What makes an engine 20W friendly?

[Geoff]

Does 5w-20 flow better than 5w-30 when colder than 40 deg C? Seems like having the same -w rating would imply they both flow the same. Factor in the usual positive displacement oil pump. Thus, one could argue the 20 weight is primarily a CAFE issue if fuel economy testing is on a warm engine.

In the older days the evil viscosity index improvers were enough to keep you away from larger spread grades. You could believe then that 5w-30 or 10w-30 was better than 10w-40. I don't think this is still the case.

After seeing that Ford failed CAFE looking back 3 years, and they make most of their money on trucks, I am skeptical of their motivations. You can imagine an internal meeting with a bunch of business managers and engineers thinking, hmmm, how do we keep making a high proportion of trucks so that our profits are fat given CAFE? Put smaller engines in them? Nah, consumer won't buy 'em. If we up our corporate average .05 mpg then we can sell 100000 more trucks in the mix. Decision made.

 

[lamont cranston]

Ford would be quite happy if your engine wore out at 36,001 miles/37 months.

Reengineering motor oil isn't done for YOUR benefit.

 

[Jay]

In the SAE paper that I mentioned above the Honda researchers formulated 3 mineral motor oils with identical add packs--one with a HTHS of 2.9cP another with a HTHS of 2.6cP and another ultra-low viscosity oil of 2.4cP HTHS. They wanted to see how low they could go before wear became an issue. They also wanted to carefully quantify friction, wear, and fuel economy for each of the grades in two different engines; one a roller cam follower engine--the other with conventional slipper followers. They never found the lower viscosity limit with the roller cam follower engine (even with the ultra-low viscosity oil) where wear significantly increased. With the conventional slipper follower engine 2.6cP was the bottom limit. Friction and wear significantly increased below 2.6cP HTHS.

So the researchers found, not surprisingly, that friction and wear go hand-in-hand, and that going too low in viscosity was counterproductive-- not only from a wear standpoint, but a fuel efficiency standpoint also.

That's why all these CAFE conspiracy theories don't hold water. If a manufacturer were to spec an oil for an engine that was too thin, friction and gas mileage would both suffer-- hurting the manufacturer's CAFE score.

 

[moribundman]

Hey Kent Allard, do you think anybody would buy the same brand car again if it's known that the engine last only 30k miles?

 

[jthorner]

quote:

---

Ford would be quite happy if your engine wore out at 36,001 miles/37 months.

---

There has been ZERO evidence shown to support your supposition. If Ford had been trying to intentionally wear out engines then they would not have issued such strict specifications for approved 5W-20 oils.

We are now into the fifth model year of Ford recommending 5W-20 for most of their vehicles and even with all of the naysaying and noise I have yet to see anyone point to evidence that 5W-20 results in more wear than does the same brand of 5W-30 motor oil.

Sometimes there are really things other than evil minded conspiracies going on in the world!

As far as the Europeans don't do 5W-20 argument, so what? Europe took much longer than the US to remove lead from gasoline, to institute pollution controls, to use catalytic converters and to increase crash worthiness standards. Maybe they are just chronically late to the engineering party!

John

What 'everyone knows' often isn't worth knowing.

[ August 23, 2004, 02:02 AM: Message edited by: jthorner ]

 

[427Z06]

quote:

---

Originally posted by Jay:
In the SAE paper that I mentioned above the Honda researchers formulated 3 mineral motor oils with identical add packs--one with a HTHS of 2.9cP another with a HTHS of 2.6cP and another ultra-low viscosity oil of 2.4cP HTHS. They wanted to see how low they could go before wear became an issue. They also wanted to carefully quantify friction, wear, and fuel economy for each of the grades in two different engines; one a roller cam follower engine--the other with conventional slipper followers. They never found the lower viscosity limit with the roller cam follower engine (even with the ultra-low viscosity oil) where wear significantly increased. With the conventional slipper follower engine 2.6cP was the bottom limit. Friction and wear significantly increased below 2.6cP HTHS.

So the researchers found, not surprisingly, that friction and wear go hand-in-hand, and that going too low in viscosity was counterproductive-- not only from a wear standpoint, but a fuel efficiency standpoint also.

That's why all these CAFE conspiracy theories don't hold water. If a manufacturer were to spec an oil for an engine that was too thin, friction and gas mileage would both suffer-- hurting the manufacturer's CAFE score.

---

You have the reference # for that SAE paper?

 

[MolaKule]

see this thread:

http://theoildrop.server101.com/cgi/ultimatebb.cgi?ubb=get_topic;f=21;t=000045

In my view, engines have always been able to tolerate 20 weights. But oils could not provide the necessary film stability, shear (viscosity)stability, and thermal stability.

With better base oils, anti-wear and FM aditive packages, and more shear-stable VII's, 20 weight oils now hold up much better.

In fact, for some older GM cars of the 40's and fifties, they used to specify 20 weight oils.

 

[TC]

2002 Honda Si
Exxon Valdez 5w-20
5,000 mi on oil
8 ppm iron
http://theoildrop.server101.com/ubb/ultimatebb.php?ubb=get_topic;f=3;t=000668#000000

2003 Honda Accord
Pennzoil 5w-20
6,792 mi on oil
14 ppm iron
http://theoildrop.server101.com/ubb/ultimatebb.php?ubb=get_topic;f=3;t=000967#000003

"Ford would be quite happy if your engine wore out at 36,001 miles/37 months." Yes, that would bring 'em tremendous business in post-warranty engine replacements. And shortly thereafter they'd go bankrupt since no one would be buying their vehicles.

