Detroit Diesel 6-71

My Viking 44 motor yacht has been running it’s DD 6-71TIBs since at least 2000 on Rotella T1 40w
The oil is changed every year except on a year I hardly used the boat. 5 hrs. I just don’t run them on the pins. Have owned her for 6 years and previous owner had her since 200o. Same guys have taken care of her since PO purchased
Starts right away and smokes for just a few seconds. No major problems. I boat in northern lower Michigan. Only use the black heaters in early spring.

Update;
Was just working with my vendor on another Delvac 40 order.
Discovered I typed wrong on this and another post.
Mobil 1640 is CF rated.
Still, 1240 is CF-2 rated.

Bottom line, if using Mobil products, use the 1230 or 1240 for Detroit two stroke engines.

I am sorry for my bad data on earlier post.

Last order July 2023. Another 10, 5-gal pails coming in.

Yep, Delo 100 is CF-2 rated.
Like my post #2, I have used many oils for my customers. At those times, Chevron Delo 100 just did not offer any discounts.
Now that we have closed shop, I shop just for our Bertram.
This year, our Mobil distributor in Jax came thru again. Their truck should be dropping on us next week.

Please re-read post #24.
For Detroits you want Mobil Delvac 1240, Not 1640.