Bob,
I bet your hypothesis is correct. I can imagine that the sound I'm hearing
could be a slack timing chain. A couple of questions if you will. Why do I
hear none of this sound across the RPM band when the car is at rest? I can
see how the "unloaded" side of the chain could have more slack when the car
is being driven compared to the same RPMs when the engine does not have the
weight of the car to pull. But, when working under the bonnet, would I not
hear something from the timing chain when I change the RPMs abruptly? Is
there a way to detect a problem with the timing chain, gears, tensioner
without taking the cover off? Tell me about Dick's distributor test. The
valve gear looks fine to me. What can I do to ensure that what I am hearing
is not related to a bad rocker rocker shaft or cam problem? The pitch and
frequency of the sound seems much too fast for an isolated valve, lifter,
push rod problem. I bet you're right about the timing gear. I'll let you'll
know
Joe Davis
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