i know it has been said any 30w oil can be used, but how does one know a30 weight oil ,Gerryoil
oil
Hi all , another oil question, What does 30w oil mean , is 15 / 20 a 30w oil, does it have to have 30w written on the can. I know im probley showing my stupity here , not hard for me i know it has been said any 30w oil can be used, but how does one know a30 weight oil ,Gerry
i know it has been said any 30w oil can be used, but how does one know a30 weight oil ,Gerry-
Mike Kuscher
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Gerry,
Normally, oil is 'thickest' when it is cold but 'thins out', so it would pour quicker when hot.
The thinner the oil, the better it is at 'penetrating' (WD40) but the worse it is at maintaining its lubricating coating.
Oil is graded by how well it 'flows' at given temperatures.
This is actually the oils SAE number, so '30' oil will usually show 'SAE 30' on the can. People started to refer to the SAE number as 'the weight' of the oil, although this is actually a 'slang' term.
This is a 'single grade' oil.
Nowdays, it is more common to find 'multi grade' oils.
The reason for this is, of course, if the oil is colder, its viscosity is thicker, so it flows more slowly.
To improve the 'flow' at low temperatures, for quicker lubrication, they started to take lower viscosity oils (thinner) then add chemicals to them so that, as they got hotter, they would actually get a higher viscosity (thicker) than they would normally have.
(The chemicals are actually Polymers).
An example of this is your quoted 15/20.
It would actually be labeled as '15W/20'.
This means the oil, when cold (the 'W' actually stands for 'Winter' not weight, but that's where the slang term came from) actually has a viscosity of only SAE 15, so it flows easily. When it gets hot though (typically 100 Celcius) the chemical additives make it 'thicken' so that it will have the same viscosity as an SAE 20 oil and, supposedly, never get worse than an SAE 20 oil.
Do you now understand that the lower the SAE number, the thinner the oil is, so it 'flows' more easily but is not as good at lubricating?
Water would have a very low SAE number.
Grease would have a very high SAE number.
Your engine needs to have a 'fine balance' of SAE number.
Low enough to get quickly through all the small holes and gaps when it's still cold.
High enough to maintain a good, thick, 'slippery surface' on the parts it needs to lubricate once it's got hot.
15 or 20 will never get 'thick enough' for the 30 your engine needs.
Ideally you want a single grade SAE 30 oil (because that is what it was designed for).
You could get away with an oil that is 20W/30, because that is down to only SAE 20 when cold (W-inter) but, so long as your engine warms up quickly enough, it will 'thicken', because of the additives, to be the same as SAE 30.
That is why they suggest that, in winter, you start your engine but let it 'idle' until it has warmed up to 'normal' temperature.
Get the idea?
It is fairly easy to buy a 25 ltr can of SAE 30 -Agriline, Old20, FNH dealers etc.
I seem to recall, from the 'old' site, somebody (was it WaynB?) said...
"You can always tell a guy who is into vintage tractors. He buys his oil in bulk."
Very true!
Mike
Normally, oil is 'thickest' when it is cold but 'thins out', so it would pour quicker when hot.
The thinner the oil, the better it is at 'penetrating' (WD40) but the worse it is at maintaining its lubricating coating.
Oil is graded by how well it 'flows' at given temperatures.
This is actually the oils SAE number, so '30' oil will usually show 'SAE 30' on the can. People started to refer to the SAE number as 'the weight' of the oil, although this is actually a 'slang' term.
This is a 'single grade' oil.
Nowdays, it is more common to find 'multi grade' oils.
The reason for this is, of course, if the oil is colder, its viscosity is thicker, so it flows more slowly.
To improve the 'flow' at low temperatures, for quicker lubrication, they started to take lower viscosity oils (thinner) then add chemicals to them so that, as they got hotter, they would actually get a higher viscosity (thicker) than they would normally have.
(The chemicals are actually Polymers).
An example of this is your quoted 15/20.
It would actually be labeled as '15W/20'.
This means the oil, when cold (the 'W' actually stands for 'Winter' not weight, but that's where the slang term came from) actually has a viscosity of only SAE 15, so it flows easily. When it gets hot though (typically 100 Celcius) the chemical additives make it 'thicken' so that it will have the same viscosity as an SAE 20 oil and, supposedly, never get worse than an SAE 20 oil.
Do you now understand that the lower the SAE number, the thinner the oil is, so it 'flows' more easily but is not as good at lubricating?
Water would have a very low SAE number.
Grease would have a very high SAE number.
Your engine needs to have a 'fine balance' of SAE number.
Low enough to get quickly through all the small holes and gaps when it's still cold.
High enough to maintain a good, thick, 'slippery surface' on the parts it needs to lubricate once it's got hot.
15 or 20 will never get 'thick enough' for the 30 your engine needs.
Ideally you want a single grade SAE 30 oil (because that is what it was designed for).
You could get away with an oil that is 20W/30, because that is down to only SAE 20 when cold (W-inter) but, so long as your engine warms up quickly enough, it will 'thicken', because of the additives, to be the same as SAE 30.
That is why they suggest that, in winter, you start your engine but let it 'idle' until it has warmed up to 'normal' temperature.
Get the idea?
It is fairly easy to buy a 25 ltr can of SAE 30 -Agriline, Old20, FNH dealers etc.
I seem to recall, from the 'old' site, somebody (was it WaynB?) said...
"You can always tell a guy who is into vintage tractors. He buys his oil in bulk."
Very true!
Mike
Nobody is perfect and I want to be a Nobody.
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Meanderer
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Good stuff Mike. Agree all the way with what you say.
With that background, an easy way for people to remember about Multigrades is:
Engine (oil) starts off cold and becomes Hot.
1st number is Oil Properties at cold followed by 2nd number when Hot.
With that background, an easy way for people to remember about Multigrades is:
Engine (oil) starts off cold and becomes Hot.
1st number is Oil Properties at cold followed by 2nd number when Hot.
See what I mean everyone, those Kiwi's even tell Porky Pies (lies). They don't understand anything easily!Kiwi Kev wrote:Mike.............. easy to understand
Kiwi Kev
'
Regards,
Rick
Regards,
Rick
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The Swanndri Guy
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