What makes an engine 20W friendly?

[Hemidart]

I have always been of the school that thicker is better. But after looking at many UOA's with 20W's I am starting to become curious about the thinner oils.

So what makes an engine 20W friendly? If a car specs a 5W-30, what would the harm be using a 5W-20? Ford and some others must be onto something and I don't think it's just CAFE.

 

[huffmuds9320]

Thats something I like to know too. I guess you are referring to xW-20 and not 20W-x oils. I don't know a whole lot about engines so correct me if I'm wrong. But newer cars that recommend a xW-20 I guess have tighter engine clearances. So tighter engine clearance would need a thinner oil. Low friction design? If using 5W-20 in an engine that recommends 5W-30, it wouldn't be a good idea. May consume oil and won't be well lubricated so more wear. So my guess is that it depends on the engine.

 

[Gary Allan]

quote:

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and I don't think it's just CAFE

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Are you suggesting that the auto industry, in cooperation with the oil refiners, just spent a ton of money in R&D to develop a new lubricant standard and market new oils just to "feel good"???

Our current movement is almost 180 out of what Europe is doing. Why would it be such a great idea for us ..and not for them?

The new 0/5w-20 oils may be the next best thing to sliced bread ...but what would inspire them to create it and use it when there are a whole bunch of other oils that work just fine before they came along? This tends to indicate that CAFE is the motivational force.

 

[cryptokid]

i think if the engine has a powerfull enough oil pump to maintain a good film of oil then 20wt is ok.

i think the oil pump is the key.

 

[Geoff]

Well I think that there are high volume, lower pressure designs, and high pressure, lower volume counterparts. The latter is probably a better candidate for lower viscosity oils. Experts please correct.

 

[tdi-rick]

In my (limited) experience well over ten years ago using light weight oils (0w-5) in small capacity race engines, we had to tighten up the bearing clearances significantly (down from 2.2 thou to 1.5 thou) and change the bore finish to a much finer finish with plateau honing.

The engines worked well before the changes, and it was well worth using for the power gains, but we had pitting of the bearings (cavitation) and bore wear before changing to a finer/tighter setup.
These engines only used 30psi @7000RPM oil pressure. (less drag=more power)

Of course, going from a SAE 30 or 40 to a 0w- 5 oil is a much bigger jump than a 0w-30 to a 0w-20

 

[Hemidart]

quote:

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Originally posted by Gary Allan:

quote:

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and I don't think it's just CAFE

---

Are you suggesting that the auto industry, in cooperation with the oil refiners, just spent a ton of money in R&D to develop a new lubricant standard and market new oils just to "feel good"???

Our current movement is almost 180 out of what Europe is doing. Why would it be such a great idea for us ..and not for them?

The new 0/5w-20 oils may be the next best thing to sliced bread ...but what would inspire them to create it and use it when there are a whole bunch of other oils that work just fine before they came along? This tends to indicate that CAFE is the motivational force.

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Ok...maybe CAFE has something to do with it. But if you can get better gas milage and your wear numbers are as good as or better then a higher weight oil, then it's a plus plus situation.

 

[Gary Allan]

quote:

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Ok...maybe CAFE has something to do with it. But if you can get better gas milage and your wear numbers are as good as or better then a higher weight oil, then it's a plus plus situation.

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Sure would be. But I keep thinking about Europe. They let the market induce fuel efficiency ..and are not jumping on this xw-20 bandwagon. Why not? Couldn't they use a plus - plus situation as well?
(I'm not just giving counter point here. I really want to know what the real goal is)

 

[KW]

As long as you are able to maintain good oil pressure with the thin 20 weight oil you should be ok. I agree that oil pressure is the key to using a thin oil.

 

[427Z06]

Another way to look at it is, a lot of people were already using 5w20 for some time now. The average dino 5w30 oil of the past 20 years essentially sheared done to a 5w20 within a couple thousand miles, give or take. This was also fuel economy motivated.

 

[Ugly3]

For years and years fuel costs in Europe have been 4 or 5 times the fuel cost in the States.

If anyone were looking to increase fuel econony it would be someone in Europe. I sure don't understand the "logic" of moving toward higher weights.

 

[mikemc]

5w20 was probably motivated by CAFE, but there was a bonus. Quick start-up lubrication, a well built oil and plenty of oil volume (as apposed to high pressure from a thick oil) to moving parts are probably the keys to the low wear numbers we are seeing.

 

[Gary Allan]

In reality, it's probably that Europe doesn't represent any where near the rolling automotive consumption that we do. They also, don't have a large SUV fleet that actually sent the national consumption backwards. I would imagine that even a .005% daily decrease in fuel consumption of the national fleet would fuel several small nations for many months with just one days savings.

