Interesting video comparing expensive and cheap synthetic oil with mineral oil

RichardS said:
It's worth remembering that many marine engines, and nearly all older ones, are actually simply road/industrial engines with a heat exchanger attached.

Richard
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That is true but the basic blocks for those engines were often first produced in the 1960s, before advanced synthetic oils were sold. Modern vehicles were designed with synthetics in mind, but old ones were designed to suit the properties of mineral oils. There is a lot to it. The material properties of the metals used, the surface treatment of the parts, engine temperatures and pressures, rpms, stresses, clearances etc were all different and all that has an effect on oil suitability and vice versa.
 
The ESSO Reasearch establishment is/was nearby and I knew several who worked there in highly technical positions.

What some suggest here appears to me to be fanciful, and what others say, from direct experience, appears factual.

I had a three cylinder Yanmar 38 HP. When the boat was purchased it had not long been sailed across the pond from the USA. It came with a half used US Gallon of Mercruiser 15/30 plus an unopened one.

The boat was in Watchet up the Bristol Channel. By the time we got to Gosport this engine had consumed all the oil plus a bit more purchased in Falmouth.

I changed to Morris 20/50 and rarely topped up between changes after this change of grade.

Marine engines are subtley different to road vehicle engines. They tend to be fairly constant speed and can often be overcooled.

They are, in most cases, fairly low power for their capacity.

Our current boat uses a Yanmar 4JH4-HTE 110 BHP Turbo Diesel donk.

I have recently changed to Castrol Magnatec from GTX.

First Mate commented, after an hours running " The engine seems much smoother-what have you done? "

I agree with her comment, but can only attribute it to the oil change.

As it is subjective, not scientificaly measured, it is of little real value, just an observation.

FYI, Castrol, one of the worlds best known oil manufacturers, are purely blenders, not refiners.

They buy in Bright Stock and the chemical additives and go from there.
 
Regarding that 'interesting' plastic cog demo tool, couldnt the additive be simply altering the viscosity of the liquid making it 'sticky on the cogs' ?

I am getting confused however. For our Perkins 4108 I have tried to follow the instructions in the manual, I guess that oil technology has moved on but would 'modern synthetics' be better or worse.

What oil should I be using ( in the med) please !! ??
 
Zing said:
That is true but the basic blocks for those engines were often first produced in the 1960s, before advanced synthetic oils were sold. Modern vehicles were designed with synthetics in mind, but old ones were designed to suit the properties of mineral oils. There is a lot to it. The material properties of the metals used, the surface treatment of the parts, engine temperatures and pressures, rpms, stresses, clearances etc were all different and all that has an effect on oil suitability and vice versa.
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I agree about the different design constraints between old and modern engines but, from my experience, the factor at play here is hot and cold viscosity. I suspect that many people make the mistake of swapping an old-style mineral oil for a modern synthetic version without realising that they are now using a much thinner oil which the engine, and particularly the oil circulation pump, was not designed for. Whilst this was a problem a few years ago, synthetic oils are now available in 20W-50 grades which would be suitable for most engines designed in the last 50+ years.

Provided that viscosity requirements are met, I cannot see any reason why a modern synthetic oil should not be fully compatible in general purpose engines. There are some applications where this might not apply, for example common engine-clutch applications.

Richard
 
pcatterall said:
Regarding that 'interesting' plastic cog demo tool, couldnt the additive be simply altering the viscosity of the liquid making it 'sticky on the cogs' ?

I am getting confused however. For our Perkins 4108 I have tried to follow the instructions in the manual, I guess that oil technology has moved on but would 'modern synthetics' be better or worse.

What oil should I be using ( in the med) please !! ??
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It could well simply be a viscosity effect which would be achieved by simply using thicker standard oil. However, I suspect that there might also be a rheopectic (shear thickening) effect which would look great in the demo cogs but I'm much less sure would be suitable for engine use, other than in very specialised applications.

