Category Archives: Polishing

Polishing a crankshaft, leaving just a fine micro-finish, is ideal for extending the life of engine bearings.

Chamfering Oil Passages

Whenever machine work is performed on a crankshaft’s journals, these surfaces must be adequately finished before use in an engine. Besides maintaining a sufficient microfinish, it is also important that any burrs are removed. A critical area where burrs are often found are just inside of the journal’s oil passages. The way to remove these burrs is by using a process known as chamfering.

Burrs develop on oil passages from a variety of machining operations. Just grinding the crankshaft .010” can leave a small burr that would restrict the proper flow of oil while the engine is running. This poses a serious concern since engine bearings need to be adequately lubricated at all times. Chamfering is the industry standard in deburring crankshaft oil passages, which is explained in more detail below. Continue reading

Crankshaft Polishing

A common service that most automotive machine shops offer is crankshaft polishing. This is a necessary step to prepare the crankshaft for the assembly of an engine. While there is some confusion about what can be expected from the polishing process, we will dispel the myths in this post and discuss why the polishing process is important.

First, many novice engine builders believe if their crankshaft is gouged that all it needs is to be polished. In most cases this line of thinking is wrong. Gouges, caused by material that may have been embedded in engine bearings, can damage a journal. Polishing can’t take these defects out of journals; at least with any degree of accuracy. If there are a lot of deep gouges, lines or other marks in a journal, chances are grinding the crankshaft first is the best course of action. Continue reading