After replacing the chain, guides and tensioner, the engine still had a ticking sound from the right hand valve cover. It was a very dirty smog pump. After rebuilding the pump all was quiet. The smog pump will run for 1 minute until the controller turns it off. One of the members here told me this could be the problem. The noisy pump was telegraphing the ticking noise allowing me to believe it from the valve train. This might be something to check. Good Luck.