Viscosity and Wear

[buster]

It seems that all of us still really have varying opinions on this subject. I'm just curious if most people subscribe to the idea that a thicker oil is better for engine wear? The Steve Bergin article makes you think otherwise. What is exactly is the relationship between viscosity and wear? I don't think we have the answer yet but Bob and others have pointed out that thinner oils with greater flow might be as good or better.

 

[Terry]

buster, you need the appropriate vis for the engine, bearings, flow rate etc. Molakule is attempting to collect enough data of bearing clearance to provide a updated scientific paper of same. My rule of thumb, is "go with the flow". I guess I need to read this article, is it here ?

 

[QuadDriver]

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Originally posted by buster: It seems that all of us still really have varying opinions on this subject. I'm just curious if most people subscribe to the idea that a thicker oil is better for engine wear? The Steve Bergin article makes you think otherwise. What is exactly is the relationship between viscosity and wear? I don't think we have the answer yet but Bob and others have pointed out that thinner oils with greater flow might be as good or better.

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Consider if you will.....>20 years ago, manual trannies in cars were filled with heavy weight, high sulphur, high EP 'gear lubes', in many cases no more andanved than 'runny grease'. About 20 years ago the same were filled with motor oils. starting about 10 years ago they are filled with ATF (some, but not many still spec motor oil. The rate of failure of car manual trannies (note I did not say clutches) is about the same as it was then: nil*. Todays trannies are also subjected to just as much HP loads as previous. This demonstrates that the additives in the oil (and yes, even ATF has such additives to aid the planetary gearset in an auto tranny which is where ALL of the power must pass) tended to be of more importance than viscosity of same. The same trend towards lighter weight oils exists for engines also (CAFE concerns notwithstanding). Of course in a perfect worlds, needle bearing bearings would be in every motor like they are in motorcycles. * in the late 80's early 90's it was found that the practice of using grpahite impregnated celluose bearings would not hold up well with motor oil, but would with ATF. Borg Warner and Getrag suffered the most.

 

[pscholte]

I'm with Terry on this one...what viscosity did the engine designers intend? This presumes that the designers/engineers get to have the major say as opposed to those within the company that are more concerned about CAFE,etc. Having said that, I'm only semi-comfortable with the 5W-20 grade although that is what M1 was when it first appeared and I had a friend in FLorida with a Celica GT towing a boat who had no problems with it, even in August!!! I would just like to see in a CAFE free world (something like a caffeine free world) what the viscosity recommendations would be (i.e. it was solely a determination by engineers/designers who wre obssessed with the most effective lubrication for their engines, transmissions, gearboxes, etc).

 

[Terry]

pscholte, Quaddriver, Hopefully guys this website will be CAFE & spin free and can be a conduit to a reliable reference for exactly what you dream of. The final product the design engineer envisions is usually readjusted significantly by the former practicing engineer in management lording over the poor CAD slave. Cut costs, redesign that !

 

[buster]

Here you go Terry. http://www.pecuniary.com/newsletters/advertising.html It is interesting how in other countries, with the same exact cars and engines, run such heavy oils. For instance, the New Zealand/Austrialian Mobil 1 websites recommend viscosities for little wussy 4cyl like mine around 40wt to even 50wt oils! These oils would have higher HT/HS but for what they can output, they don't need it. I do know that we do run lower visc. because of CAFE, but being you see that other countries run heavier oils tells me that viscosity really doesn't play that much of a role in terms of wear. I also think that we are going to be surprised at how well these new 20wts do. The new Mobil 1 0w-20 I want to run in the winter and take a UOA. It looks well built. The fact that they used this years ago suggests that it would be fine I think. [ July 12, 2003, 04:22 PM: Message edited by: buster ]

 

[labman]

I wonder if the thinner grades provide a better compromise between cold and hot operation. Most lubes now are multi grade. Some of the synthetics are inherently less subject to heat thinning even before any additives. Still they all are thinner pounding down the road when it is a hundred out than starting up after setting out in a parking lot at 40 below. And as multi grades have become more common, failures of both engines and transmissions are rare if they actually have something, anything, in them. Quad driver made a good point of manual transmissions seldom failing. And that is without regular changes of oil in many cases.

 

[Jay]

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Originally posted by pscholte: I would just like to see in a CAFE free world (something like a caffeine free world) what the viscosity recommendations would be (i.e. it was solely a determination by engineers/designers who wre obssessed with the most effective lubrication for their engines, transmissions, gearboxes, etc).

