High performance Jag, oil NOT changed for 3.5 years...
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Originally Posted by ragtoplvr
The gas is more of an issue than the oil. When one is sitting oil lraks are more common so leak stop additives, or at least some high mileage oil is good.
Rod
In the UK we only get E5 at the moment, while they have just legalised E10 as a 'standard' fuel, it isn't commonly available.
I've had a 5litre can of E5 in my garage for the last 3 years and there's still no issues with it. I'm unsure if it's the fact we only have E5 or climate but fuel doesn't seem to go off as quick here.
Our fuel is generally of a higher quality too! Our 'standard' fuel is the same as your 91.
The gas is more of an issue than the oil. When one is sitting oil lraks are more common so leak stop additives, or at least some high mileage oil is good.
Rod
In the UK we only get E5 at the moment, while they have just legalised E10 as a 'standard' fuel, it isn't commonly available.
I've had a 5litre can of E5 in my garage for the last 3 years and there's still no issues with it. I'm unsure if it's the fact we only have E5 or climate but fuel doesn't seem to go off as quick here.
Our fuel is generally of a higher quality too! Our 'standard' fuel is the same as your 91.
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Originally Posted by PowerSurge
So motor oil lasts forever?
Well let's turn the question on it's head and try and predict the chemistry and rate of any problem.
The base oil (or its precursors) has been sitting under ground for millions of years without issue, and all we did is clean it up a bit and remove the nasty bits to use as engine oil.
The anti-wear agent is ZDDP and it requires heat and pressure to activate, so it's sitting there passively waiting for an energy input to do its job.
The VM / VII are just polymers and without exposure to heat, mechanical shear or UV light, they should last decades like most plastics.
The over base detergents are there to neutralise the acid build up in the oil, but the acids come from combustion products, so without burning fuel there is little work to do and they should just be sitting there waiting.
The dispersants job is to keep small contaminants in solution and not let them settle out. But again these are combustion products and without combustion there is little for them to do.
All these products need to be chemically stable as they are designed to live in sump temperatures of about 100C and higher in the bearings etc. The rule of thumb in chemistry is that you double the reaction rate for every 10C hotter in temp. In our case we are going colder and so the reaction rate is halving. If it's stable at 100C it's basically effectively inert at 10C at any realistic time scales that would concern us.
So motor oil lasts forever?
Well let's turn the question on it's head and try and predict the chemistry and rate of any problem.
The base oil (or its precursors) has been sitting under ground for millions of years without issue, and all we did is clean it up a bit and remove the nasty bits to use as engine oil.
The anti-wear agent is ZDDP and it requires heat and pressure to activate, so it's sitting there passively waiting for an energy input to do its job.
The VM / VII are just polymers and without exposure to heat, mechanical shear or UV light, they should last decades like most plastics.
The over base detergents are there to neutralise the acid build up in the oil, but the acids come from combustion products, so without burning fuel there is little work to do and they should just be sitting there waiting.
The dispersants job is to keep small contaminants in solution and not let them settle out. But again these are combustion products and without combustion there is little for them to do.
All these products need to be chemically stable as they are designed to live in sump temperatures of about 100C and higher in the bearings etc. The rule of thumb in chemistry is that you double the reaction rate for every 10C hotter in temp. In our case we are going colder and so the reaction rate is halving. If it's stable at 100C it's basically effectively inert at 10C at any realistic time scales that would concern us.
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