Winner, winner, chicken dinner. I got a gallon of both, set for two oil changes. Both are full synthetic.
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Rotella 5w/40 or 15w/40
- Thread starter holligl
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Eville Rich
Well-Known Member
I believe that T6 is CJ rated for compression ignition and also MA2 rated, indicating suitability for wet clutches. If this is something important to you, I recommend confirming one way or the other with your own research. Oil threads can go down some rabbit holes.
In my view, Rotella T6 is good quality and suitable for motorbikes with or without wet clutches. I've become a fan of Motul 7100T 10W-40, mostly because it's red, smells like candy, and makes me feel special. But I'd run T6 without concern.
Eville Rich
In my view, Rotella T6 is good quality and suitable for motorbikes with or without wet clutches. I've become a fan of Motul 7100T 10W-40, mostly because it's red, smells like candy, and makes me feel special. But I'd run T6 without concern.
Eville Rich
As long as the oil complies with the JASO standard….it is recommended for the wet clutch. Now, diesel oil has to control the acids produced by the combustion of diesel (sulfur)….and gasoline oils have to control the alcohol in the gasoline mixture.
Lubricate, they lubricate both….but the control additives are different, because the combustion residues are different. In "new" diesel engines with DPF... the residues that arise from cleaning the DPF are sent to the oil pan and mixed with the oil. In this type of engine, the oil becomes very acidic...or a good oil is used...or it is changed more often, to avoid acid oxidation in the crankshaft/connecting rod bearings
This diesel engine has 30,000 miles….zero soot in the exhaust…soot from the DPF, goes away with an oil change
Lubricate, they lubricate both….but the control additives are different, because the combustion residues are different. In "new" diesel engines with DPF... the residues that arise from cleaning the DPF are sent to the oil pan and mixed with the oil. In this type of engine, the oil becomes very acidic...or a good oil is used...or it is changed more often, to avoid acid oxidation in the crankshaft/connecting rod bearings
This diesel engine has 30,000 miles….zero soot in the exhaust…soot from the DPF, goes away with an oil change
DPF is a filter, and when the back pressure reaches a certain level the device regens by injecting diesel fuel and burning the trapped carbon into CO and CO2. While some of the combustion products do of course make it into the oil, anything trapped in the DPF will be burnt and go out the exhaust and in no way will it enter the oil. Oil chemistry has had to change so it will not poison not only the DPF but more importanly the SCR system. So in the end any carbon pollution is not removed, it is stored and then emitted as a gas instead of a solid.
Eville Rich
Well-Known Member
As someone who owns a diesel with DPF regen, I will confirm that this is correct. That said combustion byproducts do get in the oil, which is why diesel oil quickly turns black and looks awful. But the oil is designed to deal with that as long as you don't over extend the OCI. Diesels tend to be harder on oil than gasoline engines, though it does depend on the operating conditions.
That's right...perhaps I expressed myself incorrectly or incompletely (between thinking and translating, it gets complicated for me
)…To burn the particles, the diesel uses either its own injectors...or an extra injector. This use of its own injectors, apart from generating temperature, generates excess fuel that is poorly burned and goes directly to the oil pan. Some engines saw the oil levels increase due to the continuous regenerations….they even came/come with a “maximum oil” sensor….when they reached that sensor, the oil had to be changed…Today they greatly improved the cleaning of the dpf with an injector extra directly to the turbo outlet and before the dpf (in some engines).This is a 4 cylinder diesel engine (224hp) with a fifth injector
semmyroundel
Active Member
So living in UK, would my Castrol Racing 0-30 be OK? IT very rarely gets above 30 degrees here but it can go below 0.
WJBertrand
Ventura Highway
No, not according to the owners manual. The lightest weight oil recommended is a 10w-something. There are no 5w- or 0W- recommendations.
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semmyroundel
Active Member
Thanks WJ. My understanding is clearly lacking.
nd4spdbh
Member
There are Three types of T6.
5w40 THAT IS JASO MA (ceritifed for wet clutch use) - USE THIS
5w30 and 15w40 T6 THAT are NOT I repeat NOT JASO MA certified for use in wet clutch applications
There will be no harm in using the 5w-40 where a 10w-40 is specd as even at ambient temps of 100*f "cold" oil of 5w is still thicker than its final 40w rating at operating temperature (~210*f)
5w40 THAT IS JASO MA (ceritifed for wet clutch use) - USE THIS
5w30 and 15w40 T6 THAT are NOT I repeat NOT JASO MA certified for use in wet clutch applications
There will be no harm in using the 5w-40 where a 10w-40 is specd as even at ambient temps of 100*f "cold" oil of 5w is still thicker than its final 40w rating at operating temperature (~210*f)
semmyroundel
Active Member
Ok, I get it, put in what the manufacturers tell me to put in, fine I shall continue to do so.
