THE HURRICANE BUILD MANUAL |Back to Hurricane|

CABURN ENGINEERING

1 INTRODUCTION

The Hurricane has been designed as a straightforward replacement for the rust prone steel bodyshell fitted to the Spitfire and GT6 range 1962-1980. The chassis, running gear and engine unit remain largely untouched therefore little mechanical knowledge is required to convert a rusty Spitfire or GT6 into a rust free Hurricane.

Due to the "backbone" nature of the chassis, the Hurricane body is semi-stressed and is therefore of robust construction. Materials used are best quality chopped strand mat in polyester resin with double skinning, box-section and plywood reinforcement. Tubular steel frames are used in the scuttle, doors and front end to give additional strength and rigidity.

Although only basic tools are required to complete the kit, these should include

the following:

Axle stands

Selection of wiring terminals

Terminal crimping tool or soldering iron

Tape measure

Combination spanner set

Screwdrivers

Drill bits and rotary rasps

Electric drill

Hacksaw

Hand files

Production paper (various grades)

These building instructions should be used in conjunction with a workshop manual for your car as only those building operations that apply specifically to the Hurricane are described here. Those dismantling or assembly operations that are identical to the Spitfire or GT6, such as removing and fitting door mechanisms, are not covered in these building instructions as they are covered adequately in the relevant workshop manual.

2 DISMANTLING OF BASE VEHICLE

It has been found from experience that it is advantageous to leave most of the components on the bodyshell until they are required for fitting to the Hurricane body.

a) Before starting the dismantling procedure, disconnect the battery.

b) Remove seats and carpets.

c) Remove steering column as follows:

- Disconnect multi-pin connector under dash

- Remove both steering column supports

- Remove clamp bolt from UJ where the steering column connects to the steering rack

- Withdraw the steering column complete with steering wheel and switches

d) Remove dash support and gearbox cover.

e) Remove gear lever remote (not fitted on some MK4 Spitfires).

f) Disconnect speedo cable, reversing light wiring, and overdrive wiring from gearbox.

g) Disconnect clutch pipe from master cylinder and drain clutch fluid.

h) Remove bonnet as described in workshop manual. Do not forget to remove bonnet stay and disconnect wiring.

i) Remove brake pipe from master cylinder.

j) Remove earth straps between engine/gearbox and body.

k) Disconnect rev-counter cable and starter motor cable.

l) Disconnect wiring from engine (dynamo/alternator, coil, oil pressure sender, water temp. sender, distributor) then release wiring from clips on chassis and stow on bulkhead. When disconnecting wiring make a note of where each wire leads to on masking tape wrapped around the wire, or on a separate sheet of paper.

m) Disconnect accelerator linkage and choke cable from carbs.

n) Drain coolant from engine and remove water hoses from heater.

o) Drain petrol tank and disconnect petrol pipe at tank.

p) Disconnect handbrake cable at handbrake lever.

q) Remove handbrake relay lever. This is situated under the floorpan just forward of the diff. Locking tabs are fitted to the pivot bolt.

r) Detach rear suspension radius arm brackets from body.

s) Remove rear exhaust mounting. Remove any exhaust straps fitted to body.

t) Remove the two seat belt anchorage eyes adjacent to propshaft tunnel.

u) Remove the twelve body mounting bolts. (See Figure 1)

v) The body is now ready to be lifted off the chassis with the help of three or four volunteers. When the body is raised a few inches off the chassis, check that nothing is connected between the body and chassis that will prevent the body from being lifted off completely.

REMEMBER - SAFETY FIRST

 

3 CHASSIS PREPARATION

We would advise that before proceeding, the rolling chassis assembly is decreased or steam-cleaned. This allows a thorough inspection to be made. It is unusual to find serious rust but check carefully the front outriggers and the diff mounting cross-member. Have any rust damage repaired by a competent welder. If required, new front out-riggers can be obtained from suppliers.

