Why 20wt Stubborness??

[Kestas]

Some of this has been discussed on Lubes'n'Greases. Lower viscosity helps with fuel economy. It's reached a point where the industry is now trying to figure out how low they can go with saving fuel before they start hurting the engine with wear.

 

[chevrofreak]

Originally Posted By: Smokescreen
so the weight of oil 20wt vs 30wt didn't really have anything to do with oil being consumed?


I've not kept records when topping up, but there may have been a slight increase with the 20, but most 20's also have a higher NOACK volatility number than the 10w30 I had been running previously. That alone should increase the consumption.

The lowest consumption I remember was with Castrol GTX 10w30. GTX has a fairly low NOACK % compared to the Trop Artic and Pennzoil. ----> http://www.amsoil.com/performancetests/g1971/images/noack_640px.jpg

 

[AEHaas]

Evidence that I have presented actually shows that your engine will last longer on the thinner oils than the thicker ones. So if you really want to get the most life out of your engine -use todays xW-20 grade oils. Looking up my articles / UOA will show that there is less wear and tear when a 20 grade oil is used where a 40 grade is specified.

aehaas

 

[Smokescreen]

I'm not trying to argue with you AEHaas, but didn't your articles mention that the more the engine ages the more it will need thicker wt oils? I am interested in cars that are going to have more than 100,000 miles.

 

[d00df00d]

Originally Posted By: Gary in Sandy Eggo
1. Heavy duty use has always benefited from an oil thick enough to keep moving parts separated. At full operating temperature this means viscosities associated with SAE-40-50 oils (say 16-20 Cst).

...Sort of. Don't forget, thicker oils don't cool as well and don't flow as quickly through bearings. Depending on the application (and the oil in question), those disadvantages can quickly outweigh the advantages.

Originally Posted By: rationull
Even Honda still specs 5w30 for the Civic SI and the S2000. However, Ford specs 5w-20 for the Mustang GT's 300 hp 4.6 V8. While that V8 has relatively low specific output by many modern standards (65 hp/L vs 77 hp/L for the current economy trim Civic for instance, and less specific torque than the Civic's 1.8 as well), I think it would be a stretch to say that it's expected to put up with merely "routine" driving.

I think the answer does indeed lie in the specific output numbers, plus the fact that cylinder pressures will be much higher in the Honda engines.

Also, doesn't Honda spec conventional oils for the Civic Si and S2000? That may be why they want the thicker stuff.


Originally Posted By: Smokescreen
My question is, do the 20wts show this same standard by the time it reaches the same age? If so, why aren't these being posted so we can bury this and say yes 20wt are acceptable for any use (severe or otherwise), and will take your engine to 100-150-200,000 miles just like a 30wt can.

If your question is really that broad, we can't bury it because there are so many variables involved. If you're talking about a mediocre engine with poor cooling and a 5w20 conventional, it probably wouldn't stand up to hard use; if you're talking about a finely built and tuned engine with an oil cooler and Fuchs Titan GT-1 0w-20, it'll take whatever you throw at it. You have to look at it case by case.

However, if your question is whether the RIGHT 20-weight oil is a good choice for hard use in an engine that is built for it, I would bet real money that the answer is yes.


Originally Posted By: ToyotaNSaturn
With SJ & many SL oils, 30 grade oils sheared back the 20 grade range in a hurry (your CAFE comment here). This effectively makes a vehicle that has a lifespan with 20 grade oil. In light of this, it gives us more thinner oil comparisons than we may have originally thought.

Good call.


Originally Posted By: Smokescreen
I'm not trying to argue with you AEHaas, but didn't your articles mention that the more the engine ages the more it will need thicker wt oils? I am interested in cars that are going to have more than 100,000 miles.

If the engine wears less, it will be less likely to need thicker oil at a given mileage in the first place.

 

[Frank D]

My 2002 Windstar with 3.8 V6 now has 140,000 miles on it all on 5w-20 and is not burning oil. Haven't done any used oil analysis. Still runs great.

 

[Gary Allan]

There will always be exceptions ..just like any two people in the same job ..same number of kids ..same pay grade having vastly different lifestyles.

..but generally speaking ..this is much ado about nothing. Never has been. As Doug points out ...there were TWO main oil grades in use for decades before multivisc came around. SAE 30 and SAE 20. People swapped them back and forth due to season. Multivisc oils extended the cold properties a bit lower ..at a price.