But here's what I don't get: if the first number is cold starting and it can easily get to 0 degrees here in UK in winter, and rarely gets above 30 in summer (and as someone alluded to earlier, a lower second number means the oil will run cooler) what's that oil for? And why would it be detrimental to the bike?
I won't use it, but just want to try and understand why I'm not going to use it, apart from the fact that Yamaha - he say no.
But here's what I don't get: if the first number is cold starting and it can easily get to 0 degrees here in UK in winter, and rarely gets above 30 in summer (and as someone alluded to earlier, a lower second number means the oil will run cooler) what's that oil for? And why would it be detrimental to the bike?
I won't use it, but just want to try and understand why I'm not going to use it, apart from the fact that Yamaha - he say no.
Eville Rich
Well-Known Member
The oil runs at the temperature of the engine. What differs is the viscosity of the oil at a given temperature. Even if it's 30C outside, your engine is still operating at whatever it's operating at. A 30 rated oil will have less viscosity than a 40 at operating temp. Viscosity is a measure of resistance to flow or pumping. Oil passages, pumps, and engine designs will want a certain flow of oil. But if it flows too easily, then it may not provide the lubricity that is expected by the engine designers - the oil will move away from parts too quickly or get pushed aside too easily if it is too low a viscosity.
Your cold temps aren't all that cold. OC matters, but there's not a great deal of difference between a 5W or 10W at that temperature. If you were starting typur engine from cold in -20C weather, it may matter. For cold starts, that same resistance to pumping or flow risks engine damage. For example, putting 20W oil into the S10 probably wouldn't be a good thing.
In terms of why having too low of a cold viscosity rating, I think that matters less than hot. But there's still some potential risk. How oil viscosity changes as the engine warms up is on some sort of temperature slope. As it warms up, it begins to behave more and more like its high temperature rated viscosity. So starting with too low a cold viscosity rating risks too low a viscosity as the engine warms and we start driving harder.
All that said, engine viscosity recommendations a generalization that manufacturers use. We all ride in different conditions and push the engines harder or less than others. And take what I've said here as my understanding. I'm not a lubrication engineer. Just spent a lot of time with oil and engines and too much time thinking about oil.
I hope this answers the question you had and I'm sure if I got something wrong it will be corrected.
Eville Rich
Your cold temps aren't all that cold. OC matters, but there's not a great deal of difference between a 5W or 10W at that temperature. If you were starting typur engine from cold in -20C weather, it may matter. For cold starts, that same resistance to pumping or flow risks engine damage. For example, putting 20W oil into the S10 probably wouldn't be a good thing.
In terms of why having too low of a cold viscosity rating, I think that matters less than hot. But there's still some potential risk. How oil viscosity changes as the engine warms up is on some sort of temperature slope. As it warms up, it begins to behave more and more like its high temperature rated viscosity. So starting with too low a cold viscosity rating risks too low a viscosity as the engine warms and we start driving harder.
All that said, engine viscosity recommendations a generalization that manufacturers use. We all ride in different conditions and push the engines harder or less than others. And take what I've said here as my understanding. I'm not a lubrication engineer. Just spent a lot of time with oil and engines and too much time thinking about oil.
I hope this answers the question you had and I'm sure if I got something wrong it will be corrected.
Eville Rich
WJBertrand
Ventura Highway
The lower second number does not mean it will run cooler. It means, for example if we’re using
a 10w-40 for reference, the 40 means it will behave like a 40 wt straight weight oil at operating temperature. The lower number means it will behave as a 10w when cold.
Using lower than recommended weights at the lower end may lead to excess wear since a 0w or 5w will not develop as much oil pressure when cold. Oil pressure is mostly determined by main bearing clearances. These are plain bearings and must ride on a film/wedge of oil.
Yamaha and I think most motorcycle engine manufacturers may be using larger bearing clearances than autos that specify these very light oils.
The other consideration is the unit
transmission. Gears meshing under load are very effective at shearing down the weight of the oils. A 5w-40 weight oil for example uses a base weight of 5 then adds viscosity improvers (VI) to achieve the 40w behavior at operating temps. These VIs are very long chain molecules and long chain molecules are more susceptible to shear than short chain ones. To make a 5w-40, the engineer must add more of these shear susceptible long chain molecules compared to a 10w-40.
