Oil viscosity

[Panda]

Okay, sorry about this, but I've got another stupid question for everyone's expertise.

Went to buy oil for my Series III, but couldn't remember what we usually get (or should I say, what Tony usually gets).

We always buy Penrite however, I was stunned by the different grades. They ran from 5-60, 10, 15, 30 & I think 45? (Can't remember exactly all the grades they sold).

Anyway, decided on the middle ground & bought the 15W-60. Does it make such a difference? & should you use different oils for different weather, e.g. summer v winter?? What's the optimum for an engine as old as the III?

Thanks in advance

[Tank]

Okay, sorry about this, but I've got another stupid question for everyone's expertise.

Went to buy oil for my Series III, but couldn't remember what we usually get (or should I say, what Tony usually gets).

We always buy Penrite however, I was stunned by the different grades. They ran from 5-60, 10, 15, 30 & I think 45? (Can't remember exactly all the grades they sold).

Anyway, decided on the middle ground & bought the 15W-60. Does it make such a difference? & should you use different oils for different weather, e.g. summer v winter?? What's the optimum for an engine as old as the III?

Thanks in advance
15W is the index of thickness (simply put) the W is for Winter which means when cold the oil has a thickness (or viscosity) of 15, the closer the number to Zero (0), the thinner the oil so the other half is 60 which means when it (the oil) is Hot it's thickness is 60 or in simple terms much thicker than 15W. Most oils nowadays are Mltigrade like the oil you bought, this same oil is thin (15) when cold and thick when hot (60). That way when you start your cold engine the oil is thin enough to be pumped quickly around to all parts of the engine to lube all the moving bits, as the engine and oil gets hotter the oil gets "Thicker" (60) to properly lube all the bits that are now moving faster and have more strain and stress on them. For instance my Ford GT 5.4L V8 Quad cam engine used 0W-40 synthetic oil, because each head carried 2 camshafts and 4 valves/cylinder it needs oil to be very quickly delivered to the top of the engine to lube all of those extra parts, it is critical in Hi-Tech modern engines to get oil to these parts as quickly as possible, otherwise excess wear will occurr, unlike your SIII engine with old tech OHV's it is not critical to get the oil up to the top as quickly. I'm sorry if I have simplified this explanation too much, it's no reflection on your mechanical knowledge, but a lot of people will find it easier to understand, explained this way, Regards Frank.

[Panda]

Dear Frank,

Thank you so much for that reply. It was perfectly put & I now understand. Not too technical is good for me, as I'm on "L" plates as far as all this is concerned, & your response made it very easy to understand.

Much appreciated.:)

[tony]

I do wish you'd wait till I get home I'll be back soon you know....

[hodgo]

Have a look at this web sight its what penrite rec u\you should use.

Hodgo



http://www.penritedata.com/au/db/vehiclewizard4_s.php?cid=9&make=LAND+ROVER&category=pvehiclespost80&id=1600178&x=118&y=12

[rick130]

<snip>
That way when you start your cold engine the oil is thin enough to be pumped quickly around to all parts of the engine to lube all the moving bits, as the engine and oil gets hotter the oil gets "Thicker" (60) to properly lube all the bits that are now moving faster and have more strain and stress on them. <snip>

Sorry Frank, but that is just plain wrong.
No lubricating oil gets 'thicker' the hotter it gets. They all get thinner as temperature increases.

With the SAE viscosity range, the xW part refers to an oils pumpability at sub zero temperatures. This is actually measured as a pressure reading in centipascals (cP)
The 5W, 10w, etc refers to a specific range of pressures/temps the oil must meet at low temps.

As an oil gets hotter and thins out, its viscosity is measured at 100*C. These viscosity measurements are measured in a scale known as centiStokes. (cSt) Whatever viscosity our oil 'measures' at this temp determines which SAE viscosity range it falls into (20, 30, 40, 50, 60)

Remember that SAE xW-X numbers are not absolute, but a range that an oil falls into, and ALL of the final ranges are a lot, lot thinner than any of the W ranges.

The rate at which an oil thins is measured as its Viscosity Index (VI)
The higher the number, the slower an oil thins as it gets hotter.
Generally, the higher the VI the better, as it can be an indicator of better base oils (eg Synthetics usually have a much higher VI than a mineral based oil) but trickery can often be involved here as a blender will also use a range of polymers known as Viscosity Index Improvers that can artificially reduce the rate of thinning. These VII's are generally used with thinner type base oils to get a reasonable low temp pumpability, while still meeting the higher SAE high temp range scales. It's how a multigrade mineral oil is made.
Unfortunately VII's they have a tendency to shear in service (and more so in gearboxes, etc) and so over the life of the oil the high temperature viscosity becomes thinner and thinner.

Check out this http://www.aulro.com/afvb/technical-chatter/47096-valvoline-synpower-5w-40-td5.html for the relevant charts and some typical well meaning but misguided comments and answers.

[Panda]

Yes darling one, but you're not here now are you?;)


I do wish you'd wait till I get home I'll be back soon you know....

[Panda]

That's brilliant. Next time I'll get the 40. I had no idea gear oil comes in different levels as well. :o

Geez I'm glad I'm not a mechanic!:D Too damn complicated for me!



Have a look at this web sight its what penrite rec u\you should use.

Hodgo



http://www.penritedata.com/au/db/vehiclewizard4_s.php?cid=9&make=LAND+ROVER&category=pvehiclespost80&id=1600178&x=118&y=12

[Panda]

Bloody hell!:o Now I'm definitely confused!



