silver dawn; the restoration process

Silver DawnThe Restoration Process

Classic Restoration and Services Ltd

The History

The Rolls-Royce Silver Dawn is a car that was produced by Rolls-Royce at their Crewe works between 1949 and 1955. This particular car was a J series and one of the last to be built in 1955. Chassis no SVJ 39, production stopped at SVJ133. It was the first Rolls-Royce car to be offered with a factory built body. The car was first introduced as an export only model. The left hand drive models had a column gear change, while right hand drives had a floor change by the door. Only with the R Type based model was it officially available on the home market, from October 1953.A mere 760 were produced between 1949 and 1955. Earlier models up to circa May 1954 had a different fascia (dashboard) from the Bentley Mk.VI and 'R' Type, and were fitted with a single exhaust system. Later models from the SRH chassis series had the Bentley style fascia and the twin exhaust system, as fitted to the Bentley 'R' Type. The in-line six cylinder engine had overhead inlet and side exhaust valves and had a capacity of 4,257 cc until 1951 when it was enlarged to 4,566 cc. The carburettor was a single downdraught Stromberg until 1952 when it was replaced by a Zenith. We converted this particular car to run on twin SU carburettors as it results in better performance and fuel economy.A four speed manual gearbox was fitted to all cars at first, with a 4-speed automatic becoming an option in late 1952 on the 'E' Series chassis, and on the corresponding Bentley 'R' Type chassis.The suspension was independent at the front using coil springs while at the rear the live axle used half elliptic leaf springs. The car had a separate chassis made with traditional riveted construction until 1953 after which it was welded. Servo assisted 12.25 in (311 mm) drum brakes were used, hydraulically operated at the front but retaining mechanical operation at the rear. Although many cars were fitted with factory built bodies, others were supplied to external coachbuilders.


The Challenge Is To

Transform this Into this.


Inspection And ReportWe carry out a detailed

inspection and discuss options in great detail before embarking on

the restoration process. Every customer has different goals and for some it can simply be reliable and safe to use. For others it is

the pursuit of excellence with no compromise to cost. This was certainly one of those cases.

Dismantle and assess


Undressing

Remove doors, bonnet, boot and all closing panels. Wings and

wiring loom removed followed by body mounts. The Standard steel body is quite rigid and requires

no internal bracing before removing the body, unlike coach built or convertible cars. 12 bolts

later and the body is removed. The hard work begins.


Keeping Track Of The Parts

Every item removed is photographed and inspected. It then starts its journey. Some items requiring repairing, re-bushing, re-

made or simply re-finished or electroplated. An inventory is created and

every part is accounted for. Each part goes through several processes before ending up as a sub assembly awaiting

final fit. Boxes are numbered in ascending order and during re-assemble the aim is to get to box one, the first components

removed is usually the last fitted.


Good Place To StartEvery nut, bolt, washer, brace and bracket removed. Sections are cut

out and new ones made and welded invisibly into place. All

corrosion is removed and chemically treated before being

submerged in an acid tank to remove any remaining oxides that can potentially become corrosion.

The next stage is the painting.


Time For Re-assemblyTwo pack acid etch to prevent further corrosion and provide a base for the next process. Much better than the

original process.

Industrial isocyanate two pack paint. Designed to exceed marine standards.

Needs to be treated with respect during the application.


The EngineAll parts go through a special process involving ground up walnut shells being

blasted at the surface, under high pressure, before being ultrasonically cleaned.


ImprovementsThe crank is ground, hardened and balanced before being polished and assembled with all new bearings. The block is re-bored and new, bigger pistons fitted.

Valves are changed for stellited to accommodate lead free fuel. The original inlet manifold is replaced to

allow the fitment of twin carbs. This not only improves the running but delivers more power. The engine is

refinished in full gloss epoxy paint and the original dull nickel is re-plated using the original Watt’s process.


Carburettors

Just dealing with the Carburettors requires re-plating more than

seventy components, painting a further forty and completely re-designing the original throttle

linkage. As well as changing the Jetting to deliver the best possible

performance.


In The Mean TimeCorrosion is removed by cutting out

sections, making new pieces and welding them into place. They are then

filled to provide an invisible repair before moving on to the next and

repeating this process. The original bodies were made for Rolls Royce by the London Press Steel Co. and the tooling is

no longer in existence. To remake the more complex panels requires a bit of creativity in making press tools and bucks to reform the original panels.


