Author Topic: Detergent oils and sludge trap “testing”  (Read 428 times)

Online KiwiGF

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Detergent oils and sludge trap “testing”
« on: 21.04. 2021 12:27 »
Owning a B44 I belong to the b50.org forum and thought this might be of interest to this forum. It’s not a short read.....sorry 🙄 it’s about a fairly valid attempt to “scientifically” assess whether “detergent” oils are more likely to dissolve sludge and carry it around your engine than “non detergent” oils. A topic that comes up on here quite often!

http://www.b50.org/phpBB2/viewtopic.php?f=3&t=8819

http://www.b50.org/phpBB2/viewtopic.php?f=3&t=8822



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1956 A10 Golden Flash (1st finished project)
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Online RDfella

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Re: Detergent oils and sludge trap “testing”
« Reply #1 on: 21.04. 2021 12:54 »
Sadly, the 'American Oil Institute' spokesman has confused himself and therefore made pretty meaningless assertions. He seems to rely on the fact all engines made after 1952 will have used detergent oil and therefore not have any 'crud' buildup. He therefore presumably ignores the fact that many engines of that era did not have oil filters and therefore did, indeed, circulate damaging particles now held in suspension. Strange then that a 1956 classic car I have recommends dropping the sum every 10,000 miles to clean out sludge - and when I stripped the engine ten years ago the amount of semi-hard sludge throughout the engine was unbelievable. Another case of ex spurt.
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Offline Jules

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Re: Detergent oils and sludge trap “testing”
« Reply #2 on: 22.04. 2021 05:20 »
I thought the threads were very interesting actually Kiwi, partic. the soak test with detergent vs non detergent oils, although I'm not sure what to conclude from them really!
My view of this is a bit simpler, in that detergents in the oils are there to keep the engine clean, as in carbon deposits and sludge, where sludge is due to blowby and condensation, NOT metallic particles due to wear etc. Sludge accumulation in old engines was a real issue because of poor ventilation, which was exacerbated by the large tolerances typical of that era. Then the addition of metallic particles as wear increases creates crud which over time solidifies. Detergents have since been added to fuels too for the same reason, to keep the inlet tracks clean of sludge, NOT metallic particles, fuel residues are very "gummy" and the detergents clear that out...
In summary, from my perspective, the detergents role is quite specific about engine cleanliness wrt sludge formation, its not about containing wear particles....does that make sense??

Offline fido

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Re: Detergent oils and sludge trap “testing”
« Reply #3 on: 22.04. 2021 15:22 »
My long stroke was restored before I bought it in 1995 and the current rebuild is the first time I've had it apart. I have run it on the 20W50 they sell for older cars and without a filter. I was expecting the worst when I opened the sludge traps but there was very little sludge either there or elsewhere in the engine. This is in marked contrast to my 1971 Ford Escort which I had in the early '80s. With that I once removed the rocker cover to do the valve clearances and you could hardly make out the shape of the rocker gear for all the sludge!

Online KiwiGF

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Re: Detergent oils and sludge trap “testing”
« Reply #4 on: 22.04. 2021 22:12 »
I thought the threads were very interesting actually Kiwi, partic. the soak test with detergent vs non detergent oils, although I'm not sure what to conclude from them really!
My view of this is a bit simpler, in that detergents in the oils are there to keep the engine clean, as in carbon deposits and sludge, where sludge is due to blowby and condensation, NOT metallic particles due to wear etc. Sludge accumulation in old engines was a real issue because of poor ventilation, which was exacerbated by the large tolerances typical of that era. Then the addition of metallic particles as wear increases creates crud which over time solidifies. Detergents have since been added to fuels too for the same reason, to keep the inlet tracks clean of sludge, NOT metallic particles, fuel residues are very "gummy" and the detergents clear that out...
In summary, from my perspective, the detergents role is quite specific about engine cleanliness wrt sludge formation, its not about containing wear particles....does that make sense??

I don’t know whether it is the addition of detergents that causes oil to carry around “wear particles” (eg bits of metal, some microscopic) but it is a fact that when used oil is analysed (which is done regularly by large fleet operators) the level of wear particles present in the oil is measured, as this provides info on how often to change the oil and in some cases impending disaster.

Without any basis for saying so in any given situation I think a detergent oil would be carrying round (aka suspending) more wear particles than a non detergent oil, and that’s why it is generally accepted (and not just my opinion) that it’s important to use detergent oils in combination with a filter.
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1956 A10 Golden Flash (1st finished project)
1949 B31 rigid “400cc” (2nd finished project)
1968 B44 Victor Special (3rd project,in progress)
2001 GL1800 Goldwing, well, the wife likes it
2007 KTM 950 Adventure, cos it’s 100% nuts

Offline Truckedup

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Re: Detergent oils and sludge trap “testing”
« Reply #5 on: 23.04. 2021 12:20 »
My long stroke was restored before I bought it in 1995 and the current rebuild is the first time I've had it apart. I have run it on the 20W50 they sell for older cars and without a filter. I was expecting the worst when I opened the sludge traps but there was very little sludge either there or elsewhere in the engine. This is in marked contrast to my 1971 Ford Escort which I had in the early '80s. With that I once removed the rocker cover to do the valve clearances and you could hardly make out the shape of the rocker gear for all the sludge!
Yup, same experience with an 86 Jeep ....And no doubt it was run from new on detergent oil but obliviously not changed often...
 I was involved with vintage pu trucks for many years. There were the stories of  detergent oil in an old engine and the sludge loosed and blocked an oil galley. Never any real proof, just stories. With old engine there an occasional stories of failures, maybe one of 1000 but it get passed around until it sounds like 999 out of 10000
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Re: Detergent oils and sludge trap “testing”
« Reply #6 on: 25.04. 2021 15:18 »
Quote
I don’t know whether it is the addition of detergents that causes oil to carry around “wear particles” (eg bits of metal, some microscopic) but it is a fact that when used oil is analysed (which is done regularly by large fleet operators) the level of wear particles present in the oil is measured, as this provides info on how often to change the oil and in some cases impending disaster.

