Smoke or not to smoke? D-7 3T

Tim,

Seems like you have a good engine and unobstructed air cleaner.

Get in an area that is not loose sand and doze together at least 3 good bladefulls of dirt, then open the throttle wide open, and start moving the big pile in 1 st gear so that the tractor is barely moving and not spinning the tracks. This should be enough load to load the tractor. You will see a hint of black smoke. If it is after dark, you will see slight flame out of the stack when the engine lugs down and goes to work.

Tell us what you see.

Thomas

Some of the first turbocharged engines were likely to smoke when you opened the throttle.

Anaeroid controls were added to many of them to limit the fuel (rack travel) until boost pressure built up. I remember SJ mentioning that these were a common problem on the D342/???? (truck engines) that used to come into their shop. A blown diaphragm in the control would prevent full fuel delivery under load.

Your tractor might benefit from a new governor spring etc. but from your description, that would only be fine tuning.

From my experience, if the governor is responsive so that you can operate at part throttle and it keeps you from choking down as load changes from turning, applying brake, going up slopes etc. then yours is in pretty good shape.

The old Mack engines used to have puff limiters on them too. The cowboys would take them off thinking it gave more power because it let the engine belch black smoke - all it did was slow down how quickly the fuel rate increased, giving the turbo time to spool up. It didn't limit the max fuel rate unless it was malfunctioning. Looked cool though ; )
Cheers,
Neil

The old Mack engines used to have puff limiters on them too. The cowboys would take them off thinking it gave more power because it let the engine belch black smoke - all it did was slow down how quickly the fuel rate increased, giving the turbo time to spool up. It didn't limit the max fuel rate unless it was malfunctioning. Looked cool though ; )
Cheers,
Neil