Standard vs Synthetic Oil in differential

[bertsmobile1]

And I have a 1926 BSA B2 that I have done about 125,000 miles on using SAE 30 mower oil and BSA never specified mower oil
The landlord had a set of 2000 series Cub Cadets that we mow the orchard & paddocks with to the tune of around 300 hrs each per year and they run SAE 30 in the Kohlers as well .
The oil that goes in is nowhere as important as how often it comes out .
We had a club member with a 1966 A65 that would not hold pressure at idle when hot when he bought it.
He did 180,000 km on that engine running Valvoline 20W50 and sold the bike 20 years latter with the same worn timing side bush as it had when he bought the bike .
And BSA recommended a bottom end strip & rebuild every 30,000 miles , Rhett never touched his apart from changing the oil at the end of every run .

So you point, is pointless

No such thing as a super oil that will make an engine run forever .

I had a fleet of L300's all of which went for more than 1,000,000 Km without a bottom end failure and they were run on reprocessed 20W50 strait oil and these were all LPG powered so supposed to run LPG rated oil.

Mower engines are trash , the bulk rely on splash apart from the big end for lubrication so the oil used makes little difference.
Now the XJ650 & XJ750 we used to run ( 12 at one time ) all have metering jets on each cam & crank journal and all of them are different sizes because oil pressure & volumes at each journal is citical and carefully calibrated , running a thinner base oil in them would be a disaster.

Then we come to Hydros
If you have ever pulled one down you would see there is no seal whatsoever between the cylinder body & the valve plate.
The hydro companies machine these to a specific roughness so the resistance to the oil leaking is higher than the resistance of the oil pushing they pistons .
There the wrong oil, and in particular using a synthetic with a lower specific viscosity will cause premature failure .
And the opposite will also happen as with a slower flowing standard oil there will be insufficient flow to float the surfaces.

 

[350Rocket]

And I have a 1926 BSA B2 that I have done about 125,000 miles on using SAE 30 mower oil and BSA never specified mower oil
The landlord had a set of 2000 series Cub Cadets that we mow the orchard & paddocks with to the tune of around 300 hrs each per year and they run SAE 30 in the Kohlers as well .
The oil that goes in is nowhere as important as how often it comes out .
We had a club member with a 1966 A65 that would not hold pressure at idle when hot when he bought it.
He did 180,000 km on that engine running Valvoline 20W50 and sold the bike 20 years latter with the same worn timing side bush as it had when he bought the bike .
And BSA recommended a bottom end strip & rebuild every 30,000 miles , Rhett never touched his apart from changing the oil at the end of every run .

So you point, is pointless

No such thing as a super oil that will make an engine run forever .

I had a fleet of L300's all of which went for more than 1,000,000 Km without a bottom end failure and they were run on reprocessed 20W50 strait oil and these were all LPG powered so supposed to run LPG rated oil.

Mower engines are trash , the bulk rely on splash apart from the big end for lubrication so the oil used makes little difference.
Now the XJ650 & XJ750 we used to run ( 12 at one time ) all have metering jets on each cam & crank journal and all of them are different sizes because oil pressure & volumes at each journal is citical and carefully calibrated , running a thinner base oil in them would be a disaster.

Then we come to Hydros
If you have ever pulled one down you would see there is no seal whatsoever between the cylinder body & the valve plate.
The hydro companies machine these to a specific roughness so the resistance to the oil leaking is higher than the resistance of the oil pushing they pistons .
There the wrong oil, and in particular using a synthetic with a lower specific viscosity will cause premature failure .
And the opposite will also happen as with a slower flowing standard oil there will be insufficient flow to float the surfaces.

I understand there is a difference with hydros and I have no experience with them other than seeing that both synthetic 15w50 and conventional 20w50 are recommended for mine.
And once again you put words in my mouth...I never said it was a miracle product, I said we don't know if it increases lifespan by 2% or 20% but either way it does and I'm not looking forward to pulling the engine on either my 38 year old Oldsmobile or my 9400 hour 2005 Silverado. So my point is not pointless. I just said I personally prefer to use the better product. Families vehicles I usually just use conventional because I know they won't keep it long enough to matter, but that's not the point.
Also the base oil is not thinner on synthetic oil, various oils have different base oil viscosities so it depends on the specific oil and not whether it is synthetic or not. Like I said before you need to do some research before spreading myths.

