Gearbox Noise....

[Guest mcramsay]

getting ready for my first spin in the zero tomorrow, and after moving the car around the drive i put the gearbox into neutral (type 9 box) and let the clutch up and i was greated with the following noise:

 

 

can any body shed some light on what they think it could be ? heres some more info on the car:

 

zetec engine from GBS with a type 9 box. spigot bearing was fitted into the crank and the clutch is the standard one that came with the engine. the release bearing was also purchased through GBSC so i know this is also correct (i had fitted a wrong one previously which gave me no clutch atall!)

 

the only thing i can think of is kit spares sell a pin which adapts the clutch relese arm geometry on the type 9 box...i had no idea this was needed and never fitted one, so the release arm is standard.

 

other symptoms of the noise are there is a bit of a light clunk when you let the clutch up, and the noise is only present when in neutral and the clutch is up (ive never driven the car so i have no idea if it will make any kind of noise whilst driving)

 

the noise can be loud or relativley quiet, it depends how you release the clutch. if you let it out quick it clunks like in the video, if you let it out slowly, it is much more quiet....

 

with an automotive stethoscope on various parts of the engine the noise definatley seems to be coming from the bellhousing. rather than the Gbox its self...which i got from a scrappy! any thoughts guys?

[sj-bradley]

It could be the clutch is grabbing and is slightly off centre so the input shaft is not lining up correctly.

Could be due to slight contamination of the clutch although I doubt that if you got the engine from GBS (New one?)

 

Are all the bell housing bolts tight? How much free play do you have in the clutch cable?

 

Is the gearbox mounting bolts tight? Is there any noticeable vibration when idling that you can see?

 

Is there enough oil in the gearbox?

 

Only suggestions though.

[Guest sandy77uk]

mine does exactly the same, its the thrust bearing on the clutch plate fins

 

does the noise go as soon as you press the clutch?

[Guest mcramsay]

Yea as soon as the clutch pedal is pressed the noise goes,

[Guest mower man]

Atypical rattly type 9 ,it basicaly 5 th gear rattling ,tickover speed to low is one cause ,lift idle speed alittle and it may well go away ,my ops only mower man

[BigLee]

Mine doe the same - Rattly release arm, I have a stop on my clutch pedal right at the top of the travel that "just" holds the smallest amount of tension on the pedal . Cures it...

[Guest mcramsay]

thanks simon but these are all avenues i have been down obviously looking for the simple problems first! the engine is completley standard as from GBSC. and the clutch has never been off the engine so it will be lined up as per its building at the ford factory. the gearbox has got oil in it, but in saying that there does seem to be a bit of oil which smells like transmission oil on the bottom surface of the gearbox, but ive never noticed any oil underneath the car.

 

im not sure if it is 5th gear rattling, as ive put a stethoscope along the body of the gearbox and there is no rattle, it only becomes prominent when listening around the bellhousing area... it does seem to be release bearing related, possibly due to me not using the "adaption" pin from GBSC which alters the geometery of the release arm.,,, i will put the car up on the ramps tomorrow and have a peak into the bellhousing throuhg the release arm cut out with the engine running just too see if anything is visably moving.

 

if it is the clutch bearing/release arm vibrating is it ok to have it doing this or is it something that needs looking at pronto? i will also have a play with the clutch cable tension and see if that does anything, possibly a little tighter might stop what ever is moving....from moving! haha

[Guest dinger]

If you havnt modyfied the clutch arm pivot point then you will be pressing the bearing onto the pressure plate forks at the wrong angle, Possibally damaging the bearing,

[sj-bradley]

One point about the transmission oil. Does the gearbox use the speedo take off point or is it blanked off ?

 

A 2p piece and circlip fit perfectly which seals that point. It's an awkward place to get to though, on the drivers side bottom of the box just above the mounting point.

 

The release arm pivot point should be moved in toward the engine so that the angle that the release arm makes with the bearing is not too acute. As per what Dinger says above.

 

Simon.

[Guest mcramsay]

I have nothing on the speedo drive at the moment, the oil does not seem to be coming for

There though, it looks like if could be the input shaft seal. Looking at other posts on locost builders website it looks like it is release arm rattle. I will def get it on the ramp and have a look though. I will run it as it is for the moment! I don't think I could face having to take the engine out of the car at the moment! Haha it certainly won't be the only thing rattling on the car!

[sj-bradley]

I have noticed that these cars sound a lot noisier than standard production cars.

 

Come to think of it, I have similar gearbox rattle in neutral, so I'll be checking mine tomorrow now (mt75 though)

 

That's probably because there is no sound deadening between you and all the rotating bits.

 

I'm just kind of glad that the exhaust is on the passenger side

 

Simon.

[Guest mcramsay]

Haha, yea I get paranoid over tartly noises! I plan on getting a recon box for the car do I will do the release arm then!

[Longboarder]

If you use the sierra pedal box you don't get this rattle. It uses a spring and adjuster on a quadrant to keep the release bearing tensioned against the diaphragm fingers. When you release the pedal the bearing remains pressing on the diaphragm fingers and so does not rattle.

I think the release arm angle is a red herring. The at rest angle depends on two contact points. The pivot 'pin' position and the contact face of the release bearing. Moving the pivot 10mm forward with the cct132 bearing or leaving the pivot where it is and using a cct133 bearing which is 10mm taller than a 132. Both achieve the same result and the same angles, assuming the cable is under light tension.

If you can arrange some mechanism to tension the cable you will eliminate the rattle. Below is a diagram of mine. Just a sliding section in the cable run filled with a spring. Cable is adjustable at the clutch arm end so I tweak it up now and then to compress the spring and keep a little tension on the cable

 

Nigel

[sj-bradley]

Interesting. So it seems that this little spring is there just to make sure the thrust bearing is always in contact with the clutch?

 

It's like you're always "riding the clutch" which is something I was taught never to do as it aggravates wear on these parts.

 

And yet this is designed IN Weird !

 

Simon.

[richardm6994]

Nigel's spot on.....keeping a small amount of tension on the cable prevents the release bearing rattle. It isn't like riding the clutch though as you are not really putting any significant force onto the bearing to effect the pressure between the clutch plate and flywheel.