Richard
 
Haha, and I thought I was slack at changing my engine oil! (before I got water in the engine, that is). ?
I'm in the med now, living on the boat and cruising seven months a year so, given the fickle fu... um, flipping winds I get, I do several hundred hours a year on the engine. And at twenty to thirty quid a time, I don't begrudge the old donkey a few oil changes a year. I worry slightly about the frequent changes in oil type and quality that the engine gets, especially in light of some comments above. I live in hope that frequent fresh oil even of variable quality is as good as providing it less frequently with the oil that most closely meets the manufactures spec and/or the engine's current needs (which, 1200 hours after a major rebuild and goodness knows how many hours before then, plus salt water getting into the engine, might be very different things).
My engine doesn't exactly drink oil - about 200ml disappears per 20 hours usually at 2500rpm. But after an oil change, the oil is black and opaque within a few hours, so I don't kid myself that everything in there is hunky dory.
 
RichardS said:
I agree about the different design constraints between old and modern engines but, from my experience, the factor at play here is hot and cold viscosity. I suspect that many people make the mistake of swapping an old-style mineral oil for a modern synthetic version without realising that they are now using a much thinner oil which the engine, and particularly the oil circulation pump, was not designed for. Whilst this was a problem a few years ago, synthetic oils are now available in 20W-50 grades which would be suitable for most engines designed in the last 50+ years.

Provided that viscosity requirements are met, I cannot see any reason why a modern synthetic oil should not be fully compatible in general purpose engines. There are some applications where this might not apply, for example common engine-clutch applications.

Richard
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The viscosity rating is not enough to differentiate oils. There are heaps of oil standards within a given SAE rating plus the oil film strength can vary greatly as can the thickness, not to mention all the very many additives. I will stick to an old spec oil in my old engine. The risk of changing to synthetic isn’t worth it in my humble opinion. Engines last an awfully long time anyway if looked after and may well last longest with a less advanced oil.
 
Zing said:
The viscosity rating is not enough to differentiate oils. There are heaps of oil standards within a given SAE rating plus the oil film strength can vary greatly as can the thickness, not to mention all the very many additives. I will stick to an old spec oil in my old engine. The risk of changing to synthetic isn’t worth it in my humble opinion. Engines last an awfully long time anyway if looked after and may well last longest with a less advanced oil.
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The issue is that, in 99% of of cases, all those newer SAE specs are backwards compatible i.e. the newer physical specs and additive packages encompass all the older specs. There are some cases with special oils where this is not necessarily the case, but all general purpose motor oils are backwards compatible in everything other than viscosity unless the same spec is chosen.

However, if you are changing the oil according to the manufacturers recommendation then I fully agree that you won't go wrong in using the oil that the engine was originally tested with.

In my case I'm using extended time and extended hours and using a mineral oil would be foolhardy. My last oil change in both engines was 4 years and around 300 hours ago and I have never added any oil between oil changes and both engines are totally smoke free after 3500 hours total use.

Richard
 
vyv_cox said:
The large number of warnings on classic car forums against switching to synthetics is based on hard-earned experience.
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On expert advice, I switched my DS from 20W50 mineral to 10w40 semi-synthetic a couple of years ago. The only change I have noticed is that the oil needs topped up with a litre after 3,000 miles or so, whereas it never needed topped up before.
 
JumbleDuck said:
On expert advice, I switched my DS from 20W50 mineral to 10w40 semi-synthetic a couple of years ago. The only change I have noticed is that the oil needs topped up with a litre after 3,000 miles or so, whereas it never needed topped up before.
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Now that really surprises me. Why wouldn't the expert have suggested 20W-50 semi or fully synthetic? We run our 1982 Landy on 20W-50 fully synthetic and it's fine but I would not have switched to a thinner oil on such an old engine. :confused:

Richard
 
RichardS said:
Now that really surprises me. Why wouldn't the expert have suggested 20W-50 semi or fully synthetic? We run our 1982 Landy on 20W-50 fully synthetic and it's fine but I would not have switched to a thinner oil on such an old engine. :confused:

Richard
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It seems odd to reduce the hot viscosity unnecessarily.
You can get 10W50 oil easily enough, which will have the advantage of being as runny as a 10w40 when cold, but as thick as a 20w50 when hot.
Come to that, there is 10w60 available.
 
