Mechanical fuel pump bypass

[Charger Ted]

While waiting for parts for my A/C I began working on my vapor lock problem. More than a year ago I installed an electronic fuel pump near the tank. It has helped but I still have some problems. I am going to install an electric fan on the radiator and a return line to the gas tank. I would like to eliminate the mechanical fuel pump. Can I just loop the output around to the input and leave the pump on the engine, if even for a short time. Will there be any problems with doing this or will it wreck the mechanical fuel pump? The car is 66 Charger with 318.
TIA
Ted

 

[Don Frelier]

You can do that but I think the pump will still be trying to suck in air now (and dirt).
I'd suggest putting in a block off plate and put the pump in a bag.

 

[Fran Blacker]

I wonder if you really have a vapor lock problem? Electric pump should push fuel right through mechanical pump I would think. I've only dealt with BB Carter pumps and the internal check valves I think would allow fuel through pump. I've never took apart a SB pump so...
I'd put a fuel pressure gauge near carb to see what's happening under the conditions when "vapor lock" occurs. If fuel pressure is low you do have VL. If not it's something else.

 

[Charger Ted]

Thanks Don and Fran. Guess the plan will be:
1. Blanking plate
2. Re-route gas line away from engine and only use electronic fuel pump.
3. Install electric fan on radiator.
That should at least tell me if it is vapor lock tho I am certain it is.
Will keep you posted. Thanks again.
Ted

 

[Don Frelier]

A couple other ideas:
Original starter?
Putting on a newer one from a Dakota or a Ram will flip it over more quickly and also not drop the battery voltage as much.
Just to be sure do a spark test when cranking hot as well.

 

[70chall440]

I make my own block off plates, no rocket science there. You don't have to remove the rod but I always do.

You might think about a bypass fuel regulator with a return line, it will allow any excess fuel return and keep your fuel pressure steady.

 

[Don Frelier]

I don't think the old A 318 had a pushrod just a long arm on the pump.

 

[70chall440]

Oh my bad, I was thinking B/RB motor... you are correct for a SB.