Maybe oil doesn't care about our math..

[panthermike]

I've never put too much thought into oil weights.

I wouldn't personally do this, but my mechanic does the following; uses 20w50 for everything! It never gets cold here in Phoenix but still I always thought he was crazy for doing this.

Anyways, he services countless Towncar's(4.6), many of them have 200-500,000 miles. All of them on 20w50 oil! Mind you these cars call for 5w20. My preference here in AZ is 10w30 which isn't "thick" with the exception of my 2000 Corolla that burns oil. It will see whatever, for a while Delvac 15w40, thanks to the BOGO at Checker's.

 

[Steve S]

Originally Posted By: MrWideTires
Like most of u know.. I'm a thin-ish oil kind of guy, my favorite is 0w30 and 0w40.. but today I got thinking about it while driving from school, I have yet to see some engine go to ridiculously high mileage with thin oil! I mean over 500,000+ miles..
All those engines I've seen had somewhat thick oil..

For example..
Mathematically.. you can compress water, but don't try it in real life. Also mathematically.. if you put a smaller exhaust in your car... the gases should just make up for it by flowing faster... but in reality, that doesn't happen and you loose a ton of power.

I'm thinking.. maybe mathematically... thinner oil can provide better protection, but in real life.. oil just doesn't give a a [censored] about our math, thicker just protects better (not ridiculously thick though).
I'm not a genious.. but I guess in evidence alone... I probably won't purchase any 20wt oils, 30wt will be the thinnest, and I will stick to 0w40 which seems like a great compromise of good start-up protection and just the right thickness to protect and get good performance.

What do you'll think?
The smaller exhaust may increase the gas speed but what really happens is the restriction increases and the engine looses power etc. Most cars get to the junkyard for reasons other than the engines failing. Most cars aren't driven enough to reach 500,000 miles, Though time may tell about the 20 wt viscosity.

 

[Gary Allan]

Quote:
As much as I want to agree on that section... I can't help to think about the 2.6 million mile Volvo that spends so much time driving.. and the guy uses 20W50 and 15w40 diesel rated oil!


What year did that Volvo start operation? What oil would be appropriate at that state of lubricant development?

Places like Oz where they run 20w-50 and think it's too thin are not motivated to develop durable lighter lubricants.

That is, when you see a 1975 MG with 20w-50 spec'd ..it was probably due to the fuel dilution trashing anything lighter to the point of mechanical damage ..or changing your oil ever 3 weeks. Advance 30 years in time and the same engine would probably last MUCH LONGER on a 30 weight just due to the elimination of all the insults that were dumped on the oil requiring the higher viscosity.

 

[Turk]

C'mon guys, there's lots of factors and variables in determing all of this.


- Fuel dilution

- RPM counts at cold start-ups

- Air filtration

- Oil filtration

- Lenght of oil in service

- Engine stress


We'd have to take 2 identical engines, with the same tolerances and ranges and control all of these (and more), then use thick in one and thin in the other to make our determination, right?

 

[demarpaint]

Originally Posted By: hpichris
You won't catch me using 20 weight.


If your BMW calls for a 40wt oil then use a 40wt oil. I'm a fan of 20wt oils, my son owns a BMW I told him to use a 0W40 oil, no point in me second guessing BMW at my son's expense. I figure the 0W40 will give him the cold start up protection he needs should he decide to make a trip up to Canada this winter.

 

[bigmike]

Originally Posted By: tpitcher
C'mon guys, there's lots of factors and variables in determing all of this.


- Fuel dilution

- RPM counts at cold start-ups

- Air filtration

- Oil filtration

- Lenght of oil in service

- Engine stress


We'd have to take 2 identical engines, with the same tolerances and ranges and control all of these (and more), then use thick in one and thin in the other to make our determination, right?





No, you'd need to take enough to create a distribution in order to interpret the data.

In fact, you'd need to have enough test engines to cover each engine in the market as well.

 

[bigmike]

Originally Posted By: MrWideTires
Like most of u know.. I'm a thin-ish oil kind of guy, my favorite is 0w30 and 0w40.. but today I got thinking about it while driving from school, I have yet to see some engine go to ridiculously high mileage with thin oil! I mean over 500,000+ miles..
All those engines I've seen had somewhat thick oil..

For example..
Mathematically.. you can compress water, but don't try it in real life. Also mathematically.. if you put a smaller exhaust in your car... the gases should just make up for it by flowing faster... but in reality, that doesn't happen and you loose a ton of power.