A bit of thread drift, if you'll pardon me.

Last time I was in Halfords, shopping for oil as. after 140,000 miles, my Qashqai uses a little, they had oil for Ford cars, oil for Nissan, and several other makes, maybe a diesel and a petrol version for each make.. Are these oils really different, or is it just a marketing ploy? I can see a difference between oil for diesels and petrols, but manufacturers share engines around, so why the difference?

Fully synthetic is what the book says for my engine, so is there any reason I shouldn't use a generic one of the right grade?
 
Stemar said:
A bit of thread drift, if you'll pardon me.

Last time I was in Halfords, shopping for oil as. after 140,000 miles, my Qashqai uses a little, they had oil for Ford cars, oil for Nissan, and several other makes, maybe a diesel and a petrol version for each make.. Are these oils really different, or is it just a marketing ploy? I can see a difference between oil for diesels and petrols, but manufacturers share engines around, so why the difference?

Fully synthetic is what the book says for my engine, so is there any reason I shouldn't use a generic one of the right grade?
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You're right in that it's largely kidology as the general motor oils are almost identical and interchangeable unless you have an engine with specific requirements. Euro 6 turbo diesels with Adblue and DPF systems would be a case where oil selection needs a little more care. Petrol engines are generally less specific.

Richard
 
You can find oils which list a whole load of carmakers spec's on the label.
For my car, an oil which lists the 'specific' maker's spec costs about 50p more than a reputable brand of oil of the same API spec but not listing the maker's 'long life' spec.
Possibly it's the same oil which has been through a few more tests and boxes ticked.
Possibly it's got a different cocktail of additives.
I take the view that the extra few pounds over the time I keep the car might just mean that who ever buys it from me will be impressed by my largesse, or maybe it gives slightly better odds of getting through the MOT emissions test.

When you see a car belching smoke up hill, you wonder how much they saved on oil changes and what it might cost at MOT time.
 
Stemar said:
A bit of thread drift, if you'll pardon me.

Last time I was in Halfords, shopping for oil as. after 140,000 miles, my Qashqai uses a little, they had oil for Ford cars, oil for Nissan, and several other makes, maybe a diesel and a petrol version for each make.. Are these oils really different, or is it just a marketing ploy? I can see a difference between oil for diesels and petrols, but manufacturers share engines around, so why the difference?

Fully synthetic is what the book says for my engine, so is there any reason I shouldn't use a generic one of the right grade?
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There probably is a genuine reason for having maker-specific oil. It certainly is not a marketing ploy. Vehicle manufacturers are very aware that you have choice and that making you buy more expensive oil could well influence your next car purchase, ie, buy another make.

It probably started as a standard spec oil but for some reason or another gained a few additional additives during the development process. There could be many reasons for this, for example, emissions, mechanical, chemical etc etc. Lubricating oils play a big part in engine technology. Once the engine is homologated by the Authorities with a given oil, it's no longer economically viable to make changes.

Once these vehicles are of an age where owner servicing, or back street garage, for example Richard Expert Servicing :), do the work control has been lost any pretty much "anything goes". The subtlety of the original reason for needing an additive is lost. What this affects longer term, emissions, durability etc, who knows?

If your book recommends fully synthetic, any make of the correct API grade and viscosity should be fine.
 
RichardS said:
My Son introduced me to this guy's Youtube channel and one of his tests is expensive Mobil synthetic vs cheap supermarket synthetic vs top quality mineral oil.

The results are interesting and pretty conclusive.


Richard
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Sorry i cant listen to him whining on
 
I use synthetic oils in my cars and my marine engines. The older the engine, the more important to make sure it has good lubrication. Synthetic oils are superior in every way against the old mineral oils; some people will never accept it (same argument as vinyl records against cd sound quality).
 
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