Engine oil has been described as the life blood of engine. Similar to the blood in our circulatory system oil circulates throughout the engine to supply a lubrication layer to the mechanical components of an engine. Here is the link to a short video that show just how oil lubricates an engine. How Engine Lubrication System Works. I covered this in my Blog Post on The Journey of Oil in My Engine
Oil does much more for an engine than lubricate. It provides cooling, cleaning, and a bunch of other chores. When oil is not present serious degradation and ultimate engine failure will occur. One can find a number of videos on You Tube, where people have driven a car or ran a piece of equipment without oil and recorded the failure results. Here is just one example that though not spectacular highlights how oil functions using an infrared heat sensor. What Happens to an Engine Without Oil
You already know engine function is degraded when you run out of oil. Let’s see if we can run it down to make more sense for you how it happens.
Let’s say, for lack of argument, your engine is running with very little to no oil. The engine oil light is on as the engine is running. Antifreeze is up to snuff, but that won’t stop overheating for too long. Here is what happens:
As whatever limited oil is in the engine is pushed around, it becomes hotter and hotter. It becomes hotter because the oil isn’t allowed enough time to cool down a little before it is required to go back into the engine and do its thing. As this happens, the oil will wear out faster. Fully synthetic oil will last longer than dino (refined) oil, but it will suffer defeat sooner or later as well. Several reactions happen to the oil, to include oxidation, thermal degradation, and compressive heating. Mind you, all of these things are created under normal use conditions (and thus the reason we change oils when we should), but under extreme conditions of low oil, high temperature, high load (towing) or racing, it all happens much faster.
This is a great image which describes what happens from the Machinery Lubrication website
These breakdown of the oil creates the regular: tar; sludge; varnish; soot; etc. All of these things start depositing on the internals of your engine, such as the rings, bearings, cylinder walls … anywhere oil would normally flow. If you go back to your chemistry teachings, you’ll probably remember that a large portion of oil is carbon. All of the previously mentioned nasty substances are actually carbon byproducts. As these carbon substances continue to deposit, any part which comes in contact with them gets wear on them as carbon can become quite hard and/or sticky under the right circumstances. This starts creating more friction on these parts. So now instead of cooling/lubricating/cleaning, the oil has broken down is now heating (due to more friction), creating deposits, and making the engine a really filthy place. You should realize it is now doing everything it was originally meant to replace.
As previously mentioned, this can occur under regular operation and can result in engine degradation or failure if the oil is not changed on a maintenance schedule. To see exactly what this looks like here are the links to a 2 part video produced by Cooper Lake Automotive which describe what happens when you don’t change the oil in your vehicle. They show the work needed to be done to get a 2006 vehicle with a 130K miles on it that had maybe 1 or 2 oil changes.
In the next blog article, I will cover why and what additives are put in motor oil to improve its operating efficiency.
Most of us know that it is important that our internal combustion engines have oil and the level should be checked regularly. We know that we add oil and that it drains to the bottom of the pan. Unless you’re a professional mechanic or avid car enthusiast may not know just the many roles oil in our vehicles play to keep the vehicle running. The main question most of ask is how often should I change the oil and what oil should I use. To answer these questions, I will use this blog to take you on the journey that your oil travels inside your engine.
To guide you on this journey I have included a figure taking you inside the Internal Combustion Engine and see how moves through the engine in this video. How Engine Oil Lubricates an Engine
All the oil drains to the oil pan (sump) when the engine is not operating. On starting the engine oil is sucked up through the sump strainer and tube shown in the Figure. Note that the strainer is submerged into the oil pan to a depth of 4 inches. The strainer prevents large pieces of debris (larger than 1/32 nd inches) from entering the oil pump.
The oil pump is a series of gears that take the oil from low pressure to high pressure through a chamber with a spring loaded valve that maintains pressure between 1- 60 psi. Any pressure higher than this vents the oil back to the sump because high pressure can damage the main bearings.
The oil is then pumped through the oil filter, which also has a bypass valve to insure oil get pumped into the engine if the filter gets clogged. This is because oil need to be under pressure to lubricate the rotating parts of the engine.
Under pressure the oil is forced into the space between the bearings and contacting the crankshaft journals. The bearings are metal sleeves encircling the rotating components of the engine. The main bearings on the crankshaft and the connecting rods bearings on the crank throw. A very thin film of oil usually one thousandth of an inch is held between the bearings and the moving surfaces of the crankshaft. This oil layer keeps the moving metal parts from touching.
Some of the oil is forced outside the bearings and drips back to the sump. If the bearings are wearing, this gap will result in a drop in pressure in the upper part of the engine. A flickering oil light or slight tapping in the rocker arm area of indicates that there is not enough pressure reaching the top of the engine.
Most of the oil lubricates the crankshaft and the remainder lubricates the camshaft and rocker arms. If your vehicle has pushrods (most older cars) vs overhead camshaft the oil is forced under pressure into the valve lifters. The lifters also push oil through the hollow push rods lubricating the rocker arms. If you vehicle is an overhead cam design, the oil flows onto cam and drips onto the contact point between the cam and the valve stems.
In the overhead cam engine design the oil then flows back down channels in the head and motor block back to the sump. In connecting rod design as shown in the figure, oil is sprayed into the cylinder to lubricate the piston ring contact are of the cylinder. Special rings on the bottom of the ring set wipe the excess oil from the cylinder wall to drain back to the sump.
Now that we know the journey oil takes in your engine, in the next blog I will delve into choosing the proper oil and easy ways to monitor the health of your oil.
Knowing the importance of oil in keeping your vehicle running , you will amazed to see that we produce an engine oil supplement that contains space age nano-technology that penetrates and protects the metal surfaces of an engine even when there is no oil. We never recommend running any engine without oil but we have run a used V8 engine with 281K miles on it without oil. You can see the video at www.jilcatproline.com