What else sounds like a timing chain?

[Axolotl]

I had what I thought was a timing chain rattle, so I replaced the single sprocket set with a duplex set. The rubber ring on the single set had disintegrated, which, I thought, accounted for the rattle.

Problem is, I still have the rattle. It starts when the engine is hot, and sounds like a more or less constant metallic jingle at anything over about 45 in top.

It isn't pinking, as it happens at steady speed and on deceleration. Sometimes it goes away, but never for long.

Any ideas what it could be if it isn't the timing chain? Just how quiet are other people's duplex installations?

[Willie]

My duplex mod is quiet. Could be small end rattle but this is difficult to identify. Have you tried listening around the engine with a long rod to your ear?

[Axolotl]

It doesn't seem to do it when the car is sitting still. All you can hear when you rev the engine while it is standing still is "normal" engine roar. No jingle, no rattles etc.,

The npoise is only apparent while driving, in gear. I think it does it in third as well as top (I need to check that), but it stops when I coast with the clutch down (but then the engine is idling, I'll have to try coasting and revving the engine at the same time.)

I think it sounds too "jingly" for little ends, although that's a possibility.

I could try the long stick trick anyway and see if that shows up anything.

I'll keep you posted.

[Kevin]

A couple of unlikely things but I have suffered from both a loose baffle in the exhaust and onlt discovered when the exhaust finally went and on taking the old one off you could hear the box rattle, the other was was caused by an errant water pump but you will already have checked that, the other thing is to check you dont have an extra washer or jubilee clip touching somewhere.

[Axolotl]

Just been out for a spin to check.

1) It happens in all gears, starts at the same engine speed (roughly)
2) I can still hear it if I de-clutch, coast, and simply rev. the engine to the right speed. Road speed or engine load doesn't seem to affect it.
3) I can hear it from inside the car when I rev. the engine while standing still, but I don't think I can hear it when I do the same with my head under the bonnet. I mean, I've tried to hear it, but all I can hear is the fan and the general engine roar.

I need to find a long stick .

The exhaust is quite old, but sound-looking. Might be a loose baffle.

The water pump is new, (long vane type) I put it on to try to cure an overheating problem while I had the front stripped down to do the timing chain. I still have the old one (short vane type). It would be easy enough to swap back as a diagnostic. The overheating turned out to be a blocked radiator core.

Thinking about that, the reason I swapped the timing chain was that I had what I thought was timing chain rattle, with the old water pump, so the noise didn't arrive with the new pump. Probably not that, unless all water pumps make a jingly rattly noise.

Any more thoughts?

[Willie]

It could be a resonance caused by the engine revs, especially if the noise starts regardless of which gear you are in as long as the revs are approximately the same each time or, since y ou can't hear it in the engine compartment perhaps it is removed when the bonnet is open i.e.
any of the bonnet badges or the cross piece which holds the bonnet stay
etc.