CHASSIS SECTION AQ Sub-Section Page General Description AQ.1 2 Chassis Straightness Check AQ.2 5 Rear Subframe AQ.3 6 Seat Belt Anchor Frame & Rear Stays AQ.4 8 Superficial Cosmetic Repairs AQ.5 10 First Issued 25 th July 2013 Page 1
AQ.1 - GENERAL DESCRIPTION Seat belt mounting anchor frame Composite Scuttle Seat mounting crash structure beam extrusion Seat belt mounting frame backstay Door hinge mounting Sill extrustion Main siderail Fuel tank bay Steel rear subframe b421 The chassis frame of the Lotus Exige S is constructed primarily from aluminium alloy extrusions and formed alloy sheet, with the various sections bonded together using an epoxy adhesive with secondary drive-in fasteners. The basic chassis unit includes the passenger cell, front suspension mountings, fuel tank housing, and mid mounted engine bay, with a fabricated sheet steel rear subframe bolting to the rear of the engine bay to provide rear suspension mountings and rear body support. A tubular steel seat belt mounting frame is bolted to the top of the chassis structure and incorporates a roof hoop for additional occupant protection. The cabin rear bulkhead, body sills (inc. 'B' posts), front energy absorbing crash structure and scuttle/windscreen mounting frame, are all constructed from glass fibre composite and are bonded to the chassis structure using an elastomeric adhesive. The front and rear outer body clamshells are each constructed from glass fibre composite mouldings, fixed to the body and chassis structure with threaded fasteners to facilitate service access and economic repair. Page 2
Chassis assembly exploded view Step panels Floor panel Fuel tank bay panel Tank rear cross-member Door hinge post Upper wishbone rear leg Seat back cross-member Upper wishbone forward leg Sill extrusion Front cross-member Subframe adaptor plate Lower wishbone forward leg Lower wishbone rear leg Sill extension Side-rail member Two main chassis side-rail extrusions run along each side of the passenger compartment between the front and rear suspension mountings, splaying outwards towards the rear before curving inwards around the fuel tank bay and terminating at each side of the engine bay in a vertical section to provide engine mounting platforms and a flange to which the rear subframe is attached. To enhance cockpit access, the height of the siderails is reduced in the door area, and internal reinforcement added in order to maintain beam strength and torsional rigidity. Running along the underside of the side-rails from the front suspension cross-member to the fuel tank bay are sill extrusions which carry the cockpit floor panel. The single skin floor panel is swaged for stiffness, and is reinforced by a ribbed transverse extrusion running across the inside of the tub, which also provides for the seat mountings. Behind the passenger cell, the siderails are linked by a pair of transverse crossmembers which are used in conjunction with a folded sheet upper panel to form an open bottomed fuel tank cell with a detachable, screw fixed, closing panel with swaged lightening holes. Note that this lower panel contributes to the structural integrity of the chassis, such that the vehicle should not be operated without it fitted. The rear ends of the side-rails are joined behind the engine bay by a galvanised sheet steel fabricated subframe which provides mountings for the rear suspension pivots and damper abutment, engine rear stabiliser and exhaust muffler. At the front of the passenger compartment, four transverse extrusion beams are used to provide mountings for the front suspension pivots, and house the steering rack, with an upright section used each side to anchor the top of the spring/damper unit. Five interlinked extruded floor sections together with additional extrusions connect the transverse beams to form an open topped space to house the heater/a.c. unit. An extruded scuttle beam links the tops of the siderails at the front of the cockpit, and is reinforced by a panel extending to the steering rack crossmember. These elements are used to mount the steering column and pedal box, with a vertical extrusion fixed to each end of the scuttle beam to carry the door hinge pillar. To the front end of the chassis is bonded a glass fibre composite 'crash structure' which incorporates tubular Page 3
