When rebuilding an engine, it’s crucial that you understand how to replace pistons. Also when changing the part to correct engine problems. That’s because piston replacement by a mechanic can also cost you a lot of money, often to the tune of several hundred dollars. Learn about the piston installation direction in this section of the guide, including the replacement costs.
When to Replace Pistons
Pistons are designed to last a long time. Under normal conditions and depending on the piston type, you only need to change them after more than 200 000 miles. But conditions are rarely normal and the part may require changing earlier than the expected time. Situations that may warrant piston replacement are listed below.
- When the piston head burned, cracked, or pitted and scored.
- If the piston pin is too worn
- If the piston grooves are too worn to hold the rings in place
- If any of the piston parts is broken or cracked
- If doing a piston upgrade for your engine
During piston replacement, the affected piston is removed and a new one inserted in its place. Most of the time, though, you need to change all pistons. Doing so ensures balance and prevents engine issues.
Just like with any other part of a car engine, you can either do the replacing yourself or have a professional do it. Next, let’s see how to replace pistons as do-it-yourself engine rebuilding process.
How to Replace Pistons
Piston installation requires extreme care. That’s because mistakes can cost you the engine. As such, it’s important to observe the requirements of every step involved. Without further ado, here is how to replace pistons in an engine. The process applies to most IC engines.
Things You’ll Need
- Ratchet and socket set
- Piston ring compressor
- Piston oil
- Piston hammer, also known as dead blow hammer
- New piston assembly
- Lint free cloth or towel
You can replace pistons with the engine on the car but that would be troublesome. A better way would to remove the engine and access the pistons more easily. With the engine removed, follow these steps to remove old pistons and install new ones safely.
- Slowly rotate the engine to the pistons bottom dead center
- Turn the engine to access the lower end of the piston assembly
- Using a ratchet and socket, remove piston bolts by loosening the nuts
- Remove the connecting rod cap and bearing
- Use the hammer handle to push the piston out through the cylinder head bore
Make sure that you have the new piston fully assembled, with the rings in place and the piston pin and connecting rod. Before installing the new piston, wipe the cylinder using a clean and lint-free cloth then follow these simple steps.
- Oil the new piston, especially in the movable parts
- Oil the cylinder and piston ring compressor. This will help the piston to slide out of the compressor and into the cylinder with ease
- Place the piston installer tool (compressor) on the piston so it presses against the rings
- Insert the ring compressor into the cylinder bore
- Tap the piston head gently with a hammer until it slides down and out of the ring compressor’s hold
- Remove the compressor
- Turn the engine again and rotate the crankshaft while guiding the piston rod end to it
- Install the connecting rod bearings, end caps, and bolts.
- Tighten the piston bolts to the torque specifications indicated on the manual
- Repeat the steps for the other pistons if replacing more than one
The above guidelines on how to replace a piston should be followed correctly and the installation done gently to avoid damage. Incorrect replacement can cause engine issues or even lead to a piston that breaks down soon after installing.
Ensure, also, the correct piston type for your engine. The right size, too. For piston measurements, have with you the required tools such as micrometer or feeler gauges. Next is a breakdown of the cost to replace a piston.
Piston Replacement Cost
Piston replacement is a long process that involves removing many parts. In most cases you need to remove the engine from the car. That can take a long time, up to several hours. You can therefore, expect a piston job to cost a lot of money. That’s besides the cost to buy the piston, which can be quite high.
The piston replacement cost is normally around $1000 for a 4-piston engine and higher if your car uses more pistons. This includes the piston price and the engine rebuilder’s charges. In some cars, the cost can go up to $2000.
You can spend less, of course, but only if you know how to replace pistons correctly. Only ensure that you have the right tools for the job and the steps to do safely and correctly. If you choose professional replacement, be sure to compare the rates of different installers.
The pistons in your car perform the important function of converting gas pressure into motion. When damaged, your car engine experiences problems. Engine pistons are normally better replaced than repaired. Piston replacement ensures your engine continues to run as it should, unless you intend to replace the engine itself.