{ "units": "mm", "source_frame": "Retained native engine mm,+X left,+Y up,+Z front.", "factory_sources": [ "https://www.spridgets.de/downloads/Midget%201500%20WH%20Teil%201.pdf#page=11", "https://www.spridgets.de/downloads/Parts-1977.pdf#page=57", "https://www.spridgets.de/downloads/Parts-1977.pdf#page=58" ], "hardware_source": "https://www.fredmillturnparts.com/_files/ugd/f842a9_982f9ff054f0425cb7ebbfae1012ea6b.pdf#page=6", "read_scope": "Factory general specs04-1,parts107-B78/B80 and original hardware printed3/PDF6 visually read. UK crank operation77 read only as UK architecture;not North American replacement instructions.", "supplier_conflict": "Revington HB1024 URL/catalog text says3.5in while superseding to BH607241;original hardware table and current BH607241 comparison list3in. Model uses original table3in;not a fitted bolt-length finding.", "factory_main_journal_diameter_mm": [ 58.713, 58.725 ], "factory_shell_length_mm": [ 21.34, 21.72 ], "factory_diametral_clearance_mm": [ 0.013, 0.05 ], "selected_reference_diametral_clearance_mm": 0.0315, "retained_shell_outer_radius_mm": 31.1595, "selected_shell_inner_radius_mm": 29.37525, "selected_shell_length_mm": 21.53, "owner_dimensions_applied": false, "nodes": { "rear": { "retained_journal_center_mm": [ 0, -225.0, -160.0 ], "retained_main_cap_axial_width_mm": 27.0, "retained_bolt_axes_xz_mm": [ [ -47, -160.0 ], [ 47, -160.0 ] ], "estimated_cap_bore_radius_mm": 6.0, "estimated_pad_radius_mm": 10, "estimated_cap_bearing_face_y_mm": -243.5, "estimated_head_af_height_mm": [ 18, 8.0 ], "estimated_unloaded_washer_od_id_height_mm": [ 18, 11.6, 2.0 ], "bolt_nominal_shank_diameter_mm": 11.112499999999999, "bolt_nominal_underhead_length_mm": 76.19999999999999, "bolt_axes": [ { "x": -47.0, "z": -160.0, "cap_face_y": -243.5, "bolt_underhead_y": -245.5, "bolt_tip_y": -169.3 }, { "x": 47.0, "z": -160.0, "cap_face_y": -243.5, "bolt_underhead_y": -245.5, "bolt_tip_y": -169.3 } ] }, "center": { "retained_journal_center_mm": [ 0, -225.0, 0.0 ], "retained_main_cap_axial_width_mm": 27.0, "retained_bolt_axes_xz_mm": [ [ -47, 0.0 ], [ 47, 0.0 ] ], "estimated_cap_bore_radius_mm": 6.0, "estimated_pad_radius_mm": 10, "estimated_cap_bearing_face_y_mm": -243.5, "estimated_head_af_height_mm": [ 18, 8.0 ], "estimated_unloaded_washer_od_id_height_mm": [ 18, 11.6, 2.0 ], "bolt_nominal_shank_diameter_mm": 11.112499999999999, "bolt_nominal_underhead_length_mm": 76.19999999999999, "bolt_axes": [ { "x": -47.0, "z": 0.0, "cap_face_y": -243.5, "bolt_underhead_y": -245.5, "bolt_tip_y": -169.3 }, { "x": 47.0, "z": 0.0, "cap_face_y": -243.5, "bolt_underhead_y": -245.5, "bolt_tip_y": -169.3 } ] }, "front": { "retained_journal_center_mm": [ 0, -225.0, 160.0 ], "retained_main_cap_axial_width_mm": 27.0, "retained_bolt_axes_xz_mm": [ [ -47, 160.0 ], [ 47, 160.0 ] ], "estimated_cap_bore_radius_mm": 6.0, "estimated_pad_radius_mm": 10, "estimated_cap_bearing_face_y_mm": -243.5, "estimated_head_af_height_mm": [ 18, 8.0 ], "estimated_unloaded_washer_od_id_height_mm": [ 18, 11.6, 2.0 ], "bolt_nominal_shank_diameter_mm": 11.112499999999999, "bolt_nominal_underhead_length_mm": 76.19999999999999, "bolt_axes": [ { "x": -47.0, "z": 160.0, "cap_face_y": -243.5, "bolt_underhead_y": -245.5, "bolt_tip_y": -169.3 }, { "x": 47.0, "z": 160.0, "cap_face_y": -243.5, "bolt_underhead_y": -245.5, "bolt_tip_y": -169.3 } ] } }, "basis": "Factory nominal bearing sections and six cap-fastening roles replace unbored generic