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MG Midget and Sprite Technical - Very nasty sound from clutch - or is it gearbox?

I took the frog for a run Sunday. Everything was fine until I pushed it hard turning right at a t junction. As the clutch bit and I started to move there was a very nasty grating sound - a bit like the sound of a non synchro gear change at the wrong engine speed.

When I eased off the throttle the sound stopped.

It now happens every time I try and pull away hard in 1st and even, if pushed, second gear. Otherwise no symptoms at all if driving normally with all gear changes smooth and trouble free.

It feels a bit like clutch slip under hard acceleration - the power is partly lost to the rear wheels, but the sound is like something very broken in a gearbox.

Any suggestions what this is? I will try and record the noise and post a link later. Suspect its time to get the engine out which will be a new experience for me :-(

Its a tuned 1275 with about 95HP at the flywheel and a 5 speed Toyota gearbox.

Help!

Steve
Steve 59 Frog

A wild guess from afar. If you have wire wheels it could be a hub spinning in the wheel. That would be apparent when you apply heavier power. I had one and it was a ratcheting type sound. The noise transferred to the box.
Sandy
conrad sanders

Good one sandy,

My guess is a broken or loose engine mount at the tranny....not sure about toyota tranny set-ups....But thats just a guess

might try changing the tranny fluid and see if any metal flakes show up in the oil pan....

what about the exhaust pipe, might give that a good looking over....


prop
Prop

Steve,
Check your prop shaft UJ's.
Pulling engines out is fun for the first time. You can get quite good at it after 6 gearboxes & 3 engine rebuilds.
Brad (Sprite IV 1380)

Steve - If you can make it over to me then I would be happy to help...
Toby Anscombe

Steve

Don't discount things like: exhuast/engine/box touching chassis or body; when you are WOT in 1st/2nd the torque transmitted by the engine/box combination is between 3 and 2 times engine torque - and the engine/box will move/rotate considerably under these conditions.

An a recent track day, I was cornering hard with WOT (on stickies) and heard a new vibration caused by the engine moving due to torque reaction and cornering force on the engine as well. Gauges were fine and noise disappeared on straight, so forgot about it...

A
Anthony Cutler

Firstly thank you all for your advice.

Conrad - good suggestion but its not got wire wheels.

Toby - Thanks for great offer. I might well be driving to North Weald, at least to try and diagnose problem before I start removing large pieces on metal.

I have uploaded a rather poor recording (plays with Quick Time). The noise is at 3 seconds, but not sure it really captures it well.

It sounds like gear teeth clashing but behaves like clutch slip....


http://mobiasstrip.com/public_html/Frogeye/nasty%20noise.amr


Any views appreciated.

Steve
Steve 59 Frog

Hi Steve,

The link doesn't seem to be working.
Even when I cut and paste it.
G Lazarus

tried that like you Gary

doesn't work

but Steve

just look and check that the gearbox is bolted tightly to the engine

I know how daft it sounds but many years ago I went as an AA-man to a bloke with a Cortina displaying similar symptoms

the gearbox bolts were all loose or missing (two left, loosely connected) and the noise came as the box slipped back out of the clutch splines

He was on the entry road to a busy roundabout

Bolting the box and engine together again made a permanant cure, good enough for him not to bother going back to the place that had fitted him a new clutch the week before...

Luckily for him I had a bunch of suitable bolts in the van
Bill

Bill you suggestion was such a logical fit to the sound that I rushed out with torch to look - but all bolts are present and look tight.
Damn

Had to convert sound from .amr file as it came from my phone to .wav file for PC.

Now its the last link on this page.

http://www.mobiasstrip.com/LeMans2007/Video/

Not very clear recording where it sounds a bit like wheel spin. The noise is mechanical and obviously so when driving car.

Steve
Steve 59 Frog

Bloody crackberry addicts...

Check the alt mountings..

can you work out if it is in front of or behind the firewall - I guess in front!

Near or off side?
Toby Anscombe

that sounds like an altenator bearing to me, I wonder if the starter is engaging if not the alt.

prop
Prop

Hi steve is the sound happening as you release clutch to start moving ie just as the clutch release bearing ( what type have you got ?)realeases from the fingers of the clutch or is it all the way through 1st gear ? ( im obviously thinking clutch bearing ) what about if you drive the car in 1st at a slow walking pace with foot compleatly off clutch peddle , then floor the throttle so the car accelerate s away with the clutch fully off and the bearing at rest ,
Darren 2 litre frogeye

I know nothing of Toyota gearboxes, but I wonder if your layshaft bearings have collapsed such that under excessive torque the layshaft cluster is pushed to one side and jumps teeth, but under less load it still continues to mesh.
Worth following Prop's advice and check the G-box oil for swarf.

Guy
Guy Weller

Mine too ! - Started on the way back from Spridgettreffen in August on my stnd midget Mk 3 RWA ,on reverse and has happened about 10 times since, when engaging gear from stationary - I think it is definately coming from the clutch which was all new some 20K miles ago - Could it be that the release bearing is not completely dissengaging or that the pedal now has more travel ? - I am shortly about to fit the remote slave bleeding extension so it may need only a good bleed
John M Platt

John,
if it's anything like my T9 it could be the slave cylinder rod length, i realy wish i have made mine adjustable it would have saved a lot of time.
Brad (Sprite IV 1380)

always difficult with to really hear the sound on the net but that sounded exactly like the thrust bearing making a noise. You should be able to determine this by operating the clutch when the noise occurs and see what effect it has. So I am with Darren.
Bob (Robert) Midget Turbo

Thanks all.
I have some v good advice here.
Will check to see if anything is knocking (exhaust etc).
Try to change Toyota box oil and check for swarf.
Check how noise behaves when clutch is at different points - although I am pretty sure the noise is when clutch fully engaged.

Wont get the time for next few weekends though... so if I go silent for a while on this its not because I am ignoring you!

May get chance Sat for another spin and better recording.

Thanks again.

Steve

Steve 59 Frog

To me it sounds like you are doing something nasty to a large cat. Are you running on Esso?
Clive Berry

Hi Steve did you sus your noise ?
Darren 2 litre frogeye

This thread was discussed between 26/11/2008 and 18/12/2008

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