I'm thinking.. maybe mathematically... thinner oil can provide better protection, but in real life.. oil just doesn't give a a [censored] about our math, thicker just protects better (not ridiculously thick though).
I'm not a genious.. but I guess in evidence alone... I probably won't purchase any 20wt oils, 30wt will be the thinnest, and I will stick to 0w40 which seems like a great compromise of good start-up protection and just the right thickness to protect and get good performance.

What do you'll think?


It's all about statistical analysis. There needs to be more data collected upon a *fixed* kind of engine design. Manufacturers never would allow this to happen as they design engines too often for the data collection to become meaningful.

This is why we get people using examples that are 20 years old (or older) that are trying to equate those examples into meaningful discussion when, in reality, it is meaningless.

 

[JohnBrowning]

You could be right but like I do not know for sure. I do know that past examples as in real world vechiles do speak highly for oils with an HTHS of 2.9 to 3.5 as the all around best ball park for long life. I personally like 3.3 as the all around best bang for the buck between long life and good fuel economy. I often end up though either drastically higher or lower due in part to what I will spend for oil and what is locally available. I am refering to modern engines as well. In older engines like OEM V8's pre-voller I would not go bellow 3.5 and for a high performance V8 with heavy knose loads due to radical cam profile and super strong valve springs I would not want less then 3.9HTHS and a serious load of AW and EP additives.

I too am waiting to see the 500,000 mile Toyota run on nothing but dino 5W20 and 5000-7500 mile oil change intervals. It could be a any make though as long as their where a lot of them in the club. I am not thinking we are going to see a lot of Dodge Hemi's int he club at 500,000 miles on Dino 5W20 unless they get alot of things like lifters replaced every 200,000 miles or less. They have a lot of warranty issues with their lifters in my neck of the woods! In my book a 500,000 mile engine is only legitimate if all the internal are the ones it left the factory with!So if anything has to come out of the engine ie lifter's oil pump,piston, rocker arm etc.......Then it is not a true high mileage engine in my book. Any common wear items are fine as well as accessories like starter,alternator etc....Seals are ok too as these are wear items that most people do not need to replace as first owners it is usual the second or third owner that needs to replace them but they are a wear item.

I have seen so many Toyota and Honda's with 300,000-500,000 miles run on Jiffy Lube 10W30 and 3000 mile oil changes to shake a stick at. Most of the ones I have seen have not been HWY queens either.

 

[Mitch Alsup]

Originally Posted By: MrWideTires
Originally Posted By: Mitch Alsup
It realy depends on application. And it is the application that ends up telling us the oil temperature. It is, then, the temperature that tells us the actual operating viscosity that the bearings, rings and tappets see (+/-).

I further suspect that waking up, driving 3-4 blocks, then get on the interstate, and drive the speed limits for 12 hours a day is the easiest service a motor oil can ever see. Stop and go is worse, heavy loads are worse, high performance driving is worse, sitting around idling is worse,..... But in each of these cases, if you actually keep the oil at a temperature where it is between 8 and 12 centiStokes of viscosity, you will get as much life out of the engine as is possible -- given your application.


As much as I want to agree on that section... I can't help to think about the 2.6 million mile Volvo that spends so much time driving.. and the guy uses 20W50 and 15w40 diesel rated oil!


It is very possible that without an oil cooler, that his 20W-50 oil is running in the 230dF range and actually operating near 12 cSt.

 

[Jaymus]

I think there are so many variables, it will take many years to see if math matters or not in this situation. Engine type can be prone to failure before it ever leaves the factory, and some engines just don't care as long as they have a lubricant in them.

 

[Bryanccfshr]

I find these HTHS feel good numbers quite subjective when we are speaking of low friction engine designs. 3.3 is good 2.8 is bad etc... of 3.5 is good and 3.3 is bad.

ANother factor in not many 500k+ vehicles being reported recently is more gas hogs now than when Toyota 20 and 22re engines were pushing little mini trucks around on sub buck a gallon gas.

Most vehicles on the road today are averaging not any better mileage than 20 years ago. Combine that with gas that has ranged fron 2-5 bucks and the Average discretionary mileage amongst Americans is way down.

Lets say a 20 MPG vehicle to reach 500K before the electrics started to dry rot out would have to put on a minimum of 40k miles a year. So that is 2000 gallons a year. Lets say over this course of time factoring inflation and luck gas average 3 bucks a gallon(a cheap estimate)So the annual fuel cost is going to be equivelent to 6000 dollars in 2009 standard.
At 40k a year it is going to take 12.5 years or 126 months to reach this mileage. it is going to cost 75000 in fuel if gas prices do not go up.

6k a year for fuel can put a dent in the family budget for most americans. and thats just at 40k a year!

