help ! boiling fuel ? engine flutters after 5 miles, what is going on ?

[Stanglover]

all good advice,
I changed the fuel filter and it seems to be repaired, so far.
the psi went from a fluttery 3 to a steady 9 psi at idle.
this issue was just a symptom, the cause is the fuel tank.
it will arrive tomorrow, and I will change it out.

Good to know thing have improved and it's running better.
You have a new tank on the way. Did you order a new sender as well? Also as you're going this far, I'd go for broke and install a new SS fuel line. The return line is probably ok, but check it for air flow. The tank vent has no replacement element so most guys use a piece of SS scouring pad. I used a piece of ScotchBrite but that might not have been a good idea. Here are a couple of pics that might be of interest.
I added small 1/16th solid rubber insulators, my choice. The rubber line is injector grade and the clamps are fuel line spring clamps. Another tip is to replace the tank strap bolts with 3/8" x 3.5 or 4" Galvanized carriage bolts.
The tank I bought was the Spectra Premium F32A from Rock Auto and the sender was Dorman 692232. All good quality parts. The SS fuel line I bought at NPD, but needed a little tweaking, it may have been twisted in shipping.
Anything else you can think of, let us know. Many of us have had to do this change.

 

[Rockin Ken]

Hopefully you got the Spectra F32A and not a Taiwan made one.

Don't forget to replace the fuel lines, they get rusty after 50 years, especially if it has been sitting for so long!!!! Go steel as stainless is harder to work with.

this is the one I installed. it seems to be working well.
https://www.amazon.com/dp/B07BPXZSP4?ref=ppx_yo2ov_dt_b_product_details&th=1

 

[c9zx]

Are you saying you have 9 PSI fuel pressure? At 9 PSI the carb should be in rebellion. Is it a stock type mechanical fuel pump or electric? I would not expect to see more than 6.0-6.5 PSI from stock type mechanical pump. If it is an electrical pump, does it have an adjustable regulator? Chuck

 

[Rockin Ken]

Good to know thing have improved and it's running better.
You have a new tank on the way. Did you order a new sender as well? Also as you're going this far, I'd go for broke and install a new SS fuel line. The return line is probably ok, but check it for air flow. The tank vent has no replacement element so most guys use a piece of SS scouring pad. I used a piece of ScotchBrite but that might not have been a good idea. Here are a couple of pics that might be of interest.
I added small 1/16th solid rubber insulators, my choice. The rubber line is injector grade and the clamps are fuel line spring clamps. Another tip is to replace the tank strap bolts with 3/8" x 3.5 or 4" Galvanized carriage bolts.
The tank I bought was the Spectra Premium F32A from Rock Auto and the sender was Dorman 692232. All good quality parts. The SS fuel line I bought at NPD, but needed a little tweaking, it may have been twisted in shipping.
Anything else you can think of, let us know. Many of us have had to do this change.

thanks so much for the pics and post,
are there any isolators from the factory?; or you just decided to put some in?

 

[Rockin Ken]

Are you saying you have 9 PSI fuel pressure? At 9 PSI the carb should be in rebellion. Is it a stock type mechanical fuel pump or electric? I would not expect to see more than 6.0-6.5 PSI from stock type mechanical pump. If it is an electrical pump, does it have an adjustable regulator? Chuck

it is a stock mechanical pump

 

[Stanglover]

thanks so much for the pics and post,
are there any isolators from the factory?; or you just decided to put some in?

Thanks for your reply.
There was a felt like pad on mine, but I decided it was better to go with solid rubber. While you have the tank out, check the trunk floor underneath. Hopefully it's good, but if not, that's the time to clean/fix/repair it. Mine was pristine, I got very lucky.
At the risk of being condescending, If it looks old, replace it. Don't screw around with old cruddy parts.
Good luck,

EDIT: I should have mentioned that the reason for the rubber pads was to allow an air space between the tank and trunk floor as well as stopping any vibration.

 

[jscott]

this is the one I installed. it seems to be working well.
https://www.amazon.com/dp/B07BPXZSP4?ref=ppx_yo2ov_dt_b_product_details&th=1

This is a filter, I was referring to the best fuel tank for our cars, the Spectra F32A. The ones made in Asia are not very good.

 

[Doc302]

In addition to all that has been said -- I see you are here in South Florida. I had a similar problem and a big issue is that we have heat nearly year round. although is seems counter intuitive Ethanol in E-10 lowers the boiling point of the fuel and can cause vapor lock. If the problem persists after changing the tank and lines, especially if you have the problem after running the car and stopping for a while to get fuel etc. and the engine heat sinks,-- look in the sight glass of your carb ( if you have them) and see if the fuel is boiling in the carb. if it is you may have fuel boil in the lines as well. I had this problem with my 73 429 swapped Q-code and mostly solved the problem with phenolic carb spacer ( keeps carb cooler if nothing else), but the ultimate solution was to convert to an in tank electric fuel pump ( pushes fuel not pulls it) and a return through the pressure regulator -- circulating fuel stays cooler, and because it is not being pulled from the tank ( low pressure created on the inlet side of the mechanical fuel pump ) it is less prone to boiling. You also eliminate the hot fuel pump from the equation. I you are running ethanal free you will have less problems. E-10 boils lower then ethanol free ( uses shorter chain hydrocarbons that boils lower because EtOH raises effective octane rating reducing need for long chain hydrocarbons in the gasoline) -- this is not a problem for fuel injected applications because pressurized fuel will boils at much higher temp, but is a problem in carburetors especially when the gas is pre-heated by being in the tank at 90+ degrees. I can not get 93 ethanol free nearby and don't want to go with race gas even though that is what I need at 12:1 CR.

If you are going to replace the lines and are not doing a concourse restoration consider going to a return type fuel system when you do the lines it is not much harder to run two the one line.

 

[Rockin Ken]

In addition to all that has been said -- I see you are here in South Florida. I had a similar problem and a big issue is that we have heat nearly year round. although is seems counter intuitive Ethanol in E-10 lowers the boiling point of the fuel and can cause vapor lock. If the problem persists after changing the tank and lines, especially if you have the problem after running the car and stopping for a while to get fuel etc. and the engine heat sinks,-- look in the sight glass of your carb ( if you have them) and see if the fuel is boiling in the carb. if it is you may have fuel boil in the lines as well. I had this problem with my 73 429 swapped Q-code and mostly solved the problem with phenolic carb spacer ( keeps carb cooler if nothing else), but the ultimate solution was to convert to an in tank electric fuel pump ( pushes fuel not pulls it) and a return through the pressure regulator -- circulating fuel stays cooler, and because it is not being pulled from the tank ( low pressure created on the inlet side of the mechanical fuel pump ) it is less prone to boiling. You also eliminate the hot fuel pump from the equation. I you are running ethanal free you will have less problems. E-10 boils lower then ethanol free ( uses shorter chain hydrocarbons that boils lower because EtOH raises effective octane rating reducing need for long chain hydrocarbons in the gasoline) -- this is not a problem for fuel injected applications because pressurized fuel will boils at much higher temp, but is a problem in carburetors especially when the gas is pre-heated by being in the tank at 90+ degrees. I can not get 93 ethanol free nearby and don't want to go with race gas even though that is what I need at 12:1 CR.

If you are going to replace the lines and are not doing a concourse restoration consider going to a return type fuel system when you do the lines it is not much harder to run two the one line.

thank you, all good info