Diesel vs. spark engine oil

[solocraftvs]

Just throwing this out to the crowd...
I have apparently neglected to ponder this over my career. (Granted...I'm usually focused on hydraulic oils)
What are the primary differences in additive treatments between a Diesel engine oil vs. one rated for a spark ignition engine?

https://rotella.shell.com/en_us/pro...6b2b5e1144d44/t6-multi-vehicle-5w-30.pdf

In the link above...Shell touts that their oil can work in both...which is obviously a new thing.

API CK-4 (Diesel)
and API SN (Spark engine) performance standards. (?)

Thanks for the help.

 

[Kamele0N]

Nothing new here....we all know dual rated oils for decades...

A few examples:
ACEA A3/B4 A=gasoline, B=diesel

VW 504/507 504=gasoline, 507=diesel

Etc.....

That shell multivehicle T6 is normal PCMO oil for us Europeans

.

 

[krismoriah72]

Probably an old definition but used to be

Diesel Engine oil- Higher ZDDP, Higher Viscosity range, and higher level of detergents.

Gasoline Engine Oil- Lower ZDDP (cats). Lower Viscosity Range (tighter tolerances), lower detergents (no soot in spark engines).

And theres the API Starburst S is for spark, C is for compression.

Ive never heard of a cat being destoyed by diesel oil, i think if a spark engine was burning enough oil that any oil would contaminate. I dont see how a non oil burning engine would be affected.

The new CK oils are lower in ZDDP and detergents.. so alot of them are now dual rated.

Rotella also lists JASO specs, but did not submit to JASO tests.

 

[doitmyself]

Originally Posted by solocraftvs
In the link above...Shell touts that their oil can work in both...which is obviously a new thing..

A bit of history. Through the mid 1990's the common off the shelf car oil weights (5w30, 10w30, 10w40) were all dual rated. Around 1996 federal emissions mandates resulted in the diesel rating removed from these common oils. I called Valvolene and the tech. person told me that the additive levels were lowered and they no longer were suitable for diesel engines. What tipped me off was my new 10W30 oil case box clearly stating "for gasoline engines only" - something new. I had a compact Kubota at the time and it became very difficult to find a diesel rated 10W30 for a few years.

 

[tundraotto]

Lots of new CK-4 Rotella I have seen is not API rated at all anymore.

Mobil Delvac and Chevron Delo are....

 

[wdn]

Mobil's Delvac 1300 Super is a universal oil and is SN rated and can be used in gasoline engines that take SN oil. Both of them are but the 10W-30 is a natural fit as few cars could do 15W-40. I have a Kubota too by the way and only use 15W-40 year round but we keep it garaged. It has never failed to start righ up and go and I have plowed with if as cold as -14F below zero.

 

[weasley]

Oils for diesel use often have more/better dispersant to counter soot-related thickening and wear.

 

[BillyE]

Biggest differences the oils have to deal with:

Diesels run at lower speeds and generate higher torque
-typically this means higher viscosity is speced

Diesels accumulate more soot in the oil, especially with EGR
-more dispersants and larger sump capacity

Diesels often accumulate more fuel in the oil
-higher viscosity and larger sump capacity

Diesels are often used for much longer durations under heavier loads.

 

[ddown]

It doesn't have Ford Spec on Bottle or Website.

 

[dnewton3]

Regarding PCMO vs HDEO, there's not so much a vast different in what additives are used, as there is in the quantities of the additives, based on application. The longer the intended OCI, and/or the expected application's contribution of contamination, the more additives you'd see to bolster the base stock. Example:
Amsoil PCMO has some crazy high amounts of Ca and Mg at times, but then they also were touting 25k miles OCIs under the right conditions for the Signature line, whereas the OE line is only set for OEM OCIs.
For HDEO apps, you can see similar differences; some of their diesel products are limited to OEM OCIs, but others are up-rated; most all can go longer "with oil analysis".


Most any typical lube uses some combination of parts of these:
magnesium, phosphorus, zinc, calcium, titanium, boron, barium, molybdenum, etc ... And these are just the ones we see in UOAs. There are many other compounds that are unseen in a UOA, and/or proprietary to the lube spec.
How they package these in both parings and quantity is up to the marketer/blender.

Some applications that are dual rated must concern themselves with certain additives that are detrimental to the after-treatment (cat converter) system for gas, so there's a drop in some additives such as phos. However, many of the elements used (Ca, Mg, etc) are fairly inexpensive relative to their benefits, and so they have been heavily used; they're popular additives because they do multi-function and are reasonably cheap. As they become restricted, there are other additives which can be used, but they are more expensive and may not be multi-functional. These can perform every bit as well, but may not been seen directly in a UOA, although their effect (wear data) can establish their effectiveness.


BTW, solocraftvs ... 4 posts since 2012? That's what I call "restraint"!