gearbox double roller..
Turbo Mini Forums

Its not the ball joints by any chance?

or a drive shaft joint?

Have you missed the block to box O-ring?

has the cam belt gone...

You havent got Shanes 'blown' head gasket on there have you?

or a washer in the cylinder?

What? Another one!

It could happen!

Its not the ball joints by any chance?

or a drive shaft joint?

Have you missed the block to box O-ring?

has the cam belt gone...

You havent got Shanes 'blown' head gasket on there have you?

or a washer in the cylinder?


thanks lads ,i'll get em checked !

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

well heres some more info..

all bearings fine as far as i can tell ,washed the double roller and no nastyness in the way it spins .

so back to the marks on the ring gear and bearing ..

i may be wrong , but ,looking at the chips and marks on the gear ,this has happened with the gear going anti clockwise (viewed from the water pump end)..so i could not have chipped all that off the teeth spinning it with an air gun ? see the blue marks on the bearing ...that would suggest to me it hapeened with some pressure pushing them together ,eg on high torque .

question is how did it happen ? all bolts were tight ,its been set like it is for ,2 years ,...maybe a tiny gap was left after shimming ,and the diff bearings have a micro amount of wear and let it move over ? trouble is , i snugged all the diff and end plates up and the gap between the ring gear and the bearing was .4mm ....lots !!
hmmm























edit: new thought ...how can the outer case edge of the bearing be worn ,all the way round ??? its not supposed to spin !

Edited by robert on 7th Sep, 2010.

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

ok , idler clearance was 7 thou ,so not too bad .
after a bit of investigation , it appears that thers no way the diff can move towards the pipnion bearing if the diff side plate is on and tight ..and theres no way the bearing can move towards the diff if its retaining ring is in and tight ..
so i must have done this damage, spinning it with the air gun with the retaining plate off ! so back to square one !pooh.

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

I suppose it all depends on how big your rattle gun is, but i would have said it would take a lot to score two hardened parts.

I would be suspicious of the casing, as that third motion bearing should be a snug fit needing the slide hammer to remove it. If the bearing has moved with only a rotary motion and vibration from the rattle gun, the case may be stressed? I would closely inspect that center web for fatigue.

I still have that gear case you kindly donated if you need it

hahaha it may come to that !

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

X2, any cracks?

On 7th Sep, 2010 Sprocket said:
I suppose it all depends on how big your rattle gun is, but i would have said it would take a lot to score two hardened parts.

I would be suspicious of the casing, as that third motion bearing should be a snug fit needing the slide hammer to remove it. If the bearing has moved with only a rotary motion and vibration from the rattle gun, the case may be stressed? I would closely inspect that center web for fatigue.

I still have that gear case you kindly donated if you need it

not that i can see so far ..

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

I can imagine the case twisting/ distorting enough to loose the .4mm (16 thou) clearance, that really dosen't sound like enough to me. Is the Diff shimmed the right way?

Also as Colin says the third motion bearing should be nice and snug in the case,

anyway if your main bearing is loose in the case , that last one is out for jobby, perhaps you have just opened it a bit to early...for the galery.

as colin this bearing should coming out with some effort and a good punch, then it go on as a wheel bearing. Perhaps you can use an rhp bearing too the next time
cheers
fab

nope the 3rd notion definataley needed a good tap to get back in ,you could be right fabrice , i did need to get the idlers shimmed again though so thats good and snug now ,and at least i know for sure the middle double roller is nor breaking up ..
i have noticed some marks on the primary gear floating bush ..

Edited by robert on 9th Sep, 2010.

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

That 0.4mm sounds all wrong to me.

I've just measured a brand new (RHP) bearing and the inner race is 3mm longer than the outer race which means the inner race sits proud of the outer by 1.5mm each end.

The pinion sits hard on the end of the inner race so if you only have 0.4mm betwen the crownwheel and the outer race with everthing bolted up, your crownwheel is running with 1.1mm hanging off the side of the pinion.....

The pinions are wider than the crownwheel so it should never hang off the edge. From memory they run towards one end - can't remember which and I haven't got a box open at the moment - but I've never seen them overlapping the end of the pinion.

Re. the marks, I too can't imagine that amount of damage being done with a windy gun unless you had it on there all day. The bearing could have walked slightly out of the case with the vibration and it's retaining plate off, but surely you would have heard if they touched ???

And, as you say it would then have to have rotated in the housing whilst being rubbed, to spread the damage around the whole end face.

To cause it to rotate in the housing would require a much higher load IMO, like the crownwheel being pushed against it in service.

0.4mm just doesn't sound right......

I've seen up to 12thou (0.3mm) of shims behind the retaining plate in the past - the shims vary depending on how deep the bearing sits in its housing (their purpose is to put a little bit of preload on the outer steel ring attached to the bearing) so the overall manufacturing tolerances of how deep the bearing sits in the housing (before the steel ring bottoms out) must be of the order of 0.3mm.

Schrödinger's cat - so which one am I ???

Remove the spring clip from the outer race and check that for wear, also check the retainer plate for wear. On the other end, check the big circlip for wear too.

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

Just measured a brand new 2.76 CW&P (the one destined for my Quaiffe ATB box).
Crownwheel 19.4mm
Pinion 24mm

No way should the crownwheel overhang the pinion...

I may be dreaming this but wasn't there a problem with the early ATBs over some dimensions ???

(I assume it's an ATB from the picture).

Schrödinger's cat - so which one am I ???

no rod non lsd open 4 pin diff :( in fact nic just told me i could be the fastest mini with an open diff !!! whahay!)

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

OK,

I still say there should be no overhang....

What make of 4pin (x-pin) ???

EDIT - just looked at my Quaiffe and spare X-pin and was obviously confusing the two...
My excuse is age....

But I still say there should be no overhang of the crownwheel to the pinion.

Edited by Rod S on 9th Sep, 2010.

Schrödinger's cat - so which one am I ???