All You Guys That Think OEM Recommended 16 or 20 Weight...

Obi Wan Noobi said:
They recommend 10W-30 in the Summer and 5W-40 in the Winter for a truck that you're supposed to use for work, heavy duty stuff. I would use 0/5W-40 in the Winter, depending on my location, and 15W-40 in the summer, most likely Rotella T6, as that's about the best Diesel oil you can get.
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The same as Honda for the S2000. The best guess i read in the Honda S2000 Community was that back in the year 2000 when the S2000 was introduced, the 5w-40 was the best cold flowing oil aviailable matching the need of the engine.
 
Although it's not a real issue, if you are worried about dry starts, put the gas pedal to the floor to shut off the injectors (clear flood mode), crank the engine over 4-5 seconds to prime the oil system, and then start it up. I do that after an oil change to prime the system, ensure the filter is filled, etc... Again, not a real issue with justifiable data in the real world. It's a "feel good" thing.
 
By the way, gentlemen....
i had recently my account deleted in a german forum. No discussion, only "YOU ARE WROOONG! I KNOW IT BETTER!"
Mostly from people with office jobs, o yeah... :rolleyes: i couldn´t stand it anymore.

What i like her at bitog is the mature way how things are discussed. Different opinions, but it´s O.K., no problem. Discuss it. Talk about it. Share your knowledge.

Thank you all! (y)
 
Obi Wan Noobi said:
They recommend 10W-30 in the Summer and 5W-40 in the Winter for a truck that you're supposed to use for work, heavy duty stuff. I would use 0/5W-40 in the Winter, depending on my location, and 15W-40 in the summer, most likely Rotella T6, as that's about the best Diesel oil you can get.
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It would depend on how cold the winter is too, sometimes 15w40 can be used year round
 
ChristianReske said:
We had these one here posted numeroeus times, if i remmber correctly? Are the datas fom this blog feature doubtfull?

https://blog.k1technologies.com/bearing-clearance-and-oil-viscosity-explained

When i compare these datas with the bearing clearances honda gives in the S2000 workshop manual, hondas reccomendation of a -30 oil is spot on. And Honda has a long heritage an expirience with high reving engines.
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Hard to say. Plenty of engines with just as tight of bearing clearances run with xW-50 oil and have no issues. Look at all the motorcycles that rev to 11,000+ RPM running xW-50 oil. Just because a few S2000s supposedly blew-up because of using 50 doesn't mean 50 is bad for every engine. Could be there is something about the oiling system that doesn't play well with 50 at WOT and high RPM for miles on the autobahn. Was there any oil pressure and temperature data given on these cars running these top speed runs?

I'm curious on what oil filter these cars that smoked the bearings were using? If the oil filter doesn't flow very well at high RPM (and with using heavier oil) then that could have cause the oil pump to hit pressure relief earlier and therefore cut down on the oil flow to the engine enough to cause harm.
 
Find the #50 in a funny list of #40s: https://bobistheoilguy.com/forums/threads/pao-up-to-70-in-some-lucas-synthetics.333467/post-5587614

To reflect differences in BOV a little better they of course could have run this petrol V6 a little faster than the experiment's 1500rpm ;-)
And maybe explicitly depicted a 5W-50 instead of the 5W-30 just for you. Come on, I'm gone. Good night. And feel free to just paint what I'll never get...

5W-50.webp
 
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Accent Abuser said:
Low oil is the main cause of this. At high RPM it can suck the oil pan dry and then it's goodbye engine.
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Yes, another possibility. Many manuals say to add a quart of oil for track use conditions.

When oil is at full operating temperature, the difference in viscosity between 30, 40 and 50 isn't big enough IMO to cause a major change in flow with a PD pump that would "starve" bearings. If there is an inherent oiling system flaw, or maybe an oil filter thats too flow restrictive for constsnt high RPM, then that could also be a factor. What if these couple of cars that smoked the bearings were a bit low on oil?

If thicker oil was causing bearings to fail, then no manufacturer of high performane cars would say to use a thicker viscosity for track use.
 
ZeeOSix said:
Yes, another possibility. Many manuals say to add a quart of oil for track use conditions.

When oil is at full operating temperature, the difference in viscosity between 30, 40 and 50 isn't big enough IMO to cause a major change in flow with a PD pump that would "starve" bearings. If there is an inherent oiling system flaw, or maybe an oil filter thats too flow restrictive for constsnt high RPM, then that could also be a factor. What if these couple of cars that smoked the bearings were a bit low on oil?

If thicker oil was causing bearings to fail, then no manufacturer of high performane cars would say to use a thicker viscosity for track use.
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Even regular car manuals that don't specifically recommend higher viscosity state that under extreme conditions a higher viscosity oil may be required.

It just makes no sense how a bearing can fail due to a higher oil viscosity, it just doesn't jive with the physics. As the piston and conrods spin the crankshaft around there is nothing preventing the oil from leaking out of the side of the journal except the small clearances. The faster it rotates the more force is applied to that thin film which can squeeze it out of the bearing. Thin oil is more readily squeezed out of the bearing, thicker oil is not. Then you've got things that rely on the base oil viscosity entirely like the timing chain and cam shaft. I would not be surprised if at 6000+ RPM using 5w-20 if the bearings enter a mixed or even boundary lubrication regime. It's asking for trouble in my opinion.
 
Obi Wan Noobi said:
They recommend 10W-30 in the Summer and 5W-40 in the Winter for a truck that you're supposed to use for work, heavy duty stuff. I would use 0/5W-40 in the Winter, depending on my location, and 15W-40 in the summer, most likely Rotella T6, as that's about the best Diesel oil you can get.
Click to expand...
They’re actually recommending 10w-30 year round in all new 12L coach buses and efficiency series 15L semi engines now. Haven’t seen any oil related issues yet. That being said, most truck fleets still run 15w-40 year round and buses don’t get shut off for long. 5w-40 I think is the sweet spot year round. I’ve used that in all my Cummins, Powerstroke, or 80’s Mercedes diesel engines I’ve had. Ran it in New Mexico/Arizona summers and some Canadian winter trips.
 
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