This means that an oil with a lighter first number will loose its viscosity grade more quickly than one with a higher first number as mileage accumulates.
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a 10w-40 for reference, the 40 means it will behave like a 40 wt straight weight oil at operating temperature. The lower number means it will behave as a 10w when cold.
Using lower than recommended weights at the lower end may lead to excess wear since a 0w or 5w will not develop as much oil pressure when cold. Oil pressure is mostly determined by main bearing clearances. These are plain bearings and must ride on a film/wedge of oil.
Yamaha and I think most motorcycle engine manufacturers may be using larger bearing clearances than autos that specify these very light oils.
The other consideration is the unit
transmission. Gears meshing under load are very effective at shearing down the weight of the oils. A 5w-40 weight oil for example uses a base weight of 5 then adds viscosity improvers (VI) to achieve the 40w behavior at operating temps. These VIs are very long chain molecules and long chain molecules are more susceptible to shear than short chain ones. To make a 5w-40, the engineer must add more of these shear susceptible long chain molecules compared to a 10w-40.
This means that an oil with a lighter first number will loose its viscosity grade more quickly than one with a higher first number as mileage accumulates.
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Fennellg
Well-Known Member
Sold a car to a guy that designed engines for GM. He was retired, buying a Tacoma for his graduating grand Son. He told me the thinner the oil the better. But he offered a Caveat, the oil has to be tuff enough to hold together. It can’t break down separating. That would be bad he said very bad.
The idea is simple. The thinner oil will get to areas of the engine a thicker oil won’t, Thus lubricating better not skipping areas due to thick viscosity.
Makes sense having a Hyundai Sonata that suffers from carbon build up in the valves. You address this by means of a thicker oil and catch can.
Don’t take the oil recommendations as The Ten Commandments written in stone. The 0 weight oils are recommended, chasing Federal mandated gas milage numbers. Nothing to do with the health or longevity of the engine. That weight oil does not hold together all that well. It Aggravates carbon build up on valves of GDI engines. It also leads to oil consumption in Toyotas. They went with a 0 weight oils and a less robust piston ring set up. Oils consumption issues have run amok. All in the effort to get better gas milage.
The idea is simple. The thinner oil will get to areas of the engine a thicker oil won’t, Thus lubricating better not skipping areas due to thick viscosity.
Makes sense having a Hyundai Sonata that suffers from carbon build up in the valves. You address this by means of a thicker oil and catch can.
Don’t take the oil recommendations as The Ten Commandments written in stone. The 0 weight oils are recommended, chasing Federal mandated gas milage numbers. Nothing to do with the health or longevity of the engine. That weight oil does not hold together all that well. It Aggravates carbon build up on valves of GDI engines. It also leads to oil consumption in Toyotas. They went with a 0 weight oils and a less robust piston ring set up. Oils consumption issues have run amok. All in the effort to get better gas milage.
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semmyroundel
Active Member
Many thanks Eville Rich, WJBertrand and Fennellg, those explanations have made it very clear-now I understand fully
The 15w40 I bought IS JASO MA certified, at least according to the bottle.
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SparrowHawkxx
Active Member
Yes, Rotella T6 5W-40 and 15w-40 are JASO MA certified according to the labels on the bottles and the Shell website.
Little Joe
Member
I did a lot of oil testing through blackstone labs with various viscosities with my FJR. The oil shearing from the bevel drive (mostly) and transmission gears is a very measureable thing. Long story short, the best oil to hold its original viscosity turned out to be Rotella T15/40, dino oil. I tested 5/40 T6, 10/40 yamalube, 15/50 yamalube, 20/50 yamalube.
The best at holding viscosity were #1 20/50 , #2 15/40 , #3 15/50. I tested 5/40 T6 at 3000km chg and 6000km chg. ( At time of testing, T6 15/40 was not available AFAIK.)
I would use any of the first 3 although the Rotella 15/40 is best bang for you buck. I would not however use T6 in a shaft drive bike. It shears very badly and quickly in this application.
If I lived in a hot climate like Florida I would run the 20/50. I will run the 15/40 in my ST. (I have a friend in Florida that at time of sale had more than 250K miles on his C10 and run exclusively on RT 15/40. Engine was never apart more than valve adj, and a timing chain replacement at 160K as PM.
nd4spdbh
Member
Interesting. So you are saying the 15/40 T4 dino oil would be your choice?