Sorry Frank, but that is just plain wrong.
No lubricating oil gets 'thicker' the hotter it gets. They all get thinner as temperature increases.

With the SAE viscosity range, the xW part refers to an oils pumpability at sub zero temperatures. This is actually measured as a pressure reading in centipascals (cP)
The 5W, 10w, etc refers to a specific range of pressures/temps the oil must meet at low temps.

As an oil gets hotter and thins out, its viscosity is measured at 100*C. These viscosity measurements are measured in a scale known as centiStokes. (cSt) Whatever viscosity our oil 'measures' at this temp determines which SAE viscosity range it falls into (20, 30, 40, 50, 60)

Remember that SAE xW-X numbers are not absolute, but a range that an oil falls into, and ALL of the final ranges are a lot, lot thinner than any of the W ranges.

The rate at which an oil thins is measured as its Viscosity Index (VI)
The higher the number, the slower an oil thins as it gets hotter.
Generally, the higher the VI the better, as it can be an indicator of better base oils (eg Synthetics usually have a much higher VI than a mineral based oil) but trickery can often be involved here as a blender will also use a range of polymers known as Viscosity Index Improvers that can artificially reduce the rate of thinning. These VII's are generally used with thinner type base oils to get a reasonable low temp pumpability, while still meeting the higher SAE high temp range scales. It's how a multigrade mineral oil is made.
Unfortunately VII's they have a tendency to shear in service (and more so in gearboxes, etc) and so over the life of the oil the high temperature viscosity becomes thinner and thinner.

Check out this http://www.aulro.com/afvb/technical-chatter/47096-valvoline-synpower-5w-40-td5.html for the relevant charts and some typical well meaning but misguided comments and answers.

[tony]

Bloody hell!:o Now I'm definitely confused!


as i said I will be ome soon, just as an aside here using any synthetic oils in a old engine is no good, any good quality 20w 40 is ok and your forbidden to go to the pub on Saturday


your Lord and master

T

[Panda]

:twobeers::tease::Rolling::Rolling::Rolling::Rolli ng:



as i said I will be ome soon, just as an aside here using any synthetic oils in a old engine is no good, any good quality 20w 40 is ok and your forbidden to go to the pub on Saturday


your Lord and master

T

[Panda]

Okay for all you tech heads out there - how come zinc in oil improves performance? Anyone?

[PhilipA]

Look Google "oil additive zinc" and you will find hundreds of explanations, and why too much is bad.
Regards Philip A

[rick130]

Okay for all you tech heads out there - how come zinc in oil improves performance? Anyone?

ZDDP is used primarily as an anti-scuff/anti-wear additive. It's also cheap, and also poisons catalytic converters, hence it being reduced in level and dropped in newer spec brews.
Many people think that an oil needs copious amounts of ZDDP to be any good, particularly the flat tappet V8 brigade, but new/better ( more expensive) additives are being used such as Boron esters.
Oils like Mobil Delvac 1 have virtually no ZDDP yet that oil probably has one of the most robust anti-wear additive packages of any currently available oil.

[Panda]

Look Google "oil additive zinc" and you will find hundreds of explanations, and why too much is bad.
Regards Philip A

That doesn't sound good! I'll have a look, thanks:)

[Tank]

Sorry Frank, but that is just plain wrong.
No lubricating oil gets 'thicker' the hotter it gets. They all get thinner as temperature increases.

With the SAE viscosity range, the xW part refers to an oils pumpability at sub zero temperatures. This is actually measured as a pressure reading in centipascals (cP)
The 5W, 10w, etc refers to a specific range of pressures/temps the oil must meet at low temps.

As an oil gets hotter and thins out, its viscosity is measured at 100*C. These viscosity measurements are measured in a scale known as centiStokes. (cSt) Whatever viscosity our oil 'measures' at this temp determines which SAE viscosity range it falls into (20, 30, 40, 50, 60)

Remember that SAE xW-X numbers are not absolute, but a range that an oil falls into, and ALL of the final ranges are a lot, lot thinner than any of the W ranges.

The rate at which an oil thins is measured as its Viscosity Index (VI)
The higher the number, the slower an oil thins as it gets hotter.
Generally, the higher the VI the better, as it can be an indicator of better base oils (eg Synthetics usually have a much higher VI than a mineral based oil) but trickery can often be involved here as a blender will also use a range of polymers known as Viscosity Index Improvers that can artificially reduce the rate of thinning. These VII's are generally used with thinner type base oils to get a reasonable low temp pumpability, while still meeting the higher SAE high temp range scales. It's how a multigrade mineral oil is made.
Unfortunately VII's they have a tendency to shear in service (and more so in gearboxes, etc) and so over the life of the oil the high temperature viscosity becomes thinner and thinner.

Check out this http://www.aulro.com/afvb/technical-chatter/47096-valvoline-synpower-5w-40-td5.html for the relevant charts and some typical well meaning but misguided comments and answers.
Rick, thanks for your expertise in explaining oil viscosity, you undoubtably know your oils, but as I said in my post to Panda, I was "simplifying" the explanation in terms that most would understand, I'm sure if I had explained that Long Chain Molecules unwind and lengthen when hot and give better shear strength would have been a bit of overkill for someone that wanted a simple answer to which oil to use in her SIII, Thanks again for your detailed explanation, Regards Frank.

[Blknight.aus]

adding SOME zinc to oil makes it work better in some circumstances for much the same reason that putting a handfull of sand down a steel slide makes you go down it faster if you chuck it on just as you go down. in a nutshel it reduce friction.

for a SIII in queensland I use a 10-50w oil and in the south Id be using a 10-40.