Engines take in a tremendous amount of air to mix with fuel.
Modern farm equipment often displaces nine litres or more of air with each cycle of the pistons. The air these machines need must be clean when it gets beyond the filter.
According to a major engine manufacturer, it takes about half a cup of dirt to ruin an engine, which means we cannot afford to let in any dirt.
Some people may fondly remember the old oil bath air cleaner. It was at best 87 percent efficient. It was messy to service and if you left it too long, it would really put the dirt into the engine.
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The dry air cleaner is much better. It is about 98 percent efficient and when it gets full, it will stall the engine before it lets in dirt.
It is almost always two filters, one inside the other. The inner one was never intended to keep dust out of the engine for long. It is too small and should be used only to indicate when the outer filter is damaged.
If you see any dirt on the inner filter, throw the outer one away. The filter’s manufacturer says you should be able to wipe your white shirt on it and not show dirt. It is a dependable filter except for damage caused by improper handling.
The manufacturer says that more than three-quarters of the engine failures that could be blamed on the filter were caused by the operator not handling the filter properly.
Perhaps the biggest question is how the filter should be cleaned. I suspect you have all seen your neighbour beat the corners of the filter’s metal end against the tire. (I know you would never do such a thing.) This has a tendency to crack the glue that holds the paper onto the metal end. The dirt goes through the crack and into the inner filter.
Maybe you beat the side of the filter with the flat of your hand. Remember that the slightest bend in the outer shield will cause it to touch the paper element.
And because the paper element is moving constantly, it wears a hole in the paper and allows dirt to enter.
There are only two ways to clean a filter: gently blow the dust from the inside out, or wash it with a special soap.
Most operators’ manuals willtell you to replace your filters annually. That is because they are made of paper and paper can bend only so often. They also develop cracks in the corners.
As well, the paper is treated with a special chemical that dissipates in about a year. It is better to replace the filter than to risk engine failure.
Other problems can occur if the filter is handled too often. Every time its handled, there is a chance of damage.
Remember, a plugged filter will never hurt an engine, but a cracked one will.
One way to tell when it is getting plugged is that the engine starts using oil, especially in older engines where the valve guides are worn. This happens in combines where a filter can plug quickly.
You might be used to cleaning your filter every day and you might not know that it never used oil for the first three-quarters of the day but toward the end it was just sucking the oil.
When the filter is plugged the engine draws too much of a vacuum and starts pulling oil down the valve guides.
Of course, by that time you notice that the engine is smoking and is low on horsepower.
Henry Guenter is a retired Massey Ferguson-Agco service manager.
