on the car starting with basically the plain ordinary parts then added a phenolic spacer, insulated the fuel line and now will do a full fuel delivery revamp and pass on the results. There never seems to be a shortage of vapor lock threads and questions so.. let me know and I'll share.

Please do.

 

[OH71RRunner]

I'd be interested. There's never too many ideas for dealing with this issue. And a thread detailing everything done to resolve the issue would be even better.

 

[ckessel]

Give it a whirl. It will be interesting to see how it goes for you compared to other states with different fuel recipes. Out here, along with Ethanol in the mix, we have the CARB [california air resources board] package which further creates issues on the fuel.

 

[Grabbergreendream]

I look thoroughly through every thread I see pop up with vapor lock issues. My 71' Satellite w/a 440 4 bbl and air grabber hood has me heavily concerned about the issues. I'd like to have everything needed and installed to resolve the issues during reassembly. The more ideas I can implicate to minimize vapor lock the better. I dont have the hieghth for carb spacers due to the air grabber so any info is pertinent on my application with todays fuels.

 

[toolmanmike]

I look thoroughly through every thread I see pop up with vapor lock issues. My 71' Satellite w/a 440 4 bbl and air grabber hood has me heavily concerned about the issues. I'd like to have everything needed and installed to resolve the issues during reassembly. The more ideas I can implicate to minimize vapor lock the better. I dont have the hieghth for carb spacers due to the air grabber so any info is pertinent on my application with todays fuels.

Exactly. Cars with clearance under the hood benefit with a spacer under the carb. If you are short on room there are drop bases for many air cleaners that can help the clearance issues. The spacer really helps with the running vapor lock like the OP is experiencing. It will help with heat soak and fuel evaporation after shutting the engine off but it isn't a cure for that. An electric charge pump is the best fix for that hot soak issue.

 

[747mopar]

I look thoroughly through every thread I see pop up with vapor lock issues. My 71' Satellite w/a 440 4 bbl and air grabber hood has me heavily concerned about the issues. I'd like to have everything needed and installed to resolve the issues during reassembly. The more ideas I can implicate to minimize vapor lock the better. I dont have the hieghth for carb spacers due to the air grabber so any info is pertinent on my application with todays fuels.

It's definitely a frustrating issue especially when the results aren't consistent which I attribute to differences in fuels. My car as it sits is mostly problem free throughout the summer with the fuel line insulated and the carb sitting on a 1/2" spacer but mostly isn't good enough. I live in an area where traffic is almost non existent which is a big part of why I say mostly gone, it rarely has to sit long enough for anything to get hot but it happens and when it does it's always at the worst time!

I had a guy giving me the looks at a stop light, I knew I'd obliterate him so I took off fairly easy so I wouldn't light up the tires then smoked him.. and then blahblahblaaaaaaa. Fortunately he was way behind and it had time to come out of it before he caught up so I just kept cruising like nothing ever happened. Took my boy out for Mexican one afternoon, as we started backing out some of the people in the outdoor eating area started talking to me asking questions and then blaaaaaa. It's infuriating and embarrassing as hell!

I'll do a thread but keep in mind there may be a cheaper or possibly an easier solution, the option I'm taking is one that I feel will absolutely 100% fix it once and for all just short of going full EFI. The logic is simple, today's fuel is designed for EFI period so make your system match that of a modern car the best that you can. There could still be fuel evaporating out of the carb but an electric pump gives you the ability to throw the ignition in run for a few seconds to fill the bowl before cranking it over.

 

[Some Car Guy]

Do you have a factory vapor separator setup in it? My car does and it never stalled, but had a low speed and idle surge when everything got fully soaked. I found a silly thin spacer that hid under the gasket. I think it actually held in heat. Once I added a 3/8 spacer my problems disappeared. Before that, I was adding race gas with no difference.

there are two versions of the factory separator going around. Be sure yours has the smaller orfice that is .060 and not the monster sized one that will lower fuel pressure.

now I run regular 93 that even has ethanol in it. I always run stabil 360 too to guard against ethanol issues. It has a fuel system cleaner in it to boot.

 

[747mopar]

Do you have a factory vapor separator setup in it? My car does and it never stalled, but had a low speed and idle surge when everything got fully soaked. I found a silly thin spacer that hid under the gasket. I think it actually held in heat. Once I added a 3/8 spacer my problems disappeared. Before that, I was adding race gas with no difference.

there are two versions of the factory separator going around. Be sure yours has the smaller orfice that is .060 and not the monster sized one that will lower fuel pressure.

now I run regular 93 that even has ethanol in it. I always run stabil 360 too to guard against ethanol issues. It has a fuel system cleaner in it to boot.

View attachment 1463302

View attachment 1463303

Others had suggested trying one but I didn't for 2 reasons.

1 I've heard of people having problems caused by to much bypassing.

2 and most importantly it wouldn't do anything for my float bowls going dry. I'm attempting to 100% cure everything at once.

I did however install one on another motor, waiting to see how it does.

 

[Some Car Guy]

Others had suggested trying one but I didn't for 2 reasons.

1 I've heard of people having problems caused by to much bypassing.

2 and most importantly it wouldn't do anything for my float bowls going dry. I'm attempting to 100% cure everything at once.

I did however install one on another motor, waiting to see how it does.

Too much bypassing meaning low fuel psi? If so, it’s due to the incorrect orfice separator like in my pic. My car runs just fine when fully heat soaked, including starting, with the proper sized one.

nothing will solve the bowls going dry due to their venting to atmosphere. You can start it once a week, pour gas down the primaries, or do an electric pump. Or efi. Electric pumps tend to run hot on long drives without a controller. Frieburger had that on his orange bee and had to install one so it cycles the pump.

you could find one that can be pulled through and just run it before cranking. Might be the least downsides deal if you don’t want to do the gas down the throat. That’s what I do.

 

[747mopar]

She runs again!! Time to start racking up the miles and see what happens. A few more pictures..

The lines tend to come out where the pumpkin could make contact so I made this little bracket that bolts into a few unused holes in the shock cross member.

Since I have a trunk mounted battery and a bracket for the battery disconnect it seemed like a no brained to mount the really right there.

All cleaned up!

 

[747mopar]

Too much bypassing meaning low fuel psi? If so, it’s due to the incorrect orfice separator like in my pic. My car runs just fine when fully heat soaked, including starting, with the proper sized one.

nothing will solve the bowls going dry due to their venting to atmosphere. You can start it once a week, pour gas down the primaries, or do an electric pump. Or efi. Electric pumps tend to run hot on long drives without a controller. Frieburger had that on his orange bee and had to install one so it cycles the pump.

you could find one that can be pulled through and just run it before cranking. Might be the least downsides deal if you don’t want to do the gas down the throat. That’s what I do.

That's why I went with a pump in the tank, as long as you don't run it down to E every time the pump has plenty of cooling. You also have to remember I haven't had great experience with mechanical fuel pumps either, so many parts are garbage anymore.. 3 pumps in 19,000 miles!

 

[451Mopar]

Having a fuel return system, either the original vapor seperator, or a by-pass regulator works well by keeping the fuel flowing through the lines and preventing vapor head pressure.
Basically, if the fuel starts to vaporize and increase pressure past the pump, the bypass will bleed off that pressure. This is important with a factory type mechanical fuel pump that has a built in regulator.
With a basic bypass, you could just "T" in around the carb inlet and have a bypass hose with a restrictor in it.
If doing a new fuel system, I would just start with an EFI fuel tank with internal electric pump and a by-pass regulator at the carb.
Then if you want to switch to EFI, the fuel system is already in place.