caps,short floating fastener cues and oversized display clearance. Crank/block/thrust sources held;actual cap casting and receiver registration remain unknown. Four relieved connecting-rod shanks replace rectangular stems;end interfaces remain the earlier comparison geometry,not fitted stock dimensions.", "limits": "Factory journal and bearing-length ranges retained;0.013..0.050mm diametral running-clearance range represented by midpoint0.0315mm,not fitted clearance,bearing grade,crush or oil-film behavior. Shell outer radius retains the old unmeasured1.8mm seat allowance. Three cap/journal stations and six bolt axes remain unmeasured source datums. Cap pads,bore allowance,upper ear extension,head,washer and axial seating are estimates. HB1024 is factory-listed;hardware table7/16UNF x3in supplies a nominal comparison,not fitted bolt identity,thread form or safe replacement selection. No block receiver is drilled;upper fastening/support remains unverified against the retained block. Flat split washers illustrate WL210 roles,not working spring compression or locking. Crank,block,thrust washers,sump and surrounding poses stay. No strength,torque,thread engagement,loaded lubrication,end-float simulation or verified replacement/removal path. Shank pocket,width,depth,rounded ends and reverse-face symmetry are construction estimates from supplier topology. Existing factory-center-distance datum and all big/small bore,width,cap split,boss/fixing and installed stations stay. Retained end bore/width values come from the earlier aftermarket H-beam comparison;they are not relabeled as stock146454 or fitted dimensions. No photographed lightening/oil hole,casting mark or number is copied or assigned. No cap,bolt,small-end bush,crank,piston or engine pose changes to force a fit. No forging development,material,strength,mass balance,loaded clearance,working articulation or verified replacement/removal path.", "connecting_rod_shank_revision": { "1": { "supplier_source": "https://www.sportsandclassics.com/product/146454-triumph-tr250-tr6-spitfire-herald-midget-connecting-rod/", "supplier_image": "https://www.sportsandclassics.com/wp-content/uploads/2023/01/146454-Triumph-TR250-TR6-Spitfire-Herald-Midget-Connecting-Rod-scaled.jpg", "read_scope": "Own146454 product photo visually read: relieved shank with longitudinal edge flanges and rounded pocket ends. Second image is packaging,not reverse-face evidence. Factory Midget p58/107-B80 lists146454 rod and separate119813 bush. No fitted identification or calibrated tracing.", "retained_big_small_centers_native_mm": [ [ 0, -181.25, -122.75 ], [ 0, -35.25, -122.75 ] ], "estimated_relief_y_bounds_mm": [ -145.25, -55.25 ], "estimated_relief_width_mm": 12.5, "estimated_web_thickness_mm": 4.0, "estimated_relief_end_radius_mm": 6.25, "hidden_reverse_face": "Mirrored reference hypothesis;no reverse-face photograph recovered.", "owner_dimensions_applied": false, "removed_native_volume_mm3": 13097.633664077148, "limits": "Shank pocket,width,depth,rounded ends and reverse-face symmetry are construction estimates from supplier topology. Existing factory-center-distance datum and all big/small bore,width,cap split,boss/fixing and installed stations stay. Retained end bore/width values come from the earlier aftermarket H-beam comparison;they are not relabeled as stock146454 or fitted dimensions. No photographed lightening/oil hole,casting mark or number is copied or assigned. No cap,bolt,small-end