You’re trying to cut down some trees in your yard with your trusty chainsaw, but it just won’t start. Or maybe it runs but lacks power and stalls out. What gives? Well, worn-out piston rings could be to blame.
Although piston rings are necessary to maintain compression and proper combustion within a cutting machine engine, they can wear out over time. When they become damaged, your machine will suffer, and this might lead to permanent engine damage.
However, if you have the mechanical know-how and are handy with tools, you can replace chainsaw piston rings yourself. In this article, I’ll explain why and when to replace piston rings, how to disassemble the engine safely and install the new piston rings. So, let’s get going.
How to Replace Piston Rings on Chainsaw?
To replace piston rings on a chainsaw, you’ll first need to collect the necessary materials, tools, and new piston rings. Then proceed with disassembling the engine and removing the old rings to replace them with the new ones that fit properly.
1. Removing the Engine
Step 1: Remove the Spark Plug Wire
Use a spark plug wrench to disconnect the spark plug wire. This is to prevent accidental ignition during engine disassembly.
Step 2: Remove the Air Filter and Engine Cover
Use a screwdriver to remove the bolts holding the air filter cover on your cutting tool. Once the cover is off, take out the filter and set it aside. This will expose the carburetor and engine cover. Next, use a socket set to unscrew the bolts on the engine cover and remove it as well.
Step 3: Disconnect the Throttle Linkage
The throttle linkage connects the carburetor to the chainsaw engine. Locate it and use a pair of pliers to disconnect it from the carburetor.
Step 4: Disconnect the Fuel Lines and Starter Rope
The fuel lines connect the carburetor to the gas tank. Locate them and place a rag beneath them to catch any leaking fuel. Next, use the pliers to disconnect them from the carburetor.
Step 5: Remove the Engine
Once you’ve disconnected all the connections, pull the engine out of your cutting machine’s body and set it on a clean and flat surface.
2. Disassemble the Engine
After removing your cutting tool engine, you’ll need to remove some of its components to reach the old piston rings. Here are the steps to disassembling the chainsaw engine:
Step 6: Remove the Cylinder Head
Use a socket wrench to unscrew the bolts holding the cylinder head in place. Once they are removed, carefully lift the cylinder head off the engine block.
Step 7: Remove the Piston
You’ll have access to the piston after taking out the cylinder head. Use the pliers to remove the piston ring and lift the piston out of the engine block.
Step 8: Remove the Piston Rings
After removing the piston, use a piston removal tool to pry the old piston rings off the piston.
Step 9: Clean the Engine and Cylinder
Before you install new piston rings cleaning the chainsaw engine block and cylinder head is necessary to remove any carbon buildup. Use sandpaper or a wire brush to gently clean the cylinder walls and piston head.
Let’s get started with the steps of replacing the piston rings as under:
3. Replacing the Piston Rings
After cleaning the engine, it’s now time to get down to real work, and that is replacing the chainsaw piston rings. Here’s what you’ll need to do:
Step 10: Choose the Right Rings
Make sure to have the correct size and type of piston rings for your chainsaw make and model.
Step 11: Install the Compression Ring
Start by sliding the compression ring carefully on the piston. Use a compressor tool piston ring compressor tool to compress it until it fits snugly in the groove. This ring is responsible for sealing the combustion chamber.
Step 12: Install the Oil Ring
Proceed with installing the oil ring on the piston and use the compressor tool again. This ring typically includes an expander and an oil control ring and regulates the amount of oil that lubricates the cylinder walls.
Step 13: Install the Second Compression Ring
Some cutting tools have a second compression ring. If your chainsaw has it, install it after the oil ring and compress it into the groove using the compressor tool.
Step 14: Check the Ring Gap
After you’ve installed all the rings, check the ring gap. It is the small space between the ends of the rings in the cylinder. For specific gap requirements, check your chainsaw manufacturer’s recommendations.
Step 15: Reassemble the Engine
Once you’ve found the ring gap to be correct, reassemble the engine. To do this, follow all the steps of disassembling the engine in reverse order.
Why Replace Chainsaw Piston Rings?
Restore Engine Performance
Worn-out piston rings can decrease engine performance, making completing even the simplest tasks difficult.
Prevent Engine Damage
Damaged piston rings can cause oil to seep into the combustion chamber leading to engine damage.
Save Time and Money
Replacing the engine piston rings of a chainsaw is relatively inexpensive than costly engine repairs.
When to Replace Chainsaw Piston Rings?
Poor Performance
If you notice difficulty starting your cutting machine or a decrease in its power, it may be time to think about replacing the piston rings.
Excessive Smoke Emission
If your cutting tool is emitting excessive smoke or giving a foul smell, it may be because its piston rings are worn out.
Low Compression
A compression test will also help you know whether the piston rings allow too much air to escape the engine. If too much air is escaping, this indicates they need replacement.
Things to Prepare For When Replacing Chainsaw Piston Rings
Before you know how to change piston rings on a Stihl chainsaw or on any other brand, you’ll need to gather the necessary materials, such as:
Socket Set
You’ll need a socket set to remove the bolts holding the engine cover of your chainsaw cutting tool and cylinder head in place.
Pliers
A pair of pliers is also necessary to take out the clips holding the piston pin in place.
Piston Ring Removal Tool
You’ll also need a specialized piston ring removal tool to take off old piston rings from the piston.
New Piston Rings
Of course, getting new piston rings that match your cutting tool’s make and model is necessary. As they are sold in sets and come in different sizes and shapes, make sure to tally with the manufacturer’s manual for the correct specifications.
Engine Gasket Kit
This kit is important for reassembling the engine after disassembly and includes all the necessary engine gaskets.
Piston Ring Compressor Tool
This tool is essential to compress the piston rings to fit inside the piston bore during assembly.
Clean Rag
You’ll need a clean rag to wipe off any debris or oil from the chainsaw engine.
Silicone-based Lubricant
This lubricant will help you during assembly by sliding the piston rings smoothly in place.
Learn More: How to Remove a Chainsaw Flywheel?
Once you’ve gathered all the materials, you’ll first need to remove the chainsaw engine, disassemble it, and replace the piston rings.
Frequently Asked Questions
Can you replace piston rings without honing?
It’s not recommended to replace the piston rings in the chainsaw without honing because the new rings may not seat properly. This can cause a decrease in engine performance or potential engine damage. Whereas honing creates a crosshatch pattern in the cylinder wall, allowing the new rings to seal against the wall.
How to offset piston rings?
Offsetting piston rings involves positioning the end gaps of the rings in a way that they are at different locations around the piston. This is done by rotating the ring ends to the manufacturer-recommended position in the piston ring grooves. This makes sure the gaps are not lined up, preventing blow-by and improving engine performance.
How to replace piston rings without removing the engine?
It’s not recommended to replace chainsaw piston rings without removing the engine. Otherwise, it can lead to engine components damage. Removing the engine enables you to access the piston and piston rings which need proper cleaning and inspection before installing the new rings.
Final Thoughts
Hopefully, you now know everything there is to know about “How to replace piston rings on chainsaw” safely and precisely after reading the above guide. Replacing the piston rings on your chainsaw is vital to improving your cutting machine’s engine performance. It can also save you from potential engine repairs in the future.
So, gather the necessary materials, disassemble the engine, and install the new piston rings to keep your cutting tool running efficiently for years to come. But also remember to follow the guidelines given by your chainsaw manufacturer in the user manual.
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