lower oil viscosity????????

[sportbiker929]

such as 0w-40 or 5w-40 = more power. On the other hand engine wear is also increased? Right? Why would someone prefer slightly more power and slightly better economy over engine life?

Am I off base or am I misinformed. Someone who knows please clear this up for me. I have a Land Cruiser which can use all the power and gas mileage It can get.

Thanks,

Mitch

 

[Gary Allan]

You're coming in here sprtbkr ..and the train is already moving.

(feeling like G'Kar as he was asked "What is G0D and what is truth? ..and when he was done explaining ..he was asked "..but what is G0D ..and what is truth?" ..finally replying, "Truth is the river ..and G0D is the mouth of the river.")

Except for some very limited designs there appears to be no direct relationship between viscosity and wear.

 

[Raven18940]

quote:

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Originally posted by sportbiker929:
such as 0w-40 or 5w-40 = more power. On the other hand engine wear is also increased? Right? Why would someone prefer slightly more power and slightly better economy over engine life?

---

How do 40 weights give more power? What's your question? I'm so confused.

 

[adam123]

Which ever enables less friction should allow more power. Is this what your saying ?

 

[MN Driver]

What are you running in that vehicle right now?

 

[Gary Allan]

I think due to the 0w and 5w-40 reference that he's talking about synthetics and their better cold viscs. Maybe not.

Since a Landcruiser probably, of some vintages anyway, spec a 40 weight, he maybe looking to see if going to a snyth can squeeze a little more out of it in the fuel or power dept.

 

[sportbiker929]

ok, sorry for the unclear post. I am currently running Amsoil AME which is 15w40. Will I see any improvement by switching to say a 0w40 or a 5w40 or even a 5w30 all synthetic of course. I don't want to sacrifice engine protection, but I would like slightly better performance.

Mitch

 

[bruce381]

0w40 or 10w40 ar not really any thinner, cold they would be but not hot. so try a 5/30 that will be thinner both hot and cold.
bruce

 

[Gary Allan]

It will be unlikely that you will realize any increase in performance. You may, depending on your driving habits (length of trip, etc.), realize minor gains in economy. But since you're using a synth already, I doubt it would be measurable. If you do exclusively ..or primarily, short trips ..then a lighter grade may yield some results that you can actually tabulate.

 

[mechtech]

0-40 and 5-40 may be thin for scooters, but are now rather thick for automobiles.
Thinner oils will have less internal engine drag, and will allow more power to be made.
Some air cooled roller bearing bike engines need thick oil, so watch out [Harley Davidson]!

 

[Gary in Sandy Eggo]

quote:

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Originally posted by Gary Allan: Except for some very limited designs there appears to be no direct relationship between viscosity and wear.[/QB]

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I've seen this statement made several times in several places. It is not logical. Higher viscosity oils result in a thicker film of oil between moving parts. The thicker the film, the less opportunity there is for metal to contact metal under heavier load conditions.

A plain bearing, spun at a high enough rpm, can be adequately lubricated by a very thin oil. However, if the rpm's are allowed to drop and bearing loads increase (lugging the engine), a thinner oil will not provide the same level of wear protection as will a thicker oil.

Cam lobes LOVE thick oil. The thicker the better.

Cylinder walls are fairly forgiving of viscosity, the key here is to get adequate oil throw off past the connecting rod bearings (here too thick can become detrimental).

Apparently, most cars are not kept long enough for wear rate differential with thinner oil to become a significant factor.

Regards, Gary in Sandy Eggo

 

[Gary in Sandy Eggo]

quote:

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Originally posted by mechtech:
Some air cooled roller bearing bike engines need thick oil, so watch out [Harley Davidson]!

---

Air cooled engines frequently climb to higher operating tempertures, thus needing a higher viscosity oil simply to keep moving metal parts apart. However, roller or ball bearings lubrication needs are LESS than plain bearings, not more. After all, the individual rollers carry the load between the moving metal parts, and oil is needed only to provide lubrication between the rollers themselves or the rollers and the cage that keeps them in place. And, there's no load between the rollers and the cage that keeps them in place, so any viscosity oil should do fine here.

Regards, Gary in SAndy Eggo

 

[Gary Allan]

quote:

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Originally posted by Gary in Sandy Eggo:

quote:

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Originally posted by Gary Allan: Except for some very limited designs there appears to be no direct relationship between viscosity and wear.

---

I've seen this statement made several times in several places. It is not logical. Higher viscosity oils result in a thicker film of oil between moving parts. The thicker the film, the less opportunity there is for metal to contact metal under heavier load conditions.

Apparently, most cars are not kept long enough for wear rate differential with thinner oil to become a significant factor.
Regards, Gary in Sandy Eggo [/QB]

---

Still although you speak the truth ..there is no reason to abritrarily say just what is thin and what is "thick". You would be saying the exact same thing 25 years ago when there were 10w-30 and 10w-40 ..with 40 weight being considered "best".

When they come out with 0w-10 oils ..you can then say "don't do it!" 20 weight offers more protection.


I would beg to differ with your opinion on American cars not being kept long enough. The vast majority of the American rolling fleet has been maintained on shearing 5w-30 for about 25 years. Most engines are fully functional when the car hits the scrapyard.

 

[Titan]

The affect of temperature on viscosity choice is of paramount importance.

Say you are shooting for 13 cstokes at operating temp. Is your operating temp 210 F, or is it 250 F? The operating temp is what dictates the proper viscosity choice. FLOW is more important than viscosity for protecting a properly operated engine (no lugging, as mentioned above).

When you consider transmissions, then, yes, thicker is generally more protective (of course, there are limits!). But, the ENGINE doesn't require thick oil, unless the oil temps are getting high. However, wet clutch bikes can be caught in a conundrum...you want as thin an oil as possible to lubricate the engine without causing undue drag, but, you want as thick an oil as practical to protect the transmission.