To reach 500k since lets say 2001 when 5w20 reemerged as a recomendation a large amount of drivers are going to have to make 63k miles a year! Without crashing! Or trading it in for a newer model(thus the car would on average go to a new owner with much lower annual usage) during this period of easy credit and finance(2001-nearly recently) there were alot of trade ins and ups rather than running cars to their ragged end.

I suspect with tighter credit markets and less liquidity in the used car markets we will once again begin to see some well taken care of one or two owner vehuicles reaching great mileage....in a few years.

 

[CATERHAM]

Originally Posted By: Mitch Alsup
Originally Posted By: MrWideTires
Originally Posted By: Mitch Alsup
It realy depends on application. And it is the application that ends up telling us the oil temperature. It is, then, the temperature that tells us the actual operating viscosity that the bearings, rings and tappets see (+/-).

I further suspect that waking up, driving 3-4 blocks, then get on the interstate, and drive the speed limits for 12 hours a day is the easiest service a motor oil can ever see. Stop and go is worse, heavy loads are worse, high performance driving is worse, sitting around idling is worse,..... But in each of these cases, if you actually keep the oil at a temperature where it is between 8 and 12 centiStokes of viscosity, you will get as much life out of the engine as is possible -- given your application.


As much as I want to agree on that section... I can't help to think about the 2.6 million mile Volvo that spends so much time driving.. and the guy uses 20W50 and 15w40 diesel rated oil!


It is very possible that without an oil cooler, that his 20W-50 oil is running in the 230dF range and actually operating near 12 cSt.


I agree, it's the operational vis that matters not the SAE grade.
I've always found this thick vs thin discussion of oil grades to be quite ridiculous without any mention of what the operational vis is.
Dr. Haas' running 0W-20 in his 612 hp Enzo Ferrari to the uninformed seems nuts. But the reality is he's running an oil with a k'vis ranging from about 95 cSt (at room temp) to 13 cSt (maximum bulk operating oil temp' of 182F). 13 cSt is anything but light (equivalent to a 40 wt at 212F).
If it was up to me I'd say enough is enough and implement a new BITOG rule; no more oil grade preference prognostications without divulging the operating viscosity!

 

[OVERKILL]

Originally Posted By: CATERHAM
Originally Posted By: Mitch Alsup
Originally Posted By: MrWideTires
Originally Posted By: Mitch Alsup
It realy depends on application. And it is the application that ends up telling us the oil temperature. It is, then, the temperature that tells us the actual operating viscosity that the bearings, rings and tappets see (+/-).

I further suspect that waking up, driving 3-4 blocks, then get on the interstate, and drive the speed limits for 12 hours a day is the easiest service a motor oil can ever see. Stop and go is worse, heavy loads are worse, high performance driving is worse, sitting around idling is worse,..... But in each of these cases, if you actually keep the oil at a temperature where it is between 8 and 12 centiStokes of viscosity, you will get as much life out of the engine as is possible -- given your application.


As much as I want to agree on that section... I can't help to think about the 2.6 million mile Volvo that spends so much time driving.. and the guy uses 20W50 and 15w40 diesel rated oil!


It is very possible that without an oil cooler, that his 20W-50 oil is running in the 230dF range and actually operating near 12 cSt.


I agree, it's the operational vis that matters not the SAE grade.
I've always found this thick vs thin discussion of oil grades to be quite ridiculous without any mention of what the operational vis is.
Dr. Haas' running 0W-20 in his 612 hp Enzo Ferrari to the uninformed seems nuts. But the reality is he's running an oil with a k'vis ranging from about 95 cSt (at room temp) to 13 cSt (maximum bulk operating oil temp' of 182F). 13 cSt is anything but light (equivalent to a 40 wt at 212F).
If it was up to me I'd say enough is enough and implement a new BITOG rule; no more oil grade preference prognostications without divulging the operating viscosity!


He also doesn't track the car. Which is key.

 

[GMFan]

I've been in NYC taxi cabs that had over 350,000 miles on them and the drivers either floor the gas or brakes. I know the Ford Crown Vic specifies 5w20 (newer ones anyway) but then again I have no idea what they put in their motors. They probably use the cheapest 10w30 they can find by the drum.

 

[fdcg27]

Gary,

Since you mention a '75 MGB as an example, and I have had a '76 for many years, I thought I might reply.
I can tell you that the '76, which by then no longer had a factory oil cooler, would see a serious decline in oil pressure in really hot weather when run at sustained interstate-high speeds (>80 mph or so) on early 'nineties 10W-40.
This was probably the reason that 20W-50 was specified for hot weather.
A better oil, or an oil cooler, would have made the 50 uneeded.
Yes, the MG has a real direct reading pressure gauge.