Beyond the
solid frame block.
Hollow rails, a formed crossmember with an rear/top mouth and front-face access holes, open spring pockets, upper seats, damper platforms and pickup ears now replace the old solid frame boxes and isolated spring discs. Separate buffer and unassigned rack-body pads add the neighboring interfaces.
Inspect the structure
Owner photos and manufacturer branches
IMG_6910 shows the upper opening and nearby front engine structure. IMG_6914 shows the broad underside member, suspension and anti-roll surroundings. IMG_6919 shows several underside openings and adjacent formed walls. These are shape/context observations; they supply no calibrated section, wall gauge, hole spacing, structural-condition survey or common engine/body frame.
British Motor Heritage’s drawing and application table distinguish rubber-bumper CZJ676 underframe, BMH8030/31 side members and CZJ542/543 lower-link bracket applications from earlier body versions. They support assembly architecture, not this car’s fitted repair history or dimensions. BMH8007 rack mounting rail is listed for chrome-bumper bodies; the generic rack pads here are not assigned that part number.
Factory suspension plate, PDF p. 139 and p. 141 separate lower link/pins/bushes, dampers, springs, seats and buffers. Six damper fixings are a catalog count; the three modeled bore centers per platform are estimates. The new upper seat is a body reference, not a claim that the factory 21A137 lower spring seat belongs above the spring.
Retained references, new estimated surroundings
Rail outer sections and top/bottom stations are retained: the front engine-bracket base still approaches Y=.385 and the anti-roll body interface still approaches Y=.255 body units. Lower-link axis centers remain at X magnitude .36, Y=.27, Z=.98/1.42. Spring axes and former upper-seat bounds remain; damper support reaches the existing pad underside at Y=.6225, while generic rack pads approach the existing clamp lower face at Y=.35. These are existing drawing constraints, not measurements.
Open-ended rail cavities and 2.54 mm estimated walls replace filled blocks. The formed crossmember’s large upper opening and three lower holes are recognition geometry. Revised rail pockets and eight bored pickup ears now follow the separate inner-fulcrum comparison while retaining the old pivot centerlines; they do not identify actual body cutouts or a repair bracket profile. The inboard damper webs and open-outboard spring pockets supply previously missing body obstacles without changing the running gear pose.
Profiles, inclines, wall sections, apertures, holes, weld seams, buffer shape and all joints remain estimated. Mirroring is unverified. The AHA6378-style suspension buffer is a comparison; its fitted identity, loaded contact and travel are unknown. The separate rebound-buffer attachment remains unresolved. No strength, corrosion thickness, alignment, bump/rebound limit, spring restraint, operating clearance, jacking point, repair/welding plan or verified replacement path is established.
Use with the workshop studies
Retain wishbones, coils, dampers, rack, engine mounts and anti-roll references when identifying the surrounding assembly chain. Body groups stay fixed during general separation. Isolation exposes cavities and bores for inspection; it does not make welded structure detachable or establish safe support or withdrawal conditions. Existing component dimensions and body registration remain independent estimates.
Motor, brake and suspension procedures must be checked against the fitted car and complete applicable factory instructions. The manufacturer repair-parts drawing is not a repair jig, datum chart or replacement sequence. No suspension or body movement is validated by this model.
Independent native export
Checks cover valid positive solids, STEP round-trip, local openings/bores, source scale and retained drawing datums. They do not certify fitted geometry or any structural/service result.
Continuous rails and a formed front member
The overlapping hollow rail/stub boxes are replaced by one connected hollow shell per side. Their outer bounds and forward pickup-region material stay unchanged; the joined internal cavity replaces doubled walls. The old stepped longitudinal envelope remains an estimate. The assembly photographs do not calibrate the actual rail curve or establish this car’s chassis alignment.
Owner IMG_6914 and IMG_6919 show a formed broad face with three apertures. The former reference put those apertures in the bottom web. The revised crossmember has a rounded section and sloping front face, with three open front-face holes. Its retained saddle radius now opens the rear/top while leaving a front wall and short upper return. Suspension, steering, spring, damper and engine stations stay fixed.
The owner’s underside photograph supplies visible face/opening context. Steve Clark and Bill Mohan’s firsthand 2006 BMH assembly photographs show formed-member and body-join architecture, including the rubber-bumper member. They are reference photographs, not dimensioned factory drawings or identification of this car’s fitted panels.
Front-web slope, corner radii, saddle forward limit, hole row/axes/radii and projected 2.54 mm wall are construction estimates. The old lower-hole assumption is retired. Longitudinal curvature, hidden reinforcements, seams/laps, actual section and repair/corrosion history remain unresolved. These references are not a drilling, welding, alignment or jacking template.
Native checks confirm continuous rail cavities, retained forward rail material and twelve unchanged surrounding source meshes. The three front apertures have real void and adjacent-material checks. Selected current exported sump/pulley shapes have zero crossmember source intersection at the held drawing pose; this is not a full-car or fitted-clearance audit. Rail/crossmember source overlaps remain unregistered sheet joints, not verified weld geometry or strength.
The frame references stay fixed during illustrative separation. Component support, fastener access, load restraint and actual extraction clearances require fitted geometry and applicable procedures before a replacement rehearsal can be trusted.