Guys,

Finally had the Besco 10w30 oil sample tested at a laboratory. Test results as follows, using same ASTM standards as other oils:
viscosity at 40C : 64.77
Viscosity at 100C: 9.89
TBN : 14.2

IMO, this is closer to a 5w30 oil but with very high TBN, which is necessary given the high sulfur content of our diesel fuel. I think Petron's synth, all terrain 5w30, will be a viable alternative for our 4JX-1 engines. The 5w30 synth has viscosity of 74.3 at 40C, 12.06 at 100C, TBN of 16- even better than Besco! :D

I'm planning to test used samples of the 5w30 synth oil to see if i can extend drain intervals over the usual 5Tkm.

Has anyone been using Petron's all terrain 5w30 in their 4JX1 trooper engines? Hope you find oil test useful.