Hi frogman3:
Yes,I used Tamiya made diesel engine sound unit for a Tiger tank for a steam turbined carrier.!
It passed 12 years to complete my HMS Fencer that contained about 5 intervals,some were over 1year or more...
I guess years purely spent for building possibly is 4 or so...
My first name is Kiyoshi(聖志)that means "holy will"though my family is Buddhist while my university is Christian.! It sounds something contradictory??

In this sense,many Japanese are sooo contradictory too !!!!
I'll attach a video as follows and pay attention to the simulated diesel engine sound as well as smoking test, that was taken in the video in earlier stage of sailing tests.
Can you hear the sound,sir ??
https://www.youtube.com/watch?v=TvY8JFrqUyMKiyoshi
Pic;HMS Fencer 1/96 coming back to her homeport near Glasgow at dusk

??