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Stripping the Remains and Assessing the Damage

Module by: Andrew R. Barron. E-mail the author

The demise of this particular 1971 Lotus Seven S4 occurred as a result of a fuel leak in the engine bay. Despite turning off the engine and ignition, the fire consumed the bonnet, both wings, and the majority of the cockpit moldings, as well as the steering column, windscreen, seats, radiator, carburetor, and all gauges and switches. Once the decision to restore the car was taken, the first step was to completely strip everything down to the bare chassis.

Removal of the remains of the body

The only remaining parts of the fiberglass bodywork were a portion of the main tub section and part of the seat areas (Figure 1 - Figure 3). One consequence of the fire was that the true color of the car was revealed, as the paint had pealed off in several areas. As with some of its other models, Lotus had experimented with self-colored fiberglass composites, in which the color was incorporated into the gel coat. Instead of the traditional British racing green, the original fiberglass had been bright orangish red (see Figure 2), which was one of the original colors, including: white, red, yellow, pale blue, and the very seventies lime green. According to Lotus records this car was originally red. At this point it is intended that the restored car be returned to the original bright red as a homage to the cars original configuration.

Figure 1: The fiberglass remains after removal from the chassis, viewed from the front showing the remains of the passengers seat area.
Figure 1 (graphics1.jpg)
Figure 2: The fiberglass remains after removal from the chassis, viewed from the drivers side and showing traces of the original bright red color below the British racing green paint.
Figure 2 (graphics2.jpg)
Figure 3: The fiberglass remains after removal from the chassis, viewed from the rear and showing the rear wheel mounting (A) and the positions of the rear light clusters (B).
Figure 3 (graphics3.jpg)

Prior to removal of the remains of the body from the chassis, the fire destroyed battery had to be removed, along with residual battery cables. The battery tray is bolted through the boot floor, and was considerably corroded (Figure 4) as a consequence of the damage to the battery (Figure 5). Removal of the spare wheel is accomplished by unscrewing the two long bolts that pass through the rear body into the threads on the spare wheel bracket (Figure 6).

Figure 4: The corroded battery tray from the Lotus Seven S4.
Figure 4 (graphics5.jpg)
Figure 5: The remains of the battery taken from the Lotus Seven S4 after the fire. Caution must be taken in handling and disposing of lead-acid batteries.
Figure 5 (graphics4.jpg)
Figure 6: The spare wheel bracket with the original Texas number plate.
Figure 6 (graphics6.jpg)

The body remains were removed from the chassis by removal of the mounting bolts. Detachment of the fuel filler hose was also required in order to free the fiberglass from the chassis. Once separated, the rear light clusters were unscrewed and found to be intact (Figure 7), although the wiring will need replacing.

Figure 7: The rear light clusters.
Figure 7 (graphics8.jpg)

The fire had consumed the copper core of the radiator, and a whole new radiator will be needed. The radiator support brackets were removed (Figure 8).

Figure 8: The radiator support brackets.
Figure 8 (graphics9.jpg)

The rubber brake lines to the front brake calipers had been destroyed in the fire, and the plastic reservoirs of the brake and clutch master cylinders were badly damaged. They were removed from the metal bulkhead, as was the pedal unit (Figure 9), and the remains of the handbrake.

Figure 9: The pedal unit: throttle (A), brake (B), and clutch (C).
Figure 9 (graphics10.jpg)

Figure 10 - Figure 12 show various views of the rolling chassis after removal of the body and ancillary components. The wheels and tires in these pictures are from a Type 61 Formula Ford (to allow movement of the chassis) since the original tires had ruptured during the fire.

Figure 10: Left hand side of the rolling chassis.
Figure 10 (graphics11.jpg)
Figure 11: Front view of the rolling chassis.
Figure 11 (graphics12.jpg)
Figure 12: Right hand side of the rolling chassis.
Figure 12 (graphics13.jpg)

Wheels

With the car on jack stands, the original Brand Lotus wheels (Figure 13) were removed. Several of the tires had burst as a result of fire damage, and all of the road wheels showed smoke damage (Figure 14). No physical damage appears to have occurred as a consequence of the fire; however, one of the wheels shows some indication of damage due to curbing. As a consequence of being mounted at the back of the car and hence the furthest from the fire, the spare wheel showed only limited damage other than that expected for a wheel of its age (Figure 15). Each wheel will have to be cleaned and repainted or powder coated. No hubs had survived.

