Piston rings are a vital engine component since they seal the gap between the piston and the cylinder walls. High-quality and long-lasting piston rings are a must for all types of engines.
So, how long do piston rings usually last? Piston rings are typically built to last as long as the engine. As a result, piston rings usually last somewhere between 50,000 miles to 250,000 miles depending on their maintenance.
On average, the life expectancy of piston rings is around 100,000 miles. One has to replace piston rings if they are damaged or worn out.
Life Expectancy Of Piston Rings
Piston rings are typically built to last as long as the engine. Since motorcycle engines last somewhere between 50,000 miles to 250,000 miles, piston rings should last around the same lifetime as well. On average, piston rings should last around 100,000 miles.
Again, this is a highly subjective number depending on how good your maintenance is, the piston rings quality, and several external factors including engine oil levels, riding conditions (dusty regions are bad), etc.
If the piston rings are worn out or get damaged at a faster rate, then you might have to replace the piston rings far earlier than their expected lifetime.
When Should You Replace Piston Rings
First, if your engine has run more than 100,000 miles, then probably it is time for replacing the piston rings. But, do not go to all the lengths of removing the engine cylinder and taking the piston just to replace the piston rings if you are not facing any issues with the engine.
Rather, let things continue as long as there are no problems occurring.
However, as soon as you face a problem and have to repair an engine component, it is best practice to inspect piston rings and replace them if the engine has run more than 100,000 miles.
This is because if you are reworking an engine component, it’s best to inspect all parts since you don’t want to go back to it again after some time.
Any work on the engine components like the piston, piston rings, crankcase components, and cylinder – are all cumbersome, time-consuming and most of all, a costly affair.
Other times when you need to replace piston rings are when these rings are damaged or worn out.
Piston rings are made of cast iron, usually alloyed with elements like silicon, manganese, and molybdenum. They don’t wear out fast.
But if they do wear out or get damaged, they must be replaced as early as possible. Bad piston rings will cause more damage to both the cylinder walls as well as the engine itself.
It’s better to replace the bad piston rings early rather than wait for them to damage other components.
Also, you cannot repair piston rings. Replacing is the only option. There is no easy way out here.
Replacement Cost Of Piston Rings
While piston rings cost around $50 to $200, the replacement cost of piston rings is more than $2000.
This is because replacing piston rings is a laborious task. Although piston rings themselves don’t cost much, the labor charges will be too high since piston ring replacement means taking out the engine cylinder head, removing the piston from the engine, and then replacing the rings.
Typically, this process will take around 10 hours altogether. As a result, the labor cost is far too high and costs so much for simple piston rings replacement.
How Do I Know If My Piston Rings Are Bad
If the piston rings are damaged or worn out, there is no direct method to determine it.
However, there are several symptoms which combined together will indicate that the piston rings have gone bad and should be replaced immediately.
The first and foremost sign of bad piston rings is if you are seeing white or gray smoke coming out of the exhaust. White smoke is a clear indication that the engine oil is getting burnt in the combustion chamber. And the oil can only enter the combustion chamber if the piston rings are not sealing the piston and cylinder correctly.
In the same vein, if the engine is being consumed excessively and you are constantly seeing low engine oil levels despite several top-ups, it is most likely because the piston rings are bad and are allowing the oil to move into the combustion chamber to get burnt.
Apart from the indications from oil, you can also suspect bad piston rings from the engine. If the engine power and acceleration are consistently low, then the culprit is either the inlet and exhaust ports or the piston rings.
To pinpoint the culprit, you can test the engine compression. If the engine compression is considerably lower, then it is without a doubt certain that the piston rings are damaged and are not working properly. Here is a detailed post on signs of bad piston rings for more details.
One last sign of bad piston rings is piston slapping. If you hear a piston slapping noise across the inner cylinder walls, then the piston rings are worn out and the gap between the piston and the cylinder walls has widened.
Once you know the piston rings are damaged, they need to be replaced. Along with replacement, you should also check for the root cause and what caused the piston rings to go bad. And then address the cause.
What Causes Piston Rings To Wear Out
Now that we know the signs to look for if we need to replace the piston rings, it’s time to understand what causes these piston rings to wear out or get damaged.
Here are the main reasons why pistons rings go bad:
- Engine oil is low or of poor quality
- Air filter is letting in dust
- Oil filter is not working right
- Engine blowby
- Fuel flooding in carburetted engines
For more details, here is our post on why piston rings go bad.
To Summarize
Piston rings are typically built to last as long as the engine. As a result, piston rings usually last somewhere between 50,000 miles to 250,000 miles depending on their maintenance.
On average, the life expectancy of piston rings is around 100,000 miles. One has to replace piston rings if they are damaged or worn out.
Piston rings typically cost from $50 to $200 depending on the type and quality. However, the replacement cost of piston rings is as high as $2000 since it is a labor-intensive process.
Related Questions
There are three piston rings attached to the piston on its outer diameter, namely: Compression Ring; Middle Ring; and Oil Scraper Ring.
An engine cannot run without piston rings. If run without piston rings, the piston and the cylinder walls will get damaged due to piston slapping and strong metal-to-metal contact.
If the fuel mixture in the engine combustion chamber trickles down to the crankcase, it is called engine blowby. The fuel mixture leaks through the gap between the inner cylinder walls and the piston and piston rings.
