AROC Magazine Article - Part 4

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Spacenut
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AROC Magazine Article - Part 4

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Fourth installment of the AROC article, for those of you that are still awake...

Rebuilding the Dream - continued

Powertrain improvements were incorporated in two major rebuilds, the first to change the angle of the entire engine and transmission package, and later on a gearbox change to a 1.2 Ti unit, courtesy of serial Italian car restorer and fellow Alfasud enthusiast Kev Plowman. These early 5-speed gearboxes feature the shortest gear ratios of any of the Alfa boxer range, and are therefore very popular with circuit racers. Fully rebuilt by BLS and with only 100 miles of use, Kev found the short ratios too frenetic for road use, but with my much larger 15” wheels and tyres, the equivalent gearing on the Nova is closer to that of the longer-legged Alfasud Green Cloverleaf.

The ideal suspension geometry took a while to establish. There was no consensus among the contemporary mid-engined sports cars of the 1960s and 1970s. How much negative camber would be needed to be applied at the front, or the back? How much toe-in, caster angle, Ackerman or scrub radius? And that is before we get to spring rates and damper ratios! I would have been completely lost had it not been for Graham Boulter, who I first met when NAD visited Shelsley Walsh in 2010. Driving a superbly prepared derivative of the Pelland Coupe I wanted to source parts from all those years ago, Graham proceeded to clear out the AROC trophy cabinet with his 16v boxer powered featherweight.

I cannot begin to express the debt of gratitude I owe to this guy – Graham happily shared with me his most closely guarded suspension secrets, and within 12 months of our first meeting I had the front and rear camber, caster and toe-settings perfected (and what a difference that front camber made to the steering kick-back!). Graham was also kind enough to share the dimensions of his exhaust system, which I used to fabricate a four-into-two-into-one system, finished off with crossover silencers and twin tail pipes. I don’t know how much it is adding to the performance, but it certainly sounds good!

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Finished interior. It's a squeeze to get in, but comfortable once you are there!

Finally there was the interior to consider. Although amazing to look at from the outside, the Nova interior has always been unremarkable, and yet as the driver this would be the view that I would have to put up with. I started by redesigning the main dashboard panel, filling the space with low-density foam and incorporating the windscreen and side window demister vents fed from a central plenum chamber. Face vents were sourced from a Series 3 Alfasud. Due to the limited space under the dashboard, the heater unit had to be fabricated from fibreglass, using control flaps rescued from my Alfasud unit. An 3-speed squirrel-cage fan blows through an aluminium heater matrix. The flaps are operated by cables from rotary controls on the centre console.

The centre console incorporates the “Nav Computer” (a trip computer salvaged from a Rover SD1) and the rear view telecam. The 5” black & white cathode ray tube screen is attached to a steel framework which provides the steering column support, and unlike typical reversing cameras which feature on most modern cars, the screen is active all the time and replaces the interior rear view mirror. The reason for this is two-fold – first, visibility through the rear louvre panel covering the engine is virtually non-existent, but perhaps more importantly, an interior rear view mirror gets in the way of forward vision! The original wide-angle reversing camera lens was replaced with one with a longer focal length, to reduce the field of view and improve long distance vision. The camera is mounted under the topmost louvre on the right hand side of the rear window aperture, and the remaining blind spots are covered by the period-correct Hella 4004 external rear view mirrors.

The Nav computer required a paddle-wheel fuel flow sensor which was only common to carburettor cars made over a very narrow production span of a couple of years. After some research I was very relieved to discover that the American-made Flo-Scan 264 sensor was also used in the carburettor Alfa 33 Gold Cloverleaf, and I managed to secure a new sensor, still in its Alfa-branded box, through Italian eBay.

To get both the Nav computer and the speedometer to use the same speed sensor, I bought a signal converter to match the Nav computer to the gearbox sensor, and then used the on-board calibration within the speedometer to match the road speed to the Nav calibration. After a number of iterations both the speedometer and Nav odometer readings are in agreement and my calibrated speed is slightly optimistic compared with reality, as required by law.

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Canopy interior trim, with integral side window demister. Snow outside says not a moment too soon!

So what about those instrument displays? Once more, the inspiration came from Alfa Romeo, specifically the 1975 Eagle concept car penned by Aldo Brovarone while at Pininfarina. Although not particularly attractive from the outside, it was the space-age interior that inspired me, leaping out at me from the well-thumbed pages of my 1979 Automobile Book of Dream Cars!

Of course there were some practical considerations. The speculative touch-sensitive switches were binned, and the CRT had to go somewhere that was not too far out of the drivers line of sight, so it would be located off to the left of the steering wheel. Also, the digital instruments would have to be deeply recessed in order to avoid direct sunlight. The blue digital readouts use Vacuum Fluorescent Display (VFD) technology, which was available in the early 1970s, and were purchased from Dakota Digital while I was a resident at Lockheed-Martin in California. I stripped out the VFD displays and display driver circuit boards and integrated them onto a fibreglass baseboard, with the large speed and odometer display on the left side, and the four ancillary gauges – water temperature, oil pressure, fuel and voltmeter in that order – ranged across the bottom. The tachometer would occupy the top of the baseboard. All of the instruments are framed by the steering wheel rim.

