Kohler K series oil

[flatlandtacoma]

Originally Posted By: Bror Jace
The flaw is that many XW-30 PCMOs will shear rapidly under the stress that an air-cooled engine sees. As they shear and thin out, they tend to get past the rings and are consumed. If the engine runs out of oil, it will likely seize (I saw this happen to a brand new water pump many years ago).

Conventional or synthetic in a mass-market PCMO is not likely to make a difference.
A good synthetic oil shouldn't have many VIIs to shear, right? I think that is also why they also recommend SAE 30 at high temperatures - That is what I use.

So I gather your beef is with them okaying synthetic 5w30 at high temps? I guess I can see that. No real need for it, although I don't know what would make it shear down and burn in your water pump engine if it was a quality synthetic and not loaded with VIIs.

 

[flatlandtacoma]

Originally Posted By: btanchors
Can someone please comment on the following:

Regarding easier flow of 15W-40 vs. SAE 30 at cold temperatures - I think this may, or may not be true. You can't tell just from the SAE grades on the oil. For the 15W-40 oil, it has a viscosity of SAE 40 at 210 degrees F, and at zero degrees F, it has the viscosity in the range of an SAE 15.
The bolded part is wrong. There are plenty of old posts on here that can explain it better than I can, but the 15W rating has nothing to do with zero degrees F or SAE15. 15W defines a maximum viscosity at -20C (-4F) to qualify for the rating. 10W defines a maximum viscosity at -25C (-13F) to qualify for the rating. 5W defines a maximum viscosity at -30C (-22F) to qualify for the rating.
Originally Posted By: btanchors
For a single-weight rated oil, like SAE 30, it has the viscosity of an SAE 30 at 210 degrees F, but its viscosity at zero degrees F is undefined/unrated. That means it is possible an SAE 30 may flow as well as an SAE 15 at zero degrees, we can't tell unless the actual oil involved is measured at that temperature. As evidence to support this idea, consider a couple of the few SAE 30 rated synthetic oils that are available. They actually come out at about the weight of an SAE 10 oil at zero degrees F without the use of pour point depressants or viscosity index improvers.
A SAE 30 oil has no VIIs. If it is a conventional oil, it's viscosity index will be in the range of 100-120 and it won't make the 10W rating. If it is a synthetic base oil with a high viscosity index, it might make the 10W rating without any VIIs, earning it the right to be labeled SAE 30, 10W30, or both.
Originally Posted By: btanchors
So, I am not convinced it is possible to make the blanket statement that a 15W-40 will flow better than a straight-weight SAE 30. It may, or may not be true, depending on the properties of the actual SAE 30 used. Comments?
Conventional to conventional, 15W40 will flow better than SAE 30 below 32F. If you are talking synthetic, correct, you need to know the viscosity index of both oils.

Here is the chart I made from Widman's viscosity calculator for Mystik JT-8 SAE 30, 15w40, and 10w30 HDEOs showing the SAE 30 to be thinner down to about 32F (0C)

The X-axis is degrees Celsius, I just noticed it was cut off.

 

[jstutz]

Here is a thought, How about a 10w30HM synthetic like M1HM. Top notch oxidation resistance, very good cold weather flow(compared to 15w40 or sae30), and nice HD add package. In most cases fluctuation is viscosity within reason does not harm the engine. Also remember that the add package is very important. The goal here is good cold weather flow and good high temp performance. We are really splitting hairs here between the w30 and 15w40 imo. I think the viscosity between the two are so close, it probably comes down to which one has the better add pack.

 

[JTK]

Originally Posted By: jstutz
Here is a thought, How about a 10w30HM synthetic like M1HM. Top notch oxidation resistance, very good cold weather flow(compared to 15w40 or sae30..


That would be an excellent oil for a Kohler-K. Just not as cost effective as a 15w40 given the drain interval spec on these engines.

Joel

 

[jstutz]

Originally Posted By: JTK
Originally Posted By: jstutz
Here is a thought, How about a 10w30HM synthetic like M1HM. Top notch oxidation resistance, very good cold weather flow(compared to 15w40 or sae30..


That would be an excellent oil for a Kohler-K. Just not as cost effective as a 15w40 given the drain interval spec on these engines.

