Hi,

That's a thought. This gearbox has given me trouble in the past.
When starting up the car again, I will try what it's doing under the
conditions you describe.
A way to find out is IMHO to disengage the clutch and see if the sound has
gone. If it is engine bearings - whichever - the clatter should persist, at
least some.

Thanks for the idea.

Carl

"Brian Stell" > schreef in bericht
m...
>
> > It is loudest on a cold engine, and in the afternoon, with engine still
> > warm, is never that loud again. It also becomes very high in frequency
when
> > cold when the throttle is released, after driving in low gear and low
load,
> > the clatter increases just after release in volume and frequency, and
> > diminishes after about a second ...
>
> I can see valve noise being influenced by RPM
> (more RPM => more noise) but I'm unfamiliar with
> valve noise being influenced by throttle.
>
> My experience with rod bearing noise is it is
> loudest when accelerating / hill climing
> (more engine power => more noise) and is quiet
> when off throttle.
>
> I've been told the main bearings tend to be
> noisy all the time.
>
> Now the "diminishes after about a second" makes
> me think gear lash. As in something is spinning
> and the normal resistance keeps the "front"
> side of the teeth engaged. When going off throttle
> the spinning item's inertia keeps it spinning so
> the gear is bouncing between the "front" and
> "rear" side of the teeth. When the engine speed
> stops dropping it's back to resistance / "forward"
> teeth. If the slowing is heavy then the inertia
> can keep the "rear" side of the teeth engaged.
>
> Driving down a grade, off throttle, at a constant
> speed would create a similar force on the bearings
> as off throttle but no inertia / spinning changes.
>
> Do you get the noise under this condition?
>
> Or only when the engine is dropping RPM?