My engine won’t give up smoking
QMy diesel engine’s injectors have been cleaned but nothing has been done to the injector pump apart from retiming it. The engine is emitting blue smoke when idling (even when warm), but under load there’s no smoke. PETER DEKKER, via email
ATONY REPLIES: Blue smoke is normally produced by burning oil. My initial response is that I would expect this from a newly overhauled engine, caused by burning of the oil used during the assembly of the pistons and valve gear, or by the piston rings having not yet bedded into the cylinders and passing oil into the combustion chamber. Run in the engine under varying loads, not much on idle and light loads and avoid maximum speed for several hundred hours.
Cleaning the injectors might only consist of a quick wire brush over the nozzles with the potential to snap a needle pintle, which may well cause smoke. Injectors need stripping, inspecting, cleaning and testing as part of an overhaul.
There are four tests, spray pattern, break pressure, dribble, and back leakage. Do you have the results of these tests?