Fulvia S1 subframe measurements

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Huib
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Re: Fulvia S1 subframe measurements

Unread post by Huib »

Hi Luca

The off set at the rear is 2,5 mm.

If my name would have been Sherlock Holmes my story would be:

In 1963 the responsible engineer made an entirely correct drawing for the Fulvia berlina 1C. That sub-frame was like the Flavia. It does not have the out riggers.

A year later the 2C appeared. Its sub-frame did have the outriggers. A trainee was told to modify the drawing of the sub-frame of the earlier 1C into the drawing of the later sub-frame. The trainee did not have the experience to understand what the important measurements are for the purpose the drawing was put in the DT for. He put the figures he was given in correctly but related them in the wrong way.
Huib
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Re: Fulvia S1 subframe measurements

Unread post by Huib »

I found the drawing I made to construct a table for repairing a sub frame. The table was much in such a way that the sub frame can be clamped onto it the right way up or upside down.
subframe to table.jpg
Avellino. Nice. I have not been there yet. Tufo is still on my list. For the Greco di Tufo.
Huib
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Re: Fulvia S1 subframe measurements

Unread post by Huib »

Attached photo's of the sub frame we use for measuring and for transport.
Attachments
Transpor small size.jpg
Measuring - small size.jpg
piggdekk
Posts: 33
Joined: 19 Sep 2020, 12:07

Re: Fulvia S1 subframe measurements

Unread post by piggdekk »

Hi Huib,
I'm still a bit unclear so I figured I'll provide You my own measurements, maybe they help.
See the pictures below.
Telaio front to mid.jpg
Telaio mid to 1C.jpg
Telaio mid to center outriggers.jpg
Telaio mid to outriggers.jpg
piggdekk
Posts: 33
Joined: 19 Sep 2020, 12:07

Re: Fulvia S1 subframe measurements

Unread post by piggdekk »

Fantastic information Huib, I take my frame is badly bent. I do need a jig like yours. Is it normal to find them so much out of wack?
Greco di Tufo is excellent, but don't underestimate Fiano and Taurasi either.
Huib
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Re: Fulvia S1 subframe measurements

Unread post by Huib »

The sections of the sub frame can be bent, curved, twisted, warped, torn etc.. Even all at the same time

Measuring the sub frame is thus not easy. According to my piano tuner who also restores grand piano's and according to myself it is worth the effort of doing the job correctly to the mm

Get some spirit levels. One long enough so you can put it from one inner wheel arch to the other so you can use it on the car too and a digital one of average length with magnetic base. Also get some steel square bar lengths which you can turn into spirit levels buy clamping the magnetic spirit level onto it.

Get a Messfix like https://eshop.wurth.nl/Messfix-voor-aut ... nl/NL/EUR/ The thing is made from aluminium. You need a helper to hold the spirit level on top.

Build a strong table with adjustable legs so you can set it perfectly level.

Construct two extra brackets with 4 10 mm holes on the top, the length of the mounting flange for the alloy towers and an height of 80mm. Make sure you can put the sub frame on top up as well as top down.

Start putting the sub frame on the table without bolting it to the table. Just observe and measure. Then bolt it to the two brackets. Observe and measure. Turn it upside town. Measure again. Take a few days to play with the toys and ley it sink in before you start cutting and welding,

Look at the mounting base of the towers. It is not in contact with the sub frame over the full length.

Greco di Tufo, Fiano and Taurasi. I have now 3 reasons to go to Avallino. Well. There is a fourth one.....
piggdekk
Posts: 33
Joined: 19 Sep 2020, 12:07

Re: Fulvia S1 subframe measurements

Unread post by piggdekk »

