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Lotus Elise / Lotus Exige. Instruction - part 7

Page 2

Lotus Service Notes

Section BQ

Body Panels

Door

shell

Windscreen Sill panel

Front access frame

panel Rear

window

shroud

Engine

cover lid

Front

clamshell

Cabin rear

Door hinge bulkhead

cover panel

Rear clamshell

Front crash

structure

Chassis frame

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Lotus Service Notes

Section BQ

BQ.1 - GENERAL DESCRIPTION

The body panels of the Lotus Elise are constructed of composite materials, with the external panels not

being required to contribute to chassis rigidity. The panels are attached to the aluminium chassis and/or other

body panels either by elastomeric polyurethane adhesive, or in the case of the front and rear clamshells, are

bolted on for ease of dis-assembly and access to chassis parts. The composite mouldings are manufactured

by one of several processes (see later) dependent on application, with a nominal thickness of 2.2 - 2.5 mm.

The windscreen frame incorporates foam beams to create closed box sections for optimum strength and a

‘crash structure’ bonded to the front of the chassis incorporates longitudinal box sections to provide speciﬁc

crush characteristics and absorb crash impact by progressive collapse. This structure also acts as a mounting

and duct for the engine cooling radiator which is mounted horizontally on its top surface.

BQ.2 - LOTUS COMPOSITE BODY FEATURES

Composite structures have the ability to absorb high impact loads by progressive collapse, with impact

damage being localised. In vehicle accidents this feature protects the occupants from injurious shock loads and

greatly reduces the danger of entrapment by deformation of steel body panels. This behaviour also facilitates

repair by either replacing the damaged bonded or bolt on panels, and/or integrating a replacement section

with the undamaged area, using recognised approved methods which restore the panel to its original condition

without residual strain or distortion.

The manufacturing process enables the thickness of composite mouldings to be varied in order to provide

efﬁcient structures of high strength and low weight. Composites will not corrode, so the strength of composite

components is retained regardless of age, unless physical damage is sustained. On the Elise, the body con-

struction features an assembly of mouldings to form a single piece for the whole of the nose and front wings,

and a similar assembly for the whole of the rear body aft of the doors. These two 'clamshells' are ﬁxed using

threaded fasteners to permit easy removal for access to chassis or powertrain components, or to allow simple

and economic accident repair. Other composite mouldings include the door shells, sills, front compartment

lid, windscreen frame and rear bulkhead, some panels being bonded to the aluminium alloy chassis with an

elastomeric adhesive.

A composite panel may return to its original shape after deﬂection, but beyond a certain level of ﬂexibility,

such treatment may result in the formation of surface cracks which may not be immediately apparent due to

the masking effect of the paint ﬁlm. A steel panel similarly treated would become dented or deformed. The

cracking may be conﬁned to the surface layer with no reduction in panel strength, but if the damage is more

severe the composite structure below the surface may be weakened. Localised repairs can be made in either

case. Possible causes of surface cracking include:

Vehicle collision;

Sitting, leaning heavily or pushing on the body or any composite panel;

Knocking doors against obstructions when opening;

Dropping objects onto a panel;

Allowing unrestrained items to roll about in a luggage compartment;

Fitting a front access panel or closing the engine cover onto projecting objects, e.g. luggage or tools;

Applying excessive force to parts attached to composite panels e.g. mirrors, locks, aerial etc. (inc. action

byvandals).

Incorrect jacking.

The composite body panels of the Elise are manufactured by one of several processes dependent on the

requirements of the panel concerned:

The front and rear clamshells, sill panels, windscreen frame, door outer panels, hard top roof outer panel

and front crash structure are produced by Injection Compression System Resin Transfer Moulding (ICS-

RTM), whereby a mix of polyester resin and glass ﬁbres is injected into a heated, chrome steel surfaced,

closed mould. After ﬁlling, the gap between the two halves of the mould is then reduced in order to com-

press the moulding and ensure complete material ﬂow and consistent structural quality. Panel thickness

is a nominal 2.2 mm. The absence of the 'gel coat' used with other processes results in much greater

resistance to surface damage, and minimum surface preparation for before painting.

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Lotus Service Notes

Section BQ

The front access panels, engine cover lid, door hinge panels, door and roof inners and rear window shroud

are produced from Low Pressure Sheet Moulding Compound (LPSMC), whereby ﬂat sheets of composite

material are formed using heated, chrome steel surfaced moulds to produce panels with a nominal thick-

ness of 2.5 mm.

A third process is used for the cabin rear bulkhead, bootbox and radiator mounting panel where the panel

surface is not primarily visible. These panels are produced by a Polyurethane Structural Reaction Injec-

tion Moulding (PU SRIM) process.

Body panels unique to the Exige model, including front and rear clamshells, door hinge cover panels and

tailgate panel, are 'hand lay' composite mouldings with a nominal thickness of 2.5 mm.

Whichever production process applies, conventional composite repair techniques can be used to rectify

structural or surface damage whenever repairs can be determined as being more economic than panel replace-

ment.

BQ.3 - BODYCARE

The acrylic enamel paint ﬁnish of the Elise is extremely resistant to all normal forms of atmospheric attack.

Following the simple maintenance procedure summarised below will help retain the gloss, colour and protective

properties of the paint throughout the life of the vehicle. However, car ﬁnishes are not immune to damage, and

amongst the more common causes of deterioration are:

Atmospheric contaminants; dust, soot, ash, and acidic or alkaline aerosol mist can chemically attack

paint.

