Motor Oil 104. It is not what we thought.

Motor Oil 104
Part Four. It is not what we thought.

Now let us finish talking about the differences of mineral verses synthetic oils. I will compare the same weigh or grade of oils showing that the operating viscosities are the same whereas the startup viscosities vary:

Mineral oil:

Oil type...Thickness at 75 F... at 212 F...at 302 F

Straight 30..........250....................10..........3
10W-30...............100....................10..........3
0W-30..........There are none in this range......



Synthetic oil:

Oil type...Thickness at 75 F... at 212 F...at 302 F

Straight 30...........100...................10...........3
10W-30.................75...................10...........3
0W-30...................40...................10...........3

Since the synthetic oil thickens less on shutdown your startup will be easier and so will the stress on your engine. This is perhaps the best thing the synthetic class has over the mineral based oils.

People sometimes use a thicker oil to minimize gasket leaks. This seems obvious to me. Repair the gasket. Do not destroy your engine with an oil that is too thick for proper function.

Some people have said they use thicker oils because they only use their cars every 2, 3 or 4 weeks. They are afraid that thin oils will fall off the engine parts and result in a lack of lubrication at startup. Think about your lawn mower over the winter. I gets gummed up solid. The oil and fuel thicken over time resulting in engine failure. Anyway, oil on the surface of parts does not lubricate. It is the FLOW of oil between parts that lubricates. Thick, old, waxy oil can only be bad.

I have seen several car owner manuals that are now stating that oils do not need to be changed but every 7,500 miles or more. The same manual also states OR every 12 months, whichever occurs first. My feeling is that you can probably go 5,000 miles on the average (in a sports car) but you must change your oil in the spring time at a minimum, particularly up north. Oils form waxes in icy cold weather. There is a permanent thickening of the oil.

Some automotive manufacturers are backing down on oil change intervals to 5,000 miles or less and some advocate changing the oil at least every 6 months as well. I think this is because of the tendency for oils to thicken in very hot engines (not ambient conditions, just hot engines). Also because of thickening from the cold of winter and from sludge build up that cannot be filtered out.

I truly believe that oil is much better being too thin than too thick. Over the years we have been going to thinner and thinner oils despite hotter engines with turbos and the like. The tendency is that people figure they need a 40 weight oils but then use a 50 instead. Better thinking is that if you think you need a 40, use a 30 weight oil instead. I firmly believe this based on all I know about oils.

As it turns out synthetic oils do cling to parts better as they have higher film strength than mineral oils. Synthetics are thinner overall. They have greater slipperiness. Yet they stick better to engine parts. Again, this concept is the opposite of normal thinking.

The thickness of moving oil is measured in centiStokes or cS. Most engines want the oil viscosity to be around 10 cS at normal operating temperature. The really thick multigrade oils have a viscosity of 20 cS at operating temperature. One is not twice as thick as the other, it is only 10 cS thicker.

As we increase the heat from 212 F to 302 F the most commonly recommended oil thins from 10 cS to 3 cS. The thicker oil drops from 20 cS to 4 cS. Note that in a very hot engine the difference between the two oils is now only 1 - 2 cS. In other words they have about the same thickness. There is little advantage to a thicker based oil as a 20W-50 at very high temperatures. No, the 4 cS oil is not twice as thick as the 2 or 3 cS oil. This difference is almost insignificant.

There is a huge advantage of using the thinner, 10W-30 at startup where 90 percent of the engine wear occurs. At 75 F the thicker oil has a viscosity in the range of 250 cS while the thinner oil has a viscosity of 100 cS. The thicker stuff is 150 cS thicker. This is a very big difference. I am using the 20W-50 as my thicker oil example here.

People are always asking about adding things as Slick 50 into the oil tank. Do not do this. The oil companies and engine manufacturers work together very hard to give you the product you need. Engines are running hotter, longer with more BHP from less CID. Smaller, more efficient engines are getting us more MPG and yet better acceleration. These engines last longer and are more reliable.

Part of that reason is the nature of the lubricants. There is a lot of competition to get us the best working motor oil. Independent additives cannot make the oil better and in many cases makes things worse. There have been engine failures as a result of adding some of these aftermarket additives to motor oil.

Motor oil that is labeled for RACING ONLY is not usable for every day driving. Often these have more additives that are toxic to your catalytic converters and the environment. These oils generally do not have detergents. These are very important for your engine unless you plan on taking it apart every few weeks and cleaning every single surface. The oils do not meet the API / SAE requirements for ratings as SJ, SL or now SM.