Still More CorrosionOnly with the paint removed is the true extent of the

corrosion known.


Elsewhere In The WorkshopBetween 70 and 150 components are painted each day in

our paintshop while other items are prepared and re-plated in readiness for final fit.


ChromingThis is used to protect the parent metal as well as improving the appearance.

Firstly we remove the original plating using chemicals or electrolyses depending on the parent metal. Repairs are carried out and the part is then coppered. This seals the surface and protects it from further corrosion. This may be repeated

several times if further repairs are required. Copper is said to have good bridging properties and is able to fill in minor imperfections. A close check is kept on the

original dimensions as many of the components need to fit together when finished. The copper is then polished to a mirror finish . Some of the copper is removed electrically before the anodes are changed and the nickel applied. This ensures the surface is free of oxides and a good molecular bond can take place. Nickel is

harder than copper and provides a good surface for the chrome to bond to. This is also polished to a mirror finish and inspected. Finally some of the nickel is

removed before the chrome is applied. One bolt done then onto the next. The original chrome is called Hexavalent and possesses much better properties than

the modern alternative Trivalent. However it does produce toxic waste that needs to be stored indefinitely. It is for this reason the process is due to be banned on

September 21st 2017.Classic Restoration and Services Ltd

Watts Nickel

Watts nickel plating baths can deposit both bright and semi-bright nickel. Bright nickel is typically used for decorative purposes and corrosion protection. Semi-bright, as favoured by Rolls Royce and Bentley deposits are used where a high lustre is not

required. The benefit of the process is it deposits nickel evenly over the surface with low internal stresses. This means a component can be bent or manipulated without the

nickel cracking or peeling unlike modern nickel plating methods that tend to cause embrittlement. Copper is usually applied before this process is carried out. The

disadvantages are, because the process uses low current and takes much longer it ties up the plating tanks for a long time and this adds to the cost. Most electroplaters use the more lucrative methods and choose to dull the surface with steel wool or similar.

This is not suitable and will result in the plating peeling off.


All Electrical Switches And Components Are Overhauled


The Running ChassisA bench seat is added and the chassis can be driven to test

performance.


Repairs complete, the underside is painted and coated in a Ruberoid to prevent stone chip damage.


PreparationIt is said that preparation is everything, this is very true. Before paint is applied to

the body the body is baked in the oven. 40 degree centigrade for about 40 minutes, until the skin reaches the correct temperature. It is then washed using an acid to remove any oxidation. Next stage is panel wipe, this is solvent based and removes

finger prints and any contaminants on the surface. A two pack acid etch is then sprayed on. It receives three coats, most of which is absorbed into the metal and provides a key for the next process. Baked at 60 degrees centigrade for about 40 minutes before being left for 24 hours. The surface is then prepared using a very

fine abrasive. Three coats of two pack epoxy primer is applied. After three coats, it is then baked and left for a minimum of 24 hours. It will be hand blocked and the process repeated several times to remove even the smallest imperfections. The

paint thickness is constantly checked to ensure the product is kept to a minimum.


Now It Gets Exciting

All doors and closing panelspre-fitted and gapped before

the body is painted inside and out.Now is the time to choose the colour.


Painting

As before the body is baked to reach the desired panel temperature. In this case 24 degrees centigrade. Even the

air going through the spray gun is chilled and dried to remove moisture before being heated to the correct

temperature. The base coat is then applied leaving about 20 minutes between each coat. A total of three coats are

applied before being baked at 60 degrees centigrade for 40 minutes. This chemically hardens the paint and removes any

chance of solvent entrapment. It is left to rest for a minimum of 24 hours before the next process.


Hard Choices

Because all the processes apart from electroplating are carried out in house we are able to offer an unrestricted choice. We mix, tint and blend our paint to provide any

desired colour. We use the finest hides in a wide variety of colours, with the option of having batches dyed to meet a

customers exact needs and the same is also true of carpets although we tend to favour Wilton. We can also supply veneers from thousands of species and usually supply samples for the customer to ponder before deciding.

Sometimes the greater the choice the harder it is to decide. This stage cannot be rushed.


Base Coat Is AppliedMasons Black


Next Stage

The base coat is again blocked back ready for the second colour. Because the colour continues into the door shuts, the doors are fitted and the returns are masked. The doors are then removed and the inside painted before being refitted. With the doors refitted and areas not to be painted masked the second colour is applied. Again three coats with a 20

minute gap between each coat to allow the solvent to escape.


