Why the exhaust valve setting more distantly spaced?

Intake valves fed by fuel-air mixture so that the expansion or hot is going on around the intake valves, smaller than the exhaust valve. In the exhaust valve fed by the hot gases of combustion remaining. Therefore rift between the valve stem with a hammer throw was made further. The assumption, when the excessive heat did not make the distance closer. If the distance made more meetings, there is the possibility of the engine so hard to live. This is due to continue pressing the trigger valve so that the valve continues to open that resulted in the leakage of compression. This means there is no pressure that allows the combustion in the engine. In some motors applied the same suit rift between the intake valve and exhaust valve of, but not all. Especially for the motor has to apply compression on a 9: 1. That's because high compression engines usually heat faster than low compression motor.