ASE A1 Engine RepairCylinder Head and Valve TrainMedium
A technician is measuring the installed height of a valve spring during a cylinder head overhaul. The specification for the valve spring installed height is 1.800 inches. The technician measures an installed height of 1.850 inches. What is the most likely consequence of this increased installed height?
- AReduced valve spring pressure.
- BIncreased valve spring pressure.
- CReduced valve guide wear.
- DIncreased valve lift.
Show answer & explanationAnswer & explanation
Correct answer: A. Reduced valve spring pressure.
An increased installed height means the valve spring is less compressed when the valve is closed. This results in reduced valve spring pressure, which can lead to valve float at higher RPMs and potentially poor valve sealing.
Why the other options are wrong
- B. Increased installed height means less compression, which reduces, not increases, valve spring pressure.
- C. Reduced spring pressure would not directly lead to reduced valve guide wear; if anything, it could indirectly contribute to wear if valve float occurs.
- D. Valve lift is determined by the camshaft lobe and rocker arm ratio, not the installed height of the valve spring.
Valve Spring Installed Height
The measurement of a valve spring's length when installed in the cylinder head with the valve fully closed, which directly affects static spring pressure.
- Determines the initial compression and pressure of the spring.
- Too high reduces pressure, can cause valve float.
- Too low increases pressure, can lead to premature wear or coil bind.
Memory trick: Higher installed, lower the push.