Engine/GBox/Diff oil
Discussion
SimonV8ster said:
OK - i'm going to fill it with porridge and soup. 
Ok but remember it's porridge in the gearbox, and soup in the engine.Or you could try this in the gearbox/diff.
http://www.opieoils.co.uk/p-744-castrol-universal-...
I don't know what to suggest for a turbo engine.
at teh mo i'm using mobil 1 5W-50 from opie, have also used the silky pro s 10W-50 which i think is now renamed fuchs something, and castrol edge sport 10W-60, in my bbr. sometimes used mobil 1 0W-40 in the winter too.
castrol smx-s goes really well in the box but redline MTL etc is good too, few people using that.
any 75W-90 GL5 synthetic is fine for the diff.
castrol smx-s goes really well in the box but redline MTL etc is good too, few people using that.
any 75W-90 GL5 synthetic is fine for the diff.
skinny said:
at teh mo i'm using mobil 1 5W-50 from opie, have also used the silky pro s 10W-50 which i think is now renamed fuchs something, and castrol edge sport 10W-60, in my bbr. sometimes used mobil 1 0W-40 in the winter too.
castrol smx-s goes really well in the box but redline MTL etc is good too, few people using that.
any 75W-90 GL5 synthetic is fine for the diff.
Do you have to warm up an engine using 10W-60 for longer or do anything different? Does it make a difference with operating temperatures and general performance?castrol smx-s goes really well in the box but redline MTL etc is good too, few people using that.
any 75W-90 GL5 synthetic is fine for the diff.
skinny said:
nope you don't need to do anything different at all. when you first start the engine up, a 10W-60 behaves exactly the same as a 10W-40 will.
when the engine starts to warm up, both oils will thin down, but the 10W-40 will just thin down more at high temperatures above its spec rating, whereas the 10/60 is designed for these temps and will remain stable.
I added a bit extra for clarity.when the engine starts to warm up, both oils will thin down, but the 10W-40 will just thin down more at high temperatures above its spec rating, whereas the 10/60 is designed for these temps and will remain stable.
not entirely sure what you mean by stable?
both oils will be stable at the same high temp, the 40 will just be thinner than the 60. stability tends to refer more to the quality of the oil, not breaking down or oxidising at high temps etc, and depends on the nature of the base oil (mineral vs synthetic) rather than the viscosity grade.
both oils will be stable at the same high temp, the 40 will just be thinner than the 60. stability tends to refer more to the quality of the oil, not breaking down or oxidising at high temps etc, and depends on the nature of the base oil (mineral vs synthetic) rather than the viscosity grade.
skinny said:
not entirely sure what you mean by stable?
both oils will be stable at the same high temp, the 40 will just be thinner than the 60. stability tends to refer more to the quality of the oil, not breaking down or oxidising at high temps etc, and depends on the nature of the base oil (mineral vs synthetic) rather than the viscosity grade.
I thought that when they are both in their operating temperature range they would both would have around the same viscosity. The oil with the greater range could then (to a layman anyway) be thought of as more "stable" as it can take a greater difference in temperature without being affected.both oils will be stable at the same high temp, the 40 will just be thinner than the 60. stability tends to refer more to the quality of the oil, not breaking down or oxidising at high temps etc, and depends on the nature of the base oil (mineral vs synthetic) rather than the viscosity grade.
So the 60 can run a higher temp before it "thins out" compared to the 40.
the numbers do not relate at all to the temperature that an oil can 'take'.
the numbers simply mean the following
- a 40 grade oil will be between 12.5 and 16.3 cSt at 100 deg C.
- a 60 grade will be between 21.9 and 26.1 cSt at 100 deg C.
where cSt is a measure of viscosity (time it takes to reach between two points travelling down through a small glass tube)
the temperature an oil can take depends on the quality, and is independant of the viscosity grade. very basically, a mineral oil will start to oxidise and degrade at a lower temperature, anything over 100 deg really, whereas a full synthetic will go to around 120 bulk oil temp (although you still don't want to be pushing those sorts of oil temps for too long).
the numbers simply mean the following
- a 40 grade oil will be between 12.5 and 16.3 cSt at 100 deg C.
