Lotus 79 JPS

Model
Tamiya J.P.S. Lotus 79 article number 58030 released for sale in 1980 and available until 1984
Double body one in polystyrene and one in lexan
Chassis F1 Competition special

Analysis of the model to be restored
Starting from the front going towards the rear, the analysis of the chassis reveals that

– the front wheels have red rims and sponge tyres not consistent with the original model,
– the steering column is that of the SUPER CHAMP model 58034 which was only introduced on the F1 CS chassis with the BRABHAM BT50 BMW TURBO model 58031,
– The front bumper is white plastic, while the side bumpers protecting the rear tyres are black. The white version is sold as a spare part, set number SP-5085; while in the factory new box they are black. It is evident that the front bumper was replaced after a collision. It is a repair that is in keeping with a restored car bringing it back to its 1980s condition, there is no need to look for a black replacement,
– the chassis has had some use; the screws in the lower part have been worn away by friction with the asphalt,
– the metal servo plate is complete; there are the two perforated plates to which the servos are attached with double-sided tape,
– servos, receiver, MSC mechanical speed controller are present and
– a rich dowry of accessories and spare parts are included with the model

For this set there are lexan and polystyrene bodies; for the Lotus 79 you can recognise the lexan body from the polystyrene body for these details:

– the roll bar is much more faithful to the original version for the polystyrene body,
– the air intakes on the side of the cockpit have a grille in the case of the polystyrene body and are smooth in the case of the lexan body
– the driver of the polystyrene body is a separate piece while in the lexan body it is a single piece with the body itself and
– the steering wheel of the polystyrene body is more detailed than that of the lexan body.

Starting from the front going towards the rear, the analysis of the lexan bodywork reveals that

– the body is broken in several places,
– there is a hole on the driver’s right arm and
– the driver’s head is missing.

Starting from the front going towards the rear, the analysis of the polystyrene bodywork reveals that

– the steering wheel is missing,
– the roll bar behind the driver’s head is broken and
– the rear wing is missing.

Chassis Restoration

The sequence of operations for chassis restoration involves dismantling all mechanical and electronic parts to check that all components are in order. Replace any screws whose heads are worn from rubbing against asphalt.
Treat all small parts with diesel for seven days to remove any traces of oxide and rust.
Wash all parts with hot water and degreasing kitchen soap and then run a cycle in the ultrasonic washing machine for medium to small parts:

– metal parts for 25 minutes at 70°C and
– Teflon or plastic parts for 25 minutes at 40°C.

Replace worn parts or parts that do not conform to the model:

– wheels with red front rims are to be replaced with those provided by the factory in the Diplo version,
– the steering guard must be replaced with the correct one for this chassis; it is included in the SP-5088 “F1 stearing set”,
– the left and right steering arm supports are of two different plastics; one is transparent white the other is cream white. The two parts need to be aligned and
– the rear wheels are definitely worn and need to be replaced.
The sequence of pictures shows on the left the parts immediately after they have been disassembled and on the right the parts that have been replaced or washed.

The parts have all been treated and cleaned, the last step of the chassis restoration is to re-assemble the frame components:

– installing the rear axle on the fibreglass frame. This part comprises several sections. First the rear bumper is installed, which has the function of protecting the body from rear impacts and preventing the car from tipping over under hard acceleration. The rear gearbox is made of metal and the rear axle and motor are installed on it. On the rear axle is the differential; if you wish, you can choose the fixed-gear solution without any differential.
– The second part to be installed is the front axle, which consists of the steering arms and the steering protection column. The steering saver is made up of a spring to cushion the blows that the wheels take and thus avoid damaging the servomotor.

The front and rear suspensions are absent: the action necessary to absorb bumps in the road is delegated to the tyres alone.

– install the front bumper and the two side wings,
– screw on the servo-battery-receiver holder plate. This part will then have to be dismantled to allow the installation of electronics.

The metal plate that holds the electronics is attached to the fibreglass chassis by two screws that screw into two anti-vibration mounts; it is easy to remove it from the chassis for maintenance operations; it has several functions:

– it houses the steering servo, the speed controller servo and the receiver. These parts are secured with double-sided adhesive tape,
– it houses the main battery to power the motor and the secondary battery for the receiver+servo controls. These parts are secured by a rubber band,
– hooks the body to the chassis, there are two levers that must be pressed simultaneously to separate the two parts. They are the ancestors of the clips,
– it houses the mechanical speed controller which is fixed with two screws and
– installs the antenna which is fixed by one screw.

