Marine Lubrication
01-10-2009, 11:12 AM
#1481
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Well that is very good news. I have just installed a "700hp" oil cooler and electric oil temp gage. The engine is in the 600HP range. During a very extended WOT run the gage read 290F and still climbing but very slowly by then. A later repeat but with conditions limiting the WOT run duration to less did reach the 290F mark briefly. A quick engine shut down check of the crankcase temp with a infared temp gun showed 245F. Any idea where this WOT oil temp fits in the marine engine population?
What in the oil's performance is lost as a result of the oxidation of which you speak?
Bill
What in the oil's performance is lost as a result of the oxidation of which you speak?
Bill
The base stock performance starts going away in high heat conditions. The base stock starts to oxidize, carbon molecules start joining together and start forming "longer chains" which in turn start to thicken up the oil. Oxidized oil when drained is thicker than it should be and black. In extreme cases the oil will glug out of the pan, if it moves at all, when you do an oil change.
Synthetic base stocks have more oxidative stability than petroleum stocks.
ZINC, that all important additive for engine wear is also multi-functional. It helps oil from oxidizing. Not only is it a anti-wear additive, but it is also an anti-oxidant. Another point for zinc.
If it is possible to knock another 20 degrees out of your oil on both ends, running temp 220ish and WOT 270ish, the oil would give you longer life.
My 2 cents.
Ken
01-10-2009, 01:15 PM
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Bill, my opinion is you are starting to push the upper limit on temp. If you don't do anything else, just change the oil more often and get it analysed.
The base stock performance starts going away in high heat conditions. The base stock starts to oxidize, carbon molecules start joining together and start forming "longer chains" which in turn start to thicken up the oil. Oxidized oil when drained is thicker than it should be and black. In extreme cases the oil will glug out of the pan, if it moves at all, when you do an oil change.
Synthetic base stocks have more oxidative stability than petroleum stocks.
ZINC, that all important additive for engine wear is also multi-functional. It helps oil from oxidizing. Not only is it a anti-wear additive, but it is also an anti-oxidant. Another point for zinc.
If it is possible to knock another 20 degrees out of your oil on both ends, running temp 220ish and WOT 270ish, the oil would give you longer life.
My 2 cents.
Ken
The base stock performance starts going away in high heat conditions. The base stock starts to oxidize, carbon molecules start joining together and start forming "longer chains" which in turn start to thicken up the oil. Oxidized oil when drained is thicker than it should be and black. In extreme cases the oil will glug out of the pan, if it moves at all, when you do an oil change.
Synthetic base stocks have more oxidative stability than petroleum stocks.
ZINC, that all important additive for engine wear is also multi-functional. It helps oil from oxidizing. Not only is it a anti-wear additive, but it is also an anti-oxidant. Another point for zinc.
If it is possible to knock another 20 degrees out of your oil on both ends, running temp 220ish and WOT 270ish, the oil would give you longer life.
My 2 cents.
Ken
Certainly worth a lot more than 2 cents. Thanks.
What (values) in the oil analysis should be looked at to identify / red flag that the oil has been oxidized to the point it should be changed?
Thanks,
Bill
01-10-2009, 01:54 PM
#1483
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That said,
the additives will show depletion, values will be lower and on a
report with "normal" use, the viscosity will be less.
In a situation where the is oxidation, the viscosity of the oil will get heavier, ie you have a fresh sample with a viscosity of 96 SUS at 210 (its a 50 weight), under normal use (used oil history), it shears down to a 83 SUS.
If the oil is oxidized the viscosity would come in something higher than the original viscosity of 96 SUS.
NOW, another reason for coming in with a higher viscosity is the light ends of the oil blend are evaporating, leaving behind higher viscosity basestocks.
This would be more prevelant in oils that are 0W,5w, but a blender can use a heavy base stock and light basestock to achive the finished viscosity he was shooting for.
If the above were the case, you would first notice oil consumption.
I hope I answered your question.
Ken
01-10-2009, 11:35 PM
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Minx obviously does but I am just a dumb layman asking as many questions that I can get away with within the limits of patience of you guys so as to learn enough that I do not screw up my engine. Thanks for your insight.
Bill
Bill
01-10-2009, 11:58 PM
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I am hoping you are checking a used sample against a retained sample of the the same oil.
That said,
the additives will show depletion, values will be lower and on a
report with "normal" use, the viscosity will be less.
In a situation where the is oxidation, the viscosity of the oil will get heavier, ie you have a fresh sample with a viscosity of 96 SUS at 210 (its a 50 weight), under normal use (used oil history), it shears down to a 83 SUS.
If the oil is oxidized the viscosity would come in something higher than the original viscosity of 96 SUS.
NOW, another reason for coming in with a higher viscosity is the light ends of the oil blend are evaporating, leaving behind higher viscosity basestocks.
This would be more prevelant in oils that are 0W,5w, but a blender can use a heavy base stock and light basestock to achive the finished viscosity he was shooting for.
If the above were the case, you would first notice oil consumption.
I hope I answered your question.
Ken
That said,
the additives will show depletion, values will be lower and on a
report with "normal" use, the viscosity will be less.
In a situation where the is oxidation, the viscosity of the oil will get heavier, ie you have a fresh sample with a viscosity of 96 SUS at 210 (its a 50 weight), under normal use (used oil history), it shears down to a 83 SUS.
If the oil is oxidized the viscosity would come in something higher than the original viscosity of 96 SUS.
NOW, another reason for coming in with a higher viscosity is the light ends of the oil blend are evaporating, leaving behind higher viscosity basestocks.
This would be more prevelant in oils that are 0W,5w, but a blender can use a heavy base stock and light basestock to achive the finished viscosity he was shooting for.
If the above were the case, you would first notice oil consumption.
I hope I answered your question.
Ken
Man that is some seriously insightful information. Thanks!!!
Just one follow up question. Specically, which additives would show the depletion you mention?
The viscosity is currently a problem for me to use as a reference since I have gas dilution going on which I am also trying to ID the cause/source.
95% of the time I am only cruising but I wish to know that I can run extended WOT if I want w/o doing any damaqe to my investment. I do not have the unlimited bucks that some do so I want to protect that investment with knowledge.
Thanks again for sharing your knowledge. That goes for everyone!!
Bill
01-12-2009, 06:43 AM
#1487
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For what it worth, the current API rating of SL addresses better oxidation control so current oil formulations are even better at controlling the oxidation issue than past oils.
In real life, it not a problem,we all change our oil waaaaay before we have to.
Thanks for the kind words.
Ken
Last edited by minxguy; 01-12-2009 at 06:43 AM. Reason: spelling
01-12-2009, 09:17 PM
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OK watch the Zinc levels in used oil.
You are more that welcome for the kind words from my perspective. Your sharing of your obviously professional expertise (and time) is greatly appreciatred by this layman.
Bill
You are more that welcome for the kind words from my perspective. Your sharing of your obviously professional expertise (and time) is greatly appreciatred by this layman.
Bill
Zinc, seeing how it is an anti-oxidant, would be almost gone in an oxidized oil.
For what it worth, the current API rating of SL addresses better oxidation control so current oil formulations are even better at controlling the oxidation issue than past oils.
In real life, it not a problem,we all change our oil waaaaay before we have to.
Thanks for the kind words.
Ken
For what it worth, the current API rating of SL addresses better oxidation control so current oil formulations are even better at controlling the oxidation issue than past oils.
In real life, it not a problem,we all change our oil waaaaay before we have to.
Thanks for the kind words.
Ken
