The Kendall Diaries - Motor Oil

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Stan Disbrow
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The Kendall Diaries - Motor Oil

Post by Stan Disbrow » Wed Jun 17, 2020 6:43 am

Hi,

This is the second is a series. To find out where all this comes from, see the Overview post:

viewtopic.php?f=2&t=13390

The Purposes of Motor Oil

In the operation of the internal combustion engine, an adequate and properly directed supply of lubricant is second in importance *only* to the supply of fuel and air. The four primary functions of an engine lubricating oil are:

-to lubricate
-to seal
-to cool
-to clean

To Lubricate

This requires the maintenance of a slippery surface between moving parts. It is often referred to as 'oiliness'. This oil film must adhere very tenaciously to metal surfaces. It must 'stay put' and resist being shoved away when either hot or cold, even though it is subjected to high pressures. Unfortunately, there is no laboratory procedure to fully measure these properties. "The proof of the pudding is in the eating". Actual use in the engine is the only way to evaluate the oil's ability to lubricate.

To Seal

Immediately following the burning of fuel in the combustion chamber of the engine, the gases formed are under high pressure. It is the pressure of these gasses on the piston top which causes the engine to run - so, it is necessary to keep these gases from leaking past the piston and valves. The oil acts as the sealant. If the oil thins out too much, the gases blow by. The oil must resist excessive thinning.

To Cool

Although the cooling system removes the great mass of unwanted heat, the oil must remove it from some critical areas - such as the bearings. The oil assists the cooling system. In doing this, it frequently becomes much hotter than the cooling system fluid.

To Clean

As a result of the combustion of fuel in the engine, a variety of waste products is formed. The fuel type and the conditions of combustion influence the nature and quantity of these waste materials. Some of the most troublesome of the waste materials include water, soot, carbon, lead salts and acids. Many of these materials remain in the engine and contaminate the oil. Unless these contaminates can be held by the oil in a state of dispersion - so they will be removed from the engine when the oil is drained - they will contribute to the formation of harmful and power-robbing deposits. Helping to keep and engine clean is a very important oil function. When we speak of the lubrication of an engine, we have all of these functions in mind.

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Chemical and Physical Factors Influence Properties of Oil

If it were not for troublesome chemical and physical factors influencing the properties of the oil itself, the job of lubrication would be much easier. Some of these factors and their significance are given below. Kendall oils are made to effectively lubricate engines in spite of their presence.

Temperature Extremes

Operating internal combustion engines as we do, both low and high temperatures are encountered. When oils cool, they thicken, become heavy, (viscous) and resist flow. When heated, oils thin out and become light or less-viscous. In cold weather oils may become so thick that they will not circulate freely. Excessive wear results. They can become so thick that the engine cannot be started.

When hot, oils thin out. If they become too thin, high oil consumption and engine wear results.

It is necessary to make oils so that they will not become too thick when cold nor too thin when heated.

Oxidation

When air and oil come into contact with each other, the oxygen in the air combines with the oil. This is known as oxidation. The oxidation products deposit on engine parts causing engine inefficiency or failure. Oxidation occurs very slowly when the oil is cold, but very rapidly when it is hot. as a result of oxidation, troublesome acids can also form. Oils may become thicker as they oxidize. To prevent oxidation problems, proper attention must be paid to oil refining and formulation.

Corrosion

Two types of corrosion are existent in internal combustion engines. They are rust and acid corrosion. Rusting is caused by moisture or water. Acids formed as a result of fuel combustion or oil oxidation cause acid corrosion. Both water and acids are formed in quantities great enough to cause destruction of vital engine parts in a short time, if steps are not taken by the refiner to protect against them.

Contaminants

Many people are under the impression that crankcase oils require changing because the oil wears out or breaks down. Usually oils are no longer fit for use because of the accumulation of contaminants rather than physical and chemical changes in the oil itself.

The primary source of contamination is the combustion chamber where a host of compounds are formed during the burning of the engine fuel. As these compounds get past the piston rings in the engine cylinders, they mix with and contaminate the oil. these may include water, soot, carbon, lead salts, acids and dirt. Mixture of water with some or all of these contaminants can be extremely harmful when they form sludge.

The only way to completely remove these contaminants is by regular oil changes.

Foaming

When oil and air are beaten together, foaming can occur. It consists of small air bubbles trapped in an oil film. foaming reduces lubricating effectiveness and causes malfunctioning of such engine parts as the oil pump and hydraulic valve lifters.
There's No Such Thing As A Cheap Crawler!

Have: '58 JD 420c 5-roller w/62 inside manual blade
Have: '78 JD350C w/6310 outside manual blade
Useta Have: '68 JD350, '51 Terratrac GT-25
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Re: The Kendall Diaries - Motor Oil

Post by 77 Ford » Thu Jun 18, 2020 6:55 am

I used to have some old timers tell me oil never broke down and they would change their filters every two months and replace the missing quart. This read kinda supports that but I assume at some point even with alot of filter changes the oil is going to become to dirty to function right.
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Re: The Kendall Diaries - Motor Oil

Post by Lavoy » Thu Jun 18, 2020 8:58 am

A Conoco petroleum, engineer told me once in a lengthy discussion that oil has a given capacity to absorb contaminants. Once that capacity is reached, it can not hold any more, and therefore needs to be changed. This was in reference to modern oils, we never talked about non-detergent stuff.
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Stan Disbrow
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Re: The Kendall Diaries - Motor Oil

Post by Stan Disbrow » Fri Jun 19, 2020 4:32 am

Hi,

As I enter these sections, there is one which addresses additives. And, the detergent is one. It holds the byproducts of combustion in suspension. It is why the oil turns black. When it becomes fully loaded, you change the oil. These particles are all too small for the filter to trap. In the old days, when there were no detergents, the crud built up in the corners of the block, oil pan, valve cover, etc. Made a mess. These days, a quart of oil is only half a quart of oil (called the base stock) and the other half is the additive package.

So, in the old days, the oil never became dirty looking. The engines burned a little, so the old timers just added some. Don't pull the oil pan, though. I have seen some where the crud built up until there was barely room for the crank swing. Dad would say: Clean that stuff out for me, wouldya? (!)

Stan
There's No Such Thing As A Cheap Crawler!

Have: '58 JD 420c 5-roller w/62 inside manual blade
Have: '78 JD350C w/6310 outside manual blade
Useta Have: '68 JD350, '51 Terratrac GT-25
Also Have: 1950 M, 2005 x495, 2008 5103 (now known as 5045D)

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