Motor Oil 105, 106

Let's try it again:

Motor Oil 105
Part Five. Let’s use top gear:

Let’s go racing. I will discuss driving in traffic jams in the Florida summer as well as racing in Sebring though there is no commonality. People lump these two driving situations together but there is no overlap.

On the race track one usually uses all the BHP their engine can give them. You briefly step on the brakes for the corner then put the pedal to the metal the rest of the time. Your oil will get up to 302 F, but your cooling system is around 212 F. The engine produces tremendous heat but can only pass it off so fast to the cooling system. There is a lot of air moving past the cooling radiator so the antifreeze / coolant is able to get rid of the extra heat from this part of the system with relative ease.

The temperature of oil on your gauge is not as hot as it really gets. This temperature is an average with oil from different parts of the motor. Some parts are hotter than others. It is said that some of the oil gets as hot as 400 or 500 F in these racing situations.

In an earlier section I said that thicker oils are usually needed in racing situations but not necessarily. Remember that a major function of oil is to cool the inside of your engine. In ASTM D 4485 3.1.4: “Terminology: Engine oil- a liquid that reduces friction and wear between moving parts within an engine, and also serves as a coolant.” Since the oil with a viscosity of 10 cS at 212 F thins to a viscosity of 3 cS at 302 F we will get more flow. The pressure will go down some as well. This is OK as long as we have a minimum of pressure to move the oil.

This increased flow will result in increased cooling by the oil. This is a good thing. You would probably want more oil flow in these situations and you get it. The hotter oil thins and this increases flow. The higher flow works harder to separate the engine parts that are under very high stress. It all works out for the better. Higher revving engines need thinner oils. You do not necessarily need to go to a thicker oil while racing. Only experimentation will tell.

The best way to figure out what viscosity of oil you need is to drive the car in the conditions you will use. Then use the oil viscosity that gives you 10 PSI per 1,000 RPM under those circumstances. For some reason very few people are able to get this simple principal correct. I cannot explain further.

These same rules apply to engines of any age, loose or tight. Just because your engine is old does not mean it needs a thicker oil. It will need a thicker oil only if it is overly worn, whether new or old. Yet the same principals of 10 PSI per 1,000 RPM still apply. In all cases you need to try different weight oils and see what happens. Then choose the correct viscosity.

I am using 0W-20 in my Ferrari 575 Maranello right now. It has over 5,000 miles on the clock. There will be a day (my estimate is 50,000 miles) when I will have to go to a 0W-30. In the future I will have to increase the viscosity to a 0W-40, then a 0W-50, maybe. I will use whatever it takes to give me 75 PSI at 6,000 RPM during the lifetime of my engine. This formula works in all situations.

Some people have tried this and occasionally get a somewhat low oil pressure while at idle. This is fine. There is no stress on parts at idle, the smallest oil flow will do the trick. It is at higher RPM where more BHP is produced. This is where we need the flow. Remember that Ferrari uses 75 PSI at 6,000 RPM as the place to test your oil viscosity needs. If your oil gives this value under your driving conditions then your lubrication system has been maximized. Period.

Do not go 5,000 miles with the same oil if you are racing your car. You should change the oil every 1 or 2,000 miles. If you drive your car around town then you need to change the oil for that situation. Use racing oil on the track and urban oil around town. The best situation as described by Ferrari is to use the 0W-40 around town and the 10W-60 “racing oil” on the track. It has to be that “hot” track though. A compromise situation would be to use the 5W-40 for both but this may not be optimal. Certainly, if you are just an urban driver as me use the 0W-40 or even a thinner oil as I do in my Maranello. Again, I use the 0W-20.

FYI. The Formula 1 cars that run at 15,000 RPM and higher use straight 5 and 10 weight oils.

Now let me discuss what people think is a similar situation to racing. That is hot summer traffic jam driving. Your car should be able to handle this. If you have problems then you have a problem with your car, most likely in need of a cooling system overhaul.