When most think of "wear" in regards to lower visc oils they almost invariably think of bearing wear. Yet UOA after UOA that shows little or no bearing wear with 20 grade oils doesn't shed the notion. Now surely if you see elevated bearing wear you would opt for a higher visc fluid to see if it contained the condition ..but the absence of it doesn't seem to bury this fear ..UOA after UOA ..hundreds; if not thousands of them. The rest is typically dealt with with the add package; even in those engines NOT built from the ground up with lighter visc oils in mind.

As our lesson in journal bearings in hydrodynamic lubrication has taught us, you can't trump visc in that environment. Hence this is a telltale validation (in rejection) of the MAIN objection to lighter oils. If it doesn't prove itself in that environment, one could reason that it's not an issue at all (terms and restrictions surely apply).

 

[BuickGN]

Originally Posted By: AEHaas
Evidence that I have presented actually shows that your engine will last longer on the thinner oils than the thicker ones. So if you really want to get the most life out of your engine -use todays xW-20 grade oils. Looking up my articles / UOA will show that there is less wear and tear when a 20 grade oil is used where a 40 grade is specified.

aehaas


How many teardowns have you done? I don't put a whole lot of weight on used oil analysis. It's been proven they're better at trending than showing actual wear. My teardowns have shown the exact opposite of your used oil analysis. No ifs ands or buts about it, there has always been less wear in my engines with the thicker stuff. Being that I have seen it with my own eyes, I will continue using a 30wt in the Acura and a 20-50 in the GN. Using a 20wt for no good reason other than it's the new cool thing to do or to save $1 per year on gas just isn't reasonable for me.

 

[Gary Allan]

Quote:
Using a 20wt for no good reason other than it's the new cool thing to do or to save $1 per year on gas just isn't reasonable for me.


Sure. ...but in all fairness I don't think that using a 30 thru 50 grade out of fear is any more sensible.

I wouldn't recommend 5w-20 for my buddy's bracket racer built engines ..nor his stock car built engines. I also doubt that Porsche is going to "go light" any time in the near future.

 

[BuickGN]

Originally Posted By: Gary Allan
Quote:
Using a 20wt for no good reason other than it's the new cool thing to do or to save $1 per year on gas just isn't reasonable for me.


Sure. ...but in all fairness I don't think that using a 30 thru 50 grade out of fear is any more sensible.

I wouldn't recommend 5w-20 for my buddy's bracket racer built engines ..nor his stock car built engines. I also doubt that Porsche is going to "go light" any time in the near future.


I run the ACD in the TL because of my climate and because it sees about 100 miles per startup/warmup cycle.

I understand the reasons to run a 20wt but I never thought there would be so many threads about people being afraid of hurting a motor with 5-30 when a 5-20 was factory fill yet there's a new thread every day about someone running a 20wt in a car that was originally spec'd for a 30wt.

I have no problems with 20wts in many situations, it's just the general attitude around here that they're somehow superior in every way over a 30wt that is annoying.

 

[Gary Allan]

Quote:
it's just the general attitude around here that they're somehow superior in every way over a 30wt that is annoying.

Yes ..the same issues can get old.

I'm not so much a "light head" as I'm an anti dogma head. I don't think I need to prove the issue too much on the high end of things ..although I do hear too many references to "tight clearances" and whatnot when the same engine is used from Canada to southern Texas on the same oil ..where one will be so far above a 70 weight for the entire engine running event in a Canadian winter ..while the same engine in Texas will be over a 70 weight for half of it's warm up event in summer Texas.

It's the same when someone says that you can't use 5w-40 with VTEC. Unless everyone who has the VTECH engines waits until full warm up ..then 5w20 should produce problems at some point in the warm up process ..or 30 weight further on ..and 40 weight further on. They all transition through the same high viscosity state that is well above a 20 grade.

My personal light oil distractions are just seeing how much water the fear factor(s) hold in the most unsuitable environment for such things. While it's not a racing application or high power density, it's as close to a tractor engine as you can get.

 

[BuickGN]

I agree with you 100%. In a different climate I would have no problem running a 0-20. But in my climate, my ACD is probably as thin at any given point during the driving process as a 0-20 up north.

I'm glad people like you test the limits so we don't have to. It's good to know how much of a safety margin we have.

