I had the timing belt replaced along with the pulley and water pump. When it was re-started it ran rough at low rpms but smooth at higher rpms. I checked the compression and I have two dead cylinders on the left side (drivers side)I was told that since the engine is an interference engine, I must have floated the valves and consequently they struck the pistons and bent. How long would it take to repair the left side doing a valve job and how much would it cost. With 150,000 miles should I get a complete valve job on both sides with the head machined and how much would that cost?