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Author Topic: Augusta progress  (Read 29143 times)
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Kari
Senior Member
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Posts: 114


« Reply #270 on: 16 May, 2021, 09:31:34 AM »

As I have mentioned before, I was wondering how my Augusta would look (and drive) with just one spare wheel. I bought some suitable thin walled tube and made a short stub to replace the original carrier. I have to point out that the boot lid has been modified before I have owned the car. Compared to the original there seems to be a heavier gauge sheet on the inside of the lid. I don't know if this has any influence to the dimesions of the spare wheel carrier. If there is interest to copy the short carrier, I am pleased to pass on the data.
Karl


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Mikenoangelo
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Posts: 334


« Reply #271 on: 04 July, 2021, 01:59:08 PM »

Having fixed the things which really needed fixing I donít have much to report on and am just using and enjoying the Augusta which is proving to be a delightful car and very well suited to the twisting roads around here. Iíll do a recap later of the problems we had and the outcome of the last 18 months of fettling but here is a note on the minor but rather challenging issue of the dreaded fuel gauge.

For those who havenít come across this, the fuel tank  is mounted under the bonnet above the driverís knees and connected to the gauge by a cable which is rotated by the gauge sender unit on top of the tank.. The gauge is just a dial with a 270 degree 0-40 litre scale and  a pointer.

The difficult bit is the sender which has to translate the position of a float to rotation of the connecting cable. The translation is done by hanging the float by a fine thread to a small drum about 25mm diameter which incorporates a tiny brass clock spring to tension the thread and turn the gauge pointer and is then geared with a pair of spur gears to the spindle which turns the cable. The cable then passes through a 6mm diameter tube, through the bulkhead to the gauge on the dash. I have the original float, drum and gears but the original casing in which they run, being Mazak, had evidently corroded and had been replaced by a rather crude affair. (Photos 185 and 186).The result was that the device was no longer capable of generating enough torque to turn the cable. I thought  there must be a better way. Others have adapted a modern electrical sender and gauge but I felt that a mechanical setup would be more in keeping.

Most float type gauge senders use a float and lever system but this is not possible for the Augusta as the original float works within the confines of a 62 mm bore vertical tube in the tank. However I found a simple device intended for the fuel tank of an outboard motor and cribbed the idea, adjusting it to suit the tank.  It comprises a metal strip  150mm long x 6mm x 1.5mm which is twisted through 270 degrees to form a very long pitch screw thread. This fits through a cylindrical float, engaging with a slot so that as the float rises or falls, the strip is rotated, the float being prevented from turning by guide rods. The rotating strip is connected by a pair of bevel gears to the cable, and turns the needle of the gauge through 270 degrees as the float moves from bottom to top of its range. The calibration of the instrument is easily altered by increasing or decreasing the twist of the strip. (Photos 187 and 188).

The main problem is that the bevel drive and the connecting cable must be very free to turn and the float free to rise and fall without sticking. The length of the connecting cable is also critical as the distance from sender to gauge is fixed. I used a tongue and fork arrangement at the ends of the cable to provide some tolerance. The float was made from a thick cork bung ( ex Ikea jug!) but could be made by laminating from cork floor tiles. Machined to size 58mm diameter and 42mm high, grooved at either side and  bored through 8.5mm, with a nylon disc at the upper end, slotted to slide on the helical strip, the floatís grooves engage with a pair of 4mm stainless steel rods. The rods hold a lower cross piece with a 5mm hole to form the lower bearing for the helical strip, and their top ends attach to the 80mm aluminium disc which bolts to the top of the tank. A brass fitting was made to carry the bevel gears which are 16 tooth 16mm diameter and run on a 5mm shaft, one end of which forms a tongue to engage with a fork attached to the end of the cable. A gland nut retains the outer tube just as in the original Lancia version. The end float of the  horizontal hear shaft is controlled by a pair of brass collars and the top end of the vertical gear shaft runs in a nylon bush through the top disc. An aluminium cover conceals the gears with just 5mm clearance from the underside of the bonnet top panel.

I made most of the parts in stainless steel and sealed the cork float using a marine grade epoxy resin. Although there  is no guarantee from the supplier that the epoxy will tolerate ethanol in fuel (it is proof against straight petrol) I have used it previously on a cork float fuel sender on a previous project and it was still OK after at least 8 years.

I still have a bit of tweaking to do to get the calibration right but the gauge works perfectly,
the needle being absolutely steady. It does read a few litres high when going downhill, and low going up but on the level gives a true reading.

So rather a lot if time went into the project but it was interesting and satisfying! Iíll add more pictures when I finish calibrating it.

Mike


* 185.Pulley drive sender 1.jpg (109.27 KB, 640x480 - viewed 205 times.)

* 186. Pulley drive .jpg (101.9 KB, 640x480 - viewed 205 times.)

