Results Are In On the First Batch Of Diesel Engine

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I really can't understand what is the difference between an HDEO and a normal diesel oil?? Delo is the only one that looks like my idea of an HDEO, although it's a pity they did not include the Castrol ones, although they only seem to be available in bulk, even in the EU, apart from some truck stops.
 
Originally Posted By: Garak
Technically, a diesel engine oil wouldn't be dual rated. What we call HDEOs tend to be dual rated.

so what really makes a diesel engine oil capable of being spec'd as a dual-rated oil ?
 
Not being a formulator, I'm not sure I can answer that without being terribly circular.
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I would say that would include being able to meet the SM (or whatever S spec is met). Of course, that doesn't really answer anything. I think the main contrasts you would see would be if you looked at something like a two-stroke diesel lube, whose elemental analyses are very, very different from what you'd see in a normal HDEO or PCMO. The two-stroke diesel oils whose analyses I've read have very low zinc content, if I remember correctly.

Obviously, too, in a dual rated oil, the specifications are shown as CJ-4/SM, and certain limitations (i.e. phosphorous) are handled differently than a normal SM or higher, even in a 30 grade. A 10w-30 CJ-4/SM can have more phosphorous content than, say, even a 10w-30 SM, even if the latter weren't GF-4. How much higher the limits are, I'm not sure, but if you put me on the spot, I'd suggest a couple hundred ppm.
 
Originally Posted By: Garak
Not being a formulator, I'm not sure I can answer that without being terribly circular.
wink.gif


I would say that would include being able to meet the SM (or whatever S spec is met). Of course, that doesn't really answer anything. I think the main contrasts you would see would be if you looked at something like a two-stroke diesel lube, whose elemental analyses are very, very different from what you'd see in a normal HDEO or PCMO. The two-stroke diesel oils whose analyses I've read have very low zinc content, if I remember correctly.

Obviously, too, in a dual rated oil, the specifications are shown as CJ-4/SM, and certain limitations (i.e. phosphorous) are handled differently than a normal SM or higher, even in a 30 grade. A 10w-30 CJ-4/SM can have more phosphorous content than, say, even a 10w-30 SM, even if the latter weren't GF-4. How much higher the limits are, I'm not sure, but if you put me on the spot, I'd suggest a couple hundred ppm.

Ok thanks!
what about CJ-4 only rated diesel oils... would they not contain high zinc content ?
and in this case, even if SM is not mentioned in its specs, would this CJ-4 rated oil not suffice the base oil requirements of almost any gasoline engine (with the exception of, perhaps, only a few most modern hybrid engines) ?
 
Originally Posted By: fpracha
what about CJ-4 only rated diesel oils... would they not contain high zinc content ?

A CJ-4 oil should be much the same as a CJ-4/SM. I haven't seen many examples that are CJ-4 only. The U.S. Motorcraft 15w-40 and the Mobil Delvac Elite 10w-30 synthetic blend are the only two that come to mind as CJ-4 only. The former used to have the gasoline rating, and the latter is new in North America. The real concerns with respect to gasoline engines would be the phosphorous content and the viscosity. Both numbers are obviously too high to get a GF-5 rating (or the older GF-4 rating), which is usually called for in most manuals.

So, I don't know what I'd do if I were confronted with those two oils. I'm sure they'd be "fine," particularly in an older engine, but I would be curious as to why they didn't have an SM rating as well. I could see Motorcraft's stance as wanting to make extra sure that people don't use their 15w-40 in a gasoline engine under warranty. I'm not sure what XOM's motivation is, since they do make a dual rated 10w-30 already, and both of their 15w-40 products are dual rated (along with many of the others).

I'd worry most about the two-stroke diesel oil. But,
 
The Autozone near me has the latest Mobil 1 5w40 (CJ-4/CI-4/SN) on clearance for $3 a quart.
I picked up a couple of quarts but I don't know where I'll use it. Does it have any value as a PCMO?
What would a 50/50 mix of this oil with Mobil 1 0w20 yield?
 
Originally Posted By: Garak
Originally Posted By: fpracha
what about CJ-4 only rated diesel oils... would they not contain high zinc content ?

A CJ-4 oil should be much the same as a CJ-4/SM. I haven't seen many examples that are CJ-4 only. The U.S. Motorcraft 15w-40 and the Mobil Delvac Elite 10w-30 synthetic blend are the only two that come to mind as CJ-4 only. The former used to have the gasoline rating, and the latter is new in North America. The real concerns with respect to gasoline engines would be the phosphorous content and the viscosity. Both numbers are obviously too high to get a GF-5 rating (or the older GF-4 rating), which is usually called for in most manuals.

So, I don't know what I'd do if I were confronted with those two oils. I'm sure they'd be "fine," particularly in an older engine, but I would be curious as to why they didn't have an SM rating as well. I could see Motorcraft's stance as wanting to make extra sure that people don't use their 15w-40 in a gasoline engine under warranty. I'm not sure what XOM's motivation is, since they do make a dual rated 10w-30 already, and both of their 15w-40 products are dual rated (along with many of the others).

I'd worry most about the two-stroke diesel oil. But,
...the problem with the 2-stroke diesel/CF-2 spec is that it is now an obsolete spec, which means API doesn't license (or test) those oils anymore (?)
 
The Delo LE 15w40 looks like it has the strongest additive package of all the 15w40 HDEO sampled.

Why is the TBN number the lowest of all the 15w40s?
 
Originally Posted By: bullwinkle
the problem with the 2-stroke diesel/CF-2 spec is that it is now an obsolete spec, which means API doesn't license (or test) those oils anymore (?)

That might be true, but one still could come across some inappropriate lubes. It might take some doing, though. After all, any 15w-40 HDEO you or I find on the shelves is very likely to be dual rated. I'm still wondering why Motorcraft and XOM have those two outliers with respect to gasoline ratings, though.

@DB_Cooper: That TBN might seem a bit low, particularly compared to what we're used to with HDEOs. It's actually not that out of line with a number of products out there, particularly some of the newer HDEOs. It seems that unless a newer HDEO meets an ACEA specification calling for a higher TBN, it's likely going to be in the 7 range. That's really not a problem, though, with ULSD. The guys pushing the OCIs in the diesels will likely be using an ACEA rated synthetic that will have a higher TBN.
 
Thanks Garak..Delo looks like very stout stuff. A UOA at 5k would be interesting on a 1.8 VW engine I built recently.
 
Delo ftw if you're using it in a classic gasser with high valve spring pressure.

Delvac ftw for longer oci in diesel.
 
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