A post for today on nozzles. Nozzles are the lumps of brass that screw into the manifold and do the actual fuel squirting. The McGee grey motor injection set came with six nozzles installed, and eight spare nozzles. Good opportunity for me to learn about how the McGee nozzles are identified.
McGee nozzles are made to have a -3AN fuel inlet fitting. This suits 3/16" tube, and has a 3/8"-24UNF straight thread. The thread that screws into the injector manifold is 1/8-27NPT.
The nozzles are made in five different styles:
1) X style (both Left and Right),
2) R style,
3) C style,
4) Shower Head style, and
5) Straight style.
The different styles are shown in the image below:
- Nozzles.png (554.47 KiB) Viewed 2728 times
X, R and C styles are near identical - the fuel squirts out at 90º to the nozzle body, but in a different direction for each style. Each McGee nozzle is also available in six different sizes - #8, #10, #12, #14, #16 and #18. Part numbers for the different nozzles are given in the table below:
- Nozzle part numbers.PNG (13.08 KiB) Viewed 2728 times
The grey motor injection set came with three XL nozzles and three XR nozzles (plus a spare of each). A nozzle can be seen peeking into the inlet manifold below:
- nozzle in manifold.jpg (484.53 KiB) Viewed 2728 times
- nozzle screwed into manifold.jpg (437.21 KiB) Viewed 2728 times
These are stamped X18, as per the lower image below (this is a Right-hand X style):
- McGee nozzles from grey motor injection set.jpg (387.82 KiB) Viewed 2728 times
I suspect the X18 is similar to the Kinsler coding, and that the internal fuel control orifice is 0.018” diameter (looks to be, but I need to get hold of my fine pin gauges to confirm). They are not Kinsler nozzles though, as Kinsler run either 1, 3, 4 or 6 vent holes – these have two 0.134” external vents (cant see them in the photo above as I have the nozzle turned the wrong way).
The injection set also came with six spare Straight nozzles, as per the upper image above. These have a 0.121” internal bore (massive compared to the 0.018” nozzles), and two external vent holes (0.093” and 0.063”).
The bit I am not sure of is whether these are #8, #10, #12, #14, #16 or #18 nozzles. I’ve sent a query over to McGee in the states, and see what response I get.
The 0.018” holes in the nozzles make me understand why there are so many warnings about keeping mechanical fuel injection systems spotlessly clean, and why they run such intricate filtration.
Cheers,
Harv