sections designed to dissipate collision energy and control the rate of deceleration sustained by the occupants. Ducting and mountings for the horizontally positioned engine cooling radiator are also incorporated in this structure. Servicing and Repairs The bonded and riveted alloy chassis structure described above is considered a non-serviceable single unit, jig built to fine tolerances, to which no structural repairs are approved. Superficial, cosmetic, or non-structural localised damage may be cosmetically repaired as necessary, but in the case of accident damage resulting in significant bending, tearing or distortion of the aluminium chassis, such that the specified suspension geometry cannot be achieved by the standard range of suspension adjustment provided, the recommended repair is to renew the partial body assembly, which comprises the chassis, rear subframe and the seat belt mounting frame together with jig bonded composite rear bulkhead, body sills, windscreen frame and crash structure. Also included are the radiator feed and return pipes in the chassis side-rails, and those pipes and cables routed through the sills, including the heater and a.c. pipes, battery cable, clutch and brake pipes, and brake servo and oil cooler hoses. Page 4
AQ.2 - CHASSIS STRAIGHTNESS CHECK In the absence of visual damage, the chassis may be checked for twist or distortion by utilising the tooling holes in the underside of the main side rails. If computer processed laser measuring equipment is not available, manual checks can be made with reference to an accurately level ground plane, e.g. an accurately set and maintained suspension geometry ramp/lift. Position the car on the lift, and proceed as follows: 1. Identify the tooling holes in the lower surface of each chassis main side rail. At the front end, between the suspension wishbone pivots, and at the extreme rear end of each rail. 2. Measure the height of each tooling hole above the reference plane and use jacks to adjust the height of the chassis in order to equalise any three of these dimensions. 3. Measure the deviation of the fourth dimension from the other three. Maximum service deviation = ± 2.0 mm. 4. Repeat operations (2) and (3) for each combination of corners to result in four values for the 'fourth' dimension deviation. If any one of these exceeds the service specification, the chassis should be considered damaged and replaced by a partial body assembly. FRONT REAR Tooling hole Tooling hole Front wishbone Rear wishbone a27/27a Page 5
AQ.3 - REAR SUBFRAME The rear ends of the chassis side-rails are linked by a fabricated sheet steel subframe which provides mountings for the rear body section, rear suspension pivots, engine rear stabiliser, exhaust muffler and seat belt mounting frame struts. The subframe is secured to the side-rails by two M12 bolts at each side, with an anti-corrosion shim plate interposed. Upper fixing bolt Chassis flange SBAF stay fixings Nut plate Anti-corrosion shim plate Lower fixing bolt, washer and nut Rear subframe (All ancillary components removed for clarity) Removal: 1. Remove the rear clamshell; refer to service notes section BT.7 for further information. 2. 3. 4. 5. Remove the powertrain assembly; refer to service notes section EM.6 for further information. Disconnect the inertia switch harness plug at the RH seat belt anchor frame. Remove exhaust heatshields and rear silencer. Release the M10 x 100 bolts securing LH and RH rear lower wishbone brackets to the rear chassis cross member 6. Release any harnesses or wires attached to the subframe that are part of the main vehicle harness assembly and ensure that they are positioned such that no damage will be incurred when the subframe is withdrawn from the chassis. 7. 8. 9. Disconnect the bodyside front to rear LH and RH brake pipes from the rear to flexi hose connector pipes and cap all exposed ends. Ensure all previously detached hoses and pipes are positioned such that no damage will be incurred when the subframe is withdrawn from the chassis. Release the M10 x 60 bolts and M10 flanged nuts securing LH & RH SBAF (Seat Belt Anchor Frame) stays to subframe brackets. 10. Release and discard the M10 x 35 patch bolts securing the LH & RH SBAF stays to the SBAF/rear bulkhead panel and withdraw both stays. 11. Ensure rear subframe is supported before removing chassis fixing bolts. Page 6