Joel


Agreed, its hard to beat a 15w40 in my opinion. In my case i just have my one tractor and it gets yearly changes. My last change was the M1 5w40 and i love it. I use my tractor a lot in the winter when it snows as stuff so its perfect. After the M1 is gone (2yrs) i will probably go to to RTS 5w40 as the 100C viscosity is a little thinner.

 

[QuadDriver]

point of order...are you absolutely sure those old cubs have a kohler? many of the cadets and 100 series used wisconsins...

 

[Bror Jace]

Gave this issue s'more thought. One thing flatlandtacoma said above I want to address:

"A good synthetic oil shouldn't have many VIIs to shear, right?"

Theoretically, correct. But we have seen some "premium" synthetic PCMO 5W-30s quickly shear down to 5W-20s ... one I remember in particular was in an economy car in the wintertime (light duty use). Also, engines that tend to consume any oil will often guzzle 'regular' synthetic Mobil 1 5W-30. Contrast these to a conventional HDEO 10W-30 (like Chevron Delo or Shell Rotella) which is likely to be fairly shear stable for most reasonable drain intervals and have an equal-if-not-better add-pack. That's why the generalizations from B&S are kinda misleading.

I would also like more facts or documentation on the temps at 0C (32F) for these oils. Like btanchors, I would have though the viscosity at 0C for a 15W-40 would be an SAE 15 (but I understand even that is a range and allow for a significant amount of variance).

I like and respect Widman, our guy holding down the fort in Bolivia, but I'd like to see some manufacturer's measured data that supports his calculator. After all, that chart looks a little too neat showing SAE30 exactly equaling 15W-40 at 0C and then 10W-30 exactly equaling SAE 30 at 100C and above. Theory is one thing but real world results tend to be a bit less 'tidy'.

jstutz, I agree that if you look at some of the better, even 'boutique' synthetics available, you can find a better performer than the best 15W-40 HDEOs ... but they really aren't necessary. I'd rather use a conventional for OPE ... especially motors without a spin-on filter. More chances to drain out the metal bits circulating through the sump (very important at break-in). Using a more expensive oil might tempt the owner to leave it in a bit too long to try to get his/her money's worth.

 

[flatlandtacoma]

What is SAE 15? If there was such a thing it would be defined at 100C, not 0C.

 

[kcfx4]

Originally Posted By: flatlandtacoma
is also why they also recommend SAE 30 at high temperatures - That is what I use.


and EVERYTIME I reccomend sae30,basically call me an iddiot? seriously?

 

[Bror Jace]

flatlandtacoma: "What is SAE-15?"

Take a look at this chart:

http://i229.photobucket.com/albums/ee149/BrorJace/Miscellaneous/viscositychart3.gif

SAE's Crankase measurement is just another way (scale) to compare viscosities. SAE-15 would be equivalent to a cSt of about 5.1 (+/- 0.3) at 100C or cSt 30 (+/- 0.5) at 40C. Even though the chart doesn't show it, all of these viscosities will have values at -17.7C (0F). I'd like to see those measured values ... or have someone show how they can be calculated accurately as viscosity vs. temperature may not be a straight line projection.

 

[HM12460]

Quadriver, old cub cadet's, all the way back to the "original", never had wisconsin engine's installed as original equipment. Some of the old Bolen's way, way back did.

 

[flatlandtacoma]

Originally Posted By: Bror Jace
flatlandtacoma: "What is SAE-15?"

Take a look at this chart:

http://i229.photobucket.com/albums/ee149/BrorJace/Miscellaneous/viscositychart3.gif

SAE's Crankase measurement is just another way (scale) to compare viscosities. SAE-15 would be equivalent to a cSt of about 5.1 (+/- 0.3) at 100C or cSt 30 (+/- 0.5) at 40C. Even though the chart doesn't show it, all of these viscosities will have values at -17.7C (0F). I'd like to see those measured values ... or have someone show how they can be calculated accurately as viscosity vs. temperature may not be a straight line projection.
Someone correct me if I'm wrong, but that is SAE 15W, not SAE 15. 15W is defined at -20ºC (-4ºF.) AFAIK, 15W is not defined at any other temperature. Again, somebody correct me if I'm wrong. You can heat a 15W fluid up to 40ºC and 100ºC and measure the viscosity but it would only hold true for that fluid with that viscosity index.