bush,crank,piston or engine pose changes to force a fit. No forging development,material,strength,mass balance,loaded clearance,working articulation or verified replacement/removal path." }, "2": { "supplier_source": "https://www.sportsandclassics.com/product/146454-triumph-tr250-tr6-spitfire-herald-midget-connecting-rod/", "supplier_image": "https://www.sportsandclassics.com/wp-content/uploads/2023/01/146454-Triumph-TR250-TR6-Spitfire-Herald-Midget-Connecting-Rod-scaled.jpg", "read_scope": "Own146454 product photo visually read: relieved shank with longitudinal edge flanges and rounded pocket ends. Second image is packaging,not reverse-face evidence. Factory Midget p58/107-B80 lists146454 rod and separate119813 bush. No fitted identification or calibrated tracing.", "retained_big_small_centers_native_mm": [ [ 0, -268.75, -43.25 ], [ 0, -122.75, -43.25 ] ], "estimated_relief_y_bounds_mm": [ -232.75, -142.75 ], "estimated_relief_width_mm": 12.5, "estimated_web_thickness_mm": 4.0, "estimated_relief_end_radius_mm": 6.25, "hidden_reverse_face": "Mirrored reference hypothesis;no reverse-face photograph recovered.", "owner_dimensions_applied": false, "removed_native_volume_mm3": 13097.633664142639, "limits": "Shank pocket,width,depth,rounded ends and reverse-face symmetry are construction estimates from supplier topology. Existing factory-center-distance datum and all big/small bore,width,cap split,boss/fixing and installed stations stay. Retained end bore/width values come from the earlier aftermarket H-beam comparison;they are not relabeled as stock146454 or fitted dimensions. No photographed lightening/oil hole,casting mark or number is copied or assigned. No cap,bolt,small-end bush,crank,piston or engine pose changes to force a fit. No forging development,material,strength,mass balance,loaded clearance,working articulation or verified replacement/removal path." }, "3": { "supplier_source": "https://www.sportsandclassics.com/product/146454-triumph-tr250-tr6-spitfire-herald-midget-connecting-rod/", "supplier_image": "https://www.sportsandclassics.com/wp-content/uploads/2023/01/146454-Triumph-TR250-TR6-Spitfire-Herald-Midget-Connecting-Rod-scaled.jpg", "read_scope": "Own146454 product photo visually read: relieved shank with longitudinal edge flanges and rounded pocket ends. Second image is packaging,not reverse-face evidence. Factory Midget p58/107-B80 lists146454 rod and separate119813 bush. No fitted identification or calibrated tracing.", "retained_big_small_centers_native_mm": [ [ 0, -268.75, 43.25 ], [ 0, -122.75, 43.25 ] ], "estimated_relief_y_bounds_mm": [ -232.75, -142.75 ], "estimated_relief_width_mm": 12.5, "estimated_web_thickness_mm": 4.0, "estimated_relief_end_radius_mm": 6.25, "hidden_reverse_face": "Mirrored reference hypothesis;no reverse-face photograph recovered.", "owner_dimensions_applied": false, "removed_native_volume_mm3": 13097.633664142646, "limits": "Shank pocket,width,depth,rounded ends and reverse-face symmetry are construction estimates from supplier topology. Existing factory-center-distance datum and all big/small bore,width,cap split,boss/fixing and installed stations stay. Retained end bore/width values come from the earlier aftermarket H-beam comparison;they are not relabeled as stock146454 or fitted dimensions. No photographed lightening/oil hole,casting mark or number is copied or assigned. No cap,bolt,small-end bush,crank,piston or engine pose changes to force a fit