How is camshaft wear assessed and when should replacement occur?

How is camshaft wear assessed and when should replacement occur?

• A. Check compression readings for cam wear.
• B. Inspect lobes for scoring or spalling; measure lift vs spec; replace if out of tolerance.
• C. Verify timing marks to determine cam wear.
• D. Test oil viscosity for cam wear.

Answer: (B)

Camshaft wear shows up most clearly on the lobes themselves and in the actual valve lift they deliver. The reliable way to assess it is to visually inspect the cam lobes for scoring, pitting, spalling, or any surface damage, and to measure the lift produced by the cam against the manufacturer’s specification. If the lobes show damage or the measured lift is outside the specified tolerance, the camshaft should be replaced. Other checks don’t directly indicate cam wear: compression readings can be affected by valve seals, rings, or head issues and won’t pinpoint cam damage; timing marks confirm timing but not wear; oil viscosity can reveal lubrication problems but not the actual wear state of the cam lobes.

Camshaft wear shows up most clearly on the lobes themselves and in the actual valve lift they deliver. The reliable way to assess it is to visually inspect the cam lobes for scoring, pitting, spalling, or any surface damage, and to measure the lift produced by the cam against the manufacturer’s specification. If the lobes show damage or the measured lift is outside the specified tolerance, the camshaft should be replaced.

Other checks don’t directly indicate cam wear: compression readings can be affected by valve seals, rings, or head issues and won’t pinpoint cam damage; timing marks confirm timing but not wear; oil viscosity can reveal lubrication problems but not the actual wear state of the cam lobes.