Sherman M4A2 Detroit Injectors

[Malcolm Towrie]

Originally Posted by Andrew Rowe

Hi Malcolm,
Are you running these N65's currently or are you using the older type injector?
It is a really good idea to have a fuel pressure gauge inline so you know exactly the fuel pressure going to the injectors and also what your by-pass cuts in at for the fuel pump. Also very critical to have your return line with the .080 thou,
(2mm ) restrictor hole on the end of the return line from the injectors as this holds the pressure for the injector, Cheers Andrew.

Hi, Andrew, yes, these engines both have the brown N65 tag on the injectors. I’m not sure what the “brown” signifies but it seems to be important.
I don’t have a pressure gauge installed on the engine but I did run the fuel pump on the bench and confirmed that the pressure regulator opened at 75 psi, which is in the spec range.
I pulled the elbow fitting on the return gallery and confirmed it does have a restriction orifice. Looks more like the 0.055” orifice listed as one of the options rather than the 0.080” one.
Malcolm