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* 188. Gear dirve with cover jpg.jpg (122.66 KB, 640x480 - viewed 204 times.)
« Last Edit: 04 July, 2021, 08:28:28 PM by Mikenoangelo » Logged
Raahauge
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Posts: 65


« Reply #272 on: 04 July, 2021, 08:37:20 PM »

Well done Mike.
I have taken a different route by trying to recast the original housing in zinc but have so far failed. I am getting closer and with my improving skills I think my next attempt might be a success.
The old unit had, apart from the common problem of distortion and cracking with ageing pot metal, been soldered into the recess in the tank and it was quite difficult getting it out.
The mechanism is attached to the flange at the top of the 62mm tube mentioned by Mike and the outer diameter of this flange is soldered to the underside of the roof the tank to seal it. This solder joint had failed causing a leak leading to some previous owner's expedient repair of soldering everything up. I mention all this to alert you, and anyone else, to the possibility that any leak you may have may be from this joint.


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Mikenoangelo
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Posts: 334


« Reply #273 on: 06 July, 2021, 09:05:15 PM »

It seems the main problem with the original fuel gauge setup is the need to get just the right combination of float buoyancy and tension in the small hairspring to overcome the friction of the cable rotating in the tube connecting sender to gauge. Perhaps a better plan would be to simply put a pulley at the top of the tank sender unit, extend the connecting thread, and move the rest of the mechanism to a point at the back of the gauge behind the instrument panel. Hindsight is a wonderful thing!

Mike - I never tried foundry work although I have made a few simple patterns. An interesting challenge but you will still have some machining to do. I wonder why you are using zinc rather than tossing a few old aluminium pistons into the pot? My fuel sender also leaked a bit around the rim as you can see from my photo but this was due to a poor gasket and stripped threads in some if the retaining screws. It does look as though some soldering has been done around the rim.

Mike
« Last Edit: 06 July, 2021, 09:07:57 PM by Mikenoangelo » Logged
Raahauge
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Posts: 65


« Reply #274 on: 11 July, 2021, 08:43:48 PM »

Mike.
Foundry work is very satisfying in a sort of basic way and also interesting because it is outside my general experience.
The use of Zinc is part of my improving skills and part of the learning process. I started with scrap aluminium but the sections are very thin and I couldn't get it to flow well enough. I am optimistic (hoping) that I will not have to machine it apart from drilling some holes.
It has consumed a stupid amount of time thus far!





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Mikenoangelo
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Posts: 334


« Reply #275 on: 13 July, 2021, 08:42:34 PM »

Now Iím down to the details - an annoying but minor rattle from a rear door led me to investigate the latch plates on the body for the top of the doors. These are another example of Lanciaís attention to the finer points. As mentioned in an earlier post the latch plates actuate the retractable sprung latches on the doors as they are closed but also incorporate rubber buffers for the doors and are themselves also rubber mounted  and able to turn to align with the closed door. They appeared to a bit loose because their rubber mounting bushes were perished and their fixing bolts loose. Luckily I had a sheet of 4mm rubber which when wrapped around the metal centre sleeve and pushed into the outer housing made a reasonable bush so that now the doors close and the rubber takes up any slop. Rattle gone!.

It took a dayís fiddling, as to get at the mounting bolts involves lifting the trim panels above the door which in turn requires removal of the panel above the windscreen, the mirror and the sun visors. All of these are fixed with 4mm screws which pass through a wooden filler behind the trim and into holes drilled in the inner body panels around the doors and windscreen. The wooden filler panels are a work of art rather than the usual scrap of hardboard! They are machined to incorporate various recesses and fit to the metal body frame. Interestingly the bolts (more like self tapping screws) which hold the latch plates are 5/16 inch and have half inch A/F heads, perhaps American origin.

Mike
« Last Edit: 14 July, 2021, 07:00:09 AM by Mikenoangelo » Logged
Mikenoangelo
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Posts: 334


« Reply #276 on: 23 July, 2021, 08:29:13 PM »

More experience with the helical drive of my geared fuel tank sender (Photo 189) showed that despite the epoxy coating, the cork float absorbed fuel over a week or so and messed up the calibration. The float grew in diameter by 3mm and so stuck on the guide bars. I bought an ethanol proof SU float from Burlen and was able to use a metal bridge piece across the top of the float to engage with the two side rods to stop the float rotating and it now seems to work very well without sticking. I must say the reading is much affected by the gradient of the road and possibly needs  a slight reduction in pitch of the helical bar to match the fuel level shown on my dipstick. One issue I noted was that it is essential to have a little end float to the connections at either end of the thin connecting cable from sender to gauge as any end loading puts a wave in the cable which make it bind in the guide tube.

I am now reduced to working on the only remaining known issue - rebinding the braided grab handle for one of the rear seat passengers! A job more suited to the denizens of ďThe Repair ShopĒ on TV! Of course as once famously said there will be unknown issues which I donít yet know about, but so far I canít see anything else which needs fettling.
Mike


* 189 Fuel gauge float and helical drive.jpg (113.74 KB, 640x480 - viewed 57 times.)
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neil-yaj396
Committee
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Posts: 1087



« Reply #277 on: 24 July, 2021, 07:44:02 AM »

Great that you have overcome all those niggles Mike. Often, owners, especially those not using their cars so much, just put up with them.
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1979 1300 Beta Coupe, 2014 Ypsilon 1.2 S Series Momo
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