5W30 Oil Don't Cut it, Engine Bearing Pics 58K S1 RX-8 from England.
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11-04-2009, 05:16 PM
#502
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yeah it is definitely not ground breaking in terms of design but from what I have found these gauges are very accurate and very well built. Apparently a lot of their devices are used in high end cappuccino machines in a commercial environment.
11-04-2009, 10:59 PM
#506
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11-04-2009, 10:59 PM
#507
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11-06-2009, 07:57 PM
#508
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Olddragger sold me on Rotella 15-40 diesel oil, so I've been running that in AZ the past couple of months. I know that the thinking goes that you need the cold viscosity # at at least 15, or the hot # will break down too early as the additives wear out. But, I also know that the diesel aspect has been critical in preventing viscosity breakdown in oil tests done by Olddragger (and someone else here recently confirmed almost the exact same results). My question is, in those tests the 15-40 diesel was compared against 5-30 and 10-40. Have tests been done w/ non-diesel 15-40? I'd be curious to see the comparison. Perhaps the more important factor is the anti-foaming and additional detergents, vs. the high cold #. Are there any good diesel oils that start with a cold viscosity of 10w and have either 40 or 50 as the hot weight?
11-06-2009, 10:15 PM
#510
Why would you run 15-40 when you could run 0-40 or 5-40 synthetic??
I get the diesel oil has different additive pacs...with more foam suppressants and dispersants for the "dirty" diesel combustion.....
You want the high number high...and the low # as low as possible....
I get the diesel oil has different additive pacs...with more foam suppressants and dispersants for the "dirty" diesel combustion.....
You want the high number high...and the low # as low as possible....
11-06-2009, 11:01 PM
#512
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Why would you run 15-40 when you could run 0-40 or 5-40 synthetic??
I get the diesel oil has different additive pacs...with more foam suppressants and dispersants for the "dirty" diesel combustion.....
You want the high number high...and the low # as low as possible....
I get the diesel oil has different additive pacs...with more foam suppressants and dispersants for the "dirty" diesel combustion.....
You want the high number high...and the low # as low as possible....
Also, I'm not sold on using an oil that starts at 0 weight. It's possible that that is too thin for the tolerance specs of the Renesis, causing leaking of oil through the seals.
11-07-2009, 12:06 AM
#514
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because, ideally, a 0-50 like eneos would stay as such. However, to achieve the larger spread between the weights, the oil is using larger amounts of additives to achieve that spread. And the reality is that those additives break down, and especially faster in an engine that runs at higher temps like a rotary (even with full synthetics). So, when the additives break down, a 50 operating temp viscosity, quickly drops to 40, 30, etc. But if your cold viscosity weight starts at 15, then the same breakdown in additives now reduce the viscosity to a proportionally smaller degree.
Also, i'm not sold on using an oil that starts at 0 weight. It's possible that that is too thin for the tolerance specs of the renesis, causing leaking of oil through the seals.
Also, i'm not sold on using an oil that starts at 0 weight. It's possible that that is too thin for the tolerance specs of the renesis, causing leaking of oil through the seals.
11-07-2009, 02:48 AM
#515
Guys...do some research....
INTO WHAT THE #'S MEAN..........
Also a quote from a very knowledgeable petrochemical engineer........
" In high-speed bearings the oil can be too thick to keep up with the high rubbing speeds reached in modern engines so the ‘wedge’ or hydrodynamic’ effect breaks down. I know it goes against common sense (whatever that is) but the faster a bearing is turning the thinner the oil should be. (A 4cm. diameter main bearing is rubbing its shells at 56 MPH at 12,000RPM! To avoid cavitation the oil need to be less 10cSt or less, which is SAE 30 if the oil happens to be at 100C, or SAE 40 if its at 110C.))"
INTO WHAT THE #'S MEAN..........
Also a quote from a very knowledgeable petrochemical engineer........
" In high-speed bearings the oil can be too thick to keep up with the high rubbing speeds reached in modern engines so the ‘wedge’ or hydrodynamic’ effect breaks down. I know it goes against common sense (whatever that is) but the faster a bearing is turning the thinner the oil should be. (A 4cm. diameter main bearing is rubbing its shells at 56 MPH at 12,000RPM! To avoid cavitation the oil need to be less 10cSt or less, which is SAE 30 if the oil happens to be at 100C, or SAE 40 if its at 110C.))"
