International Lancia Forums

It does sound as though stray lapping paste is the most likely culprit, simply by process of elimination.

How novel to have Huib seeking suggestions!

A bad clutch would make it impossible (or very difficult) to engage the non-synchro reverse gear. We've all had that problem once or twice.

I am reminded of things I've read about silicone car polish. The silicone is driven into the paint surface which becomes an issue when the car is repainted. I wonder if your new lapping compound contains something that is forced into the metal of the synchro rings and therefore is never cleaned away. If it's possible to go back to your old compound, I'd do so. The idea of flushing with the cheap oil sounds like a good one. I'd even consider going back to your previous cleaner just to be on the safe side. These are a lot of valuable parts being ruined, not to mention all your work.

Bingo ?? I am reconstructing all comments / opinions / guesses up until today, 2 Dec.
I am not saying that I have concluded the cause nor the solution.....
Assume:
1) Lapping paste isn't the problem nor the cause of the excessive wear.
2) Cleaning fluid isn't problem, unless it needs to be changed.
Changed due to so-much-cleaning-having-being-done in it that it has
a) lost its cleaning properties over the indicated period of time; if this can even occur / ever occur ?
b) become 'tainted' / dirty & therefore no longer is effective
c) has residue from previous operations that effect its cleaning properties
d) ad infinitum
3) gear box oil isn't the problem
OR
for reasons that may be hard / impossible to trace:
an undesirable chemical reaction has occurred (there is a specific-scientific-term for this occurrence that escapes me at this moment) by 1, 2, or 3 or a combination of 2 of 3 or 3 of 3, damaging the bronze synco rings by 1) softening ? 2) hardening (brittle) ? 3) making them pourous ? 4) actually changing the bronze into a new metal (I assume, on no scientific basis, that there is a % of other, harder metal (s), in the bronze

To trial & error it would be, as previously mentioned, time consuming & expensive.

Now that many rings are damaged...will they all be replaced with new ones or will the "least worn" rings not be replaced ? The latter sounds tutto-pericullo !

If this is all babble & / or too much Merlin-Style Hocus-Pocus, please delete this posting & I'll pretend I never wrote it.

Huib Geurink wrote:
>
> Unfortunately I did not keep a record when changing the
> cleaning fluid nor the lapping paste nor how many gear boxes
> I did when. I have done quite a few over the last few years.
> All other gearboxes I have done including the one on Tina,
> the 67 coupe which I use daily have done considerable mileage
> in the meantime. For the moment I assume they do not have the
> problem.
>
> There is at least one other gearbox done early spring which
> was done using the same lapping paste and cleaning fluid and
> also filled with the Millers CRX. As far as I know, no problem.
>
> On the 1975 S3 gearbox only one ring was replaced. The others
> were the original ones. This eliminates the possibility they
> were all from the same batch. This was done say 6 weeks ago
>
> On the 1965 1200 gearbox all synchro's were replaced. This
> was done in spring. They may all have been from the same batch.
>
> I lap the rings on the cone using lapping paste untill the
> braking force is all right. I even do that on original rings
> good enough to go back. This was recommended by the factory
> in the 60's and standard practice with Lancia dealers for
> Flavia and Fulvia gearboxes. The workshop manual also says
> the rings have to be lapped. It does not noticeably change
> the clearance which is measured again anyway before cone and
> ring go back onto the shaft. If it is under 1 mm for used
> ones or 1,1 mm for new ones, they don't go onto the shaft.
> The parts are washed in the cleaning tank. Some paste may be
> left.
>
> I stock the oil in 5 liter cans. I have one can left which
> has 1,5 liter in it. The used 3,5 liters are most probably
> used as follows:
> 2,5 liter in the S3 gearbox
> 1 liter in the 1200 gearbox
> If this is the case, 1,5 liter for the 1200 gearbox must have
> come from another can. If I had two cans from a bad batch of
> oil, there must be 3,5 liter around in other gearboxes unless
> a gearbox was drained soon after assembly and testing and the
> oil was thrown away which does occasionally happen. BTW, I
> did not test run these gearboxes on the bench.
>
> Assembly error is hardly possible, unlikely to be the same
> error on a total of 9 gears and no evidence found when
> diagnosing the gear boxes.
>
> Another possibility is electricity which sort of tries to
> weld the parts together. Unlikely on a Fulvia gearbox, very
> unlikely on two Fulvia gearboxes of different models and I
> checked for brown spots. Found none.
>
> When examining the S3 gearbox a bad clutch was a possibility.
> It is unlikely two Fulvia's had a bad clutch.
>
> I agree with you that either the oil was bad or it was
> contaminated. If the latter, most likely by remaining
> particles of the lapping paste.