You do not need to use the exact oil type and brand that your car manual tells you to use. Oils are pretty general. They are not that different. Ferrari is married to Shell. If you call them up and ask to use Valvoline instead they will tell you that they have not tested that brand in their cars. They only tested the engine with Shell oils. They cannot comment on the performance of other oils in their engines. This is a fair statement. The reality is that the Shell and Valvoline oils of the same specification (viscosity, API and SAE ratings, synthetic or not) are very similar. ( I do have my bullet proof vest on ).

People often say that their old 1980 car manual says to use a specific Brand-X motor oil. They keep trying to locate these older oils. First, just about any oil brand that meets the original specifications will do. Second, all oils are much, much better now. They are all much better. One could say that synthetic oils are better than mineral oils but is is hard to say that one brand is that much better than any other. Personally, I do stick to the big names. It does not mean that small motor oil companies are not as good. They could be better for all I know.

Using an oil that is less thick at startup has other benefits. Let us compare a synthetic 10W-30 to a mineral based 10W-30. Both give you a viscosity of 10 cS at normal engine operating temperatures. They both thin to 3 cS at high temperatures. At 75 F tomorrow morning the story will be different. The startup viscosity of the synthetic will be 50 whereas the mineral based 10W-30 will be 75. Again, both are too thick at startup but the synthetic will cause less startup time period wear and tear. You will get a little better gas mileage too.

The synthetic lubricated engine will turn over easier. This has the effect of using less power from your starter motor. It will last longer. Your battery has less of a current draw. This will also last longer. The battery was discharged less during the start so the alternator will rob less power from your engine to recharge. The alternator lasts longer and you get a little better gas economy. The only downside of synthetic lubricants is the cost. They cost 2 or 3 times as much as mineral based oils. Never-the-less I use plain Pennzoil multigrade mineral based 5W-20 in my Ford Expedition. This oil is thin enough at startup to have many of the attributes I just mentioned.

aehaas

 

You cannot make judgments about oil and pressure unless you know that you have an accurate oil pressure reading. Oil senders do fail and it seems they usually read low but who knows. Just replace the sender and see what happens to your readings.

In general, the less often you use your car the more often you need to change the oil. Drives less than 30 minutes only cause water and fuel to build up in the oil that can damage your engine. In this case it is certainly a waste to use synthetic all the time except that it allows for less start up wear.

If you are not putting your car on the track and the oil is not consistently getting above 240 F (true sump temperature) then mineral based oil is OK. And there is no need for anything heavier than a 40 wt. oil. This assumes your engine is not excessively worn.

Use a 10W-40 instead of a straight or 15W-40. And you may be able to get away with a 30 wt. oil. You say a 5W-30 is available. You need to get a true pressure reading first.

aehaas

 

My wife’s Murcielago was delivered new with Agip 5W-40 and it had a valve tappet click and considerable engine noises. After a few hundred miles I switched to 0W-30 Mobil 1 and the valve click went away. The engine was somewhat quieter as well. I then went to Red Line 5W-20 and the whole engine is nearly silent. It is truly remarkable. Engine oil analysis shows excellent wear characteristics.

Better lubrication by the use of a thinner oil may quiet an engine.

Thicker oil may result in better lubrication if the engine is worn but will also quiet an engine just by being a thicker oil. It coats the inside of the engine with a thicker layer of oil and this acts to insulate noise transmission. It may be that you actually have less lubrication but high insulation and this is hurting things.

More noise with a thinner oil may be from having the same lubrication but greater noise transmission. There could be less lubrication and greater transmission as well. But less noise with the use of a thinner oil can only occur with better lubrication.

aehaas

 

“...you should stick with type and weight of oils used all along.”

The person who said this knows nothing about motor oil. Keep reading the chapters, then start over from the first one and read them all again. Then you will be the knowledgeable one. A 30 year old owners manual may say to use an SE API rated oil. It does not mean you have to find this obsolete oil, use the SM rated oil of today.

Each time the API rating changed the same test engine was required to show less wear among many other criteria. The test engine criteria have recently become increasingly severe demanding even better oils.

“...would the synthetic be "too thin" at startup due to dilution?”