Any bare metal should be treated with Bondaprimer or similar and then painted with a polyurethane paint or underseal With the body off the chassis it is a good opportunity to check over the suspension and braking system, paying particular attention to brake pipes.

Rubber pads are provided for use between the body and chassis to reduce road noise and vibration. These should be mounted on the chassis at the body support positions.

If using a rear mounted battery, attach a heavy duty battery cable along the side of the offside main chassis rail, or run the cable through the nearside sill.

4 CHASSIS MODIFICATIONS

The only modification needed on the Spitfire or GT6 chassis is the removal of the front cross-member extensions and bonnet hinge brackets as shown in Figure 2. This is easily accomplished using a hacksaw. Once these are removed the chassis is ready to accept the Hurricane bodyshell.

Figure 2

Cut off shaded areas

5 BODYSHELL PREPARATION

Edges are hand finished and flash lines are removed, and most mounting holes are pre-drilled. Apertures are cut out for headlights, radiator air intake and outlets, fuel filler, diff cover plate, master cylinders and window winder mechanisms/locks, on the finished model.

You will need to make holes in the bodyshell for the fitting of rear lights, front sidelights, and various mountings. Before drilling, it is a good idea to cover the area to be drilled with masking tape. This will provide a good surface for marking out and will also prevent the drill from slipping on the surface of the fibreglass. An electric jig-saw and an electric drill with a variety of rotary rasps are ideal for obtaining the rough shape, using hand files and 60 or 80 grade production paper until the exact shape is obtained. Smaller holes should present no problems.

6 FITTING THE HURRICANE BODY TO THE CHASSIS

With the help of 2 or 3 assistants the body can now be lifted onto the rolling chassis.

Although mounting holes are pre-drilled it may be found necessary to enlarge some of these in order to fit your chassis exactly. NOTE: The chassis mounting points for bolts on the centre angled section and at the rear, (see Figure 1,) allow for some adjustment. Use the wheelarch to chassis measurement for accurate bodyshell alignment at the rear and the body tub to chassis measurement for the front alignment.

FIGURE 1 : POSITION OF THE BOLTS HOLDING THE BODY TO THE CHASSIS

1 Bolt - dash front outer to chassis frame

2 Plain Washer

3 Nyloc Nut

4 Bolt (Setscrew) - body to mounting brackets

5 Spring Washer

6 Mounting Block

Note: - Rubber mounting block should be inserted beneath all mounting points.

The main factor governing fore and aft location of the body is the location of the radius arm mountings, bearing in mind that the correct toe-in for the rear wheels must be achieved using as few spacers as possible between the body and the radius arm mountings. Ideally, no spacers should be used. The reason for this is that the more spacers used, the further forward the body is positioned on the chassis, and if the body is positioned too far forward on the chassis, there will be insufficient clearance between the front wheels and the bulkhead. If wider than standard wheels are used, this clearance becomes critical.

Once the body is positioned correctly, it can be bolted down, using the large washers provided, beneath each bolt head to spread the load. Use mastic sealer around the bolt heads to prevent ingress of water, and protect bolts with an anti corrosion compound such as Waxoyl.

7 REAR RADIUS ARMS

Measure the distance between the rear radius arm mounting holes on your old bodywork and by careful measurement, mark the holes on your Hurricane body so that the radius arm brackets are mounted half an inch higher than on the Spitfire/GT6 body. Bolt the radius arm brackets to the body using a steel plate or large washer behind each nut and then bolt each radius arm to its bracket.

The rear wheels tend to be pushed forwards by the transverse leaf spring when the radius arms are not attached to the body, so you will have to pull each wheel rearwards when fitting the radius arms.

Toe-in adjustment is made by the use of spacer plates between the body and radius arm brackets, or in the case of the lower wishbone suspension, by a threaded rod. This is best left until the car is completed as adjustment should be made at normal ride height. See workshop manual for further details.

