Cylinder Ridge Removal

Because the top piston ring does not travel to the very top of the cylinder, a ridge develops on the cylinder wall between the end of the travel and the top of the cylinder bore.

Pushing the piston and connecting rod assembly past the ridge can be difficult, causing damage to the piston ring lands. If the ridge is not removed, piston ring breakage and piston damage may occur.

Note: You must remove any cylinder ridges before removing any piston and connecting rod assemblies. Ridge removal is typically not necessary when new pistons are to be installed. In some cases, a ridge may actually prevent a piston assembly from being removed, necessitating the ridge to be cut.

There are several different types of ridge reamers on the market, none of which are inexpensive. Unless a great deal of engine rebuilding is anticipated, borrow or rent a reamer. To remove a cylinder ridge:

1. Rotate the crankshaft until the piston is at the bottom of its travel
2. Cover the head of the piston with a rag
3. Follow the tool manufacturers' instructions and cut away the ridge, exercising extreme care to avoid cutting too deeply
4. Remove the ridge reamer, the rag and as many of the cuttings as possible
5. Continue until all of the cylinder ridges have been removed