[changzuki]

- The D850's fuel injectors...
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The heart of any diesel lies in its fuel system. Get it right and you'll have a very nice performing engine that is very consistent across the board. Get it wrong and you'll be out some time, some money, and likely to be rolling coal.
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The fuel injectors in this unit were previously disassembled, cleaned, fingerprinted , and consequently experimented with. The goal of course was high mpg and given the previous gearing limitation, this fell into place at roughly 48-52 mph. During local mixed driving in that range returned a very respectable 100+ mpg. (The normal range being 127-158).
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Incorporating some of my ideas, and dropping the average to barely over 45mph for over 100 miles of more-or-less continuous driving, yielded a winning performance at the 2014 Green Grand Prix (200+ mpg).
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When changing out the straight 4-speed for the newer overdrive-equipped one, one cannot help but notice the substantially lower rpms that can be obtained at a given speed - and with that, a host of new problems can pile up especially if you've previously dialed in your little Kubota to perform at "X" rpm for "X" speed... All your endless hours and calculations just went out the tailpipe - in a big puff of smoke!
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It was time to revisit the injectors.. (Revisit here means to take apart! )
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In the photo below, the injector at the top is a new Nippendenso replacement.
In the photo below, the injector at the bottom is the stock D850 one.
There are physical differences between these two injectors even though they "cross reference"..
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Differences aside, the bigger question is, will there be a difference in performance?
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And if so, to what degree?
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To get an idea we could simply swap out the injectors and see what happens. I did this and although initially the engine idled marvelously, it just didn't seem to have nearly the get-up-and-go it previously had...
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The mystery vibration seemed to be gone though - so maybe a little investigative work was needed. There was only one way to attack this issue. We would need to go back in time, to the land that time forgot, and revive a "true" classic...
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Ladies and Gentlemen: Meet the "Vintage" Diesel-Kiki Fuel Injector Tester:
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~CrazyJerry