8 FITTING THE BONNET

Each bodyshell and front end is fitted to a chassis jig at the factory, and the bonnet frame is adjusted for a good fit. As production chassis do vary slightly, some small adjustments may be necessary.

Fit the bonnet hinges to the bonnet frame. The hinge bolts to the lower face of the chassis front cross-member (see Figures 3 and 4) so the mounting face of the hinge is fitted uppermost.

With the help of two assistants, offer up the bonnet to the body, and while they support the bonnet in its fitted, closed position, mark the positions of the hinge mounting bolts onto the lower face of the chassis cross-member.

Remove the bonnet and drill the holes marked. Drill through the top surface of the chassis as well, and use a long bolt with a spacer between the upper and lower surface of the chassis member (see Figure 3). For side to side adjustment the holes just drilled in the chassis may be elongated using a round file. There is a slot in each bracket for adjustment forwards and backwards, and there is a threaded adjuster at each side of the bonnet frame to give vertical adjustment. Adjust the bonnet in one plane at a time, and remember that a very small adjustment at the hinge will give a relatively large adjustment at the back edge of the bonnet. It is worth spending a couple of hours getting the bonnet adjustment right.

Figure 3: Side elevation of front chassis cross-member showing bonnet hinge mounting

Figure 4: Front of chassis (plan view) and bonnet hinges

The bonnet is best located at each side by the use of rubber cones as used on the Spitfire or GT6 bonnet, which should be bolted to the body as in Figure 5. A hole should be made in the lower bonnet flange on each side into which the cone will locate.

To keep the bonnet held down securely, a Triumph 2000 type bonnet release catch may be fitted. The cable release part of the mechanism is bolted to the front of the heater air box in the centre of the front bulkhead. The other half of the mechanism should be bolted to a block of plywood which is then bonded to the underside of the bonnet using an epoxy adhesive (araldite) or glassfibre resin.

Figure 5: Side elevation of scuttle showing bonnet location and the method of windscreen attachment.

 

Take great care to ensure that the two halves of the bonnet release mechanism are in the correct relative positions to enable the bonnet to close in the correct position.

An alternative method is to use a pair of leather, or other proprietary type bonnet straps in the area of the bonnet location cones. These are much easier to fit and also look in period with the styling of the car.

At this stage fit the bonnet and boot stays. Spitfire ones do fit, although simple

brackets will need to be made.

NOTE: When transferring parts from your old bodyshell, use these instructions in conjunction with the relevant workshop manual for your base car.

9 HANDBRAKE

Remove handbrake, cables, and relay lever from your old car and fit to the Hurricane body, using the new relay lever bracket supplied. Replace the cables. The handbrake can at this stage be connected up to the rear brakes and adjusted. NOTE: Cables are available in two lengths, check with old cable before fitting. GT6 Mk2 owners should remove cable guides from bodyshell and bolt to the Hurricane body. If you are converting your car to Rotoflex rear suspension, DO NOT USE EXISTING CABLE GUIDES. These must be modified to ensure that the handbrake cables will not foul the Rotoflex Units.

10 HEATER UNIT

Remove the heater unit from the old car and refit to Hurricane body. Use a mastic sealant around water pipes. If a GT6 Mk2 or 3 heater is used, to avoid fouling the gearbox cover, the cold air lower outlet pipes must be cut off and the hole blanked off with an alloy plate.

11 WINDSCREEN

Remove dash top crash pad, de-mister vents and windscreen assembly from your car. Fit windscreen assembly, as in Figure 5, using U-bolts. Spacer blocks may be used if necessary to obtain the correct angle, but final adjustment cannot be made until the door glasses are fitted.

Fit dash top crash pad, fit de-mister vents, and connect up heater to de-mister pipes. The retaining studs on the crash pad are not really necessary and may be cut off to simplify fitting, or may be left to hold down the crash pad.

