Consequences of less tappet clearance:
- Valve will open early & close late
- Air induced through inlet valve may leak out. So less air for combustion.
- Power will be reduced.
- Fuel consumption will increase, engine may become unbalanced, exhaust temp. will be very high.
- In worst condition, valve may remain open, resulting in loss of compression pressure, burning of exhaust valve, T/C fouling will increase.
Consequences of more tappet clearance:
- Valve will open late & close early.
- Lesser heat energy to T/C, so reduction in scavenge air & hence power.
- No proper removal of gases.
- Hammering of valve stem-may cause damage to valve stem.