Though if in doubt, I am one of the ones that will go up a grade just to be on the safe side.

 

[Brian Barnhart]

A major factor in the “stubbornness” is possibly the fact that for decades few if any manufacturers recommended straight 20 or xW20 oil for hot weather or year round use (except perhaps for areas with cool summers).

 

[06VtecV6]

Originally Posted By: Smokescreen
I have been frequenting this forum for quite a while now and it seems there is a cyclical argument over the effectiveness 20wt oil on modern day vehicles that ask/require them. I myself have been torn both ways by convincing arguments from the 30wt diehard holdouts, and those that have accepted the advances and have run the 20wt.

I guess the most convincing argument to hold me back (as well as others) from accepting the 20wt as the new standard are:
1) engines that once used 30wt now using 20wt appearing to be driven by CAFE, and
2) the perception that most buyers have that manufacturers only care that the engine lasts long enough to meet warranty and somewhat keep their reputation. Sure the wear numbers look good when the engine only has 20K miles on it, what engine wouldn't?

I can dig up many 20wt UOA that show great wear numbers but I can't refine the search enough to capture engines that have 100-150,000+ miles using 20wt oils. I think that if we could be shown that engines can last just as long as the 30wt engines have, it would be helpful. Perhaps this has already been done, but like I said, I can't seem to find it.



A friend of mine drives a Ford Ranger (~2002) and he still uses 5w30 despite "5w-20" being printed right on his oil cap in BIG YELLOW LETTERS It's just the legacy of the 5w30 weight and lack of foresight as to improving SAE standards (SM 5w-20). I also think a lot of it is the perception of how "tough" or lack-thereof "thinner" 5w-20 is for their tough little applications (truck) but I guess it's the same for cars as well. 5w30 tradition or habits are hard to break coupled with the fact that changing oil is a man's way of feeding his beast and must bring so much satisfaction to where they don't want to deviate from this feel-good tradition perhaps even thinking the car has emotions and may be grumpy if not given what it's used to.

 

[demarpaint]

I guess I'm not stubborn then As soon as I'm done with the A-Rx rinse of 5w30 Havoline I'm switching over to YB 5W-20 in the 93 Aerostar, just in time for the winter cold.

Wish the 88 E-150 4.9 was back spec'd for 5W-20, I run it in that too!

Frank D

 

[BrianWC]

I'd add that I am not opposed to 20 weight, either. Merely, there are so many more opportunities to find 30 weights on closeout....

 

[Gary Allan]

Originally Posted By: Brian Barnhart
A major factor in the “stubbornness” is possibly the fact that for decades few if any manufacturers recommended straight 20 or xW20 oil for hot weather or year round use (except perhaps for areas with cool summers).


I don't think that any US OEM has recommended a straight weight oil in over 30 years (passenger cars, anyway) ..for the same CAFE reasons (and the obvious benefits of cold start performance) ..and multivisc 20 grade fluids were not available in the market. It took Ford to desire this OEM spec'd fluid and bring it to market. They've known that 5w30 grade fluids degraded to 20 grade fluids for decades. The survivability of the engines was never in question. The ability to get tested and certified with the same operational grade fluid was what most OEM's didn't bother with. Ford, with its proprietary "gas guzzler" profit model, was unique in this regard. They were the ones who sold millions of Escorts at a loss (originally) so that Towncars (and the like) could be sold at big profits without CAFE penalties.

 

[PandaBear]

Originally Posted By: BrianWC
I'd add that I am not opposed to 20 weight, either. Merely, there are so many more opportunities to find 30 weights on closeout....


That's the other way around here, 5w30 are gone in an instant, then 10w30. There are always 5w20 left when the sales are over.

 

[BrianWC]

Well, here, usually there isn't that much 20 weight stocked to begin with. It and the 5W30 susually go first and the 10W30 is left on the shelves. The only great deal I ever got on 5W20 was Redline on closeout when the local Advance Auto stopped carrying it. Got it for $3.50 a quart. My CR-V didn't know what hit it, I'm sure! But the V usualy goes around running 10W30..and without issue, I'd add. Heck, the first year I owned it, in 2002, no one around here evey carried 5W20.

 

[Gary Allan]

When 5w-20 MC came to market, the local Walmart couldn't keep it in stock ..or rather the stock guy said that it was the hardest to keep in stock. It was probably because it was the cheapest source of the stuff.