I had my timing belt strip at the crank when trying to start my car one day. When I took it apart and inspected the head I had two lifters that showed sign on impact from the valve, so I decided to replace all the valves, lifters and valve seals. None of the valves I removed showed any damage and they were straight. I got all the parts finally and lapped the valves in. The valves all had a nice even circle showing that the head was still in good shape. After getting all the timing belt and head job complete tonight I finally was to the point of starting the car. There wasn't any fuel getting to the injector pump, but after sucking fuel through the pump from the filter return line I was able to get the car started. It seemed to be running smooth at idle for about 10 minutes, until TAP TAP TAP, immediatly shut it down and started to investigate. I rolled the engine over several times and everything seemed ok, then I did a compression check and sure enough one of the cylinders had no compression!! I had to pull the Cam out again and the intake valve was BUSTED right at the keepers. The keepers and the very tip of the valve were jammed in the cap. Can someone tell me WHY this happened? Do I need to replace all the valves again from a different supplier, Can I trust the rest of the valves?