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Honda is under no CAFE constraints for their oil recommendations. From Lubes & Greases magazine:

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As Honda's Principal Chemist Jeff Jetter puts it, "We're so far ahead of the mpg curve that CAFE was not an issue. We meet EPA requirements easily. But we're a 'green' company and believe that the fuel economy improvement provided by 5w-20 is important. "Also, our testing indicates that engine performance is generally improved with a lighter viscosity grade engine oil, resulting in reduced emissions during cold starts before the catalyst comes on line, when cars emit most of their pollutants... "...Durability is not an issue either. If it were, we wouldn't recommend 5w-20."

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[Patman]

Buster, in Terry's SpeedTalk interview he mentions starting with a 30wt oil and going from there. I believe this to be true, that just about every engine will do very well with a 30wt, but with those that have tighter clearances, they could get better wear numbers with a high 20wt to low 30wt oil, while those with looser clearances can get better wear with a high 30 to low 40wt oil. It all depends on the mileage on your engine too, as that will change your engine's appetite for viscosity too. I still stand by my firm belief that the 50wt oils are far too thick for the best engine longevity for most engines.

 

[buster]

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"Also, our testing indicates that engine performance is generally improved with a lighter viscosity grade engine oil, resulting in reduced emissions during cold starts before the catalyst comes on line, when cars emit most of their pollutants... "...Durability is not an issue either. If it were, we wouldn't recommend 5w-20."

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Very interesting. Thanks Jay/Patman for the input.

 

[Dominic]

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Originally posted by Patman: Buster, in Terry's SpeedTalk interview he mentions starting with a 30wt oil and going from there. I believe this to be true, that just about every engine will do very well with a 30wt, but with those that have tighter clearances, they could get better wear numbers with a high 20wt to low 30wt oil, while those with looser clearances can get better wear with a high 30 to low 40wt oil. It all depends on the mileage on your engine too, as that will change your engine's appetite for viscosity too. I still stand by my firm belief that the 50wt oils are far too thick for the best engine longevity for most engines.

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I agree with this, well put...

 

[pscholte]

This brings up a good point. More than once, I believe I have heard someone say, "But the Europeans..." and whatever point they are making about European car manufacturers/owners, I believe, is usually quite accurate. In this case it would be, "But European OEMS recommend 15W50 and 10W60 etc," and that would be true...but just like some of us, whose to say the Europeans don't have an "inertia" when it comes to oil specifications that is hard to change like some of the inertia on our side of the pond. I think Terry Dyson and others have made good points that engines with tight tolerances (like European engines) don't need mongo weight oils yet their OEMS continue to recommend them. Is it because they potentially have opportunity to drive at higher speeds? A lot of Europe is probably now 85mph (~130KPH) or less so that is not that much different from us. So why the continuation of the heavyweight oils. I know its changing somewhat but take a look at the overall picture...it is still biased to the heavier oils. Why?

 

[QuadDriver]

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Originally posted by pscholte: This brings up a good point. More than once, I believe I have heard someone say, "But the Europeans..." and whatever point they are making about European car manufacturers/owners, I believe, is usually quite accurate. In this case it would be, "But European OEMS recommend 15W50 and 10W60 etc," and that would be true...but just like some of us, whose to say the Europeans don't have an "inertia" when it comes to oil specifications that is hard to change like some of the inertia on our side of the pond. I think Terry Dyson and others have made good points that engines with tight tolerances (like European engines) don't need mongo weight oils yet their OEMS continue to recommend them. Is it because they potentially have opportunity to drive at higher speeds? A lot of Europe is probably now 85mph (~130KPH) or less so that is not that much different from us. So why the continuation of the heavyweight oils. I know its changing somewhat but take a look at the overall picture...it is still biased to the heavier oils. Why?

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yanno....we have more high speed highway in montana than what europe has. their speed limits are pretty low (most of their cars are in the 1.2-2.0L class anyway) and their cops are unforgiving... also, they were behind the US for 20+ years when it comes time for emissions and 'cafe', now they are playing catchup and their phase ins of each tier is actually pretty agressive.

 

[moribundman]

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yanno....we have more high speed highway in montana than what europe has. their speed limits are pretty low (most of their cars are in the 1.2-2.0L class anyway) and their cops are unforgiving...