Thanks Huib,
I see what You mean and this is how I was planning to build my jig. I also reckon it'll be hard to bend it back without some cutting and welding. It might as well be simpler to remove front cross member and outriggers and weld them back in the right position.
If You don't mind I have another question: how do You make sure that the subframe will stay straight once You bent it back? I believe lots of the spotwelds on mine are probably weak or gone and I was planning to seam weld it. There are kits out there to strengthen the subframe, but I don't really like them as I believe the frame is supposed to have some flex in it (especially looking at how flexible the body is...). Fessia knew what he was doing, and there is no mentioning on the FIA fiche of brackets on the subframe. I already have the Gr.4 modified cross member.
My plan is rather to reinforce existing welds, and seam weld the joints along the beams.
As for Your fourth reason to go to Avellino let me know. If it has got four wheels I've got very trustworthy people that can check it out for You. Covid-19 allowing I will be there for Christmas.
regards
luca
Huib
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Re: Fulvia S1 subframe measurements

Unread post by Huib »

Hi Luca,

The way of measuring I see on the pictures is very recognizable. That is how we started. It is not accurate enough. The table we built is modular and now in use to build up a complete subframe. I can't take any pictures. It is as I described. It also includes a removable clamp for keeping the M10 holes for the rear cross member in place when doing surgery.

Every case is different. In general I woulds say, if it is bent through an accident you may have to do surgery. Most of the time bending is done easily with the standard hydraulic tools for accident repair. It stays in shape I assume. I have not tested what happens after 50 years. My successor has to do that.

We put in the rear cross member when measuring. We are fortunate enough to have some sub frames from cars which were never driven fast and never had an accident. Those sub frames are unsuspected and have the correct dimensions. Those happen to be from 2C's and one from a 1974 1300 coupé with very low mileage. Its only abuse is that it was not used. There is a lot of work (even the gearbox has rusted inside because the oil had dripped to the bottom over time) but no work related to mechanical deformation.

The sub frame and the body form a box which should give enough strength for normal use whatever that may be. The body part of the box is stronger than the sub frame. Make sure it is. Put the body shell on 4 axle stands where the jack supports are. Move the front of the fenders up and down with the doors open and see if it flexes.

At Casa Lancia we don't do many race cars. Most of our customers use their Fulvia's for daily driving, Gran Tourismo, regularity rallies and the like. Reliability and safety for 100s of thousands of kilometres are of prime concern. From experience I have learned that sticking to the original concept is the most efficient way. This is a complicated way to say that we don't do any seam welding. As you say some flexing is necessary. Virtually no reinforcements. Seam welding takes away much of the flexing I have been told.
piggdekk
Posts: 33
Joined: 19 Sep 2020, 12:07

Re: Fulvia S1 subframe measurements

Unread post by piggdekk »

Thanks Huib,
the description of your jig is very accurate, thanks. Later today at latest tomorrow I'll post a picture of the jig I'm building. The primary reason for building the jig is indeed get the measurement right. I do recognize that my measurment cannot be very accurate. I would not trust them to ensure that the frame is straight to the mm, but it makes evident that right now is badly bent.
Maybe in another post we should discuss flexibility. I am really surprised by how much flexibility is built by design in these chassis. Looking at the rear mounts of the subframe it's evident they don't do anything to prevent front end flex. Front and mid mounts are designed to support compression and flex, rear aren't. They mostly support vertical movement (compression), but they are designed to let the whole front end bend upwards. This is probably why racing Fulvia tend to crack very often the A pillars (mine were cracked), and why they used to have brackets to keep the windscreen in place.
One very popular mod (included in the FIA fiche) was to install also on S1 like mine the gearbox cover from a 5 gear body. It extends a lot more in the cabin and has to provide more rigidity to the front end. The gear change mechanism is then extended using I believe a part from the Fulvia Saloon.
luca
lancia7550
Posts: 33
Joined: 10 Nov 2012, 22:26

Re: Fulvia S1 subframe measurements

Unread post by lancia7550 »

Years ago I built my first Fulvia out of 2 or 3 scrap cars. My subframe was undamaged, but while refitting I picked up that everything did not align 100%, especially after removing/ refitting some of the cross members after the subframe was back in the car. There is quite a lot of play/ movement possible between the components before tightening. Years later when I restored my current coupe, which was a low mileage unrestored car, I used a punch to mark all the subframe components' alignment before disassembly. This gave me confidence that everything was properly aligned, and when refitting to the car it was clear in the way it all came together that everything was "right". Highly recommended before disassembling your subframe.
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