Personally, I used lighter weights as a rule. I wasn't shy when M 1 was only available in 5w-20 when it came out 30 years ago. I was eager to use the 0w-30 when it first came out. I ran 10w Delo from the bulk supplies from work in my 3.0 Caravan witout any apparent troubles. The only thing that moved me away from them was the UOA results on my Jeep/AMC/DC 4.0 engines and I acknowledge that this is probably due to the, although stout, somewhat antiquated design of the engine.

 

[MikeR]

quote:

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Originally posted by Gary Allan:

quote:

---

Ok...maybe CAFE has something to do with it. But if you can get better gas milage and your wear numbers are as good as or better then a higher weight oil, then it's a plus plus situation.

---

Sure would be. But I keep thinking about Europe. They let the market induce fuel efficiency ..and are not jumping on this xw-20 bandwagon. Why not? Couldn't they use a plus - plus situation as well?
(I'm not just giving counter point here. I really want to know what the real goal is)

---

European consumers face an artificial market pressure: a tax burden 5 or 6 times higher per gallon than we pay.

CAFE places the fuel economy burden on the manufacturer. This gives the manufacturers incentive to raise fuel economy, preferably in ways that are invisible to the consumer. One mpg means a lot more to Ford and Honda than it does to you and me.

Which provides better wear numbers: traditional heavy oils or beefed-up lighter oils? I guess the folks at BITOG will be the ones who find out first!

mr

 

[Jay]

quote:

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Originally posted by Hemidart:

...So what makes an engine 20W friendly? If a car specs a 5W-30, what would the harm be using a 5W-20?...

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There's a good SAE paper on the subject--1999-01-3468 "The Effect of 0w-20 Low Viscosity Engine Oil on Fuel Economy" written by four researchers from Honda R&D Co. It outlines some of the testing Honda did with 20-weight (and lower viscosity) oils. The engines most suitable for 20-weight oils are engines they term, "low friction", i.e. engines with roller cam followers. That feature, more than any other, was cited as qualifying an engine for a 20-weight or lower viscosity oil.

 

[1999nick]

Back in my earlier days, the 1950's, 20w single grade oil occupied the status of 5w-30 and 10w-30 now. We used 20w oil until and engine began to show wear and use too much oil. Then, we would change to 30w. Straight 10w was a winter recommendation in very cold temperatures.

In those days, I had a 1954 Ford V-8 with overdrive. I used the 20w, and ran this car's mileage up to 140,000 by 1959. The car never used any oil, and it did not get very regular oil changes. I was in the Army, and I was making a 660 mile round trip home at least every other weekend for 3 years of this period. Not much time for oil changes.

Point is, the 20w of 50 years ago gave excellent protection for a long time. Inasmuch as the Ford requirements for its 5w-20 oil are that it hold up twice as long as regular dino, I would be very comfortable using this oil in any car that recommends it. It would probably be just fine in 90% of the cars and light duty trucks on the road today.

 

[Al]

quote:

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Originally posted by Jay:

quote:

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Originally posted by Hemidart:

...So what makes an engine 20W friendly? If a car specs a 5W-30, what would the harm be using a 5W-20?...

---

There's a good SAE paper on the subject--1999-01-3468 "The Effect of 0w-20 Low Viscosity Engine Oil on Fuel Economy" written by four researchers from Honda R&D Co. It outlines some of the testing Honda did with 20-weight (and lower viscosity) oils. The engines most suitable for 20-weight oils are engines they term, "low friction", i.e. engines with roller cam followers. That feature, more than any other, was cited as qualifying an engine for a 20-weight or lower viscosity oil.

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Hmm..I may order this paper..is it worth the 12 bucks or not. Most of them aren't

Anyway good information.

1999nick Also good information..thanks.

 

[Dr. T]

The answer is 'your warranty' makes them user-friendly.

In Europe, gas and oil are expensive. Hence, people generally don't drive v-8's as daily drivers and don't change the oil every 3k mi. either. And auto ownership is generally much past the warranty expiration....

 

[Ugly3]

MikeR - Which provides better wear numbers: traditional heavy oils or beefed-up lighter oils? I guess the folks at BITOG will be the ones who find out first!

If you subscribe to the notion that the vast majority of wear occurs at startup then the beefed-up lighter oils will win.

Time and tests will tell the tale.

 

[TC]

Quaker State acknowledges the impact of CAFE standards on oil weight, but then also goes on to state, "Today's smaller engines have smaller clearances and tighter tolerances between moving parts, and there have been some instances where camshaft damage has occurred because of inadequate lubrication with higher viscosity grades in colder weather...The viscosity grade(s) recommended by the vehicle manufacturer depend somewhat on engine design. Engine manufacturers have spent considerable time and expense experimenting with different viscosity grades and have indicated in the owner's manual the grades they feel will best protect the engine at specific temperatures. While one manufacturer's engine may require an SAE 10W-30, another manufacturer's engine may require an SAE 5W-20 viscosity grade. This is likely due to different tolerances within the engine or other engine design factors."
http://www.quakerstate.com/pages/carcare/whattoknow.asp

There are MANY remarkably good 5w-20 UOAs on this board.