 

[flatlandtacoma]

Originally Posted By: kcfx4
Originally Posted By: flatlandtacoma
is also why they also recommend SAE 30 at high temperatures - That is what I use.


and EVERYTIME I reccomend sae30,basically call me an iddiot? seriously?

I never called you an idiot. Or an "iddiot" either.

I think most people understood you the first 8 times you stated on this thread that the engine manual called for SAE 30, not 15W40.

But we were having a discussion about the use of other viscosities, including 15W40 and you chose to post AGAIN that 15W40 was not recommended in the engine manual.

I did ask you to please stop.

After that I think you told us two more times that the engine manual calls for SAE 30.

 

[flatlandtacoma]

Originally Posted By: Bror Jace
flatlandtacoma: "What is SAE-15?"

Take a look at this chart:

http://i229.photobucket.com/albums/ee149/BrorJace/Miscellaneous/viscositychart3.gif

SAE's Crankase measurement is just another way (scale) to compare viscosities. SAE-15 would be equivalent to a cSt of about 5.1 (+/- 0.3) at 100C or cSt 30 (+/- 0.5) at 40C. Even though the chart doesn't show it, all of these viscosities will have values at -17.7C (0F). I'd like to see those measured values ... or have someone show how they can be calculated accurately as viscosity vs. temperature may not be a straight line projection.


It appears that your chart assumes a viscosity index (VI) of 95 or 100, and the temperature projections are based on that. For example, the chart shows a range of about 75 cSt to 115 cSt at 40C for SAE 30, even though SAE 30 has no defined range at 40C. But if you know the viscosity at a given temperature, and the viscosity index, you can project the viscosity at any temperature within reason.

So by assuming a viscosity index of 95 or 100, the author of that chart was able to project SAE 10W and 15W onto the same scale as the other SAE grades, even though they are measured at different temperatures.

Incidently, using the viscosity calculators on the BITOG homepage (which use the same math and formulas that the Widman spreadsheet uses); your example of (5.1 cSt @ 100C and 30 cSt @ 40C) has a VI of 96, and a viscosity @ -17.7C of 1685 cSt. I assume at -20C it would be in the range of SAE 15W.

 

[Bror Jace]

OK flatlandtacoma, I've more than exhausted my understanding of how viscosity is calculated. That chart is a 100% cleaned up version of one I found on-line years ago.

The 15 in 15W-40 cannot be used to predict its viscosity compared to an SAE30. Understood.

If there is no advantage to 15W-40 vs. SAE30 on cold mornings, then you can toss that argument out. I'm left with, then, HDEO add-pack ... and that is available in an SAE30 as well (but availability is more limited).

Extremely high temps may give the 15W-40 an advantage ... but I don't think any of us have seen any definitive info on the effect of viscosity on an oil slinger. My gut tells me that anything from a 20 weight to a 40 weight will splash-lubricate properly.

The 40 weight will offer a bit of buffer in case of fuel dilution ... but that is only if the engine has a SERIOUS problem and/or the interval is pushed too far. If you're taking care of your equipment, neither of these factors should come into play.

I can't see a 15W-40 being sheared down to something thinner than a 30 weight at operating temp. If someone has a UOA that shows this, I'd love to see it.

 

[flatlandtacoma]

Originally Posted By: Bror Jace
The 15 in 15W-40 cannot be used to predict its viscosity compared to an SAE30. Understood.

If there is no advantage to 15W-40 vs. SAE30 on cold mornings, then you can toss that argument out.
The 15W guarantees a low temperature performance that a straight grade does not. I hope nothing I posted sounded like I was recommending SAE 30 in the cold (below freezing.) That was certainly not my intention!

 

[Bror Jace]

No, I don't think you were recommending straight 30 weight oil for cold temps ... just as I am not recommending 15W-40 for cold temps. However, for occasional cold morning starts at the beginning and end of, say, the mowing season, I thought 15W-40 had a bit of an advantage over SAE30 ... it seems that if an advantage exists, it would be insignificant.