How to prolong the life of your petrol-engined car!

[Andy Dingley]

Trade: they sell things you either can't lift, or in quantities you couldn't use in a whole lifetime.

[IMM]

You can't

[IMM]

He is very strange indeed

[Dave Plowman (News)]

It also makes no mention of whether the engine had sensible oil changes before needing overhaul. Cars used for short journeys have always needed much more frequent changes than the norm. Although you might have to look carefully in the service book to find this out. 'Classic' cars tend to be very well looked after by caring owners.

[John Rumm]

Boffins huh... ;-)

Very technical? It is ok we can do that here, tell us all about it.

So in effect you are saying that the engine is like a boiler, and the sump like a radiator, with the oil taking the place of the water.

It gets pumped over hot bits in the engine, and hence acquires heat. It gets pumped through the sump and looses (some) of it to the atmosphere.

Substitute synthetic oil for chip fat and the above process still seems to work (at least until the engine seizes)

All I can see it that properties of the synthetic oil will keep it doing the job it is supposed to do for longer and in harsher environments.

One of its jobs is cooling, but it does this by acting as a carrier of heat from one place to another. Are you suggesting that the synthetic will somehow absorb and release more heat on each pass through the engine/sump that a non synthetic?

[Dave Plowman (News)]

His boffins will be in the maker's adverts. Many adverts include a boffin for the good reason it impresses the ignorant. I expect he drives a Renault Megane.

[IMM]

[IMM]

Above your head. Just take it Synthetics cool very well.

Near enough right. The sump get cooled as the car moves along. The oil does not touch the atmosphere directly.

That would work, but not a swell as synthetic oil, which is brill at cooling.

So the tribologists told me. I believed them. Nice chaps and all that. I have also read on many occasions this fact too.

[Rob Morley]

A quick Google revealed a single source[1] that suggests that synthetic oil has a slightly higher specific heat capacity by volume than mineral oil, which would make it more effective at removing heat. Not vastly, but slightly.

[1]

[John Rumm]

I was waiting for IMM to go for that argument... (in the give him enough rope kind of way ;-)

The heat capacity may or may not be an issue. It will depend on if the oil reaches the same temperature as the "hot bits". If it does then Prevost's theory of exchanges would dictate that the oil can experience no further nett gain in heat. In this circumstance the higher SHC oil will allow marginally more heat to be moved (as would a higher flow rate). If however (as I expect to be the case) the oil does not reach the same temperature as the hottest parts of the engine that it comes into contact with then the difference in SHC becomes far less significant.

[IMM]

Mineral oils deteriorate quite rapidly, and loose their heat absorbing capabilities, far quicker than synthetics ever do.

So once again...an win, win situation.

[John Rumm]

Many things you write are beyond my comprehension, but not because of the complexity of their physics.

I get the feeling that you have (as usual) not quite got a handle on this.

Using a synthetic oil may result in better long term cooling performance, but it it not because the oil is a better coolant. It will give better results because it will resist breakdown, is less likely to burn on to surfaces (and hence restrict oil flow or form insulating layers between the metal and the liquid oil). It may also give better lubrication performance and hence lower friction and heat production in the first place. It is an over simplification to simply claim they "cool better".

[IMM]

That is obvious.

Oh I do. I know what they said, and you don't because you were not there.

What I said too.

It is a better coolant.

I also said that too.

I said that too. (remeber the old A series I mentioned?)

Infinitely better.

.............and that it does too.

I said that as well.

After going so well you ruined it all. Don't you feel ashamed?

It isn't and oversimplification at all. It is clear for many reasons that they cool better. That is what I said.

[John Rumm]

So if you know this, why do you persist in writing so poorly?

My comment was relating to the bigger picture, not your meeting...

Not really

If you persist in this claim (i.e. it is a better coolant in addition to the other advantages stated, rather than purely as a coincidental benefit of the other advantages stated) then you have yet to explain how.

That is questionable... well no in fact it is nonsense.

Don't think you did, but never mind you know now.

You claimed a few post back that "it also takes away heat too, cooling vital hot spots in the engine." as if this were some unique property of synthetic oil.

[IMM]

I am brilliant at writing.

I reported the meeting.

I did.

The tribologists told me and now I have forgot. They know what they are on about and that is all you need to know.

You are so wrong. Synthetic oil is vastly superior to mineral oil.

I did.

....and that is does.

Superior in doing this mineral oil.

Poor show by you here.

[John Rumm]

So you say... and life in general no doubt...

Ah, why didn't you say you don't know in the first place, it would have saved all this effort.

So someone who you think knows their stuff told you something, the bulk of which you can't remember, but you do still feel comfortable making cast iron claims based on this partial memory?

infinitely -> vastly... hmm heading in the right direction. At least this claim is within the realms of possibility. Keep going.

Sorry I must have missed it, where?

More of your brilliant writing I see... but you still can't remember how it pulls off this feat of thermodynamics though?

If you say so.

[IMM]

Spot on.

I do know. I know synthetic oil is superior at cooling than mineral. You know I know that.

Oh they do. Showed me the results of their tests on oils.

Firm memory. Firm in that synthetics are superior at cooling than mineral oils. Got it? Or is that too difficult?

Yes both.

Within the realms of actuality.

Keep looking.

Fabulous I know.

I don't want to know. All I need and want to know is that it is a superior at cooling than mineral oils. Got it?

Clearly so.

[The Natural Philosopher]

(i) its lose. not loose (ii) Its not true. (iii) the real issue is something you haven't struck on yet. But then you are thick, and know bugger all.

A win win, not AN win win.

[Huge]

[19 lines snipped]

Indeed. For varying values of "quite" and "rapidly".

Unmitigated garbage.

[Roger]

The message from John Rumm contains these words:

Surely you were really waiting for dIMM to show his erudition by saying that specific heat capacity was not really an issue but Thermal Conductivity was. Or perhaps not. :-)