Carb problems, to hot?

[BlueSwede]

Hello guys

I have a problem with heat I think.
Motor (348, newly rebuilt) is sitting in a 34 Tudor and runs fine for about 10 minutes and then if left running at idle it starts to hesitate and eventually stalls if I do not rew it up a bit. It hessitates and spits when trying to rew it up.
If I force the electric fan to run it goes away after a while.
Motor is equipped with 2 Edelbrook 500 on a Offy "medium" high rice.

The temp is about 180-190F (fan starts at 190).

And now to my question/suspicion, I have a fuel hose (black) from the gastank to the fuel pump and up to the carbs that is about 9,5mm diameter (0,38 inch).
This is running close between engine and the waterpump and seems to get hot. I suspect that the combination of large diameter and that it is tuching motor and waterpump to heat the fuel due to low fuel speed.
What is the inner diameter for the original metal fuel line?

And yes I have insulators between carbs anf intake (4gaskets and 3 aluminum gaskets, like a sandwich), can not get more in to close to hood!

Suggestions and ideas for solutions whanted.......!?

 

[BlueSwede]

Pic of engine.

Hello again

A little pic of the engine, you can spot the fuel line coming up between the waterpump and engine and maby the insulators aswell.

 

[Dond409]

cool fuel

Get the fuel line as far away from the engine as possible. You can get fuel line sleeveing that helps insulate it from heat from both jeg's or summit.

 

[impalaragpat]

replace that rubber hose with a steel line before you have a fire. Should have steel line from tank to carb with short rubber line as needed at tank and pump.
Fuel line from pump to carb for this engine is available from many suppliers. The steel line can be bent so no contact is made with hot spots. I think should be 3/8 or larger.

Pat

 

[impalaragpat]

Another thought on this. All that rubber line could be clogging your filter as it breaks down. Check your filter. My car ran same way and filter at carb was clogged .
Be sure to put filter inline between tank and pump when going to your new steel lines.
Pat

 

[jim_ss409]

Nice Car! bang I think the factory metal line is 3/8"od and I don't think it ran up behind the water pump. Still, you would think that the rubber would insulate the fuel from the heat. Maybe there's more heat in the tighter engine compartment of your car than there would be on a full size Impala.

 

[64ss409]

The factory line ran around and over the water pump. If you look in my photo album, there is a pic taken while the engine was still on the stand. The line routing is visable.

How hard would it be to add a return line? Could you tee just ahead of the carb? I have forgotten the factory orfice size going to the return line, but I can measure the one in my fuel bowl. This would keep the fuel flowing while it is is setting at idle.

Ron

 

[BlueSwede]

I have rerouted the fuel line now and put some sleavings on there.
Will test later today.
So there was some modells that had a return line to keep fuel flowing?
No fuel preasure device here only a restriction like a small orifis?
I think a return line could be the next step if the rerouting and sleaving does not help.

 

[BlueSwede]

Hello guys

Just came in from my test drive and it seems to work fine now!
I sleved of the hose as far as I thougt was necessary about the first 5 feet from the carbs, both before and after the fuel pump.

Not supposed to drive the car on the road yet (have to get it approved by the swedish car approval first), but I just could not resist . :

Ill be back with some more pics later.

 

[jim_ss409]

I'll bet that car really grabs peoples atention in Sweden! :? bang These cars must have had fuel problems in 61 & 62 because the 63s and 64s had return lines.

 

[bobs409]

Hmmm.... Gonna have to hijack this thread a bit. I think I'm going to try wrapping my fuel line with something now just for a test. Since day 1 mine has always run lousy when hot. Excellent when cold (even 20 degrees cold!) but once it hits 175 or higher, the idle quality gets poor. Idle surges up and down and if left go, it will stall. The hotter it gets, the worse it gets.

For a quick test, do you guys think aluminum foil wrapped around the line will work? Mine has the correct chrome line running from the pump to the carb. I don't have the return line that this engine would have had normally, the car doesn't have the return line so I plugged that port on the glass fuel bowl. Can this be a problem?

 

[BlueSwede]

Hello again

Promissed to come back with some more pic´s.

This is what it looks like with the heat wrapping in place, I bought a bigger one cut it in pieces and "zig zaged" the edges (yes I do draips and curtaint to ).
The wrapping consists of a fiberglass backing that have a aluminum coat on top.
Maby one can fabricate this a bit cheaper than to by it.
Anyhow it seems to work and that is the main thing.....

Thanks to all for the tips and ideas, this forum is GREAT!!!

 

[MRHP]

Nice motor and nice car. Congrats on all of your hard work! Brian

 

[Fathead Racing]

Heat

Hmmm.... Gonna have to hijack this thread a bit. I think I'm going to try wrapping my fuel line with something now just for a test. Since day 1 mine has always run lousy when hot. Excellent when cold (even 20 degrees cold!) but once it hits 175 or higher, the idle quality gets poor. Idle surges up and down and if left go, it will stall. The hotter it gets, the worse it gets.

For a quick test, do you guys think aluminum foil wrapped around the line will work? Mine has the correct chrome line running from the pump to the carb. I don't have the return line that this engine would have had normally, the car doesn't have the return line so I plugged that port on the glass fuel bowl. Can this be a problem?

Bob, do you have heat spacers under the carbs?? Heat passages plugged in intake??

 

[bobs409]

Ray,

Thanks for the reply. Initially, I was just using a gasket but I added the steel shim that Show cars sells long time back. Don't know how good of a heat shield that is though. The gasket I'm using also has metal inside it. (NAPA)

Heat passages are open.

 

[Fathead Racing]

Bob.

Lack of a retun line is probably the problem in your case . I would make carb spacers from 1/2" phenolic plastic and use stainless steel to block the heat passages in the intake. As the carb heats, the fuel inside the float expands and has no where to go and is pushed into the air stream resulting in a rich condition.