Oil Change

Don't know about all this oil stuff a lot to absorb :thumbsup:

You guys have me so confused about what oil to use that I can't decide so until I can I'm just not going to use any. :smile:

I only run synthetic in my truck. Everything else gets conventional.

TonyPrin said:

cpurvis, I guess we'll just have to agree to disagree on this. Independent testing over decades has consistently shown that synthetic oil is superior to conventional oil in both lubricating and protecting engines. Conversely, no analysis I've seen has ever shown conventional oil to be equal to synthetic and I never will.

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What you're missing or ignoring is that this so-called "superiority" exists in the area of where "it makes no difference." Both EXCEED manufacturer's specifications. To exceed them even further gains nothing.

Also, conversely, you or I have never seen any real-world data showing synthetic oil to add one dollar to the bottom line of companies whose bottom line depends upon the economical operation of internal combustion engines. If there was you wouldn't see 55 gallon drums of Rotella, Chevron Delo, or Mobil Delvac in their maintenance shops. These companies have people whose job is to find ways of cutting costs and they have not ignored engine oil.

TonyPrin said:

cpurvis, I guess we'll just have to agree to disagree on this. Independent testing over decades has consistently shown that synthetic oil is superior to conventional oil in both lubricating and protecting engines. Conversely, no analysis I've seen has ever shown conventional oil to be equal to synthetic and I never will.

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And what you totally fail to understand is there is more to the choice of an oil than the properties of the oil.
Just like putting A1 Avgas, which is grealty superiour to std gas in your side valve engine will not make it run any better.
Putting synthetic oil in an engine nit designed to run synthetic oils will not make that engine run any better and in fact can cause significant damage.

There are things like maintaining a stable seperation film between parts and to be able to that the oil used must flow at the rate the engineers designed into the engine,
This is a particular problem with engines that run slow, like mowers & tractors where a faster flowing oil flows too fast through the bearing surface allowing metal to metal contact.
Engines designed to run synthetics have tighter clearences so the oil remains in the boundry lubrication zone .
Engines designed to run std oils have bigger spaces and it is hit & miss as to weather they have a sufficiently large enough pump to counter the faster flow rate.
The oil pressure inside an engine is due to RESISTACE OF THE OIL TO PASS THROUGH A CAVITY.
No resistance = no pressure
No pressure = severe engine damage
Then there are things like the hammering between the rod eyes.
Engineers design in a "pillow" of oil to adsorb this and that "pillow" is directly related to the mass of oil retained and the mass of oil retained is determned by the viscosity of the oil and the friction coefficient between the oil and the surfaces it is flowing through.

Also remember that the seal between the rings and the bore is made by the oil trapped between the rings and the ring groove preventing compression bypassing them thus forcing the rings out into the cylinder wall where the oil has to remain between the rings and the cylinder wall and these are designed to work with oil of specific properties which is why a lot of older engines will not run on synthetics , or if they do they consume it by the gallons because it can not maintain a stable oil film in this critical area.
In fact no engine that runs cast iron rings will gain any benefit from running synthetics and in many cases runs worse because the rings can never make a proper seal between the piston & cylinder wall thus it uses oil, suffers from increased blow by & lower compression.
Even worse because of the very low ash content of most synthetics, the operator is unaware because while you can smell the oil, it does not burn with clouds of white smoke as conventional oils do so you end up with a too low oil situation.
Engines designed to run synthetics usually run steel rings and right now a lot are running teflon coated steel rings.

Finally NO OIL SHOULD EVER BE LEFT IN AN ENGINE TILL IT HAD BROKEN DOWN.
and in fact the determining factor for oil change intervals for most engines is the particulate load, not the physical or chemical stability of the oil.
The oil filter can not remove all of the particulate matter it picks up during it's flow round the engine.
If it did your oil would never go black.
Now detergent oils , and all synthetic oils are detergent are specifically designed to keep all of these particles in suspension, so the filter can pull as many as possible out.
The remaining ultra fine particles remain in suspension, circulating around your engine erroding oil galleries, making them larger and thus reducing the oil pressure in these galleries, thus reducing the protection the oil provides.
Oil filters generally are set to the finest oil gallery size so if it goes through the filter, it will go through the engine.
However, just because it can pass through a passageway, dose not mean that it will not cause damage in doing so.
We call this WEAR , wear in an engine is a process of errosion which can & is accelerated by chemical contaminants and also solid contaminants.

And don't get me wrong, there is nothing wrong with synthetic oils, in fact they are great and I use them, in places that they were designed to be used and places where the equipment makers have given their approval.
The problem is all the ignorant morons who do not understand the engineering of oils and their proper application spruking them as God's gift to all engines which they are not and never will be.
Nothing is universally applicable and in particular this applies to oils cause if there was one that was, then that one would be the only one the oil companies would make because when it comes to making a profit from oil refining, VOLUME IS KING.

Darryl G said:

You guys have me so confused about what oil to use that I can't decide so until I can I'm just not going to use any. :smile:

I only run synthetic in my truck. Everything else gets conventional.

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I suspect you're right about this. The discussion got deeply into the weeds. I believe I'm among those who got us there and for that I'm sorry. At the end of the day, getting into long-winded esoteric discussions on the finer points of things like synthetic oil probably don't benefit anyone but those who already agree with them.

Again, sorry about that.

Darryl G said:

You guys have me so confused about what oil to use that I can't decide so until I can I'm just not going to use any. :smile:

I only run synthetic in my truck. Everything else gets conventional.

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Most important thing is changing the oil often. Now pick your oil(I waste my money on synthetic) and change that oil. I do not like Mobile 1. It has made more than one of my vehicles start ticking.

Chuck got it .
In fact I previously mentioned it myself.
The most important thing about oil in mower engines, particulalry as a lot of them are splash lubed with no filters, is how long it has been in there.
IT should be changed at the end of every season for the home owner.
The information about synthetics is all based around CARS and not MOWERS.
They two are nothing like each other.
The big problem with using synthetics is people think they do not have to change the oil cause the oil is so much better and it costs so much more and that is the wrong approach.
My customers who do annual oil changes have old mowers and they are mostly running like Swiss watches which aren't much good for mowing cause the arms are too short.

Just as long as you stay within the viscosities mentioned in your owners handbook you mower will be fine.
I know lots of people who run diesel oil in their motorcycles, cause they get it for free from work.