The SOHC EJ Subaru boxer engines were non-interference engines through 1995, run by a single timing belt driving both cams (both sides of the engine) and the water pump. Because they are non-interference engines, if the timing belt fails, the engine of the models up to 1995 will not be damaged. The oil pump is driven directly from the crank shaft and the waterpump by the timing belt. All DOHC and 1998-up SOHC EJ engines are interference engines, if the timing belt fails the valves will likely be damaged.