Gearbox noise

[Julian]

Guys

When moving my S2 coupe out of the garage yesterday, I noticed that the gearbox is quite noisy when cold and in neutral with and the clutch up (I’ve not yet checked it warm). As the box to the best of my knowledge has not been rebuilt and covered around 90,000miles, I suspect that the main-shaft bearings are worn. Apart from some stiffness in first and second when cold, the gearbox does work smoothly and without issue.

Firstly, is this normal on an old Fulvia box or will I need to get my hands dirty soon? Secondly can anyone recommend a good oil or additive which I can use to help the problem until I get a chance to get the box out?

Also, upon doing some research this morning I have read that many modern GL-5 gear oils contain additives that can corrode the bronze bearings in older boxes. Is anyone else aware of this issue and could this be a problem with Fulvias?

Many Thanks

Julian

[P. de R. Leclercq]

I do know that Mobil 1 gear oil does affect the bronze. Amsoil's oil doesn't, neither I believe does Motul's.

Bearing failure is fairly rare in Fulvia 'boxes, mostly the problems are first the horribly under-specified input-shaft bearing (the early S1 ones were even more horribly under-specified - and with only one seal!!! )ha-ha-ha - really pathetic actually - I know Luigi Bosco was supposed to be a good engineer, but perhaps the cost accountants got him - a rare occurrence at Lancia admittedly. Second, the S1 synchros are not good and third I have come across severl clapped-out CWP assemblies and fourth the output shaft oilseals often leak.

Paul

[Huib]

It looks like the S2 gearboxes have 2 seals on the input shaft. This is however not the case. The small one in the bush holding also the needle bearing is not a seal to prevent oil leaking from the gearbox to the clutch housing. It is there to form a lubrication chamber between the input seal and that small aditional seal. Oil gets into that chamber through a hole at 12 o'clock and gets out of the chamber through a hole at 8 o'clock. So oil remains between 4 o'clock and 8 o'clock to lubricate the shaft which in turn lubricates the seal.

The original seal of the input shaft is 7mm high. I replace those with two Viton seals of 4 mm high with special silicon grease in between. The stack of seals is now 8mm high. This just leaves enough space to let oil into the lubrication chamber. We will know in about 30 years if this solution is any better.

For the output seals I also use Viton seals (with extra dust lip). Also for the crankshaft. I did the calculations for the seal on the pulley. The black MBR material that everybody uses is good for 3000 rpm at 100 degrees C. Viton is good for 8000 rpm at 200 degrees C.

[Julian]

Thanks Guys

I guess I will have to get the box out over the winter and open it up.

In the meantime I will add some Molyslip or similar friction reducer and see if this helps.

Julian

[P. de R. Leclercq]

Yes, Huib, Viton is a great improvement on the originals and always a good idea..

My issue is with the bearing itself. The later S1 and S2 bearings are slightly longer than the originals as I am sure you know, but I consider the bearing to be under-specified anyway. Once the bearing starts to get slack, then the seals have no chance regardless of their composition.

If I had money (whatever that is) then I would look into the possibility of re-engineering the whole thing incorporating a proper bearing that is fully up to the job.

Paul

[brian long]

Julian

The molyslip may affect your synchros. But others may care to comment?

Brian.