VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1929-1932 Fuel Pump

Hello All,
Any thoughts on why the fuel pump on my 29 Coach is not working. The engine and fuel pump were rebuilt. When I pump the lever by hand fuel is drawn from the tank and all appears normal. After installation in the engine no fuel at all.

Thanks

I know you have checked the line between pump and carb or a slug in the carb.

Sounds as if the pump is not installed correctly. When the pump is installed in the opening the pump arm should contact the cam before the flange of the pump is seated against the block. It will then be necessary to compress the arm by pushing the pump in and that will indicate that the arm is in the correct position on the cam.

Thanks for the help, I can't even get fuel to the pump after installing in the engine. Almost like the cam is not working the pump arm.

Either your pump arm is worn to the point that it won't get full throw on the cam lobe or the cam lobe is worn enough so that it can't activate the pump arm enough to pump gas.

Is it possible the pump is installed with the arm UNDER the cam lobe?

Remember seeing the worn lobe problem on old Chevy 307-350's years back. We would put electric pumps on them. You can put some Prussian blue (gear marking compound) on the lever of your pump and see if it at least shows contact with the lobe. You say the pump was rebuilt and I assume hasn't pumped correctly since. Was the arm changed when it was rebuilt?

I went through this scenario a couple of months ago with a person that had a rebuilt fuel pump for an early 6 cylinder Chevy. The fuel pump was rebuilt correctly and it worked great on the bench when pumped by hand but it would not pump gas when installed on the engine. It was suggested that the problem was either with a worn pump arm or a worn cam lobe.

After a lot of trial and error it was discovered that the lobe on the cam was worn to the point that the cam lobe would not activate the pump arm. The pump arm was welded up on the end where it rides on the cam lobe to extend the throw of the arm and the pump worked fine after that.

Thanks all for the input. When installing the pump I feel pressure on the arm for the last 3/16 inch or so. Pump arm shows minimal wear. I thought of cam wear but was hoping for a miracle.

Over all the pump arm should have more travel than 3/16 of an inch when going from low to high on the cam lobe.

It's alive, as a test removed the pump gasket. That was enough pulled choke once and off she goes.
I have owned the car since 1998 and that's the first time it's run. Now a dash of weld on the arm as Dog suggested.

Thanks Again

Great! It looks like you found the problem. Obviously the cam lobe is worn so adding a little weld to the face of the pump arm should do the trick. Be sure to make the face of the pump arm flat and even when you add the weld.