30 replies to this topic

[tino]

Thanks, engine out it is then.

Really appreciate your feedback and everyone else’s.

[Lplus]

If it stops with the clutch depressed it has to be gear related.  Just as a possibility I wonder if the laygear bearings are making the noise, or even the gearbox input bearing.  The laygear bearings are closer to the centre of the engine/box.

[Ethel]

Whirry clutch related noises always suggest the release bearing to me. They don't have to get worse when you depress the clutch, it could be that applies enough force to stop a stiff bearing slipping against the the pressure plate. If it's Pre Verto, you can wind in the return stop 'n hopefully lift well clear of the clutch to rule out any likelihood of it making contact at all.

 

Before you commit to pulling the engine out you could look for somewhere where you dip the clutch and coast with the engine turned off (beware of engaging the steering lock!), in neutral and as many gears as you can manage. That might help you decide where the cause is most likely to be

[coopertaz]

sounds like clutch bearing do you have distance at return stop? looks to be none in vid.  can also try running engine with clutch housing removed and engine supported securely, idler gears tend to chatter not whirr. unless shimmed too tight.

[alpder]

There is a very steady high-frequency whirr at idle. Possibly at the water-pump end. Pressing the clutch silences it.

 

Water-pump/alternator/fan are ruled out. And the only thing left at the water-pump end that's capable of high-frequency would be the chain.

 

So maybe the timing chain is rattling over something, but pressing the clutch moves the crank just far enough to push the chain off the something and so silences it.

 

If it's a duplex then here's a long-shot idea... one of the csk screws for holding the timing-plate coming undone and meeting the chain? Or vice-versa: the thrusts wearing so that the crank has moved towards the clutch end so that an original tiny clearance between chain and csk screws has reduced to zero?

Edited by alpder, 02 May 2024 - 08:08 PM.

[tino]

Whirry clutch related noises always suggest the release bearing to me. They don't have to get worse when you depress the clutch, it could be that applies enough force to stop a stiff bearing slipping against the the pressure plate. If it's Pre Verto, you can wind in the return stop 'n hopefully lift well clear of the clutch to rule out any likelihood of it making contact at all.

 

Before you commit to pulling the engine out you could look for somewhere where you dip the clutch and coast with the engine turned off (beware of engaging the steering lock!), in neutral and as many gears as you can manage. That might help you decide where the cause is most likely to be

 

The noise is more apparent without the clutch pressed. What am I listening for when coasting, I live on a hill so going down isn't the issue.

 

 

sounds like clutch bearing do you have distance at return stop? looks to be none in vid.  can also try running engine with clutch housing removed and engine supported securely, idler gears tend to chatter not whirr. unless shimmed too tight.

 

The distance is 0.50mm, isn't the engine still supported on its mounts even with the cover off? Or do I need additional support.

 

There is a very steady high-frequency whirr at idle. Possibly at the water-pump end. Pressing the clutch silences it.

 

Water-pump/alternator/fan are ruled out. And the only thing left at the water-pump end that's capable of high-frequency would be the chain.

 

So maybe the timing chain is rattling over something, but pressing the clutch moves the crank just far enough to push the chain off the something and so silences it.

 

If it's a duplex then here's a long-shot idea... one of the csk screws for holding the timing-plate coming undone and meeting the chain? Or vice-versa: the thrusts wearing so that the crank has moved towards the clutch end so that an original tiny clearance between chain and csk screws has reduced to zero?

 

I've taken two more video's and the noise is definetly louder by the timing chain one without the belt and one with, if that's due to how the sound is getting out I'm not sure.

https://tinoest.co.uk/img/IMG_8142.mov

https://tinoest.co.uk/img/IMG_8144.mov

 

Thanks once I again.

[Ethel]

It's what has an effect on what you can hear.

 

Holding the clutch in should eliminate the engine.

 

If it's in neutral, the clutch & transfer gears will also be isolated from any movement.

 

If it's in 4th, the layshaft will just be idling

 

If it's in any gear, its hub will be locked to the mainshaft and the others will be rotating around it.

 

Each gear will cause the input side, 1st motion & transfer gears, to turn at different speeds that might affect what you hear if it's coming from them.

 

The helix on the transfer idler tends to screw it in to the gearbox under power. So, on overrun (inertia/gravity driven) it'll tend to screw away from the gearbox.

