Lately I have been" blessed" with receiving really crappy thick and scuzzy waste oil. Its free, so i grab it anyway, we cannot be choosy when it comes to free stuff, we are in mid winter here and its all I can get. Lister has been a tad prima donnaish about burning it, shes getting a bit fussy in her old age and really wants to retire. The problem eventually was tracked to the injector, it needed a small mod to cope with the much higher viscosity, made worse by the abnormally cold weather.
I dont know how many of you have actually had these things apart.... the experts of all things diesel would have you believe they are highly complex and shouldnt be fiddled with.
Not true.
Inside the actual nozzle is a small needle valve, this is preloaded with a spring and the adjustment screw exiting from the top of the main body. This pingle valve is designed to seal against the seat, and to lift once the fuel pressure exceeds the spring pretension, thereby squirting the pressurized fuel into the combustion chamber.
After careful measuring, i figured this valve was slightly too long to lift enough to allow the higher viscosity oil through in a sufficient quantity, in effect it was hitting the main body way too soon, it should not hit the main body at all.. The larger diameter body of the pingle where it meets with the parallel "pin" needs to be shortened by at least .5mm, easily done by chucking it in the drill press, and carefully grinding it back slightly with a Dremel tool and small grinding disk. The actual amount is really not so important, as when burning diesel it will simply revert back to its normal opening.... its just not quite enough unmodded to cope with alternative fuel, especially when cold, thereby starving the engine. This has now been running for a few months with no problems.......
These too are very simple to adjust once reassembled.
With the engine running and under a heavy constant load, adjust the injector while watching the fuel pump rack. A point will be found where the rack will be at its minimum position, ie, furtherest back from wide open. This adjustment on mine is not critical, several turns either way from the best setting will not alter performance. This is actually a very accurate way to do this, as obviously the best spray pattern for that particular engine burning that particular fuel will automatically result in the best power output.... we are basically letting the engine tell you when its most happy.