11-07-2009, 04:28 AM
#516
Ayrton Senna Forever
Because, ideally, a 0-50 like Eneos would stay as such. However, to achieve the larger spread between the weights, the oil is using larger amounts of additives to achieve that spread. And the reality is that those additives break down, and especially faster in an engine that runs at higher temps like a rotary (even with full synthetics). So, when the additives break down, a 50 operating temp viscosity, quickly drops to 40, 30, etc. But if your cold viscosity weight starts at 15, then the same breakdown in additives now reduce the viscosity to a proportionally smaller degree.
Also, I'm not sold on using an oil that starts at 0 weight. It's possible that that is too thin for the tolerance specs of the Renesis, causing leaking of oil through the seals.
Also, I'm not sold on using an oil that starts at 0 weight. It's possible that that is too thin for the tolerance specs of the Renesis, causing leaking of oil through the seals.
A 0w-xx oil always has to be true synthetic, and a multi viscosity true synthetic oil's basic oil is always equal its warm side visc. So a 0w-50 has 50w basic oil, and it has additives to reach the 0w cold side. It means that a full syn oil doesn't thinning too much as the additives break down. It is rather thinning by fuel dillution.
The mineral base multi visc oil are on the opposite side. Those has the cold side weight base oil, and the additives help to get the warm side.
Last edited by ayrton012; 11-07-2009 at 04:30 AM.
11-07-2009, 08:34 AM
#517
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It is not true.
A 0w-xx oil always has to be true synthetic, and a multi viscosity true synthetic oil's basic oil is always equal its warm side visc. So a 0w-50 has 50w basic oil, and it has additives to reach the 0w cold side. It means that a full syn oil doesn't thinning too much as the additives break down. It is rather thinning by fuel dillution.
The mineral base multi visc oil are on the opposite side. Those has the cold side weight base oil, and the additives help to get the warm side.
A 0w-xx oil always has to be true synthetic, and a multi viscosity true synthetic oil's basic oil is always equal its warm side visc. So a 0w-50 has 50w basic oil, and it has additives to reach the 0w cold side. It means that a full syn oil doesn't thinning too much as the additives break down. It is rather thinning by fuel dillution.
The mineral base multi visc oil are on the opposite side. Those has the cold side weight base oil, and the additives help to get the warm side.
11-07-2009, 11:36 AM
#519
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Thanks dannobre, I wasn't aware that full synths additives to achieve weight spread actually ran in the opposite direction of dinos. Good to know!
I'm still wary of running a 0 weight oil for fear of leaking through the seals.
As for what Nascar, F1, drag racers etc. run, that doesn't apply unless you only drive your 8 at the track, or are talking about what to run solely at the track, or if you plan on pulling over every 1/4 mile to swap all fluids.
I'm still wary of running a 0 weight oil for fear of leaking through the seals.
As for what Nascar, F1, drag racers etc. run, that doesn't apply unless you only drive your 8 at the track, or are talking about what to run solely at the track, or if you plan on pulling over every 1/4 mile to swap all fluids.
11-07-2009, 11:40 AM
#520
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Because, ideally, a 0-50 like Eneos would stay as such. However, to achieve the larger spread between the weights, the oil is using larger amounts of additives to achieve that spread. And the reality is that those additives break down, and especially faster in an engine that runs at higher temps like a rotary (even with full synthetics). So, when the additives break down, a 50 operating temp viscosity, quickly drops to 40, 30, etc. But if your cold viscosity weight starts at 15, then the same breakdown in additives now reduce the viscosity to a proportionally smaller degree.
Also, I'm not sold on using an oil that starts at 0 weight. It's possible that that is too thin for the tolerance specs of the Renesis, causing leaking of oil through the seals.
Also, I'm not sold on using an oil that starts at 0 weight. It's possible that that is too thin for the tolerance specs of the Renesis, causing leaking of oil through the seals.
It is not true.
A 0w-xx oil always has to be true synthetic, and a multi viscosity true synthetic oil's basic oil is always equal its warm side visc. So a 0w-50 has 50w basic oil, and it has additives to reach the 0w cold side. It means that a full syn oil doesn't thinning too much as the additives break down. It is rather thinning by fuel dillution.
The mineral base multi visc oil are on the opposite side. Those has the cold side weight base oil, and the additives help to get the warm side.
A 0w-xx oil always has to be true synthetic, and a multi viscosity true synthetic oil's basic oil is always equal its warm side visc. So a 0w-50 has 50w basic oil, and it has additives to reach the 0w cold side. It means that a full syn oil doesn't thinning too much as the additives break down. It is rather thinning by fuel dillution.
