Hello and welcome to Just answer.com, Super mechanic here. About your vehicle.
The best way to tell if any valves are damaged is to take the valve cover off and turn the engine, (camshafts) so that both cam lobes for a cylinder are pointing upward and away from the valves. Then take the spark plug out and blow air into the cylinder, (with an air compressor and hose or adapter) and see if the air comes out the intake or exhaust.
Also the timing marks should line up like this,
I have the instructions in a PDF format that you can download HERE then you just click where it says “Click here to start download” Thanks
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