This is why I started writing these very chapters. Oil can never be too thin at start up. It will always be too thick. If you think you may be having a problem with oil dilution then send off a sample for analysis. It is cheap and revealing. In general it takes 4 - 5 percent fuel dilution to make the oil drop one grade. A 10W-40 may become a 10W-30. Oils thin with use mainly by the degradation of the viscosity improvers. There is a higher concentration in mineral based oils. However, today's viscosity improvers are better and longer lasting than those of the past. It is certainly true that the engine manufacturers knew how fast oils thinned from the breakdown of viscosity improvers so recommended a higher grade than was actually required. Thus a shear stable 40 wt. oil of today would actually be thicker during its whole useful period than the older 50 wt. oil.

My Maranello 575 had 3 percent fuel dilution once yet the oil thinned only slightly:


__________New __________Ferrari_______
______0W-20 Mobil 1 ___With 3,000 Mi __With 4,000 Mi on the oil
................................................................................................................
Iron__________<1__________11__________13
Chromium _____<1__________<1_________<1
Nickel ________<1___________7__________8
Aluminum ______3__________10___________9
lead __________<1__________2__________2
Copper ________<1_________16__________13
Tin ___________<1__________<1 _________<1
Silver ________<.1__________<.1 ________<.1
Titanium ______<1__________<1 _________<1
Silicon ________4___________10__________8
Boron ________247_________220_________178
Sodium _______15__________15__________15
Potassium ____<10_________<10_________<10
Molybdenum __ 164_________141_________86
Phosphorus __1375________ 1353________1243
Zinc ________ 1328________1313________1169
Calcium _____ 3456________3143________2742
Barium ______<10_________<10 _________<10
Magnesium ____53_________154_________111
Antimony _____<30________<30 _________<30
Vanadium _____<1_________<1 __________<1
Fuel %Vol _____0__________3.5__________1.0
Abs Oxid ______?__________48__________28
Abs Nitr _______?__________13__________4
Wtr %vol ______0_________<.1 _________<.1
Vis CS 100C ___9.0________8.1 _________8.3
SAE Grade ____20_________20 __________20
Gly test ______NEG_______NEG _________NEG
TBN _________9.87_______not done_____not done



I tested my oil using this company, I do recommend them: www.youroil.net
Go to this page and download this Excel file to see other peoples results: http://members.rennlist.com/oil/

aehaas

 

From an old post within BobIsTheOilGuy:
Oil analysis: compare 2003 Ferrari 575 Maranello and 2000 550 Maranello

My neighbor and I have have Maranellos. He owns the 550 but has the new SuperAmerica on order. He always runs what the book says. His last oil change was with 9,100 miles on the car. It was 9 or 10 months ago. Last week I sampled the oil with 1,800 miles on this oil.

His drive to work is 10 - 15 minutes and mine is 15 - 20 minutes and we drive about the same way, spirited. My car has 6,300 miles on it. I run the 20 wt oil while he has always run the Shell Helix Ultra 5W-40, the factory recommended oil.

Cars generally have greater wear earlier in their live because of break-in. My car has less mileage and should show more wear, not less.

One has said that since I get good numbers with the 20 wt oil that I should get better numbers on the 40 wt oil. You be the judge:

__________New _______Ferrari 550_______575
______0W-20 Mobil 1 ___With 1,800 Mi __With 4,100 Mi on the oil
....................................................................
Iron__________<1__________16__________13
Chromium _____<1__________<1__________<1
Nickel _______<1___________4___________8
Aluminum ______3___________8___________9
lead _________<1___________3___________2
Copper _______<1__________83__________13
Tin __________<1__________<1 _________<1
Silver _______<.1_________<.1 ________<.1
Titanium _____<1__________<1 _________<1
Silicon _______4___________6___________8
Boron ________247_________40__________178
Sodium _______15__________8___________15
Potassium ____<10_________<10_________<10
Molybdenum __ 164_________18__________86
Phosphorus __1375________1203________1243
Zinc ________1328________1191________1169
Calcium _____3456________1669________2742
Barium ______<10__________<10 ________<10
Magnesium ____53_________935_________111
Antimony ____<30_________<30 _________<30
Vanadium ____<1__________<1 __________<1
Fuel &#37;Vol ____0__________3.0__________1.0
Abs Oxid _____?__________na___________28
Abs Nitr _____?__________11____________4
Wtr %vol _____0__________<.1 _________<.1
Vis CS 100C__9.0_________11.0 ________8.3
SAE Grade ____20__________30 _________20
Gly test ____NEG_________NEG _________NEG
TBN _________9.87_______not done_____not done

Note that his 40 wt. Shell oil is now a 30 wt. after only 1,800 miles.

aehaas

 

Let me re-answer questions (some that were lost):

If I remember my graphs from 30 years ago oil would drop a grade or two after just 1,000 miles then thicken back up to the original starting point over the next 2 - 3,000 miles. After that oil slowly continued to thicken and thicken.

Today's oils that start in the mid-grade level probably do not thin out of grade very often nor do they thicken very fast. Improvements are at both ends.

Auto manufacturers should recommend 0W-XX oils but they are all synthetic. That could be an issue. Also, they cannot recommend oils that are not readily available. As more 0W-XX oils are produced then they should be used and I predict they will. They are also more expensive.

I have not seen 0W-30 oils thin much but I have seen 0W-40 and 5W-40 synthetic oils thin into the 30 wt. area frequently. This is another reason I believe that a stable 30 wt. oil as a 0W-30 may be best even though the 5W-40 is recommended for general street use.

I would not mix oils ever. Find an oil that has the viscosity you are looking for and use that in pure form. I will post a bunch of oil data that I have been updating recently.

aehaas

“Today's very thin synthetics 0w20 - 0w40 tend to wash out and will cause the bearings to wear prematurely. I wouldn't go any thinner than a 5w40”

Whoever said this knows nothing about motor oil or the idea was somehow lost. Again, the reason I wrote these chapters was to educate people that a 0W-40, 5W-40, 10W-40, 15W-40 and straight 40 all have the same operating temperature viscosity. They all thicken when the engine is turned off. They all THICKEN. They all THICKEN. The second the engines turns off and then on again you have start up wear again because the oil is too THICK for normal operation.

Re-read chapters 101, 2, 3, 4, 5.

In all cases where an XW-30 is indicated a 0W-30 should be used unless you want to go thinner, then a 0W-20 would be better. 10W-30 is an obsolete oil. It should never be used. A 10 or 15W-40 is obsolete, use a 0 or 5W-40.

aehaas

Mule,
For the car that recommends the 5W-30, use a 0W-30 or even a thick 0 or 5W-20. This assumes the engine is not worn. For car number two that recommends a 10W-40, use a 5 or 0W-40 or even a “thick” 0W-30. My Enzo calls for a 10W-60 but I am using a “thick” 0W-30, the European Formula 0W-30 Castrol Syntec.

For non-air cooled motors the ambient temperature is irrelevant. People do not get this but the thermostat make it equal.

aehaas

 

I cannot say that all oils are tested. Though I suspect that certified oils are tested. I trust the labels. Also, I am not worried about viscosity degradation as it occurs far less than in previous years. And what little does occur probably has little or even no effect on wear.

Automotive manufacturers have been developing their own specifications. These vary widely. Most oils probably meet or exceed all the usual specifications. There are GM specs, VW, Porsche, MB and others. I use these only when there is a lack of Oil Company Product Data Sheets giving me the information I want.

For example. There is no relevant Castrol oil data they give out for my use. But the 0W-30 Castrol European Formula is MB 229.5 approved. To me this says the HTHS viscosity is greater than 3.5. This along with the SM rating and known viscosity of a heavyish 30 wt. oil at normal operating temperatures allows me to use it in my Enzo.

When information is available, use it. If information is lacking then other specifications can be inferred by other so-called approvals.

The SAE, API, ASTM and others take specifications very seriously.

aehaas

 

I am guessing, and let us use for example an engine designed to run on a 30 wt. oil. Viscosity is not that critical. The engine will run fine on a 20 or a 40 wt. oil. The 30 wt. oil that was recommended will thin to a 20 wt. It will then thicken back to the original 30 wt. Later it goes into a 40 wt. range. All is fine because now it will be changed. The engine did fine with this variation.

If you started with a 40 grade oil it would often thin to a 20 wt. oil then thicken back up to it’s original grade. Later it thicken to a 50 wt. oil.

If both engines worked fine with a 20 wt. oil and if a 20 wt. oil always stayed in it’s original grade then why not always use a 20 wt. oil from the start? This is what we are seeing today.There is no reason to use a thicker oil if a thinner one will do. There are numerous advantages to using a thinner oil.

Used oil analysis reveals that viscosity has little to do with wear. The number one item causing wear is dirt ingested through the air filter. There is a uniform increase in wear metals with an increasing amount of silicon (sand) in the oil.

aehaas