The receiver, two servos and motor are present in the model to be restored; the restoration starts by removing the double-sided tape and cleaning the surfaces with a cloth to bring the electronics to like-new condition.
For the wiring use heat shrink tubing to insulate the soldering of the cables; the speed controller is electrically connected to the motor on one side (green and yellow cables) and to the plug for the battery on the other side (red and black cable).
These speed controllers are equipped with a fuse to protect the system against electrical problems, such as short circuits. In this application, the fuse has been replaced by a device that has the function of protecting the electronics against short circuits; in practice, in the event of a problem, it opens the circuit and in order to restore the continuity of the electrical circuit, it must be manually reset. This device replaces the fuse and is an accessory to be purchased separately code SP-5105 “circuit breaker”.

Polystyrene body restoration
In order to proceed with polystyrene body restoration, the first step is to dismantle all glued parts and remove adhesives from the body.
These are the activities to be carried out for the restoration:
– the driver’s helmet is modified with the addition of the visor,
– rear wing,
– engine exhaust,
– front wing,
– the roll bar is broken and
– the two rear-view mirrors are missing.

A sequence of pictures that summarises the restoration work on the helmet; the visor is attached to the helmet, which is a fairly thin piece of plastic similar to a film that is attached through two screws that pierce the helmet shell. The helmet reproduces that of Mario Andretti, an American driver who never hid the origins of his Italian family. To restore the helmet to its original condition when it left the factory:

– close the holes with the thickest available solution of acetone and ABS; there are three holes,
– work the helmet with 800, 1,000 and 1,200 grit sandpaper

The rear spoiler is mechanically secured to the frame by tarred scotch tape. The glue from the tape is as if crystallised and forms a rough patina on the surface. The pictures show how this part cannot be used without first restoring it. Leave the spoiler for one day in a container filled with 90….99.9% isopropyl alcohol. The liquid dissolves the glue and peels off the damaged paint layer.
The surfaces have suffered from the passage of time, treat both sides with 2,000 grit sandpaper

The engine exhaust is missing from the model; this detail is missing from the body, it is a simple small piece that often detaches from the chassis during road use. List of materials required for the restoration

– a strip of ABS 1 millimetre thick, 5 millimetres wide and a few centimetres long from which to make the base,
– a 3 mm diameter perforated transparent plexiglass tube,
– a fine abrasive file and
– a box cutter.

Sequence of pictures summarising the construction of the double engine exhaust:
– Cut out from the 5 mm wide strip the plate that will serve as a base. Use the body itself as a template, at the rear you can cut out the dimensions where this rectangle is installed.
– Cut two pipe sections of the right size, about 1 cm long.
– Weld the plate and the two truncated cones together using the most liquid version of ABS and Acetone.

Front wing is almost completely intact, only a side strip on the left side is missing. Sequence of pictures summarising the construction of the side wing of the front wing:

– the left side strip is partly present and this will help in attaching the new part to the wing,
– cut the new flap from a 2mm thick sheet of ABS, using the right side flap as a reference to draw its outline on the ABS sheet,
– cut the flap out of the sheet using scissors,
– machine the flap with 1,000 grit sandpaper to make the sides smooth and homogeneous,
– remove the excess part from the flap, which corresponds to the part that remained attached to the spoiler,
– weld together the new flap to the front spoiler using the solution of Acetone and ABS in the very viscous version; to glue the two parts together, it is useful to have a solution that does not drip off and remains where you spread it with a brush,

– as soon as the two parts are firmly attached to each other, spread a thin solution of acetone and ABS on the side of the strip to make the weld between the two parts more homogeneous,
– work the side surfaces of the strip with 1,000 and then 1,500 grit sandpaper,
– reconstruct the piece of the spoiler wing that is missing from the 2 mm ABS sheet by making a small triangle to glue to repair the wing. Use the thickest solution of acetone and ABS to glue this part,
– treat the surface with 1,000 grit sandpaper and
– to prepare the part for painting, treat all surfaces with 1,500 and 2,000 grit sandpaper.

The roll bar is present, but damaged. the right side has one of the two pins where the screw is screwed in that is broken and the upper tube is missing. Sequence of pictures summarising the restoration of the roll bar:

– glue the two broken parts with the thickest available ABS and acetone solution,
– to recreate the upper roll bar, cut a piece from a 2 mm diameter ABS tube and bend it into an arch,
– machine the two ends of the arched tube with 1,000 grit sandpaper until the desired length is obtained,
– attach the two wings of the roll bar to the frame and
– with the thicker solution of acetone and Abs weld the arc to the two wings

Sequence of pictures summarising the construction of the completely missing wing mirrors. For this restoration it was possible to use the mirrors from a new SP-1109 set as samples. List of materials required for the restoration

– cutter,
– ruler and
– 3 mm thick ABS sheet.

