DD 671 Oil

[mswinea]

What do you guys recommend on oil to use in a 1976 DD 671. The previous owner was using Delo 400 40 wt. I've heard good reports on the Shell oils. The engines have about 2700 hours on them.

New Question: I can't find in the manual how much oil these engines hold. I know this is an easy one for you guys. I'm going to try the Shell Rotella 40. This is my 1st oil change since buying the boat. Any recomendations are appreciated, i.e. best oil & fuel filter removal procedure. Also, I've noticed some light gray smoke from the starboard engine on start up. It lasts for a few minutes then clears up. Any concerns? thanks, Michael.

[Traveler 45C]

Delo 400 used to be recommended for Detroit 2 stroke engines, not any more. They have changed the formula. Delo 100 in now recommended.

Search the archives. There are many threads covering this subject.

This would be a good subject for the FAQ section.

[eze2bme]

I use Shell Rotella T40 in my 671's and transmissions.

[SKYCHENEY]

Exxon XD-3 40wt meets DD 2-cycle specs. It has .8% sulfated ash where the Rotella has 1%. You want to get that sulfated ash content as low as possible.

[spartonboat1]

Absolutely no multi-weight, only straight weight in a 2 cycle Detroit Diesel. That is well documented in other posts.

That is a good post regarding Exxon XD-3 40wgt, as it is the replacement for Mobil Delvac 1240 40 wgt that was formerly repackaged as Detroit Diesel Delvac 1240 40 wgt. When Mobil and Exxon "merged" the Mobil Delvac 1240 was "disappeared" by their marketing folks and replaced in the supply chain by the Exxon XD-3. I have been trying to learn if the DD 1240 is now the repackaged XD-3, but no luck on that info.

Another oil I've seen at Hatt yards for 2 cycle DD's is Texaco Ursa 40wgt (straight wgt).

P.s., I use the Mobil One Delvac diesel grade synthetic in my old Onan 7.5Kw genny, but which was rebuilt (1972 43' MY with 6-71's). The genny uses no oil during the season.

[Pascal]

DD dealer had Shell Rotella last time instead of the original DD packaged stuff, straight 40, they said it was fine in the 8V71...

[Capt K]

DD motors really seem to like Shell Rotella 40w. I've been using it for ten years in my 871n's and I saw a pair of 671TI's with over 2500 hours on them that used the Rotella and they looked great when torn down for rebuild.