 

[bertsmobile1]

What people fail to appreciate is engines are designed for a specific type of oil .
That includes the size of oil holes so that the right amount of oil will flow through them to do the job required and there will be sufficinet oil pressure left in the system to lubricate parts further down stream of the oil pump.
They also fail to understand that the flow charasterisc of oil under pressure is totally different to oil flow under gravity which is how the numbers on the front of the bottle are measured.
So all that the numbers on the bottle actually tell you is how the oil will drain back down the drain holes to the sump .
So for instance a synthetic oil that flows faster & easier will not provide enough oil to the last 2 journals on a strait 8 engine because all of the pressure will bleed off lubricating the first 6 cylinders .
Assuming cylinder 1 is closest to the oil pump, the slippers on it will have little rivers all through them because it got too much oil by volume because to use the synthetic oil the oil holes in the crankshaft need to be smaller because the oil flows freer .
It takes years for very experienced engineers to design & test the lubrication system in anything to ensure it all works properly with the lubricant it was designed t & tested with.
Then Joe Idiot comes along and thinks just because some race driver, big brested bimbo, whoever pops up on TV and says this stuff is better it will automatically make whatever they put it in run forever .'
Some times it might make no difference and some times it will
If it makes no difference then the user is pouring money down a hole & wasting the planets resources
If it does make a difference then that door swings both ways
Some times it will be better but most times it will be worse.
However Joe Idiot never take responsibility for his own stupidity and will blame anything else other than him using an unsuitable lubricant .
Barnets got blasted from pillar to post because their clutch plates were slipping all over the place then after several years it was found that it was the owners shoving fully synthetic oil into their motorcycles that was causing the clutches to slip .
A similar story with NSK who copped a ton of warranty claims for excessive wear in roller big end bearings and crankshaft bearings
Same story, the freer flowing synthetics floated the rollers so they slid on the outer race rather than rolling .
This was a particularly big problem for Ducatti Desmo engines and to a lesser extent Harleys , made more confusing to Joe I Know More Than The Design Engineers , as latter models used synthetic oils so it must be OK to use it in older modles , well it was not .

 

[Fish]

Tell that to a friend of mine that has a 1998 Dixie Chopper with a Kohler cv25 that has about 9,000 hours on it running Mobil 1 Synthetic oil in. I'm sure Kohler never recommended synthetic oil back in those days.

I think that Dixie Chopper used Lucas oil in everything back then.

 

[350Rocket]

What people fail to appreciate is engines are designed for a specific type of oil .
That includes the size of oil holes so that the right amount of oil will flow through them to do the job required and there will be sufficinet oil pressure left in the system to lubricate parts further down stream of the oil pump.
They also fail to understand that the flow charasterisc of oil under pressure is totally different to oil flow under gravity which is how the numbers on the front of the bottle are measured.
So all that the numbers on the bottle actually tell you is how the oil will drain back down the drain holes to the sump .
So for instance a synthetic oil that flows faster & easier will not provide enough oil to the last 2 journals on a strait 8 engine because all of the pressure will bleed off lubricating the first 6 cylinders .
Assuming cylinder 1 is closest to the oil pump, the slippers on it will have little rivers all through them because it got too much oil by volume because to use the synthetic oil the oil holes in the crankshaft need to be smaller because the oil flows freer .
It takes years for very experienced engineers to design & test the lubrication system in anything to ensure it all works properly with the lubricant it was designed t & tested with.
Then Joe Idiot comes along and thinks just because some race driver, big brested bimbo, whoever pops up on TV and says this stuff is better it will automatically make whatever they put it in run forever .'
Some times it might make no difference and some times it will
If it makes no difference then the user is pouring money down a hole & wasting the planets resources
If it does make a difference then that door swings both ways
Some times it will be better but most times it will be worse.
However Joe Idiot never take responsibility for his own stupidity and will blame anything else other than him using an unsuitable lubricant .
Barnets got blasted from pillar to post because their clutch plates were slipping all over the place then after several years it was found that it was the owners shoving fully synthetic oil into their motorcycles that was causing the clutches to slip .
A similar story with NSK who copped a ton of warranty claims for excessive wear in roller big end bearings and crankshaft bearings
Same story, the freer flowing synthetics floated the rollers so they slid on the outer race rather than rolling .
This was a particularly big problem for Ducatti Desmo engines and to a lesser extent Harleys , made more confusing to Joe I Know More Than The Design Engineers , as latter models used synthetic oils so it must be OK to use it in older modles , well it was not .

Can you share any sources for information about these examples? I have done a lot of research on oil over the last 20 years (just out of interest) and I've never heard of anything like this. And I've certainly never read that it flows freer.

