Mystery noise

[docchevron]

It hasn't actually got a flywheel has it as its an automatic?

Nope, it will have a flexi-plate, they can fracture, but it's not common, and if it had it would sound like someone throwing an empty baked bean tin down a flight of stairs all the time.

Dont suppose it's something like the cambelt rubbing on the covers? Or even more way out there, and since it's been off again I doubt it, but maybe the belts a bit tight?

[AlanS]

First thing I thought of was cambelt, so I had a new one fitted by a mate of mine who used to run a Cit service agency down south and has BXs himself.
He's such a perfectionist (which is why I asked him to fit it when he went looking for the noise) that he set and re-adjusted the tension 4 times. He's such a perfectionist that he actually makes up pins on his lathe for various models when he does cambelts where most of us use drills and bolts.
I know it impossible to desvribe the noise from the other side of the world, but I would swear the boss of the pulley on the hydraulic pump was stuffed if I hadn't heard it run with all the belts off. That's the area it seems to come from and best describes the sound.


Alan S

[mountainmanUK]

The Starter Motor pinion idea sounds very plausible (to me).
If the solenoid actuation arm thingy is getting a little lazy, it could be leaving the pinion still in contact with the ring gear teeth for a few seconds after starting.
Worth swapping out the starter if you have a spare!

Cheers
Dave

[docchevron]

Well maybe, but generally the noise a starter will make is more of a mechanical whirring kinda thing, not anything harmonic.

hhmm, is the crank pulley a tight fit on the crank? Even with the bolt done up tight, if its been run loose before it's possible that it's worn the crank / pulley mating faces and theres some chatter??

I duno, clutching at straws really!

I guess the Cam sprocket is tight??

The only other thing that came to mind whilst sipping a pint was something that happened to my TD a while back, I thought the alternator had noisey bearings, so I changed it, and it made the same noise, so I changed it again, and, er, it still made the same noise.
Turned out that the aux belt was just touching the cambelt cover and causing some noise, new cover, silence!

But I dont think it's that either in your case mate.. Sorry.

but I would swear the boss of the pulley on the hydraulic pump was stuffed if I hadn't heard it run with all the belts off. That's the area it seems to come from and best describes the sound.

Well, thaere aint alot left to look at in that area! I'm erring back towards the oil pump sprocket.. on every XU I've ever pulled down the sprocket is a pinch fit on the crank and locked purely by the crank (cambelt sprocket) butting against it.. but again, I duno!

Is there any way you could record the noise and send it as a WAV file or the such??

[Geoffrey Gould]

Hello Alan a couple of sillies really , I dont know anything about the petrol engines. If it has a distributor how about the bob weights and could it be a sensor touching the ' flexy' plate.
Cheers.
Geoff.