Vitesse Diff

[Froc]

Hi all

Just trying to gather some info/wisdom ahead of a winter job. I have a mk2 roto vitesse with J O/D, which clunks on take-up of drive (forwards & backwards). There is about 1/4 inch of free movement of the prop before the diff bites, so i am assuming this is the cause. (I know there are other possible causes for rear end noise!). I plan to swap in a replacement diff over winter, and replace the UJs, bushes, donuts etc while i am down there.

Can anyone help with the following?

-What is the correct diff ratio for a 2l OD Vitesse?

-Can anyone recommend a supplier of recon diffs?

-Failing that, is there anything i can do to reduce the free movement in my existing diff?

Many thanks

Froc

[TomL]

Hi Froc,

 

The standard diff for a 2-litre Vitesse is 3.89:1.  Always worth checking though because a PO could have fitted a different ratio.

 

i would say try Mike Papworth for a recon diff (he advertises in the Courier).  I've not had a diff or gearbox from him but I hear good things.

 

I wouldn't think that was anything you can do to reduce free movement (other than a replacement diff) but the free movement you refer to may well be normal.

 

Tom

[Froc]

Thanks for that, Tom ????

[Clive]

Is there anything else wrong with the diff?

What you describe is not uncommon, and is thrust washers (I think!)

 

If the diff is otherwise ok, it could be left if you can live with the clonk, or rather than a full recon, get Mike or other fixer-of-diffs to check yours over and repair. It should be a much cheaper option that could well last longer than some of the recon diffs available. (Mike tends to use only OEM parts, either new or good reclaimed, where possible)

[Pete Lewis]

Free movement rotational in the diff coupling is very normal its not crownwheel and pinion backlash you are finding its the backlash of the two planet and sun gears of the acfual differential part, thes are quite crude gears

and iits not abnormal for these to give nearly 1/4 of a turn from drive to overun on the prop

 

the clunk is more likely to be elswhere in the drive shafts , hubs, wheel nuts etc.

 

have a read of diff noises on dave s archive in canley classics

Diffs dont clunk or knock, they can whine due to pinion bearings or a meshing setting problems

 

clunks can even be clutch disc hub damper spring problems

 

 

pete

[Waynebaby]

Hi All,

 

Sorry to hijack the thread, but I have a related differential question. I've been checking the oil on my recently refurbished differential (1500 miles and 12 months) and notice that it is quite "sparkly" Should I expect to find tiny bits of metal in the oil (there is a lot of teeth gnashing going on in there after all) or is it a sign of something dire? Also: Molyslip. Is it worth adding to try to reduce rear axle whine?

 

Cheers

 

Wayne 

[Pete Lewis]

If the oils doing its job and the mesh is correctly set then there shouldnt be much metalic particles,

 

backed up by there, s no designed need for a drain plug as theres no contamination expected

 

pete

[Froc]

Clive, Pete, thanks for your replies. Plenty to think about before i go underneath!

[Pete Lewis]

To reduce the turn you could check the sperical thrust washers on the diff gears and maybe change them

 

But that still requires a nearly full strip down to first measure the backlash on the diff gears

and remove crown wheel and diff case from the bevel gear carrier to change the planet thrusts

 

amd youre supposed to use a case spreader to rebuild to get the shims in place which set the crownwheel backlash and pre load the crown wheel diff case bearings

 

not the best job in the plan of things

 

pete

[sulzerman]

Wayne

I had a noisy different in my spitfire I tried moly slip, it didn't make any difference at all!

Hope this helps

Cheers

[Waynebaby]

Thanks for the feedback Paul. I'll save my money and stick with unadulterated EP oil.

 

Wayne

[Pete Lewis]

Whine in a diff comes from two sources, if the pinion bearings have failed or starved of oil these will whine, the crown wheel bearings move much slower and dont cause much in the way of any noise , mabe a rumble , not a whine

 

Bearing whine on drive is the thrust bearing next to the pinion if on overun then its the outer pinion bearing, there must be some preload to arrest any hint of movement when going from drive to overun.

 

crown wheel and pinion whine down to incorrect meshing can have quiet times and build up with speed /load,

Take the pinion as a cone if you project the cone to its apex this must terminate at the centre line of the crownwheel, (its offset if its a hypoid) in the factory the gears are run as a best matched pair and on a machine like a Gleason the best run postion is etched on the end of the pinion as +- 0.00"

which has to be used in its mounting distance, the crown wheel also has a best run and must have some backlash this is quite small like 0.006" this is set by adding shims either side of the crown wheel and diff case side bearings, these also need preload or the mesh would change wih applied load , thats where they use a spreader to stretch, open the bearing cap casting to allow the shims to fit amd pre load the diff assy.

 

none of this is simple diy, you do need dial indicators, and quite accurate measuring

pete

[GT6M]

the wee cup weshers will be most likely doon to aboot 20-25 thou

should be aboot 35-40 thou.

and  aboot 10  thou total of the side ones

And  nearly always, one cup is half thickness of other,

some thing to doo wid round a boots.

 

this all adds up to alotttt of play

and does cause clonks ,esp on over run at low speeds in top gear.

 esp around idle  speeds , quite annoying  too.

 

yours wont ev the fibre thrusts, butt,maybe if its been re built

just re done 2 in last 2 days, both had only 1 fibre thrust there,

other had disintigrated., this gives uneven loadings, BUTT, still keeps it  tight on one side only

so, only one side  can give a clonk

 

just re placing thees is simples, but involves a near total strip doon

ye can, if yer got plenty of room to work, leave the rear bit int car, and just remove the front bit, wid the diff inside it

{ like a Dolomite ,or TR7 type  }

saves unbolting rear bolts, spring.

 

As for oil glinting, its a sign of trouble brewing.

somethings wearing, could be bearings, could be CW being scalloped  away

could even be bearings spinning in their races, could be nee thrusts too.

 

get it oot, an check it owa.

Ohh, an oil change evrey year is best,

 

the amount off diffs rusted away inside cos of condensation in the oil

which never gets burned off if no using it much, wears every thing away

this diff was full of oil, but look wots happened.

and this was the rust after it cleaned oot.

 

butt, it had stood for 20 odd years.

 

 

M

 

 

[Froc]

Thanks for the advice, GT6M ????