 

[hlw49]

I think that Dixie Chopper used Lucas oil in everything back then.

Yes they did and still do but it was his choice.

 

[bertsmobile1]

So how much do you know about Fluid Dynamics ?
Are you familiar with the Navier – Stokes equation or Poiseuille's law for viscous flow ?
If you want a single source that will contain every thing I have learned over the past 50 Years, then I am yet to write my memoirs .
People tend to take the lazy approach & expect to understand the nature of oil flow without any understanding of the bulk mechanics or chemistry liquids, let alone oils .
Now the first text book I had to read & understand was Lubricants Cutting Fluids & Coolants by WF Olds back in the early 70's, a good place to start
The Chemisrty and Physics of Petrolium Liquids ( translatttion from Russian ) was the next text I had to adsorb.
Post graduation hundreds of trade papers & journal articles to keep current particularly as some of the trad school students were a lot more familiar than I was
Then there were 3 or 4 conferences I managed to con the boss into allowing me to attend , but most of those papers are long lost .

The last thing I read on the subject which was reasonably accessable was a couple of years back when I was having a discussion about synthetic oils on a different forum.​

Lubricant Flow Rate - an overview | ScienceDirect Topics

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Most of the useful information will be found in industry && research journals as an individual paper with a very specific title .
using search terms like c=synthetic vs standard oil will get you nothing of any value and 99% opinion or advertising BS

 

[Fish]

Yes they did and still do but it was his choice.

"His mower, his choice"!!

 

[350Rocket]

Y

So how much do you know about Fluid Dynamics ?
Are you familiar with the Navier – Stokes equation or Poiseuille's law for viscous flow ?
If you want a single source that will contain every thing I have learned over the past 50 Years, then I am yet to write my memoirs .
People tend to take the lazy approach & expect to understand the nature of oil flow without any understanding of the bulk mechanics or chemistry liquids, let alone oils .
Now the first text book I had to read & understand was Lubricants Cutting Fluids & Coolants by WF Olds back in the early 70's, a good place to start
The Chemisrty and Physics of Petrolium Liquids ( translatttion from Russian ) was the next text I had to adsorb.
Post graduation hundreds of trade papers & journal articles to keep current particularly as some of the trad school students were a lot more familiar than I was
Then there were 3 or 4 conferences I managed to con the boss into allowing me to attend , but most of those papers are long lost .

The last thing I read on the subject which was reasonably accessable was a couple of years back when I was having a discussion about synthetic oils on a different forum.​

Lubricant Flow Rate - an overview | ScienceDirect Topics

www.sciencedirect.com

SAGE Journals: Your gateway to world-class research journals

Subscription and open access journals from SAGE Publishing, the world's leading independent academic publisher.

journals.sagepub.com

Most of the useful information will be found in industry && research journals as an individual paper with a very specific title .
using search terms like c=synthetic vs standard oil will get you nothing of any value and 99% opinion or advertising BS

It looks like you're just sending me on another wild goose chase, reading a bunch of math equations that have nothing to do with what difference there is between a conventional group 2 oil or a group 3 oil or Pao or ester oils. I'm no chemist or anything but there are several physicists/formulator/tribologists that have put this into layman's terms for us......lots of information out their dispelling myths about synthetic oil and nothing I can find that backs what you're saying.
I should have blown up my old 1981 3hp Briggs mowing down steep embankments with full synthetic Pao oil in it when I was doing it as a side job many hours a week, if what you're claiming is true.
I can see we're never going to agree on this and you're just going to throw a bunch of fluid dynamics math equations at me that don't do anything to back your statements.

 

[bertsmobile1]

Y

It looks like you're just sending me on another wild goose chase, reading a bunch of math equations that have nothing to do with what difference there is between a conventional group 2 oil or a group 3 oil or Pao or ester oils. I'm no chemist or anything but there are several physicists/formulator/tribologists that have put this into layman's terms for us......lots of information out their dispelling myths about synthetic oil and nothing I can find that backs what you're saying.
I should have blown up my old 1981 3hp Briggs mowing down steep embankments with full synthetic Pao oil in it when I was doing it as a side job many hours a week, if what you're claiming is true.
I can see we're never going to agree on this and you're just going to throw a bunch of fluid dynamics math equations at me that don't do anything to back your statements.

