Who knows diesel injection ?
 

I'm working on an old school duetz riggorini 2 cyl diesel. Very cool, like working on a vw.

But here's my question. 1 cyl was down on compression so I pulled the heads to check the valves. 1 piston and head had a solid even coat of black soot on the head and piston top. The other had a portion in the center of the piston and head which looked like it was washed clean. Do you suppose that's from an injector which is spraying a stream instead of a spray ? Is that what that might look like ?

I lapped the valves and reassembled the motor and test fired on ether. But now I'm thinking get the injectors serviced. What do you think ?

Any black or white smoke when you get on it?

I'm gonna say the lack of compression is resulting in partially unburt fuel "soot ". Could be injector too. Try switching them.

Definitely sounds like that cylinder was over fueling.
I'm not super familiar with the small stuff but on the larger displacement diesels, you can get a decent idea of what's happening with spray pattern on piston sooting.

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So the spray pattern clean spot maybe/is a good thing. ?

The clean piston was in the cyl that was down on compression.

should not be a stream - should be a spray, fine mist. The injector needle seems shot.

And that would wash the piston clean there where the stream hits ?

Hot surface + power washing/steam cleaning would be my guess.

Please post more on your project.
Seriously cool stuff.
You've spent enough time and money on the engine mechanicals.
Get the final 5% and most important done right.

The piston should have an even coat of soot on it. I would say the piston that is washed has the injector issue.

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