I would agree with Bob. My car did the exact same thing two summers
ago. The sound was only present at around 2000rpm. It was definitely
the timing chain. Not sure why it's only persistent at that one engine
speed. But replacing the chain and tensioner took care of the problem!
Tim Holbrook
1971 TR6
--- Lizirbydavis@cs.com wrote:
> 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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