When you drive that car down the road mid-winter in upstate New York or mid-summer in Florida the engine and oil temperatures will be around 212 F. But your Florida vacation is suddenly altered by a hurricane. You have to get out of Tampa, but so do a million other people. It is now 95 F and you are in a snarl. Everyone thinks they need a thicker oil for this situation. This is false.

Your engine is not producing much heat at low RPM and low BHP output. The production of heat is relatively slow. It can easily be transmitted to your cooling system. The problem is that your cooling system has trouble getting rid of the heat. The oil and the coolant will slowly rise in temperature. They both rise together. The increase is no big deal for your oil. It goes to 220, then 230 F. The problem is that the cooling system can only handle heat up to 230 F. After that you overheat the cooling system and the car must be shut off. The oil never got that hot, It was just that the water got a little hotter than its system design.

You now see that overheating in traffic is a cooling system problem and not an oil system problem. Do not change to a thicker oil based on your traffic situation.

aehaas






Motor Oil 106
Part Six. A personal recommendation. (Updated in 2007)

These are the motor oils I recommend. This is based on information that I just happened to collect. I have not gotten the specifications of all oils out there. My opinion on these oils is based on viscosities. By this I mean less honey like at start up temperatures and appropriate for the required viscosity at operating temperature. I broke it down to several classes, 1-Fully Synthetic, 1.2-Race Track, 2-Semi-Synthetic, 3-Mineral (dinosaur) oils. The asterisk is my preferred from each group of very similar products. And these are usually easier to find in my experience. Remember, all oils are too thick at start up. There is no such thing as an oil that is too thin below 100 F. The thinnest motor oil made is still too thick at start up temperatures.

It seems that many engines work best with a multigrade 30 weight oil. Others would do better with a 20 weight oil and few would require a 40 weight oil. You can only determine what is best by experimenting. Admittedly I did not think my Ferrari Maranello would need a 20 weight oil. In truth I could actually use a 10 weight oil. A 0W-10 would be good but it simply does not exist for normal use. Red Line does make 2W, 5W and 10W oils (this acts as a 0W-10 multigrade oil) but they are for racing only. One Formula 1 team has actually used these very oils off the shelf from Red Line.

…..Synthetic Class…..

60 wt:
Agip Synthetic PC 20W-50 (a thick 50 wt oil)
Redline straight 60 wt racing oil (racing only, acts as a SAE 20W-60 oil)*
Shell Helix Ultra Racing Oil 10W-60

50 wt:
Castrol Syntec 5W-50
Penn Synthetic 5W-50
Red Line 15W-50*
Shell Helix Ultra 15W-50

40 wt:
Amsoil 0W-40
Castrol European Formula 0W-30 (a thicker 30 wt oil, almost a 40 wt oil)*
Mobil One 0W-40

30 wt:
Mobil One 0W-30
Penn Synthetic 5W-30
Red Line 5W-20 (a thick 20 wt oil)*

20 wt:
Mobil One 5W-20*
Valvoline SynPower 5W-20

…..Race Oils for Street Use…..
Use these when continued sump temperatures over 240 F are expected.

60 wt:
Redline straight 60 wt racing oil (racing only, not for the street, acts as a SAE 20W-60 oil)
Shell Helix Ultra Racing Oil 10W-60
Valvoline SynPower 20W-50

50 wt:
Castrol Syntec 5W-50
Shell Helix Ultra 15W-50

40 wt:
Red Line 5W-40
Shell Helix Ultra 5W-40

30 wt:
Red Line 10W-30

20 wt:
Amsoil 5W-20
Red Line 5W-20


…..Synthetic Blends…..

60 wt:
Castrol Syntec Blend 20W-50

50 wt:
Valvoline 20W-50

40 wt:
Agip 4-Synt 10W-40
Valvoline Durablend 10W-40*

30 wt:
Castrol Syntec Blend 5W-30
Motorcraft Blend 5W-30
Valvoline Durablend 5W-30*

20 wt:
Motorcraft 5W-20*
Valvoline Durablend 5W-20

…..Non-Synthetic…..

