critical speed of drum in case of rope brake dynamometer

In rope brake dynamometer , heat is genrated due to friction between rope & drum. So cooling is provided with the rope brake dynamometer . The drum is provided with flanges turned inside on the rim, forming a channel for the flow of water . Circulation of water from bottom to the top is possible onlu when centrifugal forceon water will be greater then its weight. therefore Fc >=w Fc-w=0 For equilibrium position of water in channel Fc-w=0.

grinding valve seats

The valve seat grinder rotates a grinding stone of copper shape an valve seat. A pilot installed in the valve seat . This permits the stone to clear itself of grit & dust by centrifugal force . A steel scale can be used to measure measure seat width. When a new valve is installed it may too high above the seat . Then grind the seat slightly with a stone of the same seat angle

checking of leakage of valves

1. Check valve guides for wear, clean replace & ream for same size valve steam if necessary. 2. Check valves & valve seats. Clean valve heads & steam an a wire wheel. 3. Refinish valve seats. 4. Check rocker arms for wear. Service or replace as necessary. 5. Replace valves & springs in head. 6. Check & adjust valve clearence as necessary

valve seat grinding

For effective valve seating & sealinf , the valve face is must be concentric with the valve stem . The valve seats are of two types , 1. The integral type. 2. The insert type.

valve refacing

If the valves are good enough to reuse them. This requires a valve refacing machine. The valve refacer has a grinding wheel coolant delivery system & a chuck which holds the valve for grinding set the chuck to grind the valve face at specific angle to start the operation , align the coolant feed so that it sprays coolant on the rotating valve face. Do not take heavy cuts , if so much metal must be removed that margin is loss , discard the valve.

cylinder valver

Each cylinder has two valves , an intake & exhaust valve . Some high performance engines have four valves per cylinder . Two intake & exhaust valves. Usually, the intake valves is larger than exhaust valves is opened , the only force moving air-fuel mixure into the cylinder is atmospheric preassure when exhaust valve is opened the piston is moving up & there is a high preassure driving the exhaust gases