"Reengineering motor oil isn't done for YOUR benefit." I wouldn't care if they're reengineering for the benefit of the purple Teletubby. With wear numbers like that, JUST PLEASE KEEP REENGINEERING!

 

[Jay]

quote:

---

Originally posted by 427Z06:
You have the reference # for that SAE paper?

---

1999-01-3468 "The Effect of 0w-20 Low Viscosity Engine Oil on Fuel Economy"

 

[Patman]

I don't think anyone mentioned this yet, but one thing that can be done to make an engine more 20 weight friendly would be to control it's oil temperature better.

If you've got an engine which is going to heat the oil up to 250 degrees or more, then a 0w20 or 5w20 oil is not really a smart idea. But if you can keep the oil temps below 210, then it shouldn't be a problem.

 

[tpi]

quote:

---

Originally posted by MolaKule:

In fact, for some older GM cars of the 40's and fifties, they used to specify 20 weight oils. [/QB]

---

And into the '60's as well.

 

[427Z06]

Interesting the change in tides. From another thread:

http://theoildrop.server101.com/ubb/ultimatebb.php?ubb=get_topic;f=1;t=006361;p=1#000015

quote:

---

Originally posted by Calvin:
OK just for fun I thought I would add an old one here.I still have my owners manual from my 1968 Chevrolet Camaro Rally Sport 327/275 HP.
-------------------------------------------------

" Use only " First Line " oils witch,according to the lable on the can, are (1) intended for service MS , and (2) pass car makers tests ( including General Motors Standard GM 6041-M).... "

Note : " Non - Detergent and other low quality oils are specifically not recommended"......


-------------------------------------------------
Anticipated temps............. Viscosity number

Above freezing (+32 F ).... SAE 20W, SAE 10W-30

Between 0F and + 32F ...... SAE 10W, SAE 10W-30

Below 0 F ................. SAE 5W,..SAE 5W-20

NOTE : When changing oil consider the anticipated
temperatures for the next 4 months.

* SAE 5W and 5W-20 oils are not recommended for sustained high speed driving.

* SAE 30 and SAE 20W-40 oils may be used at temps above 90 F.

* SAE 5W-30 oils may be used at temps below 32F.

* SAE 10W-40 oils may be used at temps between 0F and 90 F.
--------------------------------------------------
The world was different 36 years ago.

---

 

[Dr. T]

Yeah....they now figured out 5-20 was acceptable at all temps for the duration of the warranty period

 

[Jay]

quote:

---

Originally posted by zoomzoom:
Well I tested different weights in my car and UOA showed that 20wt is just not up to the task of protecting my bearings from my lead foot ...

---

I found just the opposite in my RSX. My wear metals were slightly better with M1 0w-20 vs M1 5w-30 and I had good controls on the 7kmi tests.

 

[zoomzoom]

I think it has to do with our bearing clearances..I guess mine are geared towards thicker oil where yours might be designed for thiner?

 

[Brons2]

quote:

---

Originally posted by zoomzoom:
I think it has to do with our bearing clearances..I guess mine are geared towards thicker oil where yours might be designed for thiner?

---

ZoomZoom, your wear metals look very good on M1 0w20, not sure what you are talking about.

 

[zoomzoom]

Well I tested different weights in my car and UOA showed that 20wt is just not up to the task of protecting my bearings from my lead foot

Here are the wear rates(ppm/1000miles) that I got in my 626 using various oils:

OIL M1/M1/GC/M1
VIS 5W-30/10W-30/0W-30/0W-20
ALUM 0.7/0.75/0.57/0.8
CHRO 0.2/0.11/0.11/0.2
IRON 3.3/2.58/2.39/2.4
COPP 0.7/0.86/0.57/1
LEAD 2.3/1.40/1.36/2.2

I would think the UOA is really only way to find out.

 

[uconn1150]

quote:

---

Originally posted by TC:
2002 Honda Si
Exxon Valdez 5w-20
5,000 mi on oil
8 ppm iron
http://theoildrop.server101.com/ubb/ultimatebb.php?ubb=get_topic;f=3;t=000668#000000

---

Not to get into "thick vs. thin" but I also had 8ppm of iron on my DOHC Honda 1.6 with 1600 more miles with 15w-40.
here

 

[zoomzoom]

Brons2 take a closer look!
Compare M1 0W-20 to GC 0W-30:

-M1 produced almost twice the lead of GC

-M1 produced almost twice the chromimum of GC

-M1 produced almost 45% more copper compared to GC

-M1 produced almost 30% more Al compared to GC

So in 10K interval that I usualy run this is how would my wear metals look like with M1 and GC

M1 0W-20**GC 0W-30
AL ** 8 ** 5.7
CR ** 2 ** 1.1
FE ** 24 ** 24
CU ** 10 ** 5.7
PB ** 22 ** 13.6

 

[Ugly3]

I think MolaKule has it about right. There were hundreds of thousands of engines running on 20 weight oil in the 40's and 50's. Back then the oils were a far car from the oils of today.

Slightly

and proving nothing:

My Grandpa ran a 1940 Chevy the year around on a steady diet of DX Brand 10 weight oil. He lived in Indiana and the car ran 70,000 or 80,000 miles without failure.