12. From the upper rear of the LH & RH chassis flanges, release and discard the M12 x 65 hex flange headed patch bolts securing the chassis to the subframes integral mounting brackets and remove the bolts nut plate fixings from their slots located in the side of subframe. 13. From the lower rear of the LH & RH chassis flanges and lower rear of the subframe mounting brackets, release the M12 x 60 socket headed bolts, washers M12 flange head nuts. The subframe with any remaining ancillary components still attached can be withdrawn from the chassis, collect the anti-corrosion shim plates which have now been released from between the two assemblies. Any ancillary components remaining on the subframe can be removed and refitted to a new subframe as required. Refitment: Is the reverse of removal except: Prior to fitment ensure all wires, harnesses, hoses and pipes are positioned such that no damage will be incurred when the subframe is fitted. Fit new M12 x 65 hex flange headed patch bolts to the upper rear of the LH & RH chassis flanges, Fit the anti-corrosion shim plates to the exposed shank of the upper mounting bolts previously fitted. Position the subframe to the rear of chassis and raise to required height such that the mating faces of the chassis and subframe are approximately level. Manoeuvre the subframe forwards towards chassis. If lower rear suspension wishbones are attached, engage front wishbone mounting brackets to rear chassis cross member. Refit nut plates to subframe upper LH & RH mounting points. Adjust height of subframe as required; locate previously fitted LH & RH upper subframe bolts protruding from chassis flanges into subframe upper mounting points and screw in the first few threads into the nutplates. Refit the M12 x 60 socket headed bolts and washers into the subframe mounting brackets, feeding them through into the lower chassis flange mounting points. Once through apply Permabond A130 to the bolt threads before refitting the M12 nuts. Progressively tighten the upper subframe to chassis fixings. Progressively tighten the lower subframe to chassis fixings. Tighten all four bolts to 86 Nm. Renew the M10 x 35 patch bolts securing the SBAF stay to the anchor frame/rear bulkhead panel Refit the M10 x 60 bolts and M10 flanged nuts securing the SBAF stays to the subframe brackets and tighten all 4 fixings to the 50 Nm. Continue re-assembly in reverse order to disassembly. Note: A full suspension and geometry check and adjustments as necessary will also be required. Page 7
AQ.4 - seat belt anchor FRAME Bulkhead panel SBAF stay SBAF Roof hoop bond path to bulkhead panel Roof panel rear mounting point SBAF seal Lower mounting bracket Seat belt mounting points M8 x 25 screws M10 x 30 bolt Anti-corrosion shim plate M10 x 60 bolt & M10 flanged nut M10 x 35 patch bolts A tubular steel SBAF (Seat Belt Anchor Frame) provides mounting points for the driver and passenger seat belt reels and their upper anchorage points, rear mounting points for the outer hard top roof panel and also incorporates a roof hoop for additional occupant protection. It is fixed to the top of the LH/RH chassis side-rails by four M8 x 25 socket headed capped screws at each side, anti-corrosion shim plates are interposed between the mounting bases of the SBAF and side-rails. It is positioned to the cockpit side of the rear bulkhead panel; the roof hoop section is bonded to the interior face of the bulkhead panel directly above the cabin rear window. Apertures in the bulkhead panel allow the upper mountings of the LH/RH SBAF stays (located in the engine bay) to be fixed directly onto bosses on the roof hoop. Flexible seals are fitted between the bosses and interior face of the bulkhead panel. The lower mountings of the SBAF stays are fixed to brackets bolted to the rear subframe. The SBAF stays increase the rigidity to the SBAF assembly as well as providing further mounting points for ancillary components such as tailgate struts, air cleaner casing, inertia switch etc. Page 8