Without any basis for saying so in any given situation I think a detergent oil would be carrying round (aka suspending) more wear particles than a non detergent oil, and that’s why it is generally accepted (and not just my opinion) that it’s important to use detergent oils in combination with a filter.

Quite correct
FWIW I was lucky enough to be taught for a single term by Vince manners who at that time was head of the X-ray diffraction analysis team at the Defense Standards lab in Alexandria NSW.
Even more luck that when he found out I was unemployed at the time he swung me a temporary position as a lab tech in one of his teams .
This was back in the early 70's  before the end of the Vietnam war and the subsequent renaming everything associated with the was and the slashing of budgets.
The DSL became the Materials Research lab but basically did the same work with around 10% of the staff & funding.
Anyway my particular job was to prepare oil samples for XRD .and then to sift through the results looking for known Millers Indicies for the actual alloys that were in the engines .
Vince pioneered this work which built on the previous work of the DSL & CSIRO who pioneered the use of chromotography to determine what METALS were present in an oil sample and later on the actual percentages of these metals.
This is what is done by most oil labs now days as it is cheap & very reliable but generally uses atomic adsorbtion rather than strait chromotography as it is more accurate & requires less sample preparation.
However what it does not tell you is weather the iron came from the cylinder lining, the cams, the rockers , the crank, a compression ring, an oil ring , a bearing or any other iron based part in the engine.
However by using XRD you can tell exactly which alloys the wear particles are made from and also how much is in there.
This data was then plotted against actual measured wear of individual parts during a routine engine strip & examination.
In those days the aim was to corelate these so to eventually replace the fixed service hours strip down which is both expensive and does damage to the engines.
It was proven to work and be highly accurate before the whole project got dropped and the team sacked , most of which went to the USA to join oil research teams or set up to do the analysis themselves , remembering in those days XRD machines were worth multi millions .
Wear particles in oil are measured in nanometers & picometers so that makes them sub microscopic.

It should come as no surprise that near 90% of the particulates that contaminate the oil is plain old carbon and that is formed inside the combustion chamber & on the exhaust valve .
From there it has a torturious path to end up in the crank.
If you stop to have a good think about where the carbon deposits are formed and how they are transported around the engine .
Some will adhere to the cylinder wall and be scraped off by the oil ring then drop to the sump. probably after being tossed around inside the engine a few times by the various moving parts .
It then has to pass through the sump gauze, then not drop to the bottom of the oil tank, pass through the output screen on the oil tank then through the oil pump to be spun off & held by the sludge trap . Quite a long trip .
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Re: Detergent oils and sludge trap “testing”
« Reply #7 on: 21.05. 2021 12:14 »
Interesting.

Here is a link to an informative article on oil additives, what they are and how they work.
https://www.machinerylubrication.com/Read/31107/oil-lubricant-additives#:~:text=The%20combination%20of%20detergent%2Fdispersant,will%20necessitate%20an%20oil%20change.

Of particular interest to me are the detergent and dispersant additives which have been blamed in the past for issues on older engines.

My understanding is the detergent is there to dissolve and clean away gums, products of combustion and neutralise acids. They work in concert with dispersant additives who's job it is to keep tiny particles in suspension. These particles are so small they would not be caught in a normal oil filter, indeed if they were the filter would rapidly become blocked and cease to flow oil. You can see this must be so or the oil would not change colour and your filter would rapidly block.  Without these additives the tiny dirt particles, mostly soot, would combine with other compounds and wear particles and sink to form sludge wherever the flow of oil slows and they can drop out of suspension. These 1 or 2 micron size particles are kept in suspension by the dispersants to be removed at an oil change and that is why modern oils change colour so quickly. ie. The oil becomes dirty and your engine stays clean. 

I can see nothing relating the detergent and dispersant action to the oil's ability to suspend wear particles ie. larger metallic particles and I suspect there is little difference between oils in this regard and I would expect the centripital action of the trap cleverly devised by the designers of our engines to still do its job of taking out these larger particles.

My take on all this is that a filter must always be a good idea regardless of what oil you use.  However, I don't believe that a modern oil is detrimental in any way if the engine is clean to start with ie. freshly and correctly rebuilt. Running a modern oil with detergent and dispersant additives, with or without a filter should still be beneficial as long as it is changed frequently to remove the dirt that is being suspended in the oil rather than being deposited on hot surfaces inside the engine.

The combination of modern oil plus a filter must be the optimum solution although the issue then becomes what affect if any the filter might have on oil flow and the problems of actually mounting and siting one.

That's my 2c worth anyway  ;)


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Re: Detergent oils and sludge trap “testing”
« Reply #8 on: 21.05. 2021 12:57 »
interesting .
I see they distinguish between dispersants &  detergents .
Back when I was involved with oils there was no such distinction as they perform their function by the same mechanism .
They also omitted solvents & surficants & surface tension modifiers, some times also called wetting agents .
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Re: Detergent oils and sludge trap “testing”
« Reply #9 on: 21.05. 2021 13:25 »
BagONails i use cheap straight 50 oil and have a filter , no problem with oil return even when oil is cold and thick