Ticking/tapping sound

[jaguar&mg]

A new ticking/tapping sound has emerged in the engine. It disappears while the clutch is depressed, when the engine sounds exactly right again, but of course it is therefore audible whilst driving. Its may be getting louder too. I can't work out where it is coming from and therefore what it is.

Any thoughts?

[cass3958]

Thinking logically about what happens when the clutch is depressed I would say it might have something to do with your clutch release bearing. The clutch release bearing is held in place with a couple of spring clips on to the clutch arm. If one of the clips is loose or broken the clutch bearing might be flopping around hitting the rotating clutch plate causing the ticking sound. When the clutch is engaged the bearing is pushed up against the clutch plate springs and stabilizes it so the sound goes away.
If you can get under the car with the engine running try wiggling the clutch arm to see if it goes away.
There may be other theories so I will await what my learned colleagues think.

[Glyn Ruck]

Is it's frequency engine speed dependent or road speed dependent?

[jaguar&mg]

Engine speed dependent.

[Glyn Ruck]

Get yourself an automotive stethoscope ~ dirt cheap. Long touch prong can be split & shortened for convenience.

41966.gif (24.67 KiB) Viewed 2277 times

These cars do suffer from slight main layshaft rattle/swish clutch out even with new gearbox bearings. It goes away when you depress the clutch.


Take the stethoscope & try and detect where the tick is coming from. Engine, bell housing or gearbox.

1) I doubt it is engine related but get someone to operate the clutch while you check the front crank damper for movement backwards & forwards which would indicate crankshaft end float which can lead to sources of noise.

2) Listen to the bell housing. If noise is from bell housing it could be a damaged carbon thrust bearing or retaining clip or more likely the noise comes from the clutch plate/driven plate. Either due to a broken shock spring in the plate itself or a loose or damaged/worn centre spline which is known to cause ticks.

3) If it's coming from the gearbox layshaft (input shaft) which runs at engine speed it could be a number of things including a damaged or broken needle roller. Drain the gearbox oil & look for debris.

As cass says check clutch yolk lever, pins etc for looseness.

Good luck!

[jaguar&mg]

It’s definitely the gear-box. On cold start, when the oil is thick, it’s not there for the first two or three minutes.

It’s annoying — but presumably ‘acceptable’ — and I guess I’ll just have to live with it for the time being!

Thank you for all of the advice.

[JCS]

You say this noise is "therefore audible whilst driving".

Is the noise audible at all speeds, in any gear, and on overrun?

Or is it confined to slower engine speeds and perhaps on light load conditions?

Is it a noise that can be "encouraged" by altering the throttle load/demand?

Regards

Norman

[jaguar&mg]

I am told that it is the gears 'jangling around'.

The engine would have to come out to rectify the problem.....

[cass3958]

Taking the engine and gearbox out together can be expensive if you are paying someone to do it for you where as on the BW35 auto box you can remove the gearbox and leave the engine in situ. Now I know you have the manual but maybe someone on here can tell us whether the Moss gearbox on the manual can be removed whilst leaving the engine in place.

[John Quilter]

I THINK it is possible to have a look at the clutch release bearing with a light on the end of a stalk through the round hole at the bottom of the bell housing. The thickness of the carbon can be observed. Many decades ago a shop did remove my gearbox (full syncho with OD) with the engine in situ but is a bugger of a job.