[regular guy]

Proposed Solutions: Thinner Oil

I'll be first to tell you that I'm not an oil expert, but I'm very impressed with the information that kawasaki00 and BMRLVR have contributed to this discussion. I'll try to collect some of their best posts and weave it into a cohesive discussion.

I am looking at the Rotella T6 for my car on the next oil change. The T6 must be a stout oil since it has the JASO MA rating on the back...... Not many passenger car/ diesel engine oils meet motorcycle certifications which is a testament to the base stock it is blended from. Motorcycles throw a whole different curve at oils since they have to deal with lubricating a transmission and a wet clutch as well as an engine that can spin upwards of 15000RPM......... But judging by your username I don't need to tell you anything about motorcycles! -- BMRLVR

You are correct on the rotella in the motorcycles, along with my full-time job I also raced a zx-10r for a couple years. There have been some complaints over the last year or so about the t6 though, some of the high power bikes are having a touch of clutch chatter. The zinc and phosphorous levels have dropped from 1600 to about 13-1400 in the new t6. For engine bearings, flat tappet cams and the like that number is still plenty high. The tws oil is about 16-1700 on zinc numbers. BUT although it is higher that doesn't mean it is superior. Mobil 1 racing 4t is being sold as a motorcycle oil but it is really a normal engine oil with about 1500ppm of zinc and phosphorous. The problem is that it is a 10-30 so not really picking up much as far as our clearance problem. -- kawasaki00

Ok, then someone edumacate me. 10w-60 means SAE viscosity of "10" when cold, right? and "60" when at temp, right? soooo, what am I doing wrong here? -- Transfer

http://www.upmpg.com/tech_articles/motoroil_viscosity/

This explains it.
For this problem we have if there were a 5w-60 that would be the ultimate for us. Unfortunately there is no such grade. The 5w would help a ton at start up but still protect like a 60 weight at temp. This is why the rotella 5-40 is a trade off. It is better at low temps and flows better but the untimate high temp shear strength is not as much as a 60.
The second number is the protection factor not the weight. A 10w-30 and a 10w 60 is till the same weight at cold temp. -- kawasaki00

According to the lubrication system schematic for the S65 on BMW TIS it appears as though the engine uses a pressure compensated variable displacement main oil pump. (There is a signal passage off of the main oil gallery in the schematic which is shown as a dotted line...... In my industry, heavy equipment, dotted lines almost always symbolize signal oil in hydraulic schematics). The fact that the pump is variable flow (variable displacement) it would lead me to believe that pump volume should not be an issue in the S65. Variable displacement pumps are used to ensure that max pump volume is available regardless of engine speed. To me this is great news for any of us looking to run additional clearance or lighter oil. This also helps to explain why VCM power claims that the pressure stays constant from 2000RPM on up to redline........ with a pressure compensated pump pressure can remain nearly constant and the system will never have to go over relief except in the event of a system malfunction. -- BMRLVR

The 0w50 is a fantastic oil. The reason I dont bring it up is you need to be catless and be prepared to replace o2 sensors much quicker than normal. Although for most if the car has a supercharger on it they are not worried about a couple hundred bucks for sensors.

Why does the 0w 50 oil cause 02 sensors to go?

Because the 0w-50 that he is talking about is a racing only oil. It has over twice the zinc around 1850ppm I believe. That much zinc will burn coverters up and leave deposits on o2 sensors that skew the data. Kind of like running leaded fuel, but it just doesnt happen as fast. -- kawasaki00

The German castrol 0w30 is almost a 40 wt. however it is not a sn oil. The new belgium castrol 0w40 is really good and is a sn. The mobil 1 0w40 is the best of the bunch really. It is the heaviest of the 40 wt oils I have tested. I checked the 5w50 castrol has and it is higher in zinc but it will shear quickly to a 40 wt.
it really is a lot to go through but thinnest to thick is as follows
Castrol 5w30
German castrol 0w30
Belgium 0w40. This oil is replacing the current 5w40 on shelves
Mobil 1 0w40
Rotella t6
Mobil 1 0w50
Castrol5w50

Multiple 10w40s can go here
Castrol tws
Liquid moly 10w60

I would definitely not run the liquid moly because it does not have the cold flow properties as the tws but is equal hot.
I will do my best to answer questions on other oil if someone has some.

From what I have gathered from some other tests is that the mobil is better hot and thicker with higher viscosity index but is still thinner cold. Really better all around. Only question is do we have enough oil pressure to run the 0-40. But, I know a couple guys already running it so I am going to put a gauge in the car. I have asked on a couple occasions for a pressure graph to be posted but no one wants to do it. So I am working on it.

The redline is a really good oil but if going off the premise that the oil is too thick for us non track users then I would not run it.
The redline is thicker cold and hot than the tws oil. -- kawasaki00

kawasaki00,

Setting aside bearing clearance discussions for the moment, do you have any thoughts on other aspects of oil delivery? For example, during extreme acceleration, especially in 1st gear where the rate of change is the highest, is it possible there are oil delivery problems out the bore in the connecting rod? I would assume there is a negative pressure gradient along that path, and if the momentary pressure falls low enough in the extreme case of rapid rod acceleration (coupled with its high peak velocity), any entrained air could possibly be released? I would think that even a one-time situation that results in bearing film violation and cavitation could be enough to cause need to replace the bearings?

