Mechanics

Piston Ring Replacement

Step 6


Installing Second Piston Ring

Carefully choose the correct piston ring (the second and first piston rings are usually different from one another.) This ring could have a top and bottom and usually is shown by a small dot on the top flat part of the ring, near the gap. This ring can sometimes be installed without aid of a ring installer. Gently pry the piston ring open just far enough to fit straight over the piston. Do not bend, or swirl the ring onto the piston because it can bend the ring inhibiting its operation. As with the oil wiper rings be sure to locate the ring gap in the correct location on the piston.

Step 7


Installation of the Top Compression Piston Ring

The top and final compression ring is installed at the top of the piston, a tool is needed to help spread the ring due to its rigid nature. Like the second ring the main compression ring must be installed with the top of the ring facing upward. If the piston rings are installed incorrectly the piston (engine) will have low compression and may burn oil. Be sure the ring gap is in its proper placement for optimum performance.

Step 8


Completely Installed Piston Ring Set

Once all piston rings have been installed perform a final ring gap location inspection. Always be sure the piston rings are "free floating". Ring must be able to move freely on the piston or it will inhibit proper operation.

Step 9


Lubricating Engine Piston Rings
 

Before installation, piston rings must be lubricated (oiled) this helps the piston rings "mate" to the piston and the cylinder walls. Also include wrist pin and piston skirts in the lubrication process. Repeat this process for all pistons to be installed into the engine block, once completed the pistons are ready for installation. Store assembled pistons in a clean dry area if they are not immediately used.

Best Practices

  • Piston rings are a very important part of the engine and should be installed with care and cleanliness.
  • Never install new piston rings into worn cylinder walls.
  • Keep ring gap in proper locations on the piston
  • Never twist compression rings when installing

AUTHOR


Written by
Co-Founder and CEO of 2CarPros.com
35 years in the automotive repair field, ASE Master Technician, Advanced Electrical and Mechanical Theory.


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Article first published (Updated 2014-04-09)