Why Do We Complicate Things?

[Gene K]

That may be true.

Well if your particular engine design doesn't tend to shear oil it wouldn't really matter whether the oil was particularly shear resistant would it?

Some engines do and some oils shear more than others. My guess is it would be the amount and type of VII used more than anything else but that all it is. A guess.

 

[bullwinkle]

My personal theory is-why chance blowing an engine or causing serious damage by using inferior products (not ST, nor HK, nor Traveller) or by pushing synthetic blend oil too far (like my company likes to do by pushing MC 5W20 to OLM limits of 9000 miles+). If you're going to work engines hard, whether with track days, towing, or hauling loads up & down interstate hills at highway speeds with a smaller engine (equaling high RPMs), a better quality oil is always a good choice. The average grocery getter, anything in spec is probably just fine. BTW, we've lost TWO 3.7 Transit 250 engines, and Ford has fought warranty tooth & nail on them because their dealers weren't handling oil changes correctly & not entering them into Oasis!

 

[bullwinkle]

Well if your particular engine design doesn't tend to shear oil it wouldn't really matter whether the oil was particularly shear resistant would it?

Some engines do and some oils shear more than others. My guess is it would be the amount and type of VII used more than anything else but that all it is. A guess.

Long timing chains, variable valve timing, & high RPMs all contribute to shear, high VII oils are more prone to it than others. I'm not sure that anything can really stop GDI fuel dilution, other than starting with a thicker oil to begin with.

 

[ka9mnx]

But hasn't it been proven that fuel dilution causes no harm to the engine?

 

[nthach]

I bought a 2009 Ram 1500 4x4 4.7 OHC new. It belongs to a friend now. It has 240,000+ mi. So far no sign of problems following the factory counter. 5500-6000 mi OCI with PYB.

Problem engine tags sometimes I think are a euphemism for less forgiving of idiocy.

A friend religiously ran Rotella T6 in his old JGC with the 4.7 after his timing chain went out.

His mom drives it now. But then again, there’s countless examples of problem children engines still ticking away on bulk oil and filter from a quick lube done every 3K.

 

[nthach]

Long timing chains, variable valve timing, & high RPMs all contribute to shear, high VII oils are more prone to it than others.

The Japanese started the “thin” oil movement and they also use polymethylacrylate VIIs instead of the standard olefin VIIs favored by the American/European oil suppliers - PMMA VIIs are supposedly more deposit prone than olefin VIIs. But also, Japanese oils tend to have higher VIs which should also === more volatile but comparing Idemitsu to XOM oils in a Subaru I maintain, I see much less oil consumption with Idemitsu.

 

[alarmguy]

Even with flash points above 400F and no measurable fuel dilution it's pretty common for some 5W-30 to fall below 9.3 cSt at 100C in some TGDI engines.

I haven't seen this, maybe post some links to some UOAs ?
The Min of a 20 is 5.6
25 and 30 is at 9.3

 

[Gene K]

I haven't seen this, maybe post some links to some UOAs ?
The Min of a 20 is 5.6
25 and 30 is at 9.3

Assuming you are talking about viscosity at 100C that's incorrect.
Minimum of a 20 is 6.9 and 16 starts at 7.9. The difference being the HTHS which is not normally tested during a UOA.

 

[alarmguy]

Assuming you are talking about viscosity at 100C that's incorrect.
Minimum of a 20 is 6.9 and 16 starts at 7.9. The difference being the HTHS which is not normally tested during a UOA.

I cant agree, was hoping to see you post some links, this is what I come up with =

 

[andyd]

I had sussed out the cheap stuff versus name brand oil. long ago. Coming here, I realized that 3 Kmile OCIs were a waste. The main deal with PCMO isn't quality, its simpler than that. The main deal is to maintain the level on the stick. Everything else is why we're here.

PS,the quality of the Kirkland dark roast de-caff encourages me to to order other Kirkland products KISS!

