Crankshaft Rectifier: Restore Smooth Operation and Reliability to Your Engine

Crankshaft grinding is a specialized machining operation performed during a rebuild or major engine repair. The goal of grinding is to restore the crankshaft journals (main journals and crank pins) to their factory specifications, ensuring perfect cylindricity, proper diameter, and a smooth surface for the proper operation of the main and connecting rod bearings.

Why is crankshaft grinding necessary?

  • Restoration of Worn Necks: Over time and continuous operation, the crankshaft necks wear out due to friction with the bearings, creating oval or conical surfaces, as well as scratches. Reboring removes this worn material.
  • Ensuring Proper Bearing Fit: A crankshaft with journal dimensions and cylindricity allows the bearings to fit evenly, properly distributing loads and preventing premature wear.
  • Improved Lubrication: A smooth and cylindrical surface on the journals helps create the proper oil film between the crankshaft and the bearings, ensuring effective lubrication and reducing friction.
  • Reducing Vibration and Noise: A properly ground crankshaft rotates more smoothly, reducing unwanted engine noise and vibration.
  • Extending the Life of the Bearings and the Crankshaft: Reduced friction and even loading extend the service life of both the bearings and the crankshaft.
  • Undersize Bearing Preparation: Grinding allows the necks to be reground to slightly smaller, but accurate dimensions, so that undersize bearings can be used.

When is crankshaft grinding necessary?

Crankshaft grinding is usually performed when:

  • The engine is being rebuilt and the crankshaft is removed.
  • There is evidence of wear, scratches, ovality or taper on the necks when measured.
  • The bearings have been damaged due to poor lubrication or another cause.
  • There’s increased noise or vibration from the bottom end of the engine.

The Crankshaft Rectifier Process:

Crankshaft grinding is a precision job performed by specialized engineers using special machinery (crankshaft grinding machine). The process usually includes:

  • Cleaning and detailed inspection of the crankshaft for cracks or other serious damage.
  • Precisely measuring journal dimensions and geometry.
  • Mounting the crankshaft on the grinder.
  • Grinding of the necks with abrasive wheels to remove worn material and restore the correct cylindricity and diameter. The minimum possible amount of metal is removed.
  • Polishing of the ground surfaces to achieve an extremely smooth finish, essential for the proper functioning of the bearings.
  • Verifying the final dimensions to ensure they’re within spec and suitable for the correct bearing size (including undersizes).

For the reliable and long-lasting operation of your engine, proper crankshaft grinding is essential during rebuild. Trust experienced professionals for an excellent result.