Lubemaster77 - Oil Question

[kach22i]

I read the below in a forum andwondered if the concept is right or wrong.

The oil that I use in my 7.3 litre turbo diesel 4X4 is really critical.
The engine will actually run differently, depending on what oil is put
in. In some cases, the engine will not run at all if the oil is not up
to specification. The engine was designed by Caterpillar and is
licensed only to International. There are two oil pumps in this
engine. A low pressure oil pump to provide the normal engine
lubrication. And a high pressure oil pump to run the fuel injectors.
There is no fuel distributor in this truck, it is computer controlled
with a high pressure oil manifold that is used to push the diesel fuel
in the injectors into the cylinder at high pressure, even at idle. I
was surprised when I bought it. I was looking under the hood and I
couldn't find any of the common diesel components. I had to do a
little bit of research before I finally got the big picture of how it
works.

My understanding of oil is that it has small fibers that get sheared
over and over until the oil becomes too thin to be useful at preventing
metal to metal contact, then it must be replaced. .

My understanding of oil is that it has small fibers that get sheared

Is this a description of every oil's breakdown pattern?

[M.D. Holloway]

The oil can shear down for a few reasons but none have to do with the oil having fibers in them. That would not be a good thing. Shearing takes place for a few reasons and it doesn’t happen with all oils.

Finished oils (engine, hydraulic, gear, ect…) are a combination of base oil(s) and an additive collection. The additive collection are chemicals that provide performance beyond the base oils properties. These additives provide viscosity stability, anti-foaming, anti-wear, anti-corrosion ect…. The combination, chemistry and concentration of these additives along with the base oil will provide the performance needed for component protection and extended oil life.

One of the additives that are used commonly in engine oils is Viscosity Index (VI) Improvers. VI improvers control the viscosity of multi-grade oils. They are polymers which act like "popcorn". At low temperatures, they are "tight-balls" which do not significantly increase the oils resistance to flow. However, at high temperatures, these "tight balls" explode into long chain polymers, which interweave and increase the oil's resistance to flow (viscosity). The tendency of oil to "thin" at high temperatures is controlled and reduced.

These polymers (long chain molecules) help the oil remain in viscosity but under certain conditions they may cleave or break. When this happens, the viscosity of the oil actually gets reduced at operating temperature. This can spell trouble.

Also, some additives will be introduced using a carrier. This carrier will normally be in a base oil but in some cases because of the nature of dilution some are in a carrier that is high in viscosity. This is done to offset any viscosity swing that can happen upon blending. Remember, an oil blender has to hit the right viscosity.

Some people thing that the base oil shears down. This is partially true yet very difficult. The energy it takes to snap an oil molecule is pretty high. It is done all the time at oil refineries (cracking) yet for it to occur in a crankcase is pretty tough. What does happen is that the oil can cleave due to an increase in the oils acidity. If you have ever smelled oil that is acrid it is because it has become acidic. In the engine, acid formation is very common. Acids such as sulfuric, nitric and carboxylic are very common. These rascals are the one of the main reasons deposits form. The acids actually cleave the oil molecules and the active ends crosslink with other active ends and deposits such as sludge form (with the introduction of a nucleation site like grit or sand particles) and also varnish on moving, dynamic surfaces. If pressure and stress is high enough then lacquer forms. Synthetic base oils or highly refined mineral oils show a resistance to shear or viscosity breakdown - thats a much more technical reason saved for a later discussion.

Now, I have seen mineral oils shear down with ultra-sonics in industry. Thats a whole other story and possible a thesis if I ever want to finish my PhD!

The viscosity of spent oil will go thin at first then get thick. It is all a rate equation with a bunch of independent and dependent variable at play. Only way to really ever know is through oil analysis. Does that help?