 

[OVERKILL]

I cant agree, was hoping to see you post some links, this is what I come up with =
View attachment 25644View attachment 25645View attachment 25646

You are going to want to use more updated charts, those don't include the latest SAE 8, 12 and 16 oils like this one:

 

[CourierDriver]

Oil selection is like lure selections, which ever bottle with a prettier color,,,you get that one,,,,same for dog food,,,say it aint so boss,,

 

[xyxptlx]

Since were posting charts I’d like to comment on the logic that is used in grade change. Just because EU uses X grade does not mean you can use X grade in the US when Y grade is specified.

Why? Because you can change the grade requirements by selecting bearings with different clearance. It’s a simple Part substitution in assembly.

Bearing Clearance and Oil Viscosity Explained

The relationship between bearing clearance and oil viscosity is a delicate balance. Read on for more information.

blog.k1technologies.com

Iron Block
0.0034-0.0039	10w40 or 15w40	15w50-20w50	20w60 – 60w
0.0028-0.0033	5w30 or 10w30	10w40 or 15w40	15w50-20w50
0.0022-0.0027	0w20 or 5w20	5w30 or 10w30	10w40 or 15w40
0.0016-0.0021	0w10	0w20 or 5w20	5w30 or 10w30
0.0010-0.0015	0w5	0w10	0w20

 

[Gene K]

That's true in theory but in the case of the Ford 5.0 the Shop Manual calls for the same clearances with 5W-50 and an Oil Cooler and 5W-20 without a cooler.

 

[xyxptlx]

That's true in theory but in the case of the Ford 5.0 the Shop Manual calls for the same clearances with 5W-50 and an Oil Cooler and 5W-20 without a cooler.

It’s not theory, they are engineering guidelines. There are almost alway exceptions to guidelines for that matter, but that neither invalidates the guideline nor makes it prudent to ignore them because of an exception.

What years are we talking about? Is that in all applications?

 

[Gene K]

What years are we talking about? Is that in all applications?

I'm talking about the Coyote 5.0 Solid Axle Mustang. The Track Pack cars have the same clearances, oil coolers and 5W-50 Oil Spec. The standard cars use 5W-20 and have no oil cooler.

0.025 to 0.050 mm Mains
0.027 to 0.069 mm Rods

 

[xyxptlx]

I'm talking about the Coyote 5.0 Solid Axle Mustang. The Track Pack cars have the same clearances, oil coolers and 5W-50 Oil Spec. The standard cars use 5W-20 and have no oil cooler.

0.025 to 0.050 mm Mains
0.027 to 0.069 mm Rods

Ford 5.0L Coyote Oil Specs

Use M1 or PU 5w20 in the 5.0 and rest easy

www.bobistheoilguy.com

The short of the explanation is that Ford spec the track cars for very hot oil.

 

[Gene K]

Ford 5.0L Coyote Oil Specs

Use M1 or PU 5w20 in the 5.0 and rest easy

www.bobistheoilguy.com

The short of the explanation is that Ford spec the track cars for very hot oil.

True but my point is the vast majority of these cars will spend their lives with lower oil temps than the 5W-20 cars (due to the cooler) and yet they survive just fine on 5W-50. Apparently Ford doesn't think this is an issue or they would spec thinner oil for street use.

 

[kschachn]

How can oil be too thick except for cold temperatures where it cannot be pumped? I cannot conceive of any other instance where any commercially available oil grade would be too thick and could somehow threaten the engine at operating temperature.

 

[xyxptlx]

True but my point is the vast majority of these cars will spend their lives with lower oil temps than the 5W-20 cars (due to the cooler) and yet they survive just fine on 5W-50. Apparently Ford doesn't think this is an issue or they would spec thinner oil for street use.

The answer is in the specifications for the bearings. Wide enough for 60 grade. Do you think that coyote engine will last 200k miles?

How can oil be too thick except for cold temperatures where it cannot be pumped? I cannot conceive of any other instance where any commercially available oil grade would be too thick and could somehow threaten the engine at operating temperature.

I know of a gent who bought a Duramax and it’s first oil change filled it with 15w40. The engine failed within the warranty period and was denied because the spec was 5w30, IIRC.

Tighter tolerances are used for efficiency and longevity. Low viscosity is specified for reasons other than EPA requiments.