Figure 13: A copy of the original advertising for the Brand Lotus wheels (Lotus Cars, Ltd.).
Figure 13 (graphics14.jpg)
Figure 14: One of the fire damaged Brand Lotus alloy wheels.
Figure 14 (graphics15.jpg)
Figure 15: The Brand Lotus alloy wheel used as the spare.
Figure 15 (graphics16.jpg)

Rear axle, suspension, and fuel tank

In typical Lotus fashion several of the rear suspension pieces are designed to perform multiple tasks. For example, the bolt that attaches the top of the rear shock absorbers (dampers) to the chassis also holds the roll bar in. The tapered end of each bolt (Figure 16) fits in a hole in the sidewall of the roll bar (Figure 17). Once the car is on jack stands and the rear axle has been allowed to rest on the chassis (i.e., full droop), these bolts may be removed part way to facilitate removal of the roll bar.

Figure 16: The bolts used for the rear shocks that also hold the roll bar in place showing the rounded ends.
Figure 16 (graphics17.jpg)
Figure 17: Schematic showing the location of the rear upper spring/shock unit mounting combination with the roll bar retention bolt (Figure 16).
Figure 17 (graphics18.jpg)

Undoing the drive shaft at the differential allows it to be slid out of the gearbox; however, caution should be taken as this also allows the rear axle to tilt. It is a good idea to support the axle with a jack while all the rest of the suspension is removed. Care should also be taken when removing the upper radius arms (Figure 18), since this frees the entire rear suspension from the rear of the chassis.

Figure 18: The right hand lower radius arms (A) and one of the upper radius arms (B).
Figure 18 (graphics20.jpg)

Once the lower radius arms and the axle locating link (Figure 19) are removed the bolts to the shocks are removed from the axle allowing it to be removed from the chassis. With the axle removed, the shock/spring combination was coerced from the chassis with a rubber mallet. Although the rear shocks and springs (Figure 20) did not show as significant fire damage as those at the front, the springs in particular had appeared to sag, and so they are all to be replaced along with all the bushings.

Figure 19: The axle locating link.
Figure 19 (graphics21.jpg)
Figure 20: One of the rear shock absorber (damper)/spring sets removed from the car.
Figure 20 (graphics22.jpg)

With the axle removed (Figure 21), the fuel tank may be lowered after removal of the two bolts at the side (Figure 22B), and the fuel line. The two bolts at the top of the tank were removed when the body remains were detached (Figure 22A). The tank shows some fire damage with removal of paint (Figure 23) and the destruction of the fuel gauge sender unit (Figure 24).

Figure 21: The rear axle along with the exhaust and rear suspension components.
Figure 21 (graphics23.jpg)
Figure 22: The fuel tank in place after removal of the body remains, showing the position of the top (A) and side (B) mounting points. The rear section of the exhaust and silencer (muffler) may also be seen.
Figure 22 (graphics24.jpg)
Figure 23: The fuel tank after removal from the chassis.
Figure 23 (graphics25.jpg)
Figure 24: The remains of the fuel gauge sender unit on the top of the fuel tank.
Figure 24 (graphics26.jpg)

Front suspension

Removal of the wheels is followed by removal of the brake calipers (Figure 25) along with the brake hose so that the front suspension can be disassembled.

Figure 25: One of the brake calipers after removal from the front suspension.
Figure 25 (graphics27.jpg)

The bearing caps are removed by inserting a sharp pointed tool into the center hole and leveraging. Unfortunately, these required significant work since they had rusted in place. Under the cap, the retaining nut is held in place with a cotter pin. Removal of both of these allows the hub and bearings to be pulled off along with the brake disks. The disks were highly corroded (Figure 26) probably necessitating replacement. In contrast, the hubs can be reused once cleaned and with new bearings fitted. The disks are separated from the hubs by removing the four bolts.

