If one operates a diesel engine today without an engine oil bypass filter system one is cheating one's self. The soot loading that goes on in an engine equipped with EGR is terrible. Having a bypass filter system and there are many to choose from, can do a significant job in extending engine oil life
With respect to engine oil? Engine oil volatility makes a huge difference. There are 2 kinds of synthetic oils. Fully Synthetic (Fake Synthetic) and Chemically engineered synthetic. Volatility numbers can help in identifying the difference., The lower the volatility the better the oil. For example Redline, HPL, MPT and Amsoil all have lower volatility numbers than the majority of the other oils. Engine oils mist in the crankcase and that mist is collected by ccv or pcv and redeposited in the intake system as a form of emissions control
I, uh...
While I believe everything you've said here is /correct/, I'm not entirely sure it all applies.
This is the 7.3 IDI forum - these motors were built before EGR on diesels was even a thing, let alone DPF or any of the newer emissions crap.
So, we don't need to worry about any of that extra soot load(just the load from the massive ring gaps)
We also have other concern to worry about - mainly that the engines are, at a minimum, 22 years old, and unless it's been rebuilt recently, the seals are pretty worn out.
This is why running synthetics in an IDI is something to be careful with - due to the degraded seals, there's a good chance it will start to leak badly.
If the engine's always run synthetic? No big deal.
If you re-seal an IDI, yes, you can run synthetic just fine.
Also, you will find that an IDI will produce far more engine oil mist than just about any other engine out there - massive ring gaps mean massive blowby, means a constant stream of oil vapor making it's way into the intake where it is burned.