i wanna learn how to madify a cummins and other diesels

tyler_s18 said

ok thank you. i learn best by taking it apart and playing with it but that was a lot of help:) i know his is one turbo and it didnt look to much bigger then the newer cummins turbos i have seen. could you put a cam in it that opens the injectors longer or open farther?

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Interesting question, both no and yes. On the old Cummings engines you couldn't change the stroke of injector plunger as a matter of fact there was a clearance tolerance that you had to shoot for between the rocker arm and plunger head. You could go to larger orifices in each unit injector kind of like going to a bigger plunger but those changes have to be done on a special test rig/flow bench that also calibrates each injector. I'm pretty sure though that you could change the timing of the injector opening by adjusted a slotted gear or pinned on the end of the camshaft but this would also change your intake and exhaust valve opening timing also. The valves and injectors work off the same cam. I'll pull my diesel engine manual (the big one) and see what it says tomorrow, it's been a while. One other thing to consider is the old and new turbochargers had internal exhaust waste gates that controlled the RPM of the turbo therefore the boost pressure to the engine. He may of cranked up the waste gate controller to boost the air pressure to the engine but god only knows how much and if you really crank up the boost you also have to have a intercooler to cool the air after you boost the crap out of it.

Terry