Figure 26: One of the front brake disk/hub combinations along with the bearing race in place (A).
Figure 26 (graphics29.jpg)

The uprights are readily removed by unbolting both the lower trunnion and the upper ball joints (Figure 27). The lower part of the shock absorber/spring unit (Figure 28) is not attached to the upright or trunnion but attached to the two lower wishbone halves by a separate bolt. Once this is removed the shock is free to move, as are the lower wishbones. Each of the lower wishbones is attached to a threaded pin welded to the lower part of the front box section. Due to the fire damage, the metalastic bushings on the right hand side had become welded to the pins. This meant that a propane torch was needed to heat the bushings sufficiently to remove from the chassis (Figure 29).

Figure 27: One of the front Triumph-sourced uprights, with the trunnion (A) and ball joint (B) attached.
Figure 27 (graphics30.jpg)
Figure 28: One of the front shock absorber (damper)/spring sets removed from the car showing the heat damage to the spring.
Figure 28 (graphics31.jpg)
Figure 29: The rear lower wishbone (A) before removal from the chassis and the remains of the front bushing (B) still attached to the chassis prior to removal.
Figure 29 (graphics32.jpg)

The steering rack was still functioning despite the rubber gaiters being destroyed. The rack clamp insulators were also badly fire damaged and crumbled while being removed. Three of the four bolts holding the two rack clamps were readily loosened; however, the last (forward passenger side) sheered-off (Figure 30) and will have to be drilled out.

Figure 30: The front box section and steering rack mounting brackets (A) showing the single bolt (B) that sheered off while removing the steering rack.
Figure 30 (graphics33.jpg)

Engine and gear box

Without the fiberglass body, and with the rear axle and drive shaft already removed, the removal of the engine and gearbox is quiet easy. In addition to the six main bell housing-to-engine bolts the Ford 2821E gearbox is held to the chassis by a mount bolted through the chassis (Figure 31). Despite partial melting of the rubber mount, this was readily unbolted (Figure 32). Removal of the starter motor is necessary prior to uncoupling the gearbox from the engine. Once all the bolts were removed, the gearbox is slid back off the input shaft, until it is free of the clutch and flywheel. It may then be lifted out of the chassis, and set aside for further inspection.

Figure 31: A view of the gearbox in place prior to removal showing the position of the gearbox to chassis mount (A).
Figure 31 (graphics34.jpg)
Figure 32: The chassis mounting bracket for the gearbox rubber mount after removal of the gearbox.
Figure 32 (graphics35.jpg)

Prior to removal of the engine the intake manifold and remains of the fuel pump were detached. The upper housing of the Ford mechanical fuel pump had melted as a consequence of the fuel fire (Figure 33). The downdraft Weber 32DFM twin choke downdraught carburetor had melted during the fire (Figure 34) and become fused to the intake manifold (Figure 35). Removal of the intake manifold showed that the carburetor had actually melted and flowed through the manifold and into the intake ports on the head, resulting in etching of the head (Figure 36). This will be addressed during the engine rebuild. One of the intake manifold bolts was replaced to facilitate lifting the engine.

Figure 33: The remains of the mechanical fuel pump after the fire.
Figure 33 (graphics36.jpg)
Figure 34: The remains of the Weber 32DFM twin choke downdraught carburetor and the intake manifold in place on the engine.
Figure 34 (graphics37.jpg)
Figure 35: The melted Weber 32DFM twin choke downdraught carburetor fused to the intake manifold showing the damage to the latter at cylinder 2 and 3 ports in particular.
Figure 35 (graphics38.jpg)
Figure 36: A view inside the #3 cylinder intake ports showing the damage caused to the iron head by the molten aluminum metal from the carburetor.
Figure 36 (graphics39.jpg)

The exhaust system consists of two 2-into-1 manifolds (Figure 37) that join outside the chassis to a 2-into-1 collector that is part of the side pipe. Having removed the rear components of the exhaust (Figure 22) to facilitate the removal of the rear axle and suspension, the manifolds were removed (Figure 38) and a bolt was replaced to facilitate lifting the engine.

