- How to Tell if Motorcycle Piston Rings Are Bad
- Detecting symptoms of the bad piston rings
- Broken piston ring? Cause?
- 5 things that go wrong with pistons (and how to prevent them)
- Engine Piston Failures
How to Tell if Motorcycle Piston Rings Are BadWhen a tree falls on a saw, there is rarely any doubt what happened, but when the engine fails, it is sometimes difficult for pro users to understand what has occurred and why. The following images of damaged pistons illustrate what can happen inside a saw's engine. While the piston is not the saw's only internal engine part, it is often the part that "pays the price" when a saw is not operated or maintained correctly. We hope this information helps explain what can occur and why, and more over, provide knowledge of how to avoid common causes of failure in the first place. The piston above has severe scouring on the exhaust skirt with the heaviest damage on the clutch side of the piston. The lack of lubrication on the piston has caused it to seize to the cylinder wall. The damage you see was caused in the moments before the piston "stuck," which seized the engine. This kind of piston damage can also be found on a saw that was run with the carburetor set too lean or one that was run with an air leak. If you didn't know this saw had been run with no oil in the fuel, how would you know it wasn't a heat seizure? To fully understand the cause of this failure, it is important to look at the rest of the piston. The photo below is of the same piston. It shows additional damage that's usually only found on a saw engine that had been run with unmixed fuel. On this piston, notice the scouring in the wrist pin area. A heat seizure will show similar damage on the piston skirt photo onebut the conditions under the piston will look normal. On this piston, the scouring and other dry conditions provide the evidence to suggest this seizure was caused by no lubricant in the fuel. If you tear down a saw and find this kind of damage, don't forget to replace the fuel in the saw's fuel tank before you test run it after the repair. It is also important to check the contents of the fuel container that was last used to fill it. Since the repair required the replacement of both the barrel and piston read: expensive, this is a repair you don't want to do twice or on more than one saw. The damage on this piston skirt is caused by debris getting through the air filtering system. Notice the horizontal machine marks have been scrubbed off all across the bottom indicating extreme wear on the lower part of the skirt. Not shown, but the other side of the piston looked perfect. This damage was only found only on the intake side of the piston. This is typical for damage caused by intake debris. The other side of the piston is not exposed to an intake port, so it isn't affected at early stages. What damages the intake skirt is debris from a leaking filter wedging between the piston and cylinder wall causing scuffing on the piston skirt. Since the piston is made of softer material, the damage is more pronounced on the skirt than on the cylinder bore's hard surface. This wear on the piston increases the clearance, which allows the piston to "rock" in the cylinder's bore. As the skirt becomes thinner and weaker, rocking increases. Eventually the piston will break. When it does, the engine seizes. On a pro saw, the piston skirt performs another important function. Not only does it guide the piston, the skirt serves as the engine's intake valve. As the piston travels up and down the cylinder, its base opens and closes the intake port as it passes. For the engine to run its best, it is important for this valve to function well. Some intake skirt damage is not uncommon on a pro saw's piston after it has run hundreds of hours. No air filtering system is perfect, so you can expect to see the affects of debris damage even on saws whose filters have been well maintained. The important thing to learn is this damage can happen quickly when the filtering system is leaking debris.
Detecting symptoms of the bad piston rings
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Broken piston ring? Cause?
In this article we are going to share information about one of engine parts called piston rings. After read this article you will know the basic functions, bad symptoms, driving with worn piston ringstips to diagnose and tips to prevent. The internal combustion engine of a vehicle is comprised of piston rings which surround the diameter of the pistons. There are 4 primary functions to piston rings:. You cannot afford to have one of its functions go bad, let alone all of them. If you can understand what these problems mean and where they come from, then you can trace them back to bad piston rings. The piston rings should stay strong for a very long time. However, like most parts in a vehicle, they will eventually become worn out. You will need to replace these components quickly or else your vehicle will face more severe damage. This will be damage that will cost you thousands of dollars instead of hundreds of dollars. Therefore, it is important to recognize the symptoms of bad piston rings as they occur. Whenever you have worn out or damaged piston rings, they are going to leak oil from them. This oil will likely find its way into the internal combustion chamber. Once that happens, there will be an abundance of oil consumed at a fast rate. Of course, you should only do this so that you can buy enough time to get your vehicle to the mechanic and have them fix the leak. Damaged or worn piston rings will cause your engine power to diminish. You will notice this when you step on the gas pedal to try and accelerate your vehicle. Instead of going faster as you accelerate, there will be a delayed reaction to the acceleration. It may even take more than a few seconds before you start going a little bit faster. Bad piston rings can result in gray or white colored exhaust smoke coming out of your tailpipe. This is a result of the leaky oil burning inside the combustion chamber.