If the crash pad is in poor condition it can be repaired with body filler and

Re-covered in vinyl or leather.

12 FITTING THE LIGHTS

Fit headlights, sidelights, and rear light units. Various types of rear light may be used, e.g. VW Polo, Chevette, Hillman Hunter, Imp, Fiat 850 Sport, TR7, etc.

The number plate light is from the Spitfire Mk4, Triumph Dolomite, or Rover 2000. Alternatively, you may wish to fit a different type of smaller dimensions.

13 BULKHEAD FITTINGS

All bulkhead fittings (pedal assemblies, wiper motor, electrical equipment, etc.) are fitted to the Hurricane in the same relative positions as on the base car with the exception of the battery. When bolting components to the front bulkhead use a mastic sealant around the bolts to prevent fumes or water leaking into the cockpit. Use the sealant only when final fitting, after painting.

If using the aluminium master cylinders fitted to most Triumphs, bear in mind that the tops nearly always leak. To prevent your newly painted bulkhead being ruined by brake fluid (it is a very effective paint stripper) we recommend the use of silicon brake fluid which does not affect paint and does not deteriorate.

NOTE: Only use silicon brake fluid if you have changed all brake components in your re-build. The silicon brake fluid will react with any remaining standard fluid and will cause problems.

14 STEERING COLUMN

The steering column is bolted to the steel dashboard frame using the original clamp. Use shims to achieve a comfortable driving posture (don't forget the steering column is telescopic, refer to manual). The secondary support should be bolted to the bulkhead, some models will require modification to achieve this.

15 DOOR LOCKS

Door locks and handles can now be fitted. These fit in the same way as the base car. Pre-1970 door handles are much more reliable than later units, so it is best to fit these if available. The operating bolt will need to be replaced with one about half and inch longer to allow for the wider doors used in the Hurricane.

Fit the door latch plate to the door shut and adjust so that the door closes flush with the bodywork. Fit door check straps, i.e. leather or webbing.

16 FITTING THE DOOR WINDOWS AND THEIR MECHANISMS

This is probably the most difficult job in building the Hurricane. Although all the parts fit in the same way as on the original doors, there are several points to take note of:

a) Work on one door at a time. It helps to have reference to the other door in case you forget how a part is fitted.

b) If you have difficulty dismantling the door components, cut a large hole in the outer door skin so you can see clearly the type of fixings used. Sometimes special clips are used.

c) Shorten the window channels at the top and bottom by a quarter of an inch. This makes fitting and adjustment easier.

d) GT6 and Spitfire Mk4 models will require new windows with a rounded top rear corner to match the Spitfire Mk3 hood. Most glass works can supply these in laminated or toughened flat glass if given a template. You should ask for the edges to be ground to give a safe edge.

e) When fitting window inner and outer seals, do not use the original clip fixings. Fit the outer seal first using very small self tapping screws, after carefully drilling holes for them in the returned edge of the outer door skin. The inner seal can now be glued on using trim adhesive.

f) It may be found necessary to slightly lengthen the window aperture at the top of the door by using a hand file.

17 ADJUSTING THE DOORS

With the added weight of the glass and winder mechanisms, the doors will need readjustment. Slacken off the bolts mounting the hinge to the body. Lift the door slightly higher than the required position. Re-tighten the bolts. You may need to try this several times before the door is correctly positioned. An assistant will be required while adjusting the doors.

The doors may need adjustment again after a week or two of use, but they will hold their adjustment better if a gasket is used between the hinge and the bodywork.

18 PAINTING THE BODYWORK

Now is the time to think about painting the car. You can either paint the car as it is and be very careful not to damage the paint when drilling holes and fitting components, or you can trial-fit the various components, remove them from the car, then refit them once the car is painted.

The first method is not recommended as it is inevitable that the paint will be scratched or chipped during assembly. The second method is more time consuming, but it is the only way to get a professional result.