Stating the obvious, lol, I'm not an engine designer or anything. Just an old, emphasis on old, mechanical engineer with a lot of interest in the subject. -- CSBM5

One would more than likely see a pressure drop if that happens. Most gauges really dont react fast enough to see these drops in pressure. A logging system with a 100hz record rate might pick it up.

That being said it is usually never a problem with street engines. The oiling system is USUALLY way overkill for what it needs to acomplish. The only way to get a idea is to install a flow meter to measure oil flow inline but it is hard to do in a wet sump engine. That and the fact a good meter is usually a thousand dollars and then you have to have the aquisition system. This engine makes no torque anyway, it is a short stroke motor so there is not going to be much bore deformation with the NA stuff. FI might be different but I cant say for sure.

If you want my take on what is happening it is this. Imagine a garden hose that you pinch the end of it off. Still have plenty of pressure but no flow. I believe this is what is happening with the rod problem. Until it gets to full operating temp and maybe even not then, because the clearance is so tight you always have pressure but the system has a hard time pushing the thick oil through the tight rod clearance. This results in cavitation because there is no flow. When bearing shells show the typical bottom shell looks ok top shell is bad worn that is the number one indication of just a plain lack of lubrication.

It has been tested to death and there is no denying that the tws is a fantastic oil. If it were available in a 0-40/50 or a 5-40 option I would still run it. BMW and there infinite wisdon says it is ok to run the oil 15k miles no matter how hard you drive it. The only way to make this happen it to run a robust oil such as the tws. That doesnt mean it is the best option though for us street drivers. Also remember this car was designed in 2006, much has changed over the last 7 years in regards to the quality of oil available. I am currently running a 0wt but I am also changing it every 4k miles because I dont drive it all the time. I would never try to run the 0wt for even 10k miles let alone 15k miles but that s just me. -- kawasaki00

Thank you for all of your contributions. Any opinions on Red Line Synthetic Oil and which would you recommend based upon "their" techincal properties? I've listed their 10W60 as well:




10W60

TYPICAL PROPERTIES


API Service Class SN/SM/SL/CF
SAE Viscosity Grade (Motor Oil) 10W60
Vis @ 100°C, cSt 25.9
Vis @ 40°C, cSt 170.4
Viscosity Index 187
CCS Viscosity, Poise, @*C 65@-25
Pour Point, °C -45
Pour Point, °F -49
Flash Point, °C 234
Flash Point, °F 454
NOACK Evaporation Loss,1hr @ 482°F (250°C), % 6
HTHS Vis, cP 150°C, ASTM D4741 5.8



5W50

TYPICAL PROPERTIES


API Service Class SN/SM/SL/CF
SAE Viscosity Grade (Motor Oil) 5W50
Vis @ 100°C 21.0
Vis @ 40°C 130
Viscosity Index 186
CCS Viscosity, Poise, @*C 60@-30
Pour Point, °C -45
Pour Point, °F -49
Flash Point, °C 232
Flash Point, °F 450
NOACK Evaporation Loss,1hr @ 482°F (250°C), % 6
HTHS Vis, cP 150°C, ASTM D4741 5.0




0W40

TYPICAL PROPERTIES


API Service Class SN/SM/SL/CF
Viscosity Grade SAE 0W40
Vis @ 100°C, cSt 15.4
Vis @ 40°C, cSt 86
Viscosity Index 190
CCS Viscosity, Poise, @*C 57@-35
Pour Point, °C -60
Pour Point, °F -76
Flash Point, °C 230
Flash Point, °F 446
NOACK Evaporation Loss,1hr @ 482°F (250°C), % 9
HTHS Vis, cP 150°C, ASTM D4741 4.0




5W30

TYPICAL PROPERTIES


API Service Class SN/SM/SL/CF
Viscosity Grade SAE 5W30
Vis @ 100°C, cSt 11.9
Vis @ 40°C, cSt 71
Viscosity Index 166
CCS Viscosity, Poise, @*C 60@-30
Pour Point, °C -45
Pour Point, °F -49
Flash Point, °C 232
Flash Point, °F 450
NOACK Evaporation Loss,1hr @ 482°F (250°C), % 6
HTHS Vis, cP 150°C, ASTM D4741 3.7



5W40

TYPICAL PROPERTIES


API Service Class SN/SM/SL/CF
Viscosity Grade SAE 5W40
Vis @ 100°C, cSt 15.6
Vis @ 40°C, cSt 97
Viscosity Index 174
CCS Viscosity, Poise, @*C 58@-30
Pour Point, °C -45
Pour Point, °F -49
Flash Point, °C 232
Flash Point, °F 450
NOACK Evaporation Loss,1hr @ 482°F (250°C), % 6
HTHS Vis, cP 150°C, ASTM D4741 4.4
-- Fsarc

BMRLVR, Kawasaki00, and others, I'm sure I missed many important posts of yours. If there's some more relevant posts, then please send me links and I'll add them to the discussion (or feel free to add them yourselves).

Thanks to all the oil experts.