What oil grade?

[LakeSuperior]

I use Delvac I, a Mobile product, all reciprocating engines I own. It is a pure synthetic. Amsoil is the only other producer of pure synthetic oil. The remainder are derived from petroleum.

The pure synthetics are superior in every respect. Delvac I is formulated for diesel truck engines. A great write-up on synthetics below

http://cheetahcycleworks.weebly.com/...761348/oil.doc

[Lodesman]

Originally Posted by a64pilot

RE 10W-40
I doubt it's Diesel oil, check the specs to be sure, but I bet it's spark ignition oil.
10W-40 is a very common car oil, never heard of a 10W-40 Diesel oil, but then of course I'm not in Croatia.

Google's your friend

Shell Helix HX7 Diesel 10W-40 - Shell Global

http://www.mobil.co.uk/uk-english-lc...sel-10w40.aspx

http://www.valvoline.com.au/explore-...sel-engine-oil

[Liburnian]

For my brand new Beta Marine 43 (Kubota) engine, the recommendation is 10W40 mineral or semi synthetic oil (max 30% synt), and synthetic oil is not advisable.