- a 60 grade will be between 21.9 and 26.1 cSt at 100 deg C.
where cSt is a measure of viscosity (time it takes to reach between two points travelling down through a small glass tube)
the temperature an oil can take depends on the quality, and is independant of the viscosity grade. very basically, a mineral oil will start to oxidise and degrade at a lower temperature, anything over 100 deg really, whereas a full synthetic will go to around 120 bulk oil temp (although you still don't want to be pushing those sorts of oil temps for too long).
skinny said:
the numbers do not relate at all to the temperature that an oil can 'take'.
the numbers simply mean the following
- a 40 grade oil will be between 12.5 and 16.3 cSt at 100 deg C.
- a 60 grade will be between 21.9 and 26.1 cSt at 100 deg C.
where cSt is a measure of viscosity (time it takes to reach between two points travelling down through a small glass tube)
the temperature an oil can take depends on the quality, and is independant of the viscosity grade. very basically, a mineral oil will start to oxidise and degrade at a lower temperature, anything over 100 deg really, whereas a full synthetic will go to around 120 bulk oil temp (although you still don't want to be pushing those sorts of oil temps for too long).
Ok. But I thought the point of "multigrade" was that we're not looking at a 40 or a 60. But a 10 - 40 or a 10 - 60 where it's viscosity (and therefore protection) will remain "reasonable" over a variation of temperatures. And why race oil isn't multigrade as you just want it to work at the hot temperature of the engine.the numbers simply mean the following
- a 40 grade oil will be between 12.5 and 16.3 cSt at 100 deg C.
- a 60 grade will be between 21.9 and 26.1 cSt at 100 deg C.
where cSt is a measure of viscosity (time it takes to reach between two points travelling down through a small glass tube)
the temperature an oil can take depends on the quality, and is independant of the viscosity grade. very basically, a mineral oil will start to oxidise and degrade at a lower temperature, anything over 100 deg really, whereas a full synthetic will go to around 120 bulk oil temp (although you still don't want to be pushing those sorts of oil temps for too long).
I'm no expert so if I'm wrong that's ok by me. But then I'm lost as to what multigrade is.
back in the day, you had monograde oils - so you used a winter oil in the cold months (say a 10W) as cold starts were the most important thing. and you used a summer oil (like a 50 grade) in the warmer months to give you protection when the engine was hot.
using a basic mineral oil as they used to, something like a 10W would thin down quite a lot when it got hot, and a 50 grade would be very thick when cold, so you couldn't use a summer oil in the winter and vice versa - mineral oils, being very poor quality, would suffer a very large viscosity change with temperature.
With the introduction of viscosity index improvers (basically polymer additives that curl up like little balls when cold but expand out when hot), you could get a 10W oil that didn't thin down so much when it got hot, allowing you to use it all through the year. this is a multigrade oil. so you could go from having something like a monograde 15W (without VI improver) which might meet the specs of say 15W-20 if you did actually measure it, to a 15W-40 with this additive. so the multigrade means that it's now suitable for both winter and summer use.
using a basic mineral oil as they used to, something like a 10W would thin down quite a lot when it got hot, and a 50 grade would be very thick when cold, so you couldn't use a summer oil in the winter and vice versa - mineral oils, being very poor quality, would suffer a very large viscosity change with temperature.
With the introduction of viscosity index improvers (basically polymer additives that curl up like little balls when cold but expand out when hot), you could get a 10W oil that didn't thin down so much when it got hot, allowing you to use it all through the year. this is a multigrade oil. so you could go from having something like a monograde 15W (without VI improver) which might meet the specs of say 15W-20 if you did actually measure it, to a 15W-40 with this additive. so the multigrade means that it's now suitable for both winter and summer use.
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