Instructions for installing por

There are several reasons why a racer might need more than one nozzle in each port. Some applications are - constant flow fuel injection with nitrous, two stage fuel systems, or the ability to move the nozzle to get optimum performance from your fuel system. Some racers place the nozzles side by side but I prefer over and under. I fear the side by side puts the nozzle too close to the side of the port and if the fuel spray touches the port wall it will change from an anatomized spray back to a liquid and run down the port. As a liquid it will not burn completely and create an environment in the engine where although you are putting enough fuel in the engine but since all the fuel is not being “offered” to the combustion process it can create an situation where the fuel system is correct (or even rich) for the application but if fact it is lean in the engine since you are not giving the engine enough fuel to burn. On the over and under configuration although some racers will run a slightly longer nozzle holder on the top position but this is not necessary as both fuel sprays will be parallel to each other as they mix with the air as it is passing down the port past the valve.

Locate the bottom port nozzle location 1 ½” from the manifold gasket surface and in the center of the port. Measure this accurately and center punch to locate.

Make sure when the nozzle is installed later that the nozzle and hose will clear the valve cover. In some applications it may be necessary to angle mill the port nozzle bung to get the angle adequate for the application.

The correct drill size for tapping to 1/8”npt is actually an “R” drill which is .339” but a 5/16” (.312) will do just fine. The port nozzle bungs provided have a 5/16” pilot hole in the bottom. Once you have located at least one of the port nozzle hole locations and have center punched it the carefully and accurately drill through with a 5/16” drill bit. I would suggest that you pilot drill it first as often the aluminum casting can allow the drill bit to “walk” and lose its center running all your hard work getting the port nozzle in the right location.

Once the port nozzle holes are drilled to 5/16” you can use 5/16” bolts to hold the port nozzle bungs in place while they are welded. I strongly recommend only a tig welder be used for welding.

Once the bungs are welded in place you can use your 5/16” drill bit to drill through the other holes in the port nozzle bungs.

The threads in the port nozzle bungs are the same thread as used in all Enderle, Hilborn, and Kinsler nozzle holders. It is 1/8”-27 npt, which means it is 27 threads per inch. It is NOT 1/8”bsp!! 1/8” bsp is 28 threads per inch.

Once the bungs are welded in place and the holes drilled follow back up with a 1/8”-27 npt (National Pipe Taper) tap to chase the threads to the correct depth. As a taper fit this must match the taper on the port nozzle holders you are using.

The distribution block mounting bracket can be located under the tunnel ram plenum either on the bottom of the plenum or on the valley plate of the manifold. Be sure to seal the bolt threads with sealer to prevent vacuum leaks.