IF you don't understand the basics then all you can do is put blind faith that what some one else has said is factually correct .
As you are totally unwilling to put in the work to educate yourself then you will never actually understand how lubrication works.
I started my learning curve back in 1972 in the final years of my degree with a 2 hour lecture once a week for 13 weeks.
So that is 26 hours of face to face lectures + 13 more of tutorials + 13 more of practicals + 51 of pre lecture back ground reading before lectures.
How many hours have you spent on face book ?
As for mower engine as was previously stated is all using a synthetic or semi synthetic will do is cost you more money .
But if it makes you feel good then do it all it will do is waste your money .
While their history goes back decades fully synthetic oils were developed commercially for F1 racing where spending $ 1000 / gallon on oil is petty cash.
The engines in F 1 are pushed to their max they run at a lot higher temperatures than you mower ever will and every part has been cut down to the absolute minimum weight that will hopefully stay together for the length of a race and the manufacturing tollerances are substantially tighter than your mower ever will plus the oil plays a massive part in cooling the engine , or rather keeping the internals at a constant temperature , again totally irrelevent to an ir cooled mower engine and requires a bit of maths .
Viscious friction robs power from the tailshaft so anything that can reduce it is a big + in racing.
When we raced speedway all of the engines run total loss oiling and you do notice the difference in responce between that and the same engine mounted into a Hagon frame with an oil tank for short circuit
Synthetic oils they stayed as an exotic item even during the oil crisis of the 70's when I was in college . untill California tightened emission laws then all the major engine makers found that the thinner oils allowed the engine to crank faster so the first cylinder to do a full induction cycle fired reducing the unburned fuel passed out the tail pipe thus meet the starting emissions tests for almost no developement costs.
The engines were run to destruction & oil galleries modified where necessary.
The oil companies were then told we want engine oils with these properties of the fully synthetic oils for our production engines but we will only pay $X / gallon for them .
Thus the semi-synthetic ( and that name is total BS as the oil is not synthetic & never was ) oil was born by stripping the dreaded "Dino oil" into some componant parts then recombining them in proportions that would not normally happen and that is part & parcel of the normal processing of normal oils .
All that the oil companies did was add a couple of extra distillation processes to the regular processing .
True synthetic oil, created by reacting gasses together under pressure is a different animal but you won't find it at your local discount car parts shop.

The oil companies then had a premium product that cost marginally more than the standard product but because of the hype around it could be sold for 3 times the price of regular oil and pushed it hard by extolling its better properties, most of which was almost true but none of it of any real benefit for any engine not specifically designed to run it .
So you can run it for 3 times as long as you can run standard oil before it oxadises and starts to brake down chemically.
But that is not why you change your oil
You change it to remove the acid byproducts of combustion which happen regardless of the oil used and more importantly to remove the ultra fine particulates that errode your engine the exact same was as the Colorado river has erroded the Grand Canyon , but they fail to tell you that.

As for mower engine what can I say?
Probably once or twice a year an old worn out 2.5Hp side valve B & S powered mower comes into the shop with about 1/3 of the original oil still in the crankcase burned to the consistency of triple cream on a mower that the owner has had since the 80's and never so much as checked to oil let alone change it or even top it up.

And I would imagine every tech on here would have the same thing happen to them every year
Your 1981 B & S engine will run happily of full splash lubrication and there is a good chance it was actually full splash .
So your use of it just goes to show your absolute failure of understanding of the fundamentials of lubrication inside an engine.
The tug-o-war between adheason, coheasion & gravity let alone the significance of valence inbalance at the terminals of the molecules, and the difference the shape of them makes to the flow of the oil through the galleries.

And FWIW the only calculations in OLDS are just barely high school level and mainly about temperature flow & heat removal .
Get yourself a copy & read it then if you have understood what was written you will have just enough information to work out weather you are being fed fact, fiction or hype.
As an old text book it is probably everywhere used for $ 5 rather than the $ 50 I had to pay when it was a brand new publication.

Over the years I have found oil to be like religion and those who most strongly argue about it do so from a position of blind faith.

On one of the motorcycle forums we ran a survey to see just how much the members understood about oil
The question was
Do multigrade oils get thicker as they get hotter. yes / no
Over 90% got it wrong .

In my TAFE classe I used to ask the question
What is the purpose of the detergent molecules in oil ?
In the 11 years I taught not s single student got the question correct
We put the same question in the final exam and agin just about every student got it wrong
They all correctly described the mechanism of how they work but the students could not get the "detergents clean" BS out of their heads that the advertising companies had implanted .
And if you are wondering.
The function of the detergent is to carry away the particulates that they encounter & prevent them from combining
Secondary purpose is to make the contaminants close to the SG of the base oil so they will circulate freely within the oil to facilitate mechanical removal .
You will find that in OLDS as well no maths required .