The operations to be performed are as follows

– cut out the two outlines by placing the original mirrors on the ABS sheet and cut out the overall dimensions,
– work the surfaces with sandpaper to optimise the dimensions of the mirrors by rounding the four corners of the rear view mirror rectangle and making the mirror arm oval. The rear view mirror has a non-planar shape, so add a piece to what you have cut out, a piece that simulates a mirror housing.
– From a 2 mm high strip, cut two rectangles,

– glue the two rectangles to the mirrors using acetone. In this case use pure acetone to spread with a brush on the two surfaces to be joined, leave to act for a few hours,
– work with 1.000 grit sandpaper to round off the four corners of the rectangle and
– work with 1,000 grit sandpaper to round off the rear cover of the mirror.

Now remove the previous layer of paint from the body. To remove the colour, the fastest and least environmentally damaging system is to soak the body in 90 to 99% denatured ethyl alcohol in the version without added colouring agents and perfume. Alcohol can be used for several cycles.
The paint is attacked by the alcohol and can be removed with a simple mechanical action using a wooden spatula or paper towels. The friction pulls the paint off the bodywork.
Repeat the operation of letting the body soak and the mechanical action until the paint has been completely removed.
Use a wooden toothpick to remove the paint in the corners. The task of removing the paint is quite time-consuming because you have to proceed with several passes and repeat the same operation until the end result is satisfactory.
Once the paint has been removed, it is clear that the body is green polystyrene so it is not the original Lotus 79, which is black; but it is accessory number SP-1109, Lotus 79 Martini in the edition that raced the Formula 1 Grand Prix in Monte Carlo. The design is unchanged; the body will be completed in the black John Player Special livery.

There are three parts that complete the body that are made of aluminium: the rear wing support and the rear wing side wings. All of these parts have suffered the passage of time and are covered with glue, colour stains, oxidation and small cuts.
Work the surfaces with 1,500 grit paper and 2,000 grit paper; when the surfaces are perfectly smooth to the touch, apply two coats of fine white primer.
Prepare the polystyrene body for painting by applying fine white primer.
Colour the aluminium parts and exterior of the body with TS14 black paint and interior of the body with TS82 Rubber black, which is less glossy than the exterior body

To complete painting operation:

– X-04 blue for the driver’s helmet,
– XF-07 red for the driver’s gloves,
– XF-01 matt black for air intake grilles on the left – right side panels and engine intake trumpet surround,
– XF-56 grey for the arrow tail under the engine exhaust in front of the rear wing, and
– XF-16 dark grey for the upper part of the engine and roll bar.

Apply stickers.

Restored model
Images showing the finished model

Lexan body restoration
Now remove the previous layer of paint from the body and the three aluminium supports. Use the same method as for the polystyrene body.

For the lexan body, the rear wing is completely missing.
From a 2 millimetre thick sheet of ABS cut a strip as wide as the wing, as a unit of measurement use the V-shaped metal support directly.
Draw two lines on this plate: the dotted line is the fold that copies the wing shape and the solid line is the cut line.
The plan is to heat the ABS sheet with a normal 2 kWatt hair dryer, the high temperature allows the sheet to be shaped. Hold the hair dryer at a distance of 5…10 mm from the strip, which heats up to such an extent that ABS can be machined. To shape the future wing, place a wooden board along the dotted line, when the ABS sheet is hot lift the free end of the strip by pulling it upwards as if to bend the strip.
The round bend will not be guaranteed by the shape of the wooden plank, but it will be ABS itself that will bend it into a shape that covers a perfect curve.
Repeat the operation until the bend provides the desired shape. It’s better to do one more operation than to strain and weaken the ABS strip.
Once the desired shape has been obtained, cut the ABS strip along the continuous line, thus obtaining the rear wing.

The wing brackets contain the nuts on which the screws will be screwed to secure them to the two aluminium side wings. Sequence of pictures summarising the construction of the brackets:

– cut two pieces as long as the width of the side wing from a 5 mm square section bar. The length is slightly longer than the distance of the two holes on the side brackets, holes through which the screws to fasten the brackets will pass,
– round off the two ends of each support using 1,000 grit sandpaper,
– use the side support as a template for where to drill the holes to pass the screws through,
– heat a 1-1.5 mm diameter wire over an open flame to drill the 4 holes,
– finish the parts with a normal utility knife by removing the melted plastic and
– try out the brackets.

Sequence of pictures summarising the construction of the slots to install a nut to allow the screw to screw in and secure the bracket:

– Using a pencil, mark what the size of the nut should be for each hole. This will give you the section to be cut,
– use the modeller’s drill with the appropriate blade to make the cut and cut out the recess,
– carry out yet another installation test,
– draw two lines at the screws as a reference to always find the correct position of the wing between the two supports.

– apply the acetone and ABS solution to bond the supports and the wing,
– machine the wing inlet and outlet profile with sandpaper 800, 1200 and then 1500,
The lexan body and this wing will not be coloured at this stage

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