Thin vs Thick Discussion, Chapter 7

Status
Not open for further replies.
Messages
1,420
Location
Sarasota, Florida
Motor oil 107
Chapter Seven. What is the terminology from SAE and API

Many think that the “W” in 10W-30 means “winter”.
From SAE J300 p.2:
"Two series of viscosity grades are defined in Table (1): (a) those containing the letter W and (b) those without. Single viscosity grade oils with the letter W are defined by maximum low temperature cranking and pumping viscosities and a minimum kinematic viscosity at 100C. Single grade oils without the letter W are based on a set of minimum and maximum kinematic viscosities at 100C and a minimum high shear rate viscosity at 150C. The shear rate will depend on the test method. Multi-grade grade oils are defined by both of these criteria....
The W is a designation of one type of testing vs another.

What is the viscosity of the various grade oils? Of the most commonly used oils today the definitions are as follows:

From SAE J300, viscosities at 212 F...

20, range - 5.6 to 9.2
30, 9.3 - 12.4
40, 12.5 - 16.2
50, 16.3 - 21.8
60, 21.9 - 26.1


By a modified analysis the min. viscosity at 302 F...

20, 2.6
30, 2.9
40, 2.9 - 3.7
50, 3.7
60, 3.7

Today there are other grades defined as 8, 12 and 16 but these are not in widespread use right now. The 8 and 12 grades were, as of this writing, defined so that oil producers have a goal for further developments in motor oils. They are not produced in any volume at this time.

Note again that the difference between the 20 grade and 60 grade oils at 302 F is only about 1 (one). Whereas the difference in viscosity at 104 F is 120 units. The 20 grade has a viscosity of 40 and the 60 grade a viscosity of 160. The difference at startup (75 F) is even higher, probably 250 or 300. At ice cold temperatures the difference might be in the thousands.

The American Petroleum Institute, API, and Society of Automotive Engineers, SAE, have rated engine oil performance over the years. We have seen the ratings go from SA, SB, SC, SD, SE, SF, SG, SH, SJ, SM, SN and with SP to follow. SI and SK were eliminated as they are used by other businesses. There are over 3 dozen tests that oil now must pass in order to make the next higher rating. The tests are defined by the American Society for Testing and Materials, ASTM. Some tests have progressed to a zero tolerance level. For example there can be no sticking of any piston rings any more. I will compare the older SL rated oil to the previous SJ oil in a few categories. There may still be some of these oils floating around. For simplicity I will skip the units of measurement:


.......S J........S L......

.......30........20......maximum cam plus lifter wear
........9.........7.8.....sludge build up
........5.........8.9.....varnish rating (more is better)
.......60.......45.......high temperature deposits
.......17.......10.......high temperature volatility

Other categories include: Resistance to rust, resistance to foaming, resistance to oil consumption, homogeneity and miscibility, flow reduction with varying amounts of absorbed moisture, gelation index and others.

As one can see just going from the previous SJ to the SL rating is a significant improvement. As the ratings have progressed today there have been less difference between them. But in all cases they are back specified.

Regarding cool whether gel formation, a small except from SAE j300 1999:
4. Because engine pumping, cranking and starting are all important at low temperatures the selection of an oil for winter operation should consider both the viscosity required for oil flow as well as cranking and starting, at the lowest expected ambient temperature.
Pumping viscosity is a measure of an oils ability to flow...during the initial stages of operation. Test in ASTM D 4684. ....samples are tested after a slow cool cycle. This cycle has predicted as failures several SAE 10W-30 and 10W-40 oils which are known to have suffered pumping failures in the field after short-term (2 days or less) cooling. These field failures are believed to be the result of the oil forming gel structures that result in excessive yield stress and viscosity of the engine oil...
A.2.1...After preliminary warming, the sample is subjected to a controlled temperature/time cycle over 5 1/2 to 7 days. The cycle reproduces ...instability or reversion which has occurred during storage of oils in moderately cold cyclic conditions. Recent work shows relevance to engine oil pumpability failure. Oils exhibiting pour reversion have solids resulting from wax gel formation, at temperatures significantly higher than their ASTM D 97 pour points.
Extracted, from ASTM D 4485-03 Standard Specification for Performance of Engine Oils, copyright ASTM International, 100 Barr Harbor Drive, Wets Conshohocken, PA 19428, USA.

My point is that tests are not just laboratory concoctions. They design tests to match real life conditions.

I used 5W-20 Pennzoil mineral based multi-grade oil in my Expedition as it has many of the low temperature characteristics of higher grade synthetic oils. My '04 manual stated that the SUV is delivered with a Ford semi-synthetic oil and although regular oil can be used they recommend a semi or full synthetic oil. For the differential gear oil they used 75W-140 in my ‘98 Expedition but now recommend 75W-90. If I was towing 8,000 lbs. then I would need the semi or full synthetic 5W-20. But for my usual around town driving a mineral based oil is plenty good.

