I don't want you to think I am being a jerk at all, I'm just messin. I know that 2 stroke motorcycle engines have pressure pulses because they use the downward stroke of the piston to jam the mixture through the port into the cylinder. I was thinking there has to be a little jamming in the detroit also because there is still some exhaust pressure in the cylinder when the inlet port is exposed.
That said, you are the expert who works on them, and I bow to your knowledge

 

the exhaust valves are open before the scavange ports are exposed, so there is very little pressure in the cylinder when scavanging happens

i'm pretty good with the emd versions, but i haven't touched a small ddc 2 cycle since i was in school 02

 

That's why they sound so nasty, the exhaust valve openes while the piston is still going down!

 

That's how most engines are. Once you pass 90 degrees of crank rotation on the power stroke there isn't much point in keeping the spent gases in the cylinder except on very slow speed engines. We just dump 'em to reduce pumping losses on the exhaust stroke.

 

Not Gassers, fuel is still oxidizing and expanding as it goes out the exhaust port. That's why you need catalyst, and why catalyst works in the first place. I assumed a diesel would be the same way, but maybe not since diesel burns faster than gas.

 

And the neighbors on cold mornings!