Abrasion; blowing sand and dust, or a dirty washing cloth.

Tree sap and insect ﬂuids; can form a water-insoluble polymer that adheres to the paint.

Bird excrement; highly acidic or alkaline, they can chemically etch the paint. Wash off immediately.

Leaves; contain tannic acid which can stain light ﬁnishes.

Impact damage; granite chippings thrown up from poor or recently dressed road surfaces can subject the

body to severe localised impact, and result in paint chips, especially around the vulnerable frontal panels.

Do not follow other vehicles too closely in such circumstances.

Washing

Lotus recommends that the car be hand washed, using the following instructions:

Many contaminants are water soluble and can be removed before any harm occurs by thorough washing

with plenty of lukewarm water, together with a proprietary car wash additive (household detergent and washing

up liquid can contain corrosive salts, and will remove wax and accelerate oxidation). Frequent washing is the

best safeguard against both seen and invisible contaminants. Wash in the shade, and use a cotton chenille

wash mitt or a sponge rinsed frequently to minimise entrapment of dirt particles. Use a straight back and forth

washing motion to avoid swirled micro scratches, and rinse thoroughly.

In order to minimise degradation from road salt, the underside of the chassis should be rinsed with clean

water as soon as possible after driving on treated roads. Many fuel ﬁlling stations offer pressure washing facili-

ties ideal for this purpose, but to not use on the painted bodywork or soft top roof.

Soft Top Roof:

1. Careful vacuuming of the soft top before washing may be helpful in removing excess dust and other foreign

particles.

2. Wash in partial shade rather than strong sunlight, and wet the whole car before tackling the soft top.

3. Using only clean lukewarm water and a sponge (a chamois or cloth will leave lint, and a brush may abrade

the threads) wash the entire top uniformly. Do NOT use a detergent, which may affect the waterprooﬁng

properties of the material.

4. Rinse the whole car to remove all soap from the fabric and to prevent streaking on the car bodywork.

5. Remove surface water with a sponge and allow to air dry in direct sunlight. Ensure that the roof is fully dry

before stowing, as prolonged stowage of a wet or damp roof will promote rotting of the fabric.

Keeping the soft top clean by regular washing will enhance the life and maintain the appearance of the

roof, and facilitate subsequent cleaning. The use of stronger cleansers should be left to professionals experi-

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Lotus Service Notes

Section BQ

enced in handling this type of fabric as discoloration and degradation of the special protective inner layer may

result. The application of wax ﬁnishes, dressings or preservatives will cause stains which are difﬁcult to remove

and therefore should be avoided.

Paintwork Polishing

Eventually some loss of gloss, and an accumulation of trafﬁc ﬁlm, will occur. At this stage, after normal

washing, the application of a good quality liquid polish will restore the original lustre of the paint ﬁlm. Higher

gloss of the paint ﬁnish, and added protection against contamination, can be obtained by the use of a wax

polish; however, this can only be used successfully on a clean surface, from which the previous application has

been removed with white spirit or a liquid polish cleaner.

Ventilation

Water lying on the paint surface for a lengthy period will eventually penetrate the paint ﬁlm. Although the

effects will not be visible immediately, a deterioration in the protective properties of the paint ﬁlm will ultimately

result. It is not recommended to store a wet car in a poorly ventilated garage. If good ventilation cannot be

provided, storage outside on a hard standing or under a carport is to be preferred.

BQ.4 - ACCIDENT DAMAGE ASSESSMENT

The repair method to be employed in the rectiﬁcation of accident damage to composite panels, is to be

assessed reletive to the particular panel and its method of attachment:

Bolt-on Panels: - Front Clamshell;

- Rear Clamshell;

- Door Shells;

- Front Body Access Panels;

- Engine Cover Lid;

- Door Hinge Cover Panels;

- Rear Window Shroud;

- Hard Top Roof.

These panels are secured by threaded fasteners and are easily removed for access to the back of any

damaged area for repair by conventional composite techniques. Instructions for the removal and reﬁtment of

these panels are contained in section BR.

Bonded-on Panels: - Windscreen Frame;

- LH & RH Sill Panels;

- Front Crash Structure;

- Rear Bulkhead

These panels are bonded to the chassis or to other panels using a ﬂexible polyurethane adhesive which

must be cut before the panel may be removed. In some cases, it may be necessary to partially remove another

panel before the subject panel can be released. It is not generally economic to attempt to remove a bonded

panel intact for later re-ﬁtment.

The integrity of the front crash structure is crucial to the safety of the car in a frontal collision, and it is rec-

ommended not to attempt any major repair of this component. The damaged structure should be cut from the

front of the chassis, and a new assembly bonded into position. The shape and positioning of the windscreen

frame is crucial to the ﬁt of the windscreen and sealing of the soft top roof, such that the only repairs which

should be considered for this panel are cosmetic and superﬁcial; any structural damage should entail panel

replacement.

The sill panels include the ‘A’ and ‘B’ posts, and involve much labour time to replace. Localised repairs

should be performed whenever possible, although access to the inside surface of some parts of the panels is

not freely available.

Note that if damage is such as to require replacement of the chassis, replacement chassis assemblies are

provided only as a 'partial body assembly' which includes jig bonded front crash structure, windscreen frame,

side sills and rear bulkhead. The roof hoop and rear subframe are also included, as are the pipes, hoses and

cables routed through the sills.

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