detroit 253 injector top to rocker arm clearance?????

[kouvakis]

does anybody know what the gap is supposed to be between top on injector and bottom of rocker arm on a 253 detroit engine in a jd 440. i had to replace injectors and manual tells how to set gap on exhaust valves. but a special tool is needed to gap the injector. i dont have a specail tool j1242. anybody got and idea????? manual does not give spec other than special tool just passes over rocker arm extension.

Bill in texas

[Cold Iron]

Bill, the rocker arm and the injector plunger should not have any gap in it at all. After you adjust the valve clearance rotate the engine so the cylinder that you are adjusting the exhaust valves are open and the rocker arm is all the way down. Then measure the distance between the injector housing by the little hole to the top of the plunger using a dial caliper with the depth rod. this clearance is adjusted to be 1.484 inches exactly. This is your injector timing so it is important to get it right. Follow the same procedure on the other cylinder. Next step is the rack adjustment. Gota love those Detroits