5 things that go wrong with pistons (and how to prevent them)
Piston is one vital part that plays a very important role in a car. Piston acts as a movable plug in the cylinder, forming the bottom part of the combustion chamber. Over sixty percent of the friction inside the engine comes from the motion of the piston assembly, and so this is a major area of focus for improving the efficiency of engines. Today there are so many factors that can be responsible for a piston to be blown or damage thereby causing problems to the engine. The rings ride within annular grooves in the piston. The compression rings contain the pressure of the expanding gases within the combustion chamber, helping to harness or fetch the power being generated while preventing blow-by gases from entering the crankcase. The oil control ring assembly scrapes excess oil from the cylinder walls ahead of the compression rings to prevent the oil from entering the combustion chamber. A failure in any of these rings will result in a loss of performance coupled with other problems and symptoms. It is important to know that some factors could cause broken rings. However, if the rings are properly sized and fixed or installed during the time of coupling the engine, any failure in the rings are most likely caused by another mechanical problem. When an engine becomes overheatedthe piston will expand, thereby reducing the piston to cylinder clearance. This reduction can cause a metal to transfer from the piston to the cylinder wall, which is known as Galling. At this juncture, the transferred aluminum can be build up on the cylinder wall and cause the top compression rings to leak or break. Oil control rings can break if there is excessive piston to cylinder clearance allowing too much slap to occur. The skirt of the piston, and the cylinder wall itself can be damaged and this damage can in turn wipe out the oil control ring assembly. Whenever there is a broken compression rings the effect of it is immediately and clearly shown. You will notice a form of loss of performance, rough idle and possibly a dead miss in the affected cylinder. Lack of containment of the combustion gases will cause blow- by gases to enter the crankcase and exit through the positive crankcase ventilation system. The positive crankcase ventilation valve will most likely be located on a valve cover. Disconnect the breather tube from positive crankcase ventilation, and if you notice a stronger and smoky discharge from the valvethen chances are good that compression rings are broken. Besides the obvious performance problems, other problems can develop over time. For example, a diesel engine that runs high —sulfur fuel, such in farm or marine applications, can be severely damaged by a compression leak. Partially burned fuel blows by the rings, and the sulfur in the fuel mixes with water traces in the oil, and combines to form sulfuric acid, which will damage the internal components of the engine. In gasoline engines, the fuel acts as a solvent that thins the oil and prevents it from properly protecting the internals. When there is a broken oil control ring in the assembly, the obviousness of it will be shown by the quality of the exhaust. The exhaust will turn blue and have a decidedly oily smell to it. The exhaust will emit a puff of blue smoke per revolution for the bad cylinderand normal looking exhaust for the good cylinders. This staccato puff makes it easy to diagnose visually. Other symptoms include oil loss in the absence of leaks, and oil fouling on the spark plug of the affected cylinder. Irrespective of the fact that some piston can be damage by blown gases, inadequate lubrication and free hydrocarbon in the oil can damage piston; there may be presence of mechanical error. This mechanical error makes the ends of the rings scratch the cylinder wall, thereby preventing walls and worsening the symptoms. The rings grooves in the piston can be damaged, and since the cylinder walls and rings are both harder the aluminum piston. The piston itself can be damaged or partially broken, leading to even greater damage. Note that broken pieces can likely cause problem in the bottom of the crankcase, possibly causing more damage, you should repair broken rings properly to avoid mechanical damages in a car. Blown piston has actually been discussed for the benefit of maintaining our car. Therefore, the symptoms has been disclosed on this article for us to look out in other to avoid further damages in our car. Your email address will not be published. Notify me of follow-up comments by email.