debate of thinner oils

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Originally Posted By: Clevy
Exactly. For most operating conditions the suggested 20 grade in no way reduces engine life in any way.
If anything if one takes the data from today's engines they make more power than ever and last longer than ever before. Even when compared to the thick oil days.
And today's 20 grades at 100 times better than anything ever before,


Well, I would not put all the credit into the advancement of oil technology.

The internal engine design changed quite drastically since early 2000's. If you look at the block and how the mains are supported, most econoboxes today are built like sport's car engines of 80's and 90's. They are quite stiff with little crank flex.
These things were done in co-operation. Oil development alone would've never succeeded without changes in engine design.
 
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Originally Posted By: Clevy
For one some collects in the filter. Two, the analytical methods do not measure all of the particle sizes in the oil. So no, UOA does not wear give rate. This seems to need to be explained constantly on this site. Lastly, the amount of data needed to compare two oils on even the same engine type is beyond looking at UOAs on the web.



Exactly Nate

Why people have such a hard time grasping this concept is beyond me. It's posted over and over again yet for some it just isn't getting thru.

As far as North America and the trend to thinner lubes it's driven by CAFE. Because of the typical driving habits,speed limits and ambient temps a 20 grade fits most drivers however it's not a one size fits all and even though it fits most some people and some duty cycles may require something different.



Before becoming a member here I too believed you could compare wear rates using different oils in the same engine. Thanks to Overkill and Doug Hillary I learned it's not quite that simple.


I don't know how the quotes above got messed up. They should be opposite.


If engine shed metallic particles and only part of those metallic particles are from wear. Measuring different size metallic particles still brings you to square 1. The relationship is still indirect.

This particle thing seems like a red herring.
 
Originally Posted By: RedOakRanch
I have an old CAT diesel that I run 15w40 in. The manual says to use 10 20 or 30 grade oil depending on the temp. No 40 was even mentioned. It also gave ratios for cutting the oil with kerosine in cold weather, talk about fuel dilution!
30 for the 4 cycles and 40 for the 2 cycles. The good old days.
 
Originally Posted By: OVERKILL
Different oils will provide different levels of change in certain metals in a sample due to the surface interaction between the additive package and the materials the engine and its components are made of. This is not an increase in wear, which is why when people are chasing the Golden Goose through UOA's and switching lubes over minute PPM variances they are embarking upon a fools errand.



Appreciate further elaborations/explanations on bold above.
confused.gif


Novice here.
 
Hi,
CT8 - DD's two stroke engine families are certainly special cases. The history of these "throwaway" engines is most interesting - WW2 is a good starting point. The 149 Series marine engine had special requirements too. FE up to 250ppm was allowed in marine engines. Condemnation points via UOAs were 2.5% fuel dilution, 25ppm Copper and 10ppm Lead and 150ppm FE

The API CF-2 Standard applies and SAE40 and 50 were the base viscosities but 15W-40 or SAE30 could be used where temps of 0-25F (-18 to -32C)were experienced. SAE30 & 15W-40 viscosities are barred from any marine application

Alkalinity is a prescribed spec level which also feature Zinc & Calcium to be above 700ppm. The SA level is also critical in operating these engines

I've operated these engines (71 Series) in very cold and high altitude conditions - we always used a start aid (very carefully !!!) Oil consumption was always a big factor until the 92 series appeared. These in the 92TTA DDEC versions were excellent power units

They could/can be rebuilt quickly and relatively inexpensively

The biggest requirement is lots of clean air...................
 
Originally Posted By: mjoekingz28
TT,

In these new OTR rigs, are they generally consuming more oil? Like having to add two gallons in the first 50k miles of its life? Are they doing better than the ones that 'were' specced 15w-40 in the past. Also, does DEF matter any?


Many of the newer HD motors using 10w30 are consuming no more oil, or even less, during initial phase and lifetime. Not sure why DEF would matter. That is used by the SCR unit downstream from the motor.
 
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