AMSOIL 5W30 Series 3000 HDD Oil
Standby Genset. Starts, goes to 1200 RPM and waits for oil pressure (1-2 sec) then to 1800 RPM. Spends 99% of it's time at 15-35% load. Block heater runs 24 hours by forever and holds engine at 100-120F, except when it gets below zero then the block temp hovers around 50. No heat in oil pan. For kicks, I make sure it gets tested at least a few times a year when it's below zero. Run genset on 100% number 1 diesel.
The steam show (not white smoke, but steam) from the exhaust when it's below zero is impressive until it warms up. People slow down going by on the highway to watch.
This genset will probably have less than 2000 hr. on it at end of life. Hopefully much less. (So it can be replaced with a larger one as business grows!!)
25 hours on oil, 83 on engine. Been in crankcase for about 75 weeks. No make up oil. Chose synthetic due to less than 1/2 time required to build oil pressure from start, at all temps over Cat oil, and extending drain intervals. Used to wait at 1200 RPM for 3-5 sec on start with zero oil pres.
[Bracket indicate test at 13 hours on same oil]
Anything listing at zero, I skip.
Al 1 
Iron 6 
Copper 17  (A little elevated, and trending up)
Lead 1 
Molly 1 
Potassium 3 
Boron 8 
Silicon 14  (Has had valve covers off, and valve lash adjusted since last test)
Sodium 2 
Calcium 3088  (trend down... additives being used?)
Magnesium 39 
Phosphorus 1017 
Zinc 1083  (Quite the downward trend again, additives being used?)
Barium 1 
Flash point 450