Double wall exhaust system, anybody do it ?

[mtnmankev]

The reason I am not running a mechanical pump with the return is because the cam lobe that runs the fuel pump went south.

 

[ali_c20]

https://www.gmsquarebody.com/threads/fuel-tank-selector-valve-2-types.20720/

Info bout the selector valves. This forum is such a great source of knowledge.

 

[82sbshortbed]

Reroute gas line away from exhaust?

 

[MrMarty51]

How about an in the tank strainer sock being partially plugged ?

 

[legopnuematic]

Something else to check is make sure you don't have any sources of air being able to enter the fuel line before the electric pump. Those types of leaks dont typically show themselves since they are vacuum not pressure but can and will cause headache. Also make sure the selector valve isn't getting stuck between the two tanks, I've had that happen before and can make things go funky.

Sent from my Moto Z (2) using Tapatalk

 

[gotyourgoat]

An actual heat shield from something newer that would cover the area in question would be the way I'd lean. Or wrapping the lines to insulate them.


The vapor locking issue might go away if the fuel pump was pushing a further distance instead of trying to pull a greater distance. Guessing it ended up front because of the gap in the line and the dual tanks though eh?

 

[mtnmankev]

An actual heat shield from something newer that would cover the area in question would be the way I'd lean. Or wrapping the lines to insulate them.


The vapor locking issue might go away if the fuel pump was pushing a further distance instead of trying to pull a greater distance. Guessing it ended up front because of the gap in the line and the dual tanks though eh?

The electric pump is below the tanks and behind the selector solenoid.
I know electrics prefer to push and mechanical likes to pull.

 

[gotyourgoat]

The electric pump is below the tanks and behind the selector solenoid.
I know electrics prefer to push and mechanical likes to pull.

Ok, the spray bottle comment made me think it was under the hood. Sounds like it's more of a no return line issue then.

How are the fuel lines routed if the pump is behind the tank selector switch but in front of the two tanks? Are there 2 pumps?

 

[tobiahr]

The other issue is the fact that the fuel is pressurized while passing the heat source. the pressure lowers the boiling point of the liquids and can cause vapor lock where a standard mechanical vacuum fuel pump would not. crap...i had that backwards....nevermind

 

[Mrisinge]

In the early 1980s with the smog rules and engine controls that went with them some of our government Chevrolet 1/2 ton PUs had extremely hot exhaust systems and were starting fires when we travelled through grass pastures. Two of the fires got out of control and cost the gov’t several thousand dollars in restitution. Our solution at the time was to wrap the muffler with a section of double wall wood stove pipe and slide oversized flexible exhaust tubing over the exhaust pipes from the muffler to the manifold and from the muffler to the end of the tail pipe. This rather simple fix stopped us setting grass fires.

 

[Craig 85]

Wix #33041 or Napa #3041 fuel filter have the return Frankenchevy spoke about.

3/8”, 3/8”, ¼” vapor

You must be registered for see images attach

 

[DoubleDingo]

Wix #33041 or Napa #3041 fuel filter have the return Frankenchevy spoke about.

3/8”, 3/8”, ¼” vapor

You must be registered for see images attach

Have never seen one of those. Does it just return to the filter and recirculate?

 

[Craig 85]

Have never seen one of those. Does it just return to the filter and recirculate?

These are designed for 60's and 70's Mopar vehicles. From what I've read, any excess fuel not needed at the carb will return to the tank. Probably similar to my OEM 3 port fuel pump.

 

[80BrownK10]

I’m guessing with the clickity-clack fuel pump you’re running a return-less fuel circuit?

If so, you can pick up one of those fuel filters with a built in return and run the return to the 5/16” barb on the sender.

Also, most generic electric fuel pumps will put well over 10 psi through a 3/8” fuel line. So essentially the pump is being dead headed and will overheat and/or prematurely fail. Make sure the pump is below the tank then try this order in the engine compartment: return style fuel filter, fuel regulator, then fuel pressure gauge. All those parts from spectre or mr. gasket should be relatively cheap, yet reliable. Or you can buy a return style regulator, but they’re a bit more pricey.


I’m guessing trying to double wall an exhaust will end in rattles that will drive you nuts.

edit: is there a reason you aren’t running a mechanical fuel pump with return?

I was going to say these two things. One get the filter with a return and make a loop. Also get rid of the clickety clack pump and run a factory mechanical.

 

[WFO]

These are designed for 60's and 70's Mopar vehicles. From what I've read, any excess fuel not needed at the carb will return to the tank. Probably similar to my OEM 3 port fuel pump.

That's right. I put one of those filters on my 69 Chevelle SS, because when I bought it, it had a new 2 port fuel pump on it. Whenever that pump fails, or I get a wild hair, it'll get a 3 port pump like it came from the factory with.