Anyone have knocking sound on bj60? It is more audible when engine is cold. Just had new head put on, rebuilt injectors and timing adjusted to factory specs. Mechanic at toyota said it is nothing to worry about unless it gets really loud. He said he could retard timing but then I would be back to my previous problem of a ton of smoke. If timing is right it shouldn't knock at all right? The work was done at toyota. thanks!