Piston rings have triple purpose

Piston rings seal the combustion chamber. They are set with precision so as to apply the correct pressure on the cylinder wall or liner, which ensures there is a consistent film of oil across the cylinder's working surfaces. This provides sufficient lubrication and protects against wear.

Piston rings from Perkins come as three rings. They are the top compression ring, then the intermediate compression ring and finally the oil control ring. These parts are relatively small in size but play a large role in the main cylinder block of your engine.

Their function is to seal off gases generated in the internal combustion process, help with transferring heat to the cylinder wall and then to both lubricate and scrape down oil from it. Getting the quantities of oil right is vital. Too much oil will cause it to burn off during combustion potentially making your engine produce blue smoke, too little will cause the engine ultimately to seize.

The primary role of the top compression ring is to seal off the majority of the combustion gases to ensure you get the maximum power output from your engine. Any failure or weakening of the piston ring in this area means your engine is working less efficiently than it should.

The bottom ring is responsible for most of the oil control, helping to make sure the right amount of oil is used to lubricate the working surfaces of the cylinder, while the intermediate ring helps with both functions, playing a finishing role in the combustion sealing as well as the downward oil scraping.

The result of these three rings working in harmony is sufficient lubrication within the cylinder bore, ensuring that no undue wear occurs at any time.

How Long Do Piston Rings Last?

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 an 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 an 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 far earlier than their expected lifetime.

When Should You Replace Piston Ring

Firstly, 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 occuring.

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 on an engine component, its best to inspect all parts since you don’t want to go back to it again after sometime. Any work on the engine components like piston, piston rings, crankcase components, 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.

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 it to damage other components.

Also, you cannot repair piston rings. Any sign of damage, just replace it. There is no easy way out here.

Replacement Cost Of Piston Rings

While piston rings cost around $50 to $200, replacement cost of piston rings is more than $2000.

This is because replacing piston rings is a laborious task. Although piston rings themselves doesn’t cost much themselves, the labor charges will be too high since piston rings replacement means taking out the engine cylinder head, removing piston from the engine, and then replacing the rings.

Typically, all this process will take around 10 hours altogether. As a result, the labor cost is far too high and costs so much for a simple piston rings replacement.