Please note that it makes no difference what oil you are using. The 5W-30 Mobil 1 that is SN rated meets the same criteria as that SN rated 10W-30 synthetic or mineral based Pennzoil. That SL or in particular that SH oil some people are looking for (from their older automotive owners manual) is no where near as good as any SL or SN oil of today. Always use the most currently available, highest rated motor oil, even in the oldest, most worn engine. You may require a thicker grade but just make sure it is SN or SP rated.

The SH rating was used in oils starting 1993. The SJ rating started in 1997 while the SL became effective in 2001 oils. According to ASTM D 4485, SL rated oils are superior to previous oils and from:
X2.3.1 and 2: SL oil is for use in current and all earlier passenger cars, sport utility vehicles, vans, and light trucks. This SL rated oil can be used in engines requiring SJ and All Earlier Categories.

Concern: People are worried about the SM oils not having as much ZDDP as the SL and older oils. The reason ZDDP has been used for years is not because of its superior performance but rather its low cost and dual function as an antioxidant. It also has anticorrosive properties. Today oils are going with less or no zinc and lower or no phosphates of the past but still have superior performance.


See: American Society for Testing and Materials- www.astm.org
........Society of Automotive Engineers- www.sae.org
........American Petroleum Institute- www.api.org

AEHaas
 

OVERKILL

$100 Site Donor 2021
Messages
46,064
Location
Ontario, Canada
Another week, another kick at the same old cat I see. I'll just copy and paste my previous reply below. Since the OP seems to be allergic to this data for whatever reason, this is for the benefit of whomever else might be reading this thread.

Motor oil 107
Chapter Seven. What is the terminology from SAE and API

Many think that the “W” in 10W-30 means “winter”.
No, it actually does in fact mean Winter.
Savant Labs offer testing according to (Society of Automotive Engineers) SAE J300 to determine an engine oil’s SAE viscosity grade. Four viscosity tests determine the multi-grade parameters. A multi-grade oil’s viscosity grade is often expressed as #W##, for example 5W30 or 0W20. The “W” in the viscosity grade stands for “winter”.

SAE J300 is the standard for automotive oils used in combustion engines (crankcases). These are complex oils that can be divided into three categories: winter, high-temperature and multi-grade.

The winter (W) group measures the cold-cranking and pumping ability of oil temperatures as low as minus 10 to minus 40 degrees C. They are measured in centipoise (cP). However, SAE viscosity grades 0W to 20W are also measured in centistokes (kinematic viscosity) at 100 degrees C as part of the high-temperature or operating-temperature group.
The viscosity grade of a lube oil is determined by the Society of Automotive Engineers (SAE). Oils can be separated into multigrade oils and monograde oils. Multigrade oils must fulfill two viscosity specifications, their viscosity grade consists of two numbers, e.g. 10W-40: 10W refers to the low-temperature viscosity ("Winter"), 40 refers to the high-temperature viscosity ("Summer"). Currently, most automotive engine oils are multigrade oils, while oils for restricted usage, e.g. for seasonally used engines like lawn mowers, are often monograde oils. While the two numbers specify the SAE viscosity grade, the viscosity index shows the temperature related change of viscosity.
Motor oil viscosity is commonly measured at lower and higher temperatures. The properties of the oil at lower temperatures define the first part of the motor oil grade. In the example of a 0W-20, the “0W” part of the grade is related to the measurement of viscosity at low temperatures as defined by SAE J300 (and the “W” stands for Winter – relating it to low temperature performance). The better the oil performs at lower temperatures, the lower the number before the W. The numbers are ranges defined by SAE J300, so zero doesn’t mean zero performance; it means the oil performs better at lower temperatures and flows easier than oils that fall in 5W, 10W, 20W, etc. ranges.
Overview: ASTM D5893 -Cold cranking viscosity or CCS - is used to simulates the viscosity of oil in crankshaft bearings during cold temperature start up. This is another viscosity requirement specified in SAE J300 standard which defines the viscosity grade of the oil. CCS viscosity helps define the “W” or “winter” part of a multigrade oils. As with kinematic viscosity, J300 defines mandatory ranges which must be met – one must claim the lowest “W” level met. For a 5W-30 engine oil, numbers in the red, indicate the oil does NOT meet the requirements to be labeled a 5W oil.
Note: This chart only includes viscosity at 100°C for the summer grade. It excludes winter grades designated by SAE ##W, it must meet additional low temperature testing listed on the corresponding SAE J300 or J306 viscosity classification table (not shown here).
Engine lubricants are classified using the Society of Automotive Engineers (SAE) J300 oil viscosity classification system. Multi-grade engine lubricants, such as SAE 5W-30 or 10W-30, must meet both low temperature and high temperature viscosity requirements. In a SAE 5W-30 engine lubricant:

  • “5W” refers to low-temperature viscosity (the "W" denotes winter) and is an indication of how easily the lubricant will flow in cold start-up conditions. At a given temperature a 5W lubricant has a lower viscosity than a 10W lubricant so flows faster during critical start-up. This is sometimes referred to as cold cranking simulator (CCS) viscosity.
  • “30” refers to the high temperature viscosity at 100°C, therefore replicating an engines operating temperature.
Hopefully Chevron, Lubrizol, Castrol...etc are authoritative enough sources to put this one to rest.
 
