Motor Oil Education

[chrisb33]

I just read the article Dr. Haas link This is a very good article that actually increased and verified my knowledge on oils and might benefit the others too. it's a bit long and i hope i am able to summarize this correctly. For the others who have patience in reading please do so, especially for those who are into track racing.

To sum up: (on synthetics only)

1. Synthetics are superior vs. mineral based oil (reasons explained in the article)
2. Edit: Oil gets THICKER during low temps and THINNER at high temp
3. Most engine wear and tear occur during cold start. The THINNER the oil viscosity the better
4. most engines only requires a viscosity of 10 during drive around town condition - 212F (i guess this is where us dd and weekend warriors fall in)
5. Multi-grade viscosity oils e.g. 5W30 is better than straight 30 viscosity.
6. all multi-grade viscosity achieve a viscosity 10 at 212F but a lower 1st number e.g. 0w30 vs. 5w30 produces a THINNER viscosity during cold start up.
7. It is a misconception that it is recommended to use thicker oil when oil leaks through your gaskets. Solution is change your gasket! Again rule of thumb, the thinner the oil, the better.
8. The thickness of moving oil is measured in centiStokes or cS. So check the typical properties in choosing oil. focus on lower temp cs figures. the lower the better.
9. look for SL and SJ rating in choosing oils and not based on viscosity alone.

having reviewed all these, i went ahead in checking the mobil 1 website (my preferred brand). using the summary above, i immediately thought that i was on the right track in choosing the right viscosity for my engine which is 0w40. This is based on item number 6 above. it is has SL and SJ approval. However as i went to review its cs properties (see item number 8 above) and compared it to the 5w20. It seems like although 5w20 has a higher 1st number value vs. 0w40, the cs properties on low temp on the 5w20 is significantly lower vs. 0w40: cs@40*c - 48.3 and cs@40*c - 78.3 respectively.

having said all these. I think im going try 5w20 instead of 0w40 and see the improvement in cold start and check oil pressure if it is still within range when driving. I just hope we do have 5w20's available here in the PH.

Thanks to GST95 at the tuners who shared this link.

chris b

 

[G]

What is the lowest temp you will be starting your car in?

 

[chrisb33]

it actually doesnt matter how cold. it could be room temp like cooled down engine over night lets say around 75* just like the article says or extreme cold condition like winter snow cold. Oil gets THICKER when it's cold so the thinner viscosity you can find the better because most of the engine wear and tear occurs during start up.

None of the oils of today can be THIN enough when cold. So we're left with choosing the thinnest rating we can find.

 

[chrisb33]

Edited first post item number 2. I got it mixed up when i first wrote it. Oil gets THICKER when cold and THINNER when hot.

 

[14u2nV]

5w's are almost always the best bet. I run 10w's in the summer, especially in my truck, but 5w's would work too.

 

[turbowop]

I run 15w50 Mobile1 in 1051. The motor now has 137k miles and I've owned the car since 70k. I have a hard time believing that more wear occurs on my car during start-up than during one of my spirited drives at 30psi. It sees WOT everytime I take it out of the garage.

I run 10w40 in 503, since it's used for ski duty and thinner oil overall helps cranking during cold starts. I want to make sure the engine will crank over when it's really cold out so that I can get home from various ski areas. I don't think start-up wear is a big enough deal to worry about as far as oil is concerned in such an application, IMO.

 

Quote:
I have a hard time believing that more wear occurs on my car during start-up than during one of my spirited drives at 30psi.



^^ Then you would be wrong.
Talk to any tribologist and he will tell you that short of oil starvation, cold startup is the highest wear event in your engine's life cycle. There is the least amount of residual oil present at the mating surfaces, and the lubricant has the highest viscosity and greatest resistance to flowing into the clearances between those surfaces. And that is a good reason to avoid excessive viscosity in cold weather.
Mike R.

 

I used synthetic 10w30 year round the entire time I owned my first Talon, in both Ohio winters and Texas summers. Car got wrecked with 160,000+ on the odometer. I pulled the motor and tore it down. The only wear I could find was a little bit of wear on the balance shaft bearings. The main and rod bearings were still beautiful, crank was beautiful, cylinder walls looked great. Unless your daily driving in an extremely cold environment or beating the hell out of it regularly on the track, anything besides a good synthetic 10w30 is unnecessary.

 

[chrisb33]

Quoting mj_rosenfeld:
Quote:
I have a hard time believing that more wear occurs on my car during start-up than during one of my spirited drives at 30psi.



^^ Then you would be wrong.
Talk to any tribologist and he will tell you that short of oil starvation, cold startup is the highest wear event in your engine's life cycle. There is the least amount of residual oil present at the mating surfaces, and the lubricant has the highest viscosity and greatest resistance to flowing into the clearances between those surfaces. And that is a good reason to avoid excessive viscosity in cold weather.
Mike R.



+1. When your engine is cold. most of the oil goes down (law of gravity). Although there is still residual oil present in the areas where it is needed, those tight places like the cylinder wall dont get the lubrication it needs because as mentioned, the oil is too thick to flow properly there.

 

[chrisb33]

we also should not only look at viscosity - those number xw30 or 5wx. As mentioned in my first post, you should also look at if there is SL, SJ, and now SM rating.

Also look at the cst properties. Focus on the cst properties at low temp. The lower the number there the better.

As my example: Mobil 1 0w40 vs. 5w20, if we base it only on viscosity, clearly 0w40 wins. it does not only have a wider range of visosity, but the thinnest. However, when i checked the cst rating, the 5w20 wins by a big margin. check mobil 1's website:

0w40 properties: link

scroll down and look at the cst value at 40*c

chris b
5w20 properties: link

 

[turbowop]

Quoting mj_rosenfeld:


^^ Then you would be wrong.




Well, how about if I added a healthy dose of detonation? /ubbthreads/images/graemlins/hsugh.gif

 

[G]

Chris i think your over analyzing this, the following is direct from mitsubishi:

And another, you get the idea.

 

+1

This issue comes up every few months and its always way over-analyzed.

 

[chrisb33]

not over analyzing /ubbthreads/images/graemlins/smile.gif I just want to be updated on new technologies. the oils of today are better than yesterday's.

chris b

 

[Brianawd]

Using a 5w20,0w30,0w40,10w30 is great if you just use your car for DD and a little bit of playing. But for a lot of us on here that thin of oil will just not cut it. My galant has never seen any thing but 20w50. Reasons being that my car sees 8500rpms 90% of the time its on the rod. Reving a car that high with a thin oil is going to kill your oil pump gears. It has been proven time and time again.