Figure 37: The two 2-into-1 exhaust manifolds in place.
Figure 37 (graphics40.jpg)
Figure 38: The two 2-into-1 exhaust manifolds after removal.
Figure 38 (graphics41.jpg)

As with other Sevens, the engine in the Series 4 is held by two mounting brackets that are bolted via engine mounting rubbers, which are bolted to the chassis side rail with two bolts each (Figure 39). The engine mounting brackets (Figure 40) are bolted to the engine using four bolts per bracket. Once an engine hoist supported the Ford crossflow engine all of the mounting bolts were removed to allow the engine to swing free of the chassis (Figure 41).

Figure 39: View of the engine in place showing one of the engine mounting brackets (A).
Figure 39 (graphics42.jpg)
Figure 40: One of the engine mounting brackets after removal.
Figure 40 (graphics43.jpg)
Figure 41: The 1600 cc Ford crossflow engine after removal from the chassis.
Figure 41 (graphics44.jpg)

Miscellaneous components

The handbrake multiplying lever (Figure 42) was removed by unscrewing the two bolts through the chassis mounting bracket and the chassis. All other brackets and bolts were removed from the scuttle (Figure 43).

Figure 42: The handbrake multiplying lever shown with the remains of the secondary cable to the rear axle and the pivot bolt. The chassis mounted pivot is shown in the upper left of the picture.
Figure 42 (graphics45.jpg)
Figure 43: Fuse box brackets and the remains of a solenoid on the passenger side scuttle.
Figure 43 (graphics46.jpg)

Removal of side panels

The Seven S4 chassis is actually comprised of a tubular structure reinforced by two sheet steel side panels that are spot welded along the side and underside of the chassis. Unfortunately, the passenger’s (right hand) side panel was significantly warped due to the melting of an ignition module that had been attached to it. In addition, there were signs of corrosion of the tubular chassis below the sheet panel (Figure 44), and it was decided to remove both panels and make new ones.

Figure 44: The lower passenger side showing the presence of corrosion on the side panel and the chassis beneath.
Figure 44 (graphics47.jpg)

Using a wire brush to clean the surface rust revealed the position of each spot weld. Using a pilot point drill bit, each weld was drilled out allowing for the sheet to be removed. In most cases only a small dimple is formed in the chassis (Figure 45); however, in some cases the bit resulted in a small hole in the chassis rail. These will have to be repaired with the replacement of new side panels.

Figure 45: Two of the dimples remaining after drilling the original spot welds used to attach the side panel to the side of the chassis.
Figure 45 (graphics48.jpg)

While the chassis was upside down to drill out the spot welds it was found that the lower front box section had corroded resulting in the destruction of a significant portion of the lower half (Figure 46). The two side panels are badly corroded (Figure 47 and Figure 48) and will be replaced. Figure 49Figure 52 shows a range of views of the bare chassis.

Figure 46: Underside of front box section showing significant corrosion.
Figure 46 (graphics49.jpg)
Figure 47: The outside of the two chassis panels of the Lotus Seven S4 after removal from the chassis. The panel from the right hand side of the car (A) shows more external corrosion, while the exhaust outlet is shown in the panel from the left hand side of the car (B). Note that the lower edges of the panels are facing each other.
Figure 47 (graphics50.jpg)
Figure 48: The inside of the two chassis panels of the Lotus Seven S4 after removal from the chassis. The panel from the right hand side of the car (A) shows more corrosion, while panel from the left hand side of the car (B) shows more smoke damage. Note that the top edges of the panels are facing each other.
Figure 48 (graphics51.jpg)
Figure 49: A view of the left hand side of the bare chassis (see Figure 10 for comparison).
Figure 49 (graphics52.jpg)
Figure 50: A view of the front of the bare chassis (see Figure 11 for comparison).
Figure 50 (graphics53.jpg)
Figure 51: A view of the right hand side of the bare chassis (see Figure 12 for comparison).
Figure 51 (graphics54.jpg)
Figure 52: A view of the rear of the bare chassis (see Figure 22 for comparison).
Figure 52 (graphics55.jpg)

Bibliography

  • T. Weale, Lotus Seven, Osprey Automotive Publishing, UK (1991).
  • D. Ortenburger, Legend of the Lotus Seven, Mercian Press (1987).

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