But where could I find a suitable tachometer display? There was nothing for it, I would have to build my own, using technology available in the 1970s – LM3914 bargraph display drivers (used in contemporary Hi-Fi), the LM2917 precision tachometer IC, plus a load of blue LEDs. Hyper-blue LEDs draw a lot more current from the LM3914 than conventional LEDs, so a bank of BCY71 transistor drivers are used to handle the extra current. This makes the display bright enough for daylight viewing behind a blue filter.

I did deviate slightly from the Eagle concept by having a separate illuminated scale running along the bottom of the coloured segments, which I think is more visible than the original concept. All of the backlighting was done with white LEDs. Diffuser film is used to create a uniform illumination of the segments.

The other notable omission from the Eagle concept was the display of “idiot lights”, warning of low oil pressure, battery charging problems etc. I managed to fit a slim row of warning lights between the tachometer display and the secondary instrument readouts, which also received their own identification symbols. These were printed on to 35mm slide film and cut out and bonded into a set of tunnels made from black card. This gave me the opportunity to add the famous “thrash light”, unique to early Alfasuds, which illuminates at start-up and warns against the use of excessive engine revs until the cylinder head has reached 30 degrees Celsius. I know that with modern semi-synthetic engine oils this is unnecessary today, but I just couldn’t resist the sense of theatre this light conveys! The alternator warning light required a low-value series resistor to trick the field winding into thinking that there is a filament bulb in circuit – without this additional load the alternator does not charge.

To dim the dashboard lighting during night driving, I designed an LED dimming circuit using another old favourite, the NE555 timer IC. The complete instrument panel, including tachometer and bargraph drivers, signal converter, speedometer and ancillary instruments forms a single unit which attaches to the top of the steering column support and interfaces to the vehicle wiring harness using 3 Cannon “D” type connectors – a pair of 25-way connectors for engine sensors and other control functions, and a single 9-way connector for power. A fibreglass binnacle is attached over the top once the dashboard is fitted. This allows for easy servicing or recalibration of the instruments in the car, or facilitates easy removal for testing on the bench if required. Circular polarised film on the instrument glass reduces reflections.

As I noted earlier, the original wiring harness was a mess. I therefore made up a new wiring harness based around a combined relay block and fuse board located on the steering column support beside my right leg. All the wiring is now implemented using the latest automotive thinwall cable, bundled into two conduits running the length of the drivers side sill panel. Instead of a small number of heavy current (35A) circuits I split the demand across a larger number of 8A circuits, each protected by its own fuse, an idea that I copied straight from the pages of an Alfa 33 factory manual. A secondary switch panel, operating the canopy, fuel pump, radiator fans and hazard lights is semi-recessed into the cockpit side panel so that the switches are easily visible from the drivers seat, but at the same time are less vulnerable to accidental operation when getting into the car.

The dashboard and cover, centre console, centre tunnel, secondary switch panel, cockpit side panels, rear window tunnel, even the gear lever shift plate all had to be moulded from scratch using lots of cardboard and gaffer tape to make patterns. These were then covered in resin-proof tape and fibreglass matting laid over the top. For one-off mouldings this is much quicker than making a negative mould from the positive pattern. Once the basic shape was obtained, a layer of fibreglass tissue and resin covers the majority of blemishes, and a thin scrim of filler is all that is needed to finish it off. Once in primer, I used copious amounts of textured paint, which when lightly sanded and top-coated in satin black looks very similar to leather grain vinyl. The matte finish helps to cut down reflections in the steeply raked windscreen.

The rear bulkhead panel was a flat section of aluminium honeycomb composite left over from a satellite programme and looked very… flat. To add some interest I applied a hexagon motif using a modified cake tin (yes, really) as a “cookie cutter”. I used this to cut hexagons out of 10mm polyurethane foam and then bonded them to the bulkhead panel. A thin layer of fibreglass mat and resin, primer, texture coat and paint completed the job. Four handwheels hold the panel in place; they are normally used to assemble flat-pack furniture.

The cockpit side panels feature a mixture of hard and soft surfaces, the latter made from a flat fibreglass base topped with scrim foam (thin fabric-backed foam used to add dashboard padding) and covered in black vinyl. I couldn’t find a supplier of hexagon padded vinyl so each of the interlocking hexagons is a separate item. They are held in place by twisted wire.

The seat runners were fabricated from scratch. Originally designed to be fixed in place, I needed a way of moving the seats forward to gain access to the front of the engine through the removable bulkhead panel. Because I could not put the seat runners underneath the seats (which would reduce headroom as well as being wobbly), I opted for competition-style side mounts, which easily attach to the fibreglass bucket seats which came with the original kit. The problem of course is that competition side mounts are not normally adjustable, so I attached a pair of floor-mounted runners vertically on either side of the seat. Once attached to the chassis, the seat bucket bolts to the runners using fixtures concealed by the foam padding of the side bolsters. They are not the easiest seats to adjust but they do work, and as far as I can tell this idea has never been used before. Patents pending!

The silver strip that runs along the base of the steering wheel crash pad had “Rover” etched onto it, so I sanded off the script, and the clear anodising, polished it up and then glued a strip of laser printer film over it using clear PVA adhesive. The “Nova” script is reverse printed onto the film. The text font is almost identical to that used in the company sales brochures in the late 1970s, but was actually used on a European export version of the Russian Lada, of all things.

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The Nova stands out in a crowd - Auto Italia 2021

To be concluded... :roll:

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