 

As this has turned in to a bit of an essay, the speedo drive is another possible cause. It can be eliminated if you get your noise with the car stationary, as can the diff/final drive & driveshafts.

[Ethel]

There is a very steady high-frequency whirr at idle. Possibly at the water-pump end. Pressing the clutch silences it.

 

Water-pump/alternator/fan are ruled out. And the only thing left at the water-pump end that's capable of high-frequency would be the chain.

 

So maybe the timing chain is rattling over something, but pressing the clutch moves the crank just far enough to push the chain off the something and so silences it.

 

If it's a duplex then here's a long-shot idea... one of the csk screws for holding the timing-plate coming undone and meeting the chain? Or vice-versa: the thrusts wearing so that the crank has moved towards the clutch end so that an original tiny clearance between chain and csk screws has reduced to zero?

 

 

Doesn't sound that bad to me, but that could just be the recording. 

 

Holding the clutch in will take a bit of work off the crank. In turn that will affect how it pulls on the timing chain with the other end.

 

If it warrants further investigation I think I'd whip the chain cover off before pulling the whole engine out. Dunno what mileage it's done, but a new chain & sprockets usually brings some improvement in how an engine runs.

[tino]

Thanks, I’ll see what it sounds like down a hill this weekend.

Not sure if it’s relevant or useful but the noise gets worse as the engine warms up. On cold it’s noticeably quieter.

Edited by tino, 03 May 2024 - 12:10 PM.

[Ethel]

If it does it idling while parked, it's only the transfer gears you'll want to investigate. So in gear (any gear will do) vs neutral when the clutch is held down. You won't have to go at 4th gear speeds without the engine involved, so comparing it to, say, 2nd at about the same road speed would have the transfer gears going at about half the speed.

[alpder]

Seems like a good candidate for a listening-rod, to narrow down the source. Easy to make a basic one - or even use a large screwdriver. Anything with a hard tip at one end and a large (safe) blunt surface at the other end that you can put to your ear/skull. The main trick is... to avoid touching it into the fan from where it might come flying out and through your head, Phineas Gage-style. I'd take the fan-belt off, to be properly safe, if poking around at that end. There are also gadgets which have a stethoscope ear-piece attached to a rod at the other end to prod about with, they're easier and safer to use and are much more precise but they cost money and take time to source. Whereas a suitable lo-tech stick is probably already kicking around in a corner of the shed.

[tino]

Seems like a good candidate for a listening-rod, to narrow down the source. Easy to make a basic one - or even use a large screwdriver. Anything with a hard tip at one end and a large (safe) blunt surface at the other end that you can put to your ear/skull. The main trick is... to avoid touching it into the fan from where it might come flying out and through your head, Phineas Gage-style. I'd take the fan-belt off, to be properly safe, if poking around at that end. There are also gadgets which have a stethoscope ear-piece attached to a rod at the other end to prod about with, they're easier and safer to use and are much more precise but they cost money and take time to source. Whereas a suitable lo-tech stick is probably already kicking around in a corner of the shed.

I’ve tried a long flat head screwdriver and the frequency of the noise doesn’t seem to be transmitted through it. All I can hear is the general noise from the engine and it sounds identical at both ends.

[alpder]

Hmmm... maybe the mechanics stethoscope would do a better job - the ear-pieces would help exclude other noises. Some 3-day sellers have them on ebay for under a tenner.

 

 

[tino]

Hmmm... maybe the mechanics stethoscope would do a better job - the ear-pieces would help exclude other noises. Some 3-day sellers have them on ebay for under a tenner.

I switched to using an extension bar rather than a screwdriver, it’s definitely coming from the gearbox rather than anything else. It’s louder radiator side but only marginally.

[Homersimpson]

Seems like a good candidate for a listening-rod, to narrow down the source. Easy to make a basic one - or even use a large screwdriver. Anything with a hard tip at one end and a large (safe) blunt surface at the other end that you can put to your ear/skull. The main trick is... to avoid touching it into the fan from where it might come flying out and through your head, Phineas Gage-style. I'd take the fan-belt off, to be properly safe, if poking around at that end. There are also gadgets which have a stethoscope ear-piece attached to a rod at the other end to prod about with, they're easier and safer to use and are much more precise but they cost money and take time to source. Whereas a suitable lo-tech stick is probably already kicking around in a corner of the shed.

Phineas Gage, now theres a blast from the past.  I will get my coat.