Royal Claret For The Second ColourAfter weeks of hand blocking the effort is reflected in the finish.


The Marriage

The body is put back on the chassis and it starts to look like a car again.


The Fit Up

Doors and closing panels re-fitted and every gap measured.


Keeping It Cool

The original radiator core is replaced by a slightly

thicker and more efficient film type core. Two

thermostatically controlled fans are fitted in the space between the core and the shell. Four condensing radiators are

fitted in a space under the front wings. These

have a further two cooling fans fitted and a cover made to protect

them from stones.Classic Restoration and Services Ltd

Time For Some AlterationsDoors have been previously altered to accept additional speakers.

Check straps are fitted to conceal the speaker wires.

We also took the opportunity to install remote central locking.


Air ConditioningProbably the hardest modification to do well, as there are several things to consider. Firstly you have to provide additional power, or the compressor can effect the vehicles performance. We carried out several modifications to the engine to offset any additional load created by the compressor. The compressor itself must be powerful enough to run the system. Most compressors supplied for our UK domestic market are completely unsuitable for middle or far east countries. Calculations are carried out to establish the Kw rating of the compressor needed. Better to use a large one with extra capacity than a small one that can only just cope. In hot countries the sun radiates heat on the body panels and this in turn conducts the heat inside the car, this is referred to as heat gain. Any system should incorporate a high level of thermal insulation. The method we use has very good thermal and acoustic insulation properties but we will come to that later. Finally appearance and functionality. It has to look like it belongs and it has to be usable without excessive noise and causing your knees to freeze while your body is still hot. On this application we used a very powerful compressor with four condensers to loose the heat and two evaporators to supply the cold air. The whole system was built in to the frame of the car and concealed from view.


Hiding Components

This is planned at a very early stage and the assemblies are made and pre fitted. They are then

boxed and ready for final fitment. The compressor and high power alternator(165amp) are fitted at the

running chassis stage while the front evaporator is made and fitted while the body is undergoing corrosion repairs. This occupies the space that used to house the

only speaker. The speaker is replaced by fifteen speakers ranging from tweeters to woofers. The

original vent is remade to incorporate movable louvers and when finally fitted appears almost invisible.


Rear Air Conditioning

The rear vents provide a curtain of cold air above the rear door with the ducting concealed behind the head lining. The parcel shelf incorporates a return vent

that also provides cooling for both audio amps. In the picture you can also see the

high level brake light. The boot is repanelled to create a false bulkhead to house the rear evaporator, audio amps,

additional speakers and seat belt mounts. Most of the room is used by a sub woofer that requires 1cubic foot of

air space. Seriously loud!


Optional Extras

Space is running out. We need to create room to house some additional switches and controls. We dismantle the arm rest and experiment with options. We then make the frame of the new arm rest and house air conditioning rear controls. The USB is connected to the front head unit and allows music to be played using a flash drive. It also incorporates a charging point and not to forget the phone. It is then lined and covered in leather to match the rest of the interior trim. Behind the arm rest is the rear sub woofer so you can quite literary feel the music.


The Audio System

Again carried out at an early stage. This section of dash is remade to mirror the nearside glove box. The head unit is trial fitted. This will also house the front air conditioning

controls and a further USB plug. It is then re-veneered and lacquered to match all other interior joinery before being boxed for a later date.


JoineryAll woodwork is remade or repaired before being veneered using the same log. In this case the cluster burr walnut and straight grain walnut cross banding came from a tree in the south of

France. The veneers are all hand picked based on depth of colour and figuring.


More Toys

In order to make the car more usable we installed some features common in modern motor cars. Programmable

parking proximity sensors fitted in rear reflector. Electric seats mounted inside the seat frame. Reversing camera and

high level brake light with housings made to match existing joinery. Electric power

steering. Remote central locking. Bluetooth and infrared sensors mounted

in the headlining. An integrated microphone is also mounted in the headlining and of course the studio

quality sound system.Classic Restoration and Services Ltd

The Finished Car

Rolls Royce factory only a few miles from our workshop makes

the perfect backdrop for our photoshoot. Notice the seats in the background all empty. All

the staff couldn’t resist coming out and admiring the finished

car.


Pride Of Place


Before And After


A Bit Of An Improvement


silver dawn; the restoration process

Automotive