[bondsman]

does anybody out their have any knowledge about mechanical fuel injection. I have seen several old units for sale enderle and hilborn, but I don't quite understand how the fuel is injected into the correct cylinder at the proper time. I know that the fuel is delivered via the pump to a distribution block. What tells this distribution block what cylinder to inject?

[hvyeqpmech]

The Hilborns are constant flow. Don't know anything about the Ederle. There is fuel flowing to all the nozzles at all times. I worked with some 15 years ago. I am sure they have changed some. Some have up nozzles.(located in manifold) and some have down nozzles(located in the heads. Some also have both.Go to a sprint car show and talk to them about more specifics. Thats what they use. Hope I have helped.

[xtreme off-road]

I've heard about this system too, and if memory serves me right, it is the cylinder pressure during the compression stroke that opens the injector.

[46_stvblt]

I have run both Hilborn and Crower inj which are both similar to Enderle and hvyequp is right, they are constant flow. the cylinder that needs the fuel takes it from the manifold. the way that you keep from flooding the engine is by way of a by pass jet that sends fuel back to the tank. beleive it or not, they can be tuned pretty good. almost streetable. Hope this sheds a little light on it for you.....GK

[engineguy]

The mechanical injectors do work quite well, even though it seems like they would flood the engine. The calibration of the system is done with a "pill", which is actually like a jet and it goes in the fuel return line to the tank. Just the opposite of a jet, a large pill makes the engine run lean and a small pill makes the engine run rich. Have used Hilborn injectors and they are very responsive when tuned correctly. The real pain is in getting the engine started. Since there is no accelerator pump circuit, fuel must be sprayed into the engine to get it started. This is why you may see crew members squirting gas into the injectors, while the driver cranks the starter. Ah, the good ol' days.

[bondsman]

thanks for the responses, it helps to clear up some of my questions.

[67chevy1967]

can the new high pressure electric fuel pumps replace the old crank driven ones when using a mech fuel injection unit such as a hillborn?

[Highball]

I have a set of Norden Injectors and used the set on a Wayne 12 Port Head on a 261 Chevy six. I supplied the fuel with dual Stewart Warner Electric Fuel Pumps and used an in line Fuel Pressure regulator. They always did the job but like it was mentioned starting could be a chore. I push started the car.