The mineral base multi visc oil are on the opposite side. Those has the cold side weight base oil, and the additives help to get the warm side.
In a multi-viscosity oil the oil is always thicker at room temperature than operating temperature. Instead of thinking that oil thins as it gets warmer you need to think that oil gets thicker as it cools. A 0w oil at room temperature is still going to be much thicker than at operating temperature.
A 0w-30, 5w-30, and 10w-30 all have the exact same viscosity at operating temperature. Their only major difference is their thickness at room temperature. A 0w oil is going to be the least thick while a 20w will be the most thick. Since the majority of wear occurs at startup (when there isn't any oil on the metal surface) you want the oil to flow as quickly and easily as possible.
" In high-speed bearings the oil can be too thick to keep up with the high rubbing speeds reached in modern engines so the ‘wedge’ or hydrodynamic’ effect breaks down. I know it goes against common sense (whatever that is) but the faster a bearing is turning the thinner the oil should be. (A 4cm. diameter main bearing is rubbing its shells at 56 MPH at 12,000RPM! To avoid cavitation the oil need to be less 10cSt or less, which is SAE 30 if the oil happens to be at 100C, or SAE 40 if its at 110C.))"
11-07-2009, 01:01 PM
#521
Thanks dannobre, I wasn't aware that full synths additives to achieve weight spread actually ran in the opposite direction of dinos. Good to know!
I'm still wary of running a 0 weight oil for fear of leaking through the seals.
As for what Nascar, F1, drag racers etc. run, that doesn't apply unless you only drive your 8 at the track, or are talking about what to run solely at the track, or if you plan on pulling over every 1/4 mile to swap all fluids.
I'm still wary of running a 0 weight oil for fear of leaking through the seals.
As for what Nascar, F1, drag racers etc. run, that doesn't apply unless you only drive your 8 at the track, or are talking about what to run solely at the track, or if you plan on pulling over every 1/4 mile to swap all fluids.
Why would you think it would leak through the seals........it is the same "thickness" at operating temp. Also....the punishment that a racing engine sees in an enduro length event is way more than your car would see in a long time.
Except for the starting/cold oil issues that racing engines don't have to endure.
There are so many misconceptions on oil out there...that's why all the old wives tales allow the petroleum industry to "con" people with the advertising
It's all about the money guys
11-07-2009, 01:06 PM
#522
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The oil change interval is pushed by manufacturers because it aid their warranty process. It helps oil manufacturers because they sell more oil!
Don't expect the oil companies to come out and correct all this misinformation. As long as people buy their products they don't care.
11-07-2009, 01:54 PM
#524
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Guys...do some research....
INTO WHAT THE #'S MEAN..........
Also a quote from a very knowledgeable petrochemical engineer........
" In high-speed bearings the oil can be too thick to keep up with the high rubbing speeds reached in modern engines so the ‘wedge’ or hydrodynamic’ effect breaks down. I know it goes against common sense (whatever that is) but the faster a bearing is turning the thinner the oil should be. (A 4cm. diameter main bearing is rubbing its shells at 56 MPH at 12,000RPM! To avoid cavitation the oil need to be less 10cSt or less, which is SAE 30 if the oil happens to be at 100C, or SAE 40 if its at 110C.))"
INTO WHAT THE #'S MEAN..........
Also a quote from a very knowledgeable petrochemical engineer........
" In high-speed bearings the oil can be too thick to keep up with the high rubbing speeds reached in modern engines so the ‘wedge’ or hydrodynamic’ effect breaks down. I know it goes against common sense (whatever that is) but the faster a bearing is turning the thinner the oil should be. (A 4cm. diameter main bearing is rubbing its shells at 56 MPH at 12,000RPM! To avoid cavitation the oil need to be less 10cSt or less, which is SAE 30 if the oil happens to be at 100C, or SAE 40 if its at 110C.))"
The thing I really wonder about is whether or not the oil temp spikes as it flows through the journal bearing. Any thoughts, guesses, conjecture......
11-07-2009, 02:35 PM
#525
The oil heats up when it is in the area with the friction and heat....so yea...the bearings cause a localized heating.....that is controlled by flow volume
It also picks up a lot of heat from the cooling of the inside of the rotors and e-shaft
It also picks up a lot of heat from the cooling of the inside of the rotors and e-shaft