19 ELECTRICAL EQUIPMENT AND DASHBOARD

Before removing the wiring loom, mark the wires by writing the details on tape tags if their use is not obvious from the wiring diagram in your workshop manual. In particular, take note of switch wiring as this is not always made clear in wiring diagrams.

When you have removed the wiring loom from the car, clean it thoroughly, and repair any breaks in the outer sheathing with electrical tape. Most fires in cars are initiated by electrical faults, so make sure that your wiring is safe. Replace any broken terminals using soldered connections. Soldering is much more reliable than crimped connections.

The loom can now be fitted to the car. The front-to-rear section of the wiring loom can be passed through the left-hand sill section, once suitable holes have been cut. Alternatively, the wiring can be fitted alongside the sill section beneath the carpets.

Connect up the wires for the gearbox reversing light switch and overdrive solenoid. Cut a hole in the gearbox cover for the gear lever. This is marked for Spitfire models. GT6 based cars have the gear lever further to the rear. Fit the gearbox cover and seal using self-tapping screws.

Connect up the wiring for the lights, voltage regulator, horns, relays, and to all electrical equipment.

Cut holes in the dashboard for instruments and switches. The dash can be covered in padded vinyl or veneered and varnished.

Fit instruments, switches, wiring, speedo rev counter, choke cables, and then fit the dashboard to its steel frame using chrome dome headed bolts, or hidden screws from behind. You can space the dashboard out at its lower edge if required.

Ensure that all dashboard instruments are connected to an earth wire (these are colour coded black). The starter solenoid and rear light units also require earth wires, but these are usually fitted as standard in the loom.

There are two points on the bulkhead where the earth wiring from the loom is earthed to the bodywork on the base car. These wires should be earthed to a point on the chassis. The heavy duty earth cable from the engine unit should also be connected to the chassis.

The battery box is usually fitted in the boot, but on Spitfire based cars there is room to fit it alongside the radiator, bolted to the chassis. The earth lead is connected to the chassis and the positive lead is connected to the solenoid.

Before connecting the battery re-check all the wiring and ensure that there are no stray wires. It is a wise precaution to get an auto-electrician to check your work. Do not fit the battery until all the wiring is completed and checked.

When working on the car always disconnect the battery. A battery master switch fitted at this stage will make life a lot easier.

20 GETTING THINGS WORKING

Fit the exhaust system. If fitting a new one, the twin box SAH or Triumphtune exhausts are much better than the horrid looking Triumph system, and prices are comparable.

Connect up the heater pipes. Connect the throttle and choke cables. Fit the brake and clutch pipes to the master cylinders and bleed the system. Connect the solenoid to the starter motor cable.

Fit the fuel tank and connect the pipes at both ends of the fuel line. Fit the filler cap, pour in some petrol and check for leaks. Pump fuel into the carbs using the lever on the fuel pump. If petrol leaks from the carbs, tap the carburettor body with a spanner to seat the float valve.

Check the engine, gearbox, and diff oil and check the water level in the radiator.

Connect up the battery.

Now check that all the electrical equipment is working, and check that you are getting ignition by opening the contact breaker points with the ignition on. If you are getting a spark, then you can start the engine. If you do not get a spark, first check that the solenoid body is earthed.

If indicators, stop lights, or side lights do not work properly (eg. rear side light goes out when brake light is applied) the fault is nearly always a poor earth connection.

21 RADIATOR INTAKE AND OUTLET GRILLS

The radiator intake and outlet grills provided by Caburn Engineering should be fitted to the apertures using self tapping screws.

22 SUSPENSION MODIFICATIONS

You will probably want to fit wider wheels than standard on your Hurricane. Up to 6J by 13 wheels with 205/60 or 185/70 by 13 tyres can be accommodated within the bodywork.

If you are fitting wider wheels, check the front wheels for clearance on full lock. You may need to cut away part of the inner wheelarch. Also, check that the rear wheels do not foul on the radius arms. Spacers may be necessary with some wheels.