Johnny48
try alchemy *
a sort of catalytic-conversion*

I've changed some words to your posting & not retyped some, so - for anyone reading this post, refer to the previous posting, for the full Johnny48 text

assume
1) Lapping paste isn't the problem nor the cause of the excessive wear.

2) Cleaning fluid isn't problem, unless it needs to be changed.

Changed due to so-much-cleaning-having-being-done in it , that it has
a) lost its cleaning properties over the indicated period of time; if this can even occur / ever occur ?
b) become 'tainted' / dirty & therefore no longer is effective
c) has residue from previous operations that effect its cleaning properties

-------------------------------------------------------------------------------------------------------------------------------------------

1) Lapping paste isn't the problem nor the cause of the excessive wear.
2) Cleaning fluid isn't problem, unless it needs to be changed.
Changed due to so-much-cleaning-having-being-done in it that it has
a) lost its cleaning properties over the indicated period of time; if this can even occur / ever occur ?
b) become 'tainted' / dirty & therefore no longer is effective
c) has residue from previous operations that effect its cleaning properties
d) ad infinitum



.... chemical reaction has occurred (......a specific-scientific-term* / **for this occurrence that .... )
by 1, 2, or 3
or
a bad combination of 2 of the above 3 or the 3 of above 3, damaging the bronze synco rings by
1) softening ?
2) hardening (brittle) ?
3) making them pourous ?
4) thereby changing the longevity of the bronze into a metal more prone to quick wear(I assume, on no scientific basis, that there is a % of other, harder / more resistant metal (s), in the bronze)

I found some of the old paste which I used for rebuilding these two gearboxes. The Monte Carlo is running since saturday. The 1200 is a bit more work as the bolt holes of the 3 cross members of the subframe refused to line up. Fortunately Claire was there today to help, giving up is not in her dictionary and we got the bolts in finally.

The two things in common between the 2 gearboxes are the oil and the lapping paste. Or of course something we don't see yet.

About the oil
I have used that type of oil for many years in a few dozen gearboxes. Elena's gearbox is still shifting better than new after 200.000 km and without changing oil.
There might be something wrong with one or two 5 liter cans. If the problem is with two cans, then there might be another gearbox with that oil. It should have done a few thousand miles. I drive my cars a lot and also the type of customer I have is the person who uses his Fulvia for frequent medium and long distance driving, demands safety and reliability and does at least 10.000 km per year with the Fulvia. The problem showed itself within a few 100 km.

About the lapping paste
I am reasonably sure that the new lapping paste was used on more gearboxes than these 2. A problem would have showed itself already. See above.

I look forward to seeing the test results of the oil sample.

> .... chemical reaction has occurred (......a
> specific-scientific-term* / **for this occurrence that .... )
> by 1, 2, or 3
> or
> a bad combination of 2 of the above 3 or the 3 of above 3,
> damaging the bronze synco rings by
> 1) softening ?
> 2) hardening (brittle) ?
> 3) making them pourous ?
> 4) thereby changing the longevity of the bronze into a metal
> more prone to quick wear(I assume, on no scientific basis,
> that there is a % of other, harder / more resistant metal
> (s), in the bronze)

"No scientific basis" is right. A chemical reaction between the gear oil and the bronze seems pretty far-fetched. Unless someone switched Huib's gear oil for hydrochloric acid, it's a little bizarre to think that the gear oil is somehow changing the metallurgy of the bronze (and this in only 400 km).

Given all of Huib's 'clues' so far, the problem seems to be abrasive contamination of the gear oil; the real question is how this is happening.

Lest we forget - how about some cudos to Huib for coming forward with this problem, and a bit of support through what must be a perplexing and difficult situation.

Not easy to do. Thanks, Huib.

Geoff

And the rings worn down from 1,1 / 1,2 mm clearance to zero clearance in 700 km. Lapping those by hand is quite a bit of effort. New lapping paste has to be put on several times. After the lapping the clearance has changed by 0,1 mm at the most, usually no change. Embedded particles should have broken off before doing more damage than say a clearance change off 0,1mm

Thanks, Geoff. We learn every day. Thanks to the internet and in particular this forum we learn with the speed of light.

rite U R.........I was just athinkin ,yesterday,........ more of old-cleaning fluid reacting to newest paste or visa-versa & less about the lubricating properties of the oil......or, that perhaps (for a unknown reason) these properties were negated. Which they certainly seem to have been.
Not by abracadabra.
Not that I've ever heard of that happening...but I've read, on motor oil cans, that synthetic & mineral-based oils or combustion & diesel oils shouldn't be mixed. If mixed, expect ????
Which sorta got me to thinkin.....
Next time I'll just flip on the TV & watch the Simpsons save the World.