Using Secondhand Engine Oil

Assassin

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Its a simple question, would you use second hand oil in your engines?

Most used oil is collected and recycled by burning it as cheap fuel for intense and prolonged heat applications such as cement making for example, but what most people never realise is that oil and its additives actually do not wear out when used in most applications as it actually deteriorates in use by becoming contaminated mainly through the acids and other compounds produced during the combustion process and by the inclusion of solid particles such as soot from use in diesel engines.

Engine oil specifications stated by the manufacturer are not the specifications of the oil before it is used in an engine as they are the specifications at the end of its life when it has run its amount of cycles or hours in marine applications, or mileage in road vehicles such as cars and lorries and is replaced as part of a service schedule.

So, if we take old oils and remove the solid particles and remove the acidic and other compounds then it is perfectly serviceable and can be used indefinitely then? in a word yes; and if we look at the huge marine engines used in larger ships such as container ships we see the "filled for life" engines are actually in current service and many have the inbuilt capability to filter out these solid particles and neutralise the acidic and other compounds to the point where by doing this on a constant cycle, the oil will outlast the engine by several times. Why aren't we doing this? in point of fact we already are and currently around 10% of all oil is sent for recycling into new oils is sent for reblending and is used mainly in gearbox applications such as high capacity gearboxes in harsh working conditions as there are conflicting messages from the oil industry who have a huge financial stake in finding oil reserves and extracting crude and selling it on for profit; and the oil recycling industry who can cut the cost of engine and other oils by using old oils and while they have the additional costs of additional filtration, they don't have to pay market or spot prices for crude oil as filtering is a much lower cost than refining crude oil.

Didn't companies such as Silkolene in Belper do this for years? yes they did so its not new technology and has been around for decades, so if Silkolene did it for decades before being bought out by Fuchs then why aren't we doing it now? in a word MONEY and perception. For many years small reblenders of oils have had it all their own way by rerefining used oils and this was a small or niche market as people believed the hype and tosh spouted by the huge oil corporations in their attempts to preserve and protect their huge profits; but times are a changing with the support of recycling and the information these people are putting out.

What is the process? basically its no different to the refining of crude oil except for the additional filtration process at the beginning of the refining process as this needs to be better than the original filtration processes of new oils as all refining does is remove as much of the solid matter as possible and they do this in many ways as the purer the base oil is determines its quality and classification as a base oil as the finer it is, the purer it is, and the smaller and more uniform the molecules are, the better quality it is. Therefore, standard refining processes and equipment can be used to reblend old oils into new oils with minimal outlay and investment.
 
I have always read that, apart from the build-up of acids, sulphur and tiny bits of engine, there is another issue: since the days when some cars, eg minis, have had their gearboxes and diffs inside the engine, using the same oil, the oil has had additions.
The name ' long-chain polymers' springs to mind, meaning long molecules designed to accept the pressures between gear teeth transmitting the entire power of the engine. These molecules get broken up in use, and like humpty-dumpty, no amount of filtering can put them together again.
It's an interesting subject but the chemistry,although interesting, is far above my pay-grade..do any of you motorboatists still use straight oils, just out of interest?
 
If it's second-hand re-blended and purified etc oil that comes in a blue plastic container with Volvo emblazoned on it sure, no issues. If it's Roy's hand me downs because he's too lazy to cart it to the oil recycle bin definitely not.
 
Yeh it’s the longchain molecules side that recycled oil falls down .
Theses “ oil for life “ ships run at 75 rpm .
I think you need a different type of protection for higher , substantially higher rpm .
So think 75 or 120 rpm compared to my boat 1800 or one of my cars 7700 rpm .
Imagine if you were a spot on the wall of the cylinder watching how many times the rings scrape by in minute ? Or a spot on a ball in a crank bearing spinning in the oil ?

Life for the spots in the ship is a hell of a lot easier .
 
If it's second-hand re-blended and purified etc oil that comes in a blue plastic container with Volvo emblazoned on it sure, no issues. If it's Roy's hand me downs because he's too lazy to cart it to the oil recycle bin definitely not.