[M.D. Holloway]

Here is something one of my guys wrote a while back. It is decent and provides some good insight. Take a look:

"Engine sludge is a thick, jelly-like substance that is detrimental to the performance and extended life of an engine. Sludge obstructs oil passages and restricts oil flow. Once built up, it reduces heat transfer, increases the operating temperature and hampers engine operation. Sludge will ultimately lead to shortened engine life.
Although the oil appears to be at fault, it is actually the victim of mechanical and chemical attack. The formation of sludge is a complex interaction of components. Each of the following
factors deserves attention.
SOOT: Soot is fine powder that is a product of incomplete combustion. This carbon substance enters the crankcase with exhaust blow-by gases that escape past the piston rings. Since soot is a very fine powder, it thickens oil by a process called “soot loading.” It gels the oil like a cake mix thickens milk. If your motor oil becomes excessively thick, there will be less oil circulated through the engine. Also, the oil will leave a thicker oil film on the engine parts, which prevents proper heat transfer. By remaining on the hot parts, the oil will burn and form deposits.
HEAT: Engine heat, a natural result of internal combustion, takes its toll on your motor oil. In the presence of air, oil undergoes a process called oxidation, which becomes more severe as the temperature increases. Oxidation thickens the oil and produces corrosive acids. Left unchecked, your oil would degrade into a tar-like mess.
While you want your engine temperature above 210ºF to evaporate unwanted contaminants, above 250ºF the oil is more prone to oxidation. At temperatures of 300ºF, this process occurs rapidly. Oil companies have some additives that contain powerful oxidation inhibitors. These additives break down the oxidation cycle as shown in Figure 1.
As long as these inhibitors are present, no significant oxidation will occur. However, these additives are consumed with time. After their depletion, oil oxidation proceeds rapidly. Regular oil changes are needed to remove the unwanted products of combustion and to replenish the supply of oxidation inhibitors.
FUEL: Fuel enters your crankcase with exhaust blow-by gases in unburned and partially burned forms. It is chemically unstable; therefore, it reacts with itself and the oil to form gums, varnishes and asphaltic-type compounds. These resinous substances are also unstable and react further to cause even more oil thickening.
WATER: Water gets into your crankcase typically through condensation or in exhaust gases that escape past the piston rings. It’s your engine’s job to get rid of this moisture by operating at sufficiently high temperatures. However, all engines operate periodically at low temps and experience some water contamination. When this occurs, water becomes emulsified. That is, it is absorbed by the oil, which thickens the lubricant. As a result, the oil does not flow or cool well. The increased viscosity can cause the oil to burn, creating engine deposits. Unfortunately, there is not much that engine oil can do to reduce the harmful effects of water. Oil changes every 3000 miles are the best way to take care of this problem.
ACIDS: When fuel burns, some products of combustion react with moisture in the system to form acids. These include sulfuric, hydrochloric and organic acids. Sulfur-based acids are undesirable because they attack the oil, reducing its detergency. Organic acids react with unburned fuel to promote sludge and varnish. In addition, acids can cause additive settling, or dropout.
DIRT: People associate dirt with engine wear. It can also play a role in sludge formation. Wear of piston rings and cylinder walls causes an increase in piston blow-by.
Since exhaust gases contain harmful by-products, their presence in the crankcase should be minimized. Some of these compounds will escape past the rings.
ENGINE COOLANT (Antifreeze): Coolant is your engine oil’s number one enemy. Engine sludge is inevitable when oil meets engine coolant. Contamination of your oil with coolant promotes sludge by two means. First, it introduces water into the oil. This presents problems that we’ve previously discussed. Second, it brings into contact oil and coolant, which are incompatible fluids.
Oil and coolant react to form deposits as they experience temperature changes in your engine. Some are gooey or gel-like. Others are hard, brittle deposits that plug oil passageways, reducing oil flow. These two types of deposits guarantee a shortened life for your engine.
No oil additives available will help solve this problem. The only solution is to drain the oil and locate the source of contamination. Then, have the mechanical problem repaired. These are the enemies of your engine oil — Soot, Heat, Fuel, Water, Acid, Dirt & Engine Coolant.
Sludge formation is the result of one or more of these factors:
• severe service driving with improper drain intervals
• mechanical malfunctions
• inadequate engine maintenance
Severe Service Driving: The term “severe service” refers to:
1. Short Trip/Stop & Go
• going to the corner store
• driving in crowded downtown
2. Extended Idling
• sitting in traffic
• delivery truck operation
3. High temperature operation
• low speed driving at high
• ambient temperatures
4. Extreme Cold
• starting engine below 0˜F
5. Heavy Loads
• operating in hilly regions
• trailer Towing
6. Dusty Conditions
• more common than expected
Although some of these situations may not seem severe, they all put additional demands on your motor oil. Under these conditions, automakers require that drain intervals be reduced to three (3) months or 3000 miles. Compare this to “normal” drain intervals of 6000 to 12000 miles. Severe conditions are not uncommon. It is estimated that we operate our vehicles 80% of the time under severe service. Therefore, it is wise to establish 3000 mile or three (3) month drain intervals to assure proper maintenance unless you are sure that you’re driving under the normal category.
Mechanical Malfunctions: A flat tire, engine knock or an electrical problem is easily identified. However, a small, subtle malfunction, like a leak from your cooling system into your crankcase, can create big problems for your engine. The resulting oil and coolant mixture reacts to form harmful deposits. An improperly operating cooling system will cause problems, too. If your thermostat sticks and does not allow coolant flow when needed, your engine will run hot. You might not even notice the difference on your temp gauge. Constant elevated temperatures promote oil thickening, after thousands of miles, this can create sludge.
A clogged or defective PCV valve can contribute to sludge formation. If this valve does not operate properly, harmful exhaust gases remain in the crankcase. These gases, which contain water, acids, soot, etc., promote sludge.
Poor Engine Maintenance: Lack of engine maintenance is probably responsible for more sludged engines than all other categories. Establish proper drain intervals for your type of driving. A timely oil change interval of 3,000 miles or every 3 months is inexpensive insurance for your car’s engine.
Use the proper quality oil for your engine. Never use oil that is rated less than the minimum API Service Category specified by your car manufacturer. To assure yourself proper quality, use oil that is rated API SJ or contains the ILSAC “starburst” symbol on the product label. This symbol assures that the oil has been tested and certified to meeting minimum requirements.
Finally, the cooling system must be flushed and refilled periodically with a proper water/coolant mixture to prevent engine overheating and offer optimum engine performance.
Some other conditions that promote sludge are: clogged air filter, low oil level, low coolant level, bad fuel, etc.
Often, the oil seems to be at fault. But more often, oil is the victim of mechanical malfunctions, extended oil drains or a poorly tuned engine. What can you do to make sure that sludge won’t drive your engine to an early grave?
• Change your oil and filter every 3000 miles or three (3) months, whichever is sooner.
• Maintain your vehicle in good operating condition.
• Make sure your car is well tuned. Efficient, lean combustion produces fewer harmful acids, soot, unburned fuel than a rough running engine.
• Be aware of unusual indicators like high oil pressure, gummy oil on the dipstick, a flooded valve deck or excessive exhaust smoke.
• Use an API SJ, high quality motor oil or the latsest API spec oil.

[kach22i]

Originally posted by LubeMaster77
Does that help?

Yes and then some. Very readable though which is pretty tough to do on a topic this expansive and complex.

Thanks, great job.

Popcorn...............now that I understand.

[kach22i]

Engine sludge

Did you catch Motorweek on speed channel and or PBS when they did the anti carbon treatment to the Mustang? Looks like they use a small electrical charge in the process. The gunk comes out the tailpipe exhaust and cleans up the catalytic converter in the process.

Do you approve of such treatment for let's say an old air cooled Porsche?

[scottmandue]

My head hurts!

[scottmandue]

You said "tight balls" huh... huh, huh

Didn't think I was going to let you get away with that did you?

[M.D. Holloway]

Originally posted by kach22i
Engine sludge

Did you catch Motorweek on speed channel and or PBS when they did the anti carbon treatment to the Mustang? Looks like they use a small electrical charge in the process. The gunk comes out the tailpipe exhaust and cleans up the catalytic converter in the process.

Do you approve of such treatment for let's say an old air cooled Porsche?

I was gonna try it on my Volvo. Not sure what it would do to your engines. I wonder how hot it gets? Might be a good question for Wayne.