If an engine produces white or grey oil smoke or consumes too much oil, it may be a sign of worn piston rings; other symptoms of this problem include poor overall engine performance and a lack of acceleration power. Compression loss is a common result of piston ring wear and may cause the engine to backfire.
An improperly-sized or damaged cylinder bore can cause piston ring malfunction. The bore should match the manufacturer's specifications to ensure that the piston rings can be effectively sealed. This allows proper compression inside the engine and ensures the correct amount of oil use. Cast iron bore sleeves can provide a tighter fit for piston rings; they can also reduce wear to the cylinder and solve the problem of a scratched cylinder bore, which does not allow the piston rings to seat properly. Ample lubrication of the bore can also reduce abrasions that disrupt cylinder function.
Owners can use compression gauges to perform a compression test on the engine to determine if worn piston rings are at fault; they should test each cylinder to isolate the problem. When replacing damaged piston rings, owners may have to re-bore the engine and select replacement parts by the same manufacturer to keep it working efficiently. New piston rings may take time to break in so that they match the bore. If the engine is not performing optimally after installation, it could be a sign that the new rings are still breaking in. During this time, rings should be amply lubricated and engines should only be lightly used.