Oct 24, 2015 (4 years ago)
That's some pretty comprehensive testing.
assuming as stated everything is good I'm going back to basics.
black smoke is either fuel air mixture related,
too much fuel or not enough air.
both of which you seem to have addressed.
So if it were here with me now,
and seeing as the injectors have been out so ought to be easy to come out again I'd be measuring the piston height down through the injector holes.
You can actually do this with a welding rod,
BDC then TDC on each cylinder.
mark the position on the rod,
masking tape and biro works just fine.
your not shooting for minute accuracy here just comparative differences.
If,like I have found in the past with a couple of engines 6mm of difference then the head comes off for a more accurate dial gauge measurement.
Oh and both of the engines exhibited good compression readings.
not too surprising as when you do a compression test your actually testing the pumping ability of the cylinder.
not piston height.
A simple old school test with a welding rod,
little or no cost but can be surprisingly revealing.
Oh and if I recall right on one engine when stripped down revealed an "S" bend con rod.
The owner THEN remembered driving through a big BIG puddle.
You can't compress water so the con rod let go.