The Ford Barn - View Single Post - Why Shimming A Fuel Pump Changes Fuel Pressure

FlatheadTed · 01-20-2014, 05:20 PM

To work out your question you would need the height of the spring in the pump under compression divide that by 625 then work out the variation over the stroke range of the pump just over 1/4 or 3/10 "travel ,What I am saying is if a stock pumps pumps at 2.1/2 Ib and it takes 2min to fill the carburettor, then you shorten the rod by say 1/8"It then might take 4 Min to fill the carb but at that point it should reach the 2.1/2 Ib

01-20-2014, 05:20 PM	#13
FlatheadTed Senior Member Join Date: May 2010 Location: Auckland Posts: 4,705	Re: Why Shimming A Fuel Pump Changes Fuel Pressure To work out your question you would need the height of the spring in the pump under compression divide that by 625 then work out the variation over the stroke range of the pump just over 1/4 or 3/10 "travel ,What I am saying is if a stock pumps pumps at 2.1/2 Ib and it takes 2min to fill the carburettor, then you shorten the rod by say 1/8"It then might take 4 Min to fill the carb but at that point it should reach the 2.1/2 Ib __________________ http://www.flatheadted.com Flathead Ted brake Floaters , Last edited by FlatheadTed; 01-20-2014 at 07:45 PM.