Hilborn Fuel Injection END510S Secondary Bypass Valve, Brass
This brass valve is designed to control high rpm, closed throttle fuel pressure. It consists of a body, cap, poppet, spring, a .187” shim, and seal. The body is marked with the letter “S” and an arrow. It connects directly off the metering valve, with the arrow pointing toward the fuel tank. Since fuel flow is controlled mechanically by the metering valve, any open throttle position 25 degrees or more will automatically shut of the Secondary By-Pass Valve. This eliminates the possibility of a lean condition when throttle is open. Shims and springs can be added to change fuel pressure.
A .016 wires spring is the most commonly used, however, .020 and .024 are also available. Using a thicker wire spring will give more spring tension, resulting in a richer fuel mixture at idle and low rpm operation.
The jet (pill) controls the amount of fuel the engine will receive at all rpm ranges. The larger the jet size, the more fuel is allowed to return to the tank, therefore leaning out the mixture. To richen the mixture, use a smaller jet size. To lean the mixtrue, use a larger jet size.
Drop the jet into the valve so the number is visible to you. This side of the hole has been champfered and is the side that fuel enters.
Q & A
Speedway Motors employee Pat O. is back to talk about a cool little nostalgic piece now available at Speedway Motors, our Fiberglass Tunnel Ram Shark Scoop.
Speedway Motors employee Pat O. is back with Dave's 1951 Chevy Truck project to talk about the 1947-1954 Chevy Truck EFI Fuel tank available from Speedway Motors.
Speedway Motors employee Pat O. takes some time to discuss the Fuel Gauge Interface Module that allows you to use any gauge set with almost any fuel level sending unit.
Speedway Motors and Classic Trucks built a 1952 Chevy truck in celebration of the 65th anniversary of Speedway Motors. Check out the short video on one of the products used in the build.