Bit unfair on Roy there Bruce, the recycle bin is only in the car park:encouragement:
 
I have always read that, apart from the build-up of acids, sulphur and tiny bits of engine, there is another issue: since the days when some cars, eg minis, have had their gearboxes and diffs inside the engine, using the same oil, the oil has had additions.
The name ' long-chain polymers' springs to mind, meaning long molecules designed to accept the pressures between gear teeth transmitting the entire power of the engine. These molecules get broken up in use, and like humpty-dumpty, no amount of filtering can put them together again.
It's an interesting subject but the chemistry,although interesting, is far above my pay-grade..do any of you motorboatists still use straight oils, just out of interest?

This is exactly the issue, the long chain polymers do become shorter with use and this is mainly due to contamination and in some cases it overloading the oil and it is the exact reason it is cleaned and reblended using the original cracking process again to reinstate these long chain polymers.
 
This is exactly the issue, the long chain polymers do become shorter with use and this is mainly due to contamination and in some cases it overloading the oil and it is the exact reason it is cleaned and reblended using the original cracking process again to reinstate these long chain polymers.

Very interesting Assassin, thank you
I am fairly clued up on oils related to leisure engines
In one of My former lives I purveyed oils to the Motorcycle Trade
Being a conscientious sort of Chappie, I did research the subject as best I could
Mind you this was 'pre google' the best I could do was mither the 'teccies' at said oil brewery for any information I could back then
Interesting, there are So many 'boffins' etc on this Forum, it's amazing
Then there is BruceK /Roy etc
Oh well!
:D
 
Kwakkers, you trying to elevate your social status by climbing the backs of your mates again? I'm sure it was you who lent me some tar once in Caernarfon and then proceeded to denude the boat of tea and biccy while holding fort to all and any conversation.
 
If it's second-hand re-blended and purified etc oil that comes in a blue plastic container with Volvo emblazoned on it sure, no issues. If it's Roy's hand me downs because he's too lazy to cart it to the oil recycle bin definitely not.
Bruce surely its the marina staffs job to carry ones oil to the bin ,also as you know I am recycling out of the sea next year, so on our first trip out next season ,we are going looking for the props you have lost, and the fridge in bardersley sound ,which will have no beer in it ,I guess
 
This could persuade me to do an oil test and just change the filters of all ok

120 lt If volvos finest and the hassle of changing it

Just had the boat serviced. The primary fuel were clear as a bell. Secondaries changed as well. Engineer did say next time don’t bother if the primary is clean
 
Bruce surely its the marina staffs job to carry ones oil to the bin ,also as you know I am recycling out of the sea next year, so on our first trip out next season ,we are going looking for the props you have lost, and the fridge in bardersley sound ,which will have no beer in it ,I guess

If you find my props be sure to give them back. They're somewhere off Penmaenbach and Dutchmans Bank, right about where I openned up and still left you behind.
 
This could persuade me to do an oil test and just change the filters of all ok

120 lt If volvos finest and the hassle of changing it

Just had the boat serviced. The primary fuel were clear as a bell. Secondaries changed as well. Engineer did say next time don’t bother if the primary is clean

120 litres?! Good God, just what have you got in your engine room? A Wartsila-Sulzer ?
 
And here I wince every time I have to buy 25 litres and bemoan the 3 litres spare at the end. Different league entirely. On a cold winter day on the hard when I cant warm up the engines it's a four hour job trying to get that oil out with a Pela pump. I dont envy your mechanic.
 
120 litres?! Good God, just what have you got in your engine room? A Wartsila-Sulzer ?
Tee hee the numbers are crazy BruceK. I had Volvo D12s and I can confirm you need 3x 20 litre oil drums per engine. FWIW Caterpillar C32 that I love but have to keep feeding are 140 litres per side. So 14 x 20 litre oil drums to service the engines, not counting gearboxes.
 
I'm beginning to appreciate the concept of an oil analysis. Up until now I was thinking maybe it was for the OCD among us. I'll have to put this as a reminder somewhere in case a big old girl comes on the market and I'm tempted to buy because it looks cheap. Damn.
 
Brother used to have an old tug, you could divert oil to a device that heated it with steam and centrifuged it to clean the oil. Don't think you needed to change it much.
At one time you could buy cheap oil in gallon rather than five litre cans that was recycled oil.
 
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