I've seen postings here about different sounds that are produced by a Diesel engine, and have experienced them all, I'm sure. One thing I would like to see here is a solid set of definitions for these sounds. For instance- what I've noticed from my car-

-Normal warm idle- smooth sewing machine sound- probably no special name for this one, except maybe "all's well"
-Cold Idle on straight Diesel fuel- winter or summer- idle is much more noisey- what causes this in a Diesel but not a gas engine?
-Cold idle with 30% WVO- deep knocking sound- almost like rod bearing failure, but it goes away after 5 mintutes of warm-up. Is this called "nailing" or just "knock"?
-Warm idle with 30% WVO- engine becomes so quiet, you might believe it's not a Diesel. Why does WVO make the engine so much quieter?
-Cruising with straight Diesel, especially winterized fuel- frequent bursts of what sounds exactly like spark knock or pinging in a gas engine, except it happens opposite to gas engine- on trailing throttle, as opposed to accelerating. Should this be called nailing, knock or pinging, and again what causes it?
-Cruising with 30% WVO- absolutely no pinging sounds, smooth drone, seemingly more power. Seems like such a good thing, but again, I can't understand why WVO would cause this.

Dave

1976 300D