With wider wheels, it is advantageous to change the camber angle of the front wheels to zero degrees, or even slightly negative for competition use. To do this, use extra spacers (usually about 0.3 0.5 mm is sufficient) between the chassis and lower wishbone mountings.

Lowered front springs are also recommended. Standard ones can be lowered by cutting off one coil or more, but lowered and uprated springs can be obtained from SAH or Triumphtune, or other suppliers.

To improve the handling of cars based on the Spitfire Mkl - 3 and GT6 Mkl, the simplest and cheapest method is to fit the Spitfire Mk4 rear spring and front anti-roll bar, together with Spax adjustable shock absorbers fitted front and rear. In addition, fit lowered and uprated front springs and a set of five and a half inch J wheels with a decent set of tyres, and set the front wheel camber to zero degrees. With these simple modifications, you will no longer have to put up with XR3i's getting away from you at roundabouts!

The rear transverse leaf spring may need to be modified to achieve the correct ride height and degree of softness. This can be achieved only by trial and error, by removing leaves from the spring if necessary. Unfortunately, there is no simple formula that can be applied to every spring, as all seem to be different. In some cases the spring is correct as standard, and in others it is necessary to remove one or two of the leaves to achieve a comfortable ride, and then to have the spring re-arched to get the correct ride height.

As the car will settle on its springs after a few miles driving,, it is wise to try the spring as standard at first, and to modify it only if necessary. In the case of GT6 based cars, it will save a lot of time if a Spitfire rear spring is fitted.

The ride height is correct when the distance from the centre of the rear wheel hub to a point on the wheelarch vertically above is about fourteen inches. This measurement should be taken with the car in a finished state, complete with spare wheel and any other items normally carried in the car, and after the car has been driven to allow the suspension to settle.

23 CARPETS AND TRIM

Carpets fit as per standard instructions.

Door trim panels are best fitted to the door using stainless steel countersunk self tapping screws and cup washers. These are obtainable from boat shops or trim suppliers.

The standard door seals do fit, but in some cases the fibreglass edge may need to be ground thinner in places. Special door seals are available from specialist trim suppliers to fit the thicker fibreglass sections. We can supply these if you have trouble locating a source. The top rear edge of the door seal may need to be retained by a small screw.

The dash to crash pad, windscreen surround and door cappings may be re-covered in vinyl or leather to match the rest of the interior trim. The lower edge of the dashboard can be finished off using an aluminium j-section strip covered in trim material.

24 SEATS AND SEAT BELTS

Fit the standard Spitfire seats. Unless you are very tall, you will probably find the seating position more comfortable if you raise the seat by about an inch by using wooden blocks under the seat runners. Seats can be re-covered if in bad condition or torn. Later Mk4 Spitfires use reclining seats with head restraints.

Earlier type seats look more "in period" and are surprisingly comfortable, with good sideways support.

Seat belts are fitted in the same position as the Spitfire, but it is essential to make up steel backing plates for the rear inner wing mounting points. These should be at least 2" x 2". They are not necessary if the roll bar is being used as mountings are provided on the roll bar.

The inertia reel mechanism (if fitted) should be bolted to the rear cross-member at its junction with the sill, but this can prevent the seat from being adjusted to its most rearward position. If fitted anywhere else, use a steel backing plate.

25 HOOD AND HOODFRAME

Hoodframes from the Spitfire Mk l, 2 or 3 may be used and are fitted in the same way as the Spitfire. The Mk3 uses a folding hood mechanism, which is much more convenient than the earlier type, but cannot be used with the optional roll bar.

Spitfire Mk4 hoods may be used only if the rear cockpit coaming is cut back as shown in Figure 8.

 

Figure 8

 

 

 

WE HOPE YOU HAVE ENJOYED BUILDING YOUR HURRICANE

NOW GO ENJOY DRIVING IT!

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