Messages
176
Location
Central FL
I was read to remember the xW-whatever rating was for a chilled sump. The lower the xW-123 number (speaking for x) the less the oil gelled up through a test orifice, implying an immediate oil pump charge up through the upper valvetrain and the big end. That oil is there matters more than brand, hot (123) numbers, etc.

Am I mistaken? Am I "killing" an engine prematurely by feeding it something like Mobil-1 0w-40 FS eurocar that the cap and manual says to use an SL 5w-30 full synthetic? By my reading again, the Mobil-1 FS is a tad closer to a 30 grade oil when fresh, and is a mildly thrashed heavier grade 30 when done at end of OCI? My manual also permits full synthetic 40 grade on heavy use/track days but for economy; recommends a spill -n- fill once back to civilian life to a 5w-30 full synthetic. (Mobil-1 all the way is explicitly stated)

Ugh,I hate threads like this as they make me second guess myself every time.

Faggedabbouddit. I was re- reading my response and she's lived 180k so far. No dead or weak compression tested on any cylinder and runs like a scalded cat. Being in Florida I'll run her hot, hard and thick until she's scrap.

(There's a really basic joke in that last sentence, I think)
 

BeerCan

$50 Site Donor
Messages
1,716
Location
FL
I was read to remember the xW-whatever rating was for a chilled sump. The lower the xW-123 number (speaking for x) the less the oil gelled up through a test orifice, implying an immediate oil pump charge up through the upper valvetrain and the big end. That oil is there matters more than brand, hot (123) numbers, etc.

Am I mistaken? Am I "killing" an engine prematurely by feeding it something like Mobil-1 0w-40 FS eurocar that the cap and manual says to use an SL 5w-30 full synthetic? By my reading again, the Mobil-1 FS is a tad closer to a 30 grade oil when fresh, and is a mildly thrashed heavier grade 30 when done at end of OCI? My manual also permits full synthetic 40 grade on heavy use/track days but for economy; recommends a spill -n- fill once back to civilian life to a 5w-30 full synthetic. (Mobil-1 all the way is explicitly stated)

Ugh,I hate threads like this as they make me second guess myself every time.

Faggedabbouddit. I was re- reading my response and she's lived 180k so far. No dead or weak compression tested on any cylinder and runs like a scalded cat. Being in Florida I'll run her hot, hard and thick until she's scrap.

(There's a really basic joke in that last sentence, I think)
Don't worry about it, really. Most of this is FUD. All my cars except the diesel get 0W-whatever and they all are doing fine. I think many others will tell you the same. As a WKM say's all the time it's approvals that matter.
 
Messages
17,239
Location
Upper Midwest
I was read to remember the xW-whatever rating was for a chilled sump. The lower the xW-123 number (speaking for x) the less the oil gelled up through a test orifice, implying an immediate oil pump charge up through the upper valvetrain and the big end. That oil is there matters more than brand, hot (123) numbers, etc.

Am I mistaken? Am I "killing" an engine prematurely by feeding it something like Mobil-1 0w-40 FS eurocar that the cap and manual says to use an SL 5w-30 full synthetic? By my reading again, the Mobil-1 FS is a tad closer to a 30 grade oil when fresh, and is a mildly thrashed heavier grade 30 when done at end of OCI? My manual also permits full synthetic 40 grade on heavy use/track days but for economy; recommends a spill -n- fill once back to civilian life to a 5w-30 full synthetic. (Mobil-1 all the way is explicitly stated)
This makes no sense. You aren't going to "kill" and engine by using a 40-grade in an engine that recommends a 30-grade. Winter rating won't kill it either unless you're starting the car at a temperature that is wholly inappropriate for the rating and cannot be pumped, in this case that would be somewhere below -35F. So much misunderstanding about the winter rating and what it means and does not mean.

Besides the incorrect understanding about what the "W" rating means, in this instance the oil recommendations are based on minimum HT/HS not grade per se. Both 30-grades and 40-grade oils can have the required HT/HS and that's what is important. Grade is secondary and largely irrelevant here.
 
Status
Not open for further replies.
Top