redline incresed zinc and phos

[jpr]

Originally Posted By: glennc
Does SM not now set minimum HTHS standards for the various grades? I do recall having read that many of the pre-SM oils had relatively poor HTHS. Perhaps those oils were shearing inside engines to a degree that high levels of ZDDP were required, but SM oils with high HTHS perform better under high stress and therefore much less anti-wear is required.
Sort of, but indirectly.
API requires that the oils meet the SAE J300 viscosity standard. The J300 calls for a minimum HTHS of :
* 2.6 for grade 20
* 2.9 for grade 30
* 2.9 for 0W-, 5W-, and 10W- grade 40
* 3.7 for 15W-, 20W-, 25W-, and straight grade 40
* 3.7 for grades 50 and 60

 

[buster]

JB, just by looking at how much additives on in a particular oil doesn't tell you much.

 

[glennc]

Originally Posted By: jpr
Sort of, but indirectly.
API requires that the oils meet the SAE J300 viscosity standard. The J300 calls for a minimum HTHS of :
* 2.6 for grade 20
* 2.9 for grade 30
* 2.9 for 0W-, 5W-, and 10W- grade 40
* 3.7 for 15W-, 20W-, 25W-, and straight grade 40
* 3.7 for grades 50 and 60


Thanks for posting that. I recall reading a survey of older oils in a technical paper of some sort that was attempting to document the pros and cons of adding an HTHS standard to the (then future) J300 spec. They tested oils in all common grades and the HTHS variability was very high, suggesting that many of the lesser oils were fairly low quality base stocks fortified with VIIs that would shear away quickly under stress.

As I recall the main arguments against an HTHS spec were that those lesser oils still performed well in service (and presumably they were cheaper to manufacture). Whether they would have performed well even with today's lower ZDDP levels I do not know. SM oils appear to be of very consistent high quality and I have a feeling the HTHS requirement is largely responsible for that, as the oils need to be blended using improved base stocks. I do not doubt that additive quality has also been enhanced.

Thanks again for the post.

 

[buster]

Shear stability has definitely improved with SM. Most use some Grp III. Fuel dilution will shear any oil if it's bad enough and some off the thinning you see is not the oil's fault, just a result of excess fuel.

 

[Fat_Larry]

Originally Posted By: TallPaul
Hey, that's great if they are making a break in additive with 9000 zinc and 7500 phos. 10 ounces would boost a 6 quart system by about 400 ppm zinc.


Has any one here tried ZBoost? (www.MotorHeadOil.com)They claim that their 1 ounce bottle will boost a 6 quart system by 580 PPM (or a 5 quart system by 700 ppm). I have never tried the stuff, but I do use their Classic motor oil (1500 ppm).