dnewton3
Staff member
I would completely disagree on the topic of wear. IMO that is the single largest factor for using a lubricant.
Lubes do several things:
clean
cool
reduce friction (power savings = fuel economy)
reduce wear
By far, the reduction of wear is the greatest. The friction reduction and wear pretty much go hand in hand; they are not purely the same, but they are very much related. However, I will note that as oil ages, the reduction in friction pales in comparison to the reduction of wear. The reduction of friction might be 20%, but the reduction of wear has been shown to be on an order of magitude! The older oil gets the better it gets. Proven in a few SAE studies and certainly UOA shows this to be true as well.
As for the cleanliness, that is a matter of the detergents and dispersents. (BTW - dispersents can actually be counter productive to wear film barrier initiation and end up in their degredation. Did you know that?) In short, you can have too much of a good thing.
Yes - I believe that sludger engines are a result of poor design. If they did not have "hot spots" they would not coke oil at localized areas. Those engines don't overheat oil in the entire engine; they are localized. That is a design flaw. Or, in the case of some Saturn engines (of which I recently learned) was a matter of lack of oil drain at the piston rings; no "synthetic" is going to magically create a drain where it does not physically exist.
Oil sludging is an event that happens when oil is overheated. Simple right? Any oil can get too hot. The EGT in a light duty diesel engine gets up to 1400 degF, and the turbo gets HOT. And yet dino oils do very well in those applications. Here's why ...
Thermal loading is a matter of many criteria, not the least of which is exposure duration.
Here is a simple experiement to try at home to get the point.
Light a candle.
Pass your fingers over it quickly. No pain felt.
Pass your fingers over it slowly. You'll feel pain by no damage done.
Hold your fingers steady over the flame. Tissue damage is the result.
Same goes for oil. Oil does not sludge because gets warm. Oil sludges in an engine that has a design flaw; the oil flow rate and volume is not sufficient such to achieve the thermal transfer at a rate which satisfies both the requirement of energy removal and yet not damage the medium (oil).
Oils do not sludge because they are inferior; oils sludge because the equipment has a flaw, and the engineers are expecting (or accidentally discover) the oil to perform past a reasonable expectation.
Which you do suppose is more likely:
1) those engines are a result of poor engineering or undiscovered errors resulting in undesired poor thermal transfer
2) those engines you list are a result of engineers that stood around and said "Hey, let's create an engine that is designed to REQUIRE a syn, and we'll create a lube sytsem that cannot survive on conventional oil, so we'll spec out the lube system flow and volume rates so that it only can support the bare minimum of thermal transfer where ONLY a synthetic can survive some minimum duration".
Yeah - I'm going with the first one.
Syn's may or may not last longer, depending upon situational conditions unique to each condition.
You said it yourself; allow me to quote you:
Quote:
" ... but the stability of the synthetic oil and its ability to resist breaking down and creating sludge is exactly what allows it to be run longer."
You hit it on the head, and you perhaps need to reread my signature line. Synthetics last longer in service!
I've said this a thousand times; if you are in a situation where a synthetic can affect a benefit past the capability of a dino, then it makes sense, as long as the ROI payment ratio can be equal or greater than the cost. If there are no conditions that allow a disparity to reveal itself, then there is no benefit to capitalize upon. It's that simple.
If you have a sludger engine, then you'd have to do some experimentation to see just when both the dino and syn would "sludge", and then see if the ROI could be met vs. the cost structure. It may or may not be "cheaper" just to OCI more often with dino. I don't know; you don't know. That is a unique condition to each individual piece of equipment.
But the VAST majority of engines on the face of this planet are not plagued by real sludging issues.
If you know you have a sludger, and it does get sludged, then it's a result of failure of the person to properly maintain the engine relative to the choice of lubricant selected. That's not the fault of the oil; it's negligence.
Lubes do several things:
clean
cool
reduce friction (power savings = fuel economy)
reduce wear
By far, the reduction of wear is the greatest. The friction reduction and wear pretty much go hand in hand; they are not purely the same, but they are very much related. However, I will note that as oil ages, the reduction in friction pales in comparison to the reduction of wear. The reduction of friction might be 20%, but the reduction of wear has been shown to be on an order of magitude! The older oil gets the better it gets. Proven in a few SAE studies and certainly UOA shows this to be true as well.
As for the cleanliness, that is a matter of the detergents and dispersents. (BTW - dispersents can actually be counter productive to wear film barrier initiation and end up in their degredation. Did you know that?) In short, you can have too much of a good thing.
Yes - I believe that sludger engines are a result of poor design. If they did not have "hot spots" they would not coke oil at localized areas. Those engines don't overheat oil in the entire engine; they are localized. That is a design flaw. Or, in the case of some Saturn engines (of which I recently learned) was a matter of lack of oil drain at the piston rings; no "synthetic" is going to magically create a drain where it does not physically exist.
Oil sludging is an event that happens when oil is overheated. Simple right? Any oil can get too hot. The EGT in a light duty diesel engine gets up to 1400 degF, and the turbo gets HOT. And yet dino oils do very well in those applications. Here's why ...
Thermal loading is a matter of many criteria, not the least of which is exposure duration.
Here is a simple experiement to try at home to get the point.
Light a candle.
Pass your fingers over it quickly. No pain felt.
Pass your fingers over it slowly. You'll feel pain by no damage done.
Hold your fingers steady over the flame. Tissue damage is the result.
Same goes for oil. Oil does not sludge because gets warm. Oil sludges in an engine that has a design flaw; the oil flow rate and volume is not sufficient such to achieve the thermal transfer at a rate which satisfies both the requirement of energy removal and yet not damage the medium (oil).
Oils do not sludge because they are inferior; oils sludge because the equipment has a flaw, and the engineers are expecting (or accidentally discover) the oil to perform past a reasonable expectation.
Which you do suppose is more likely:
1) those engines are a result of poor engineering or undiscovered errors resulting in undesired poor thermal transfer
2) those engines you list are a result of engineers that stood around and said "Hey, let's create an engine that is designed to REQUIRE a syn, and we'll create a lube sytsem that cannot survive on conventional oil, so we'll spec out the lube system flow and volume rates so that it only can support the bare minimum of thermal transfer where ONLY a synthetic can survive some minimum duration".
Yeah - I'm going with the first one.
Syn's may or may not last longer, depending upon situational conditions unique to each condition.
You said it yourself; allow me to quote you:
Quote:
" ... but the stability of the synthetic oil and its ability to resist breaking down and creating sludge is exactly what allows it to be run longer."
You hit it on the head, and you perhaps need to reread my signature line. Synthetics last longer in service!
I've said this a thousand times; if you are in a situation where a synthetic can affect a benefit past the capability of a dino, then it makes sense, as long as the ROI payment ratio can be equal or greater than the cost. If there are no conditions that allow a disparity to reveal itself, then there is no benefit to capitalize upon. It's that simple.
If you have a sludger engine, then you'd have to do some experimentation to see just when both the dino and syn would "sludge", and then see if the ROI could be met vs. the cost structure. It may or may not be "cheaper" just to OCI more often with dino. I don't know; you don't know. That is a unique condition to each individual piece of equipment.
But the VAST majority of engines on the face of this planet are not plagued by real sludging issues.
If you know you have a sludger, and it does get sludged, then it's a result of failure of the person to properly maintain the engine relative to the choice of lubricant selected. That's not the fault of the oil; it's negligence.
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