SBAF removal: The main SBAF and bulkhead panel is fitted to the chassis prior to fitment of the bonded sill/ B panels and cannot be removed from the vehicle without performing extremely invasive actions such as cutting/deforming or completely removing the one or both of the sills and rear bulkhead panels. SBAF stay removal: The SBAF stays may be removed by releasing the M10 x 35 patch bolts (securing it to the roof hoop bosses and M10 x 60 bolts and flanged nuts securing the lower end of the stay to the subframe mounting brackets. Both upper and lower bolts are torqued to 50 Nm but if disturbed, t is recommended to discard renew the upper M10 x 35 patch bolts. Page 9
Lotus Service Notes AQ.5 - SUPERFICIAL COSMETIC REPAIRS Dependant upon the vehicle trim options selected, the interior cabin s aluminium sill extrusions as well as the footwell and floor pan area may be left exposed. Over time general scuffing/wear and tear may occur to these surfaces. Exposed areas may also be vulnerable to accidental damage such as: Description Damage Category 1. Blemishes A 2. Scratches A or B 3. Cuts B Acceptable rectification Method A - defect No s 1,2, 3, & 8. 4. Indents and grazes. B Not requiring filling to rectify. Example defect scratch 1. Blemish 2. Scratch to surface 3. Cut to surface 4. Indents & grazes No.2 Blemish: If visible within visual chassis area (ref Chassis Superficial, cosmetic, or non-structural localised types of damage to the chassis anodised surfaces such as A117A0217 Section 8) then use rework A those listed above maymethod be cosmetically repaired. Type A category damagebrush (Stop filler not required) method Acceptable rectification B -- defect Acceptable rectification Method B No s defect No s 4,5, & & 66 Acceptable rectification Method Method B - defect 4,5,No s & 6 4,5, Chassis preparation: (If the defect is in a non Rub flat with 240 then visible 600 free cut paper chassis area, this is Cuts Cuts // Intents Intents // Grazes Grazes requiring requiring filling filling Cuts / Intents / Grazes requiring filling only needed if the anodised Type B category damage (Stop filler through) required) surface is broken Chassis preparation: No.3 Scratch To Surface: If visible within visual chassis area 1. (ref Chassis Rub down surrounding damaged area. A117A0217 Section 8) then use rework method A ISSUE: 4 2. Clean area. Example Example TypeExample B Example 18 No.5 Indents: Must not interfere with fit of parts if does must be Chassis rectified. Rework method B Ref: Ref: Chassis Ref:then Chassis If visible A117A0217 within visual chassis area (ref Chassis A117A0217 88 A117A0217 Section Section 8 Section Section 8) of of visual visual quality-chassis quality-chassis of visual A117A0217 quality-chassis then use rework method B Full respray ISSUE: 4 20 (Required when the defect is within a visual chassis area 3. Lightly bevel edge of repair with a router and Ref: Lotus Technical abraded dry with 240 free cut paper, fill reift.s.3014/10 part pairs with u-pol to stop filler and allow dry. To Surface: No.4toCut visible within visual of Chassis Doc 1. Rub down 1. 2.2.Clean 1.Rub Rubdown down 2. Clean Clean 1. Rub Clean 2. chassis (refdown Chassis 4. Rub flat with 240 free cut paper and finish area A117A0217 ) with 600 free cut paper to removea117a0217 any heavy ISSUE: 4 scratches. Section 8) then use15rework method B If surface broken in any other area use method A to protect from corrosion. ISSUE: 4 Stop filler 3.3. Stop filler 3. Stop filler 3. Stop filler 19 4. 4. Rub Rub down down Rubdown down 4.4.Rub 5. Mask off 6. 6.6.Respray 5. 5.Mask Maskoff off 6. Respray Respray 5. Mask off Respray NB: repairs are to Tank Bay NB: No Noare repairs are permitted permitted to the the Tank Bay Panel or or NB: No repairs permitted to the Tank Bay Panel or Panel Page 10 Front Top Panel without prior agreement Front Top Panelprior without prior agreement Front Top Panel without agreement from Lotus from Lotus Cars Cars from Lotus Cars ISSUE: 44 ISSUE: 4 ISSUE: DATE: 14/07/05 16 16 16
Chassis preparation for paint: Thoroughly degrease area with DuPont 3290 using wipe on wipe off method. 5. Mask off area/panel as required. Chassis Colour Lotus Paint Code Colour DuPont Code B35 New Aluminium BS97 Mix paint as per DuPont specification. 6. Apply paint in several light coats allowing each coat to dry before applying the next until the repaired area is covered. Please note: Basic principles of re-spraying apply as on any body panel, i.e. fade out or if necessary complete panel spray to a joint line. Page 11