Valve Timing

This was done using lawn mower engines. Which allowed you to see when the valves were opening and closing in time with the position of the piston in the cylinder. 

This is read by using a degree wheel which is attached to the crankshaft of the engine. The amount of valve movement is also measured by a dial test indicator.

Results

Inlet opening: 14 degrees before TDC

Inlet Closing: 60 degrees after BDC

Exhaust Opening: 38 degrees before BDC

Exhaust Closing: 18 degrees after TDC

these results were obtained by taking readings off the degree wheel and watching for when the valves begin to open and close 

Piston Travel 

This was also measured using a vernier calliper to measure how far the piston has travelled at various degrees of crankshaft rotation this is also read from the degree wheel attached to the crankshaft.

These results showed that the amount of distance the piston travels increases at each degree of rotation more so when the piston is heading towards BDC as the mm measurements increase as the degrees go up. 

The first measurement at TDC shows 0mm but by the time the piston has reached the bottom of its stroke it has travelled 46.5mm. 

Importance of valve timing

Correct valve timing is very important because if it is wrong the engine power is greatly reduced as valves will be open at incorrect times or open too long or not long enough affecting the air fuel mixture, drawing mixture out at the wrong time leaving it unused affecting economy, allowing the mixture to burn to cold and taking power if exhaust gasses cannot be removed in time.

How it can be improved

if belt is out of alignment it can be re timed to improve valve operation and cams can also be aligned as well while belt is off. This will correct the timing.