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Well, when I'm in Germany I drive routinely for a couple hours +120mph (that's redline at about 6200 RPM) if traffic allows (which it still does occasionally). In Montana I did drive ONCE 130mph with my A4, but it's not a good idea. Montana highways are NOT the Autobahn. I was afraid a deer might hop on my hood, too! The German Autobahn has still no speed limit (130km/h is a suggested speed), and even my old '89 Scirocco GT with the 1.8 engine could go 125mph (200km/h). The oil in that car would reach easily 140 degr.C (284 degr F). That's probably why ultimate protection is preferable under those conditions, and 5W-40 and 10W-60 oils are popular. It's true that many engines are small (the higher the displacement, the higher the yearly tax!), but they are usually high performance engines. Just look at the VW/Audi 1.8T engine. Not to mention the plethora of bigger BMW, Mercedes, VW, Audi, Porsche engines that are quite common.

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also, they were behind the US for 20+ years when it comes time for emissions and 'cafe', now they are playing catchup and their phase ins of each tier is actually pretty agressive.

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European engines were far ahead of the US in terms of lower fuel consumption, though. Catalytic converters became pretty much standard in the early '80s. They should have gotten rid of leaded gas a long time ago, though. I don't know if Europen car makers are really playing catch-up when it comes to emissions. Without seeing their requirements to pass the bi-annual TÜV (smog and safety check) I will not comment on this issue. But I will say that Europeans generally maintain their vehicles MUCH better than Americans. 3/4 of the beaters I see stink up the air here in the "Republik of California" wouldn't have a chance to pass the German smog and safety check!

 

[nortones2]

QD: It is dangerous to generalise about speeds when you haven't been out of the USA, which is the impression I get from some of your posts! By the way, how many miles of high speed highway are there in Montana? On OEM recommendations on viscosity in Europe, without generalising too much, the UK seems to be using 30 to 40 weight on new/recent cars. For high performance cars (M3 BMW etc. 40- 50 weight) For competition cars, 50-60 weight.

 

[moribundman]

nortones2, The speed limit had been lifted in Montana some time back in the mid/late '90s. The speed limit has been 75mph for cars and 65mph for trucks in Montana since '99. That's because people went hogwild, and because those highways were not suitable for higher speed.

 

[nortones2]

Moribundman: thanks. I'd heard about the Montana no-limit roads, but didn't realise they'd been limited again. Not exactly an Autobahn-fest then!

 

[QuadDriver]

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Originally posted by moribundman: nortones2, The speed limit had been lifted in Montana some time back in the mid/late '90s. The speed limit has been 75mph for cars and 65mph for trucks in Montana since '99. That's because people went hogwild, and because those highways were not suitable for higher speed.

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The autobahn (which simply means motorway, not high speed proving track) now has a 130kph speed limit for its entire length, and due to safety emissions concerns, is 100kph in populated areas - welcome to the 2000's. (I did nothing more scientific than ask a friend in beverstadt) just because you DONT get pulled over is not a replacement for speed limits (btw deer dont exist in germany? when did *that* happen?) I have routinely driven 100mph between RR pass south of vegas to the laughlin cut on the sam kinnison highway (save searchlight) and dont get stopped. Signs say 65. as for european fuel efficiency, a 1.3L diesel lupo yes, will probably get better mileage than a 6.0L tahoe. On another board someone once made the bold assertion that european fleet mileage is 2-4 times that of the US. I pulled up some data that showed the US fleet mileage (cars+trucks) is about 24ish and the europeans is hovering around 30. when you consider half of their vehicle sales are NOT suvs and trucks.... there is a misconception that the average joe in europe drives a bimmer or mercedes or lambo, and I have seen it repeated on this board now at least thrice in the last few days....and the misconception is just plain flat out *wrong* for data and trends on mileage and emissions, just pull up data on the OECD

 

[buster]

Most Europeans cannot afford BMW's and MB, this I do know bc I work with many europeans. Ever watch a foreign movie? They drive those little MG/ Cooper type cars, not BMW's.

 

[cvl]

You guys should check out manufacturer's recommended viscosities for cars sold in the US versus the exact same car sold overseas. One such example is the new Civic Si in the States. Honda USA recommends 5w20 (their house brand is a semi-syn) or Mobil 1 0w20. For the EXACT same car sold in England (it's actually produced there and imported to the US) that's called the Civic Type-S, Honda UK recommends semi-syn or full synthetic 10w-40 oil. Guess which recommendation was made by bean-counters with no concern for engine wear past their 3yr/36,000 mile powertrain warranty and guess which one was made by the engineers who designed the car.