50 wt:
None recommended - all relatively too thick at start up.

40 wt:
Penn regular Multigrade 10W-40*
Valvoline All Climate 10W-40

30 wt:
Penn regular Multigrade 5W-30*
Valvoline All Climate 5W-30

20 wt:
Penn regular Multigrade 5W-20
Mobil Clean 5000 5W-20*

If while on the road you are forced to add oil there are rules. Let us say for example that our engine has synthetic Mobil One 0W-30. Use the same type and brand if you can. If you are using Mobil 1 then it is acceptable to mix different grades but use a close grade when possible. It is not a good idea to mix say 1/2 your oil tank with 0W-30 and 1/2 with 15W-50 Mobil 1. If there is no Mobil 1 available then use the mineral based Mobil oils next,.

The last choice is to mix a synthetic of another brand. They should not react adversely if mixed but it may dilute additives. This is not a good combination. Use this combination if you must but only until an oil change can safely be performed some time soon.

I personally used 0W-20 Mobil 1 in the 575 Maranello and for the first oil change I drained the Murcielago’s (OEM) 5W-40 Agip and replaced it with 0W-30 Mobil 1. The engine became much quieter. A valve tappet noise disappeared. I am now using the 5W-20 Red Line in the Lamborghini. Used oil analysis shows that this oil works well for my non racetrack application. The same oil went into my Maybach 57. My Enzo Ferrari calls for the Shell Helix Ultra racing 10W-60 but I am using the Castrol Syntec European Formula 0W-30. This is different than the easy to find plain 0W-30 Syntec. It MUST say European Formula across the front of the label. I buy it at AutoZone stores but it is often mixed with the plain stuff.

You have to try by experimentation what operating oil grade your engine requires. In all cases however, you want the oil that gets least honey-like at startup and thins to the appropriate thickness for normal operation. Always recheck the oil label as they change a lot.

aehaas

 

Do not mix oils to come up with a “better” viscosity. Instead, look up the actual specifications and you will find an oil with the viscosity you want. There are thin, medium and thick viscosity oils within each grade.

From SAE J300, viscosities at 212 F...

20, range - 5.6 to 9.2
30, 9.3 - 12.4
40, 12.5 - 16.2
50, 16.3 - 21.8
60, 21.9 - 26.1

Example: Regular Castrol Syntec 0W-30 has a viscosity of 10 at 212 F whereas the European Formula 0W-30 has a viscosity of 12.1 and other 0- and 5W-30 oils are around 11.

Next - a mineral based oil in particular has a fair amount of viscosity index improver (VII). Synthetic oils have less. The wider the spread the more VII used and the more the oil will shear (thin) with severe use during racing conditions in Hot temperatures. Very high temperature oil in very high RPM conditions will thin sooner than the same oil in lesser conditions.
Note that the thinning is less in synthetic than mineral based oils. And the thinning of both is less than in past years.

I never tow anything up long hills nor race cars so oil temperatures are normal (relatively low actually) therefore 0W-anything is always preferred.

aehaas

 

You may have missed chapters 101, 2, 3, 4. Read these and your questions will be answered. 10W-30 is out dated and should not be used nor sold. However, there are a lot of people who think it is what they should use by a lack of knowledge.

The SAE / API actually saw this and re-labeled the original 5W-30 as a 10W-30 some 15 years ago. I bet they will re-label again because people refuse to change or just lack the knowledge.

It is hard to make a 0W-30 out of mineral based oil so it needs to be synthetic. People may not want to buy it so the best that can be done with mineral oil is a 5W-30. This may change as more companies formulate semi-synthetic oils.

aehaas

 

The ONLY pressure that matters is the pressure when the oil temperature has reached whatever you normally drive at.

aehaas

PS: Prepositions are not good to end sentences with.
From: How to write good.