Is this right?

[Tikvah]

I don't want to start the age old discussion again, but forgive my ignorance (or even interest) about oil.  But O'Reilly Auto Parts has this on sale.

[HighTechRedneck]

It has the CF-2 rating and approved for Detroit Diesel 2-stroke applications according to the Shell website.

[Tikvah]

You can buy this same oil, In the SAE30 at Walmart.  I bought some when I couldn't find anything else.  I wasn't sure it was right, but it's oil....so

[Nick Badame Refrig/ACC]

YES,

I noticed it at Wally World last week.. Cool!

[HighTechRedneck]

In a bind on the road we all do what we have to.  But otherwise, unless operating exclusively in a sub-freezing climate, Detroit Diesel does not advise the use of 30W oil in their 2-stroke engines.  It can result in dangerously low oil pressure, especially at idle.

[baker4106]

That is what I use.   Found some at TSC for $15.00.

[brmax]

If its wrong I will be wrong with ya, as I replaced with it and bought more all in 40, not sure why but I ran in to the same deal with the weight and had time so I ask if they could get 40 and was no problem next morning. Curious to know how it works out for others.
Good day there

[wg4t50]

Might give a lot more thought to using the SAE 40 wt oil, I would, but I have read the DDC manuals.  Unless your at -20f, would not be using SAE30.
Dave M

[digesterman]

Dave there is a very old saying that goes, "The proof is in the pudding".  It seems the 40 works better for most. Sometimes the manuals aren't updated to include million of  miles of success stories. I imagine that DD really isn't spending a lot of time updating a lot on the two stokes are they? It is the practical experience that wins out every time.


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[Tikvah]

I just ordered a case of three gallons.  That should last me for years.

[eagle19952]

Alaska...30 wt
drive to Texas, winter....dump the oil....nope.
400 hrs. change it....yup...40 wt. in 2006.
still purring... on 40 wt.

[wg4t50]

Oil is an interesting subject and full of opinions, even Greyhound used SAE30 back when my MC7 was new, even ran the 30 in front wheel bearings & tag bearings, now we all know better don't we.
Even the older DDA books said 30wt, but they finally went with the 40wt, and if your running a high output 8V-92, you best be thinking 50wt. Most know the 8V-92 has a tender rear main bearing.
Of course, forget everything you hear and do what makes you happy, pay for it later.
All opinion of course.
Dave M

[luvrbus]

  No one ever pays any attention to the book when it says @ 100 degrees air temp you are supposed to use 50W I can see people looking for 50w on the road because it is a 100 degrees that is not happening in the real world

[eagle19952]

You'll love this one...
1975....working 16 hour days on a flood control dyke, no time, paid the local Fairbanks ford dealer to R+R a diff seal in my Lincoln MKIV, (a few bucks, I'm a mechanic)...
drove it around a few days and hooked up to my 31ft airstream.
Heading to Valdez in the middle of nowhere my kids in the back seat telling me their asses are getting hot...huh 
pull over and stick my hand between the seats....ouch...dam near burned my fingers....
Now what.
I check it out...no pumpkin oil, zilch...sh^%...
worse yet...not a drop of dead dinosaur anywhere...
double dam....
looked around and found a half gallon of Wesson oil and a turkey baster.
Drove another 60 miles to a place I could park,camp and get help,pulled the axles to see what parts I'd need...nada...zip...put it back together added gear oil....drove it for another 3 years.

[HighTechRedneck]

I don't think anybody would change their oil to a different weight on the road based on the climate they are visiting.  And I don't think the manual even eludes to that.  What it is referencing is the typical operating environment of the engine.  If it will spend the majority of its time in subfreezing, then 30wt.  If it will spend the majority of its operation in 100+ degrees, then 50wt.  Otherwise 40 wt.

The issue as I understand it is oil pressure, especially at idle, and oil flow, especially at load. Thinner oil at high temps, makes it harder to maintain minimum oil pressure at idle/low rpms. Thicker oil at low temps reduces flow under load.

No one ever pays any attention to the book when it says @ 100 degrees air temp you are supposed to use 50W I can see people looking for 50w on the road because it is a 100 degrees that is not happening in the real world