question on engine oil
12-05-2006, 09:02 PM
#41
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i was told by the gentlemen in garage that mobil1 10w30 is not fully synthetic. i am just wondering if this is the right one ? mobil 1 10w30 ? he recommeded me mobil 1 5w50 instead, should i go for it or what ? thanks
12-05-2006, 09:34 PM
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Originally Posted by apple2000,Dec 5 2006, 10:02 PM
i was told by the gentlemen in garage that mobil1 10w30 is not fully synthetic. i am just wondering if this is the right one ? mobil 1 10w30 ? he recommeded me mobil 1 5w50 instead, should i go for it or what ? thanks
12-06-2006, 01:02 AM
#43
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Originally Posted by 90crvtec,Nov 30 2006, 04:50 PM
"Fully Synthetic" used to mean an oil was formulated primarily with Group IV/V base stocks, those are Esters and PAOs. These are truly man made synthetic base stocks and they are what gives synthetic oils superior flow characteristics when cold and excellent sheer resistance when stressed. Group III oils are naturally occuring and pulled from the earth, but Group III is highly refined and shot full of additives to the point of being able to perform very close to a Group IV/V based product.
Mobil lost the lawsuit with Castrol concerning labeling a Group III product as a "fully synthetic" oil. As a result, companies like Castrol, Pennzoil, Quakerstate, Rotella, and others have started using Group III synthetics. It appears as though Mobil took the 'if you can't beat em', join em' approach and has also started formulating at least some of their "fully synthetic" products with Group III dino basestocks.
Mobil lost the lawsuit with Castrol concerning labeling a Group III product as a "fully synthetic" oil. As a result, companies like Castrol, Pennzoil, Quakerstate, Rotella, and others have started using Group III synthetics. It appears as though Mobil took the 'if you can't beat em', join em' approach and has also started formulating at least some of their "fully synthetic" products with Group III dino basestocks.
Group 3 oils are now as good as PAOs, they just don't last as long. For 6,000 mile oil changes this is not a real issue. Oxidation being the main reason for why an oil needs changing, expecially on a car like the S2000 where it is regularly topped up.
It's not just the Cst values you want to look at, but also the HTHS figures. (High temp high shear). The S2000 will like a nice low HTHS (eg 2.9) as it is designed with small bearing clearances, US engine typically have bigger clearances and like a higher HTHS (eg 3.5) to keep the oil film there under high loads.
12-06-2006, 03:49 AM
#44
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apple2000 Posted on Dec 6 2006, 07:02 AM
No matter what you do, DO NOT use that 5W-50 oil, that is way to thick at operating temp, syn or dino.
If it was a typo and you mean 5W-30 then it is ok to use it without any problems.
Si2k Posted on Dec 6 2006, 11:02 AM
In an ideal world one would want a thin oil with high HTHS values.
I'm afraid that is not possible, yet.
Bearing clearances have nothing to do with this in the way you describe.
Operating temp viscosity (cSt) does and that is linked to HTHS, a xxW-30 oil will have less HTHS then a xxW-40 oil because of the viscosity at 150C (that is the temp the HTHS is measured).
Your oil pump provides the oil at the bearings, "at their doorstep" and the bearings themselfs suck it in (because they rotate) and that generates the forces to seperate the moving parts.
Thinner oil will be pumped with less pressure and more flow, more oil "at the doorstep" is better for lubrication and cooling.
HTHS comes into play when there isnt enough fresh oil "at the doorstep", the oil in the bearing warms up and still needs to seperate the moving parts, IOW keep the film strength up.
HTHS is also needed at parts that are splash lubricated, like rockers and piston rings.
Basically, what you are saying is :"Use a xxW-30 oil because the bearing clearances are small".
Better would be to say: "Use xxW-30 oil because it will give you more oil flow"
And I would like to add: "Use the highest HTHS numbers that a xxW-30 oil can give you. (with 2.9 as a max available because of the viscosity at operating temp IIRC)"
i was told by the gentlemen in garage that mobil1 10w30 is not fully synthetic. i am just wondering if this is the right one ? mobil 1 10w30 ? he recommeded me mobil 1 5w50 instead, should i go for it or what ? thanks
If it was a typo and you mean 5W-30 then it is ok to use it without any problems.
Si2k Posted on Dec 6 2006, 11:02 AM
It's not just the Cst values you want to look at, but also the HTHS figures. (High temp high shear). The S2000 will like a nice low HTHS (eg 2.9) as it is designed with small bearing clearances, US engine typically have bigger clearances and like a higher HTHS (eg 3.5) to keep the oil film there under high loads.
I'm afraid that is not possible, yet.
Bearing clearances have nothing to do with this in the way you describe.
Operating temp viscosity (cSt) does and that is linked to HTHS, a xxW-30 oil will have less HTHS then a xxW-40 oil because of the viscosity at 150C (that is the temp the HTHS is measured).
Your oil pump provides the oil at the bearings, "at their doorstep" and the bearings themselfs suck it in (because they rotate) and that generates the forces to seperate the moving parts.
Thinner oil will be pumped with less pressure and more flow, more oil "at the doorstep" is better for lubrication and cooling.
HTHS comes into play when there isnt enough fresh oil "at the doorstep", the oil in the bearing warms up and still needs to seperate the moving parts, IOW keep the film strength up.
HTHS is also needed at parts that are splash lubricated, like rockers and piston rings.
Basically, what you are saying is :"Use a xxW-30 oil because the bearing clearances are small".
Better would be to say: "Use xxW-30 oil because it will give you more oil flow"
And I would like to add: "Use the highest HTHS numbers that a xxW-30 oil can give you. (with 2.9 as a max available because of the viscosity at operating temp IIRC)"
12-06-2006, 08:26 AM
#45
Just a note of interest. I remember a few years ago a test using Mobil-1 that was done by GM in which various intervals of removing and replacing certain amounts of Mobil-1 over the life cycle (5000miles?) were done. An example- remove one quart and replacing every 1000miles between each oil change. Obviously, the test was to determine if the oil was as good after doing this as it would have been doing only a normal oil change. The answer was NO. No benefit was noted in any of their tests at any interval. The conclusion that adding one quart of new synthetic to one quart used synthetic yields two quarts used synthetic.
I can't say absoluty that this would also carry over for all oil ,even non-synthetic, but it probably does.
For those people who may be losing or burning an unusual amount of oil and are replacing several quarts between changes should not get comfortible with the feeling that the oil in thier crankcase is relatively new and should change thier oil on schedule as prescribed.
I can't say absoluty that this would also carry over for all oil ,even non-synthetic, but it probably does.
For those people who may be losing or burning an unusual amount of oil and are replacing several quarts between changes should not get comfortible with the feeling that the oil in thier crankcase is relatively new and should change thier oil on schedule as prescribed.
12-06-2006, 10:08 AM
#46
Originally Posted by JackS,Dec 6 2006, 12:26 PM
Just a note of interest. I remember a few years ago a test using Mobil-1 that was done by GM in which various intervals of removing and replacing certain amounts of Mobil-1 over the life cycle (5000miles?) were done. An example- remove one quart and replacing every 1000miles between each oil change. Obviously, the test was to determine if the oil was as good after doing this as it would have been doing only a normal oil change. The answer was NO. No benefit was noted in any of their tests at any interval. The conclusion that adding one quart of new synthetic to one quart used synthetic yields two quarts used synthetic.
I'd like to mention that I agree with all of the comments made by SpitfireS, and the link to AE Haas' site is priceless. Although I agree with AE Haas on most of what he says, I disagree with his comments on oil getting thicker just by being exposed to cold temperatures. I can link comments made by a reputable person about this if anyone is interested.
I'd also like to mention that there is one point that hasn't been emphasized which significantly affects wear on an engine. Besides oil flow (rather than pressure), increasing RPM increases film thickness at the bearings. Here is some information on the subject: Bearing Film ThicknessThis means that the faster the engine is turning, the thicker the hydrodynamic oil film on the bearings. This is similar to hydroplaning, or sliding down a water slide - the faster you go, the less contact between surfaces.
12-06-2006, 10:19 AM
#47
This has become a very informative thread. Lots of really good detail.
I fear that apple2000 is reading all this and becoming a bit overwhelmed. While all very good information, and certainly appropriate for an "under the hood" thread, it is perhaps unnecessery for the casual S2000 owner.
So, to all who are contributing to this informative thread, thank you and keep it up.
To Apple2000, who simply wants to know a decent oil to keep in his car, I think most of us would agree that the following is appropriate: Follow this link for Mobil 1 10W30 synthetic. Yes, it is fully synthetic. For the filter, many recommend the OEM S2000 filter. It is different from the general purpose OEM filter. Look for it on this page. This setup will be fine until you want to delve deeper into the intricacies of oil.
I fear that apple2000 is reading all this and becoming a bit overwhelmed. While all very good information, and certainly appropriate for an "under the hood" thread, it is perhaps unnecessery for the casual S2000 owner.
So, to all who are contributing to this informative thread, thank you and keep it up.
To Apple2000, who simply wants to know a decent oil to keep in his car, I think most of us would agree that the following is appropriate: Follow this link for Mobil 1 10W30 synthetic. Yes, it is fully synthetic. For the filter, many recommend the OEM S2000 filter. It is different from the general purpose OEM filter. Look for it on this page. This setup will be fine until you want to delve deeper into the intricacies of oil.
12-06-2006, 07:39 PM
#48
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Originally Posted by slalom44,Dec 6 2006, 11:08 AM
Although I agree with AE Haas on most of what he says, I disagree with his comments on oil getting thicker just by being exposed to cold temperatures.
I'm confused by this statement? Haas implied that if a car is run up to full operating temperature, then shut off and left to sit overnight, the oil in the crank case will indeed be thicker upon starting up the next morning. Is this what you don't agree with?
12-07-2006, 07:09 AM
#50
Originally Posted by 90crvtec,Dec 6 2006, 11:39 PM
I'm confused by this statement? Haas implied that if a car is run up to full operating temperature, then shut off and left to sit overnight, the oil in the crank case will indeed be thicker upon starting up the next morning. Is this what you don't agree with?
Motor oil becomes permanently thicker with exposure to northerly winter type weather. This is more of a problem to mineral based oils. Waxes form. This is why it is a bad idea to even store a bottle of oil in a cold garage. It goes bad on the garage self just because it is exposed to the cold.