Hard-drive like clunking noise at low revs

[nwxh]

My 1098cc traveller with a low milage engine has started making a noise which best sounds like an old hard-drive clunking. The noise
does not usually happen at idle throttle but I think did happen once turning left at a traffic lights slowly

• happens at low throttles
  above 30mph seems to happen at a wider range of throttles
  does not happen under load, for example going up a moderate hill top gear (with 3.9 diff) at 45mph

To make matters confusing, I did change the distributor but I am sure the noise did not sound initially as I am sure I would have noticed it. I think 3 journeys after the distributor was the start and after I had a throttle return spring snap so revved the engine quite a bit getting it to the next village to pull over and sort it.

I wondered if this is the start of timing chain rattle and the sound will not sound as bad as the wear increases with it going from more of a clunking to a rattle? It does seem to be under similar conditions to such a rattle before in the previous engine which did not sound the same. Could it also be caused by the ignition being too retarded or vac advance issues? Otherwise, can it be something else?

[oliver90owner]

Engine mounts? ‘Clunking’ does not make much sense to me, if emanating from the engine internals.

[nwxh]

I think the sound is best described as the sound of an old computer hard-drive seeking, as clunking is too broad. It is regular/consistent rather than off and on if throttle/speed not changed etc. Would engine mounts change so much with the throttle moving?

[mowogg]

Your description of the noise makes me think of the petrol pump. Assume this is not the source.

I have had some noise out of the voltage regulator boxes before.

Can you hear it while stationary?

[nwxh]

Not at all while stationary and now I wonder if I really heard it much under 30mph. It seems to peak around 50mph:

I made a recording earlier of it on a short stretch. The exhaust is a bit noisy but the noise will come in and out.
https://www.youtube.com/watch?v=VtpZ4Liv5_o

It now makes me wonder if the prop shaft could be loose, given the engine should't realy "know" the speed of the car. It is a rebalanced one installed recently so the car is now very smooth, but could there be something loose which sounds worse around 50mph but not at overrun or high load when it "locks" together as the torque is higher either one way or the other?

[mowogg]

I have listed to it. It's very dificuilt to tell but it does not sound like transmission or propshaft related to me.

From thr video it sounds like something is knocking. Do you have any noises from thr suspension?

[kevin s]

Have you checked the wheel nuts? Easy to check and can make a similar noise to the one you describe.

[StillGotMy1stCar]

As you’ve recently changed the distributor and noticed the noise shortly after, and with the high revs due to the throttle return spring, makes me wonder if something is going on with the weights in the distributor, perhaps contacting the distributor body due to weak springs or weights stuck in the extended position.

Edit: Just noticed you say the noise is at low revs so I'm most likely wrong

Regards John

[nwxh]

Sorry that should be low throttle. I'm mixing up revs and throttle.

Suspension has no noises out of the ordinary squeals etc. Exhaust is getting a bit rattly and expected to drop in next 2 years as second hand mild steel.

Wheel nuts I'd be surprised as buzz gunned up not by me and usually they require more torque than the spec to untighten when this happens but I could look. Unfortunately can be pain to push covers back on.

[Myrtles Man]

Unfortunately can be pain to push covers back on.

Don't push 'em, hold in position hooked under three of the bumps with one hand and give 'em a firm slap where the fourth bump is with the other. Works every time.

[dudload]

I think the sound is best described as the sound of an old computer hard-drive seeking, as clunking is too broad. It is regular/consistent rather than off and on if throttle/speed not changed etc. Would engine mounts change so much with the throttle moving?

sounds almost exactly like a fuel pump

[nwxh]

Having driven it again, I'm convinced the noise is coming from behind. The wheel nuts and the 4 nuts from the prop to diff seem tight, that's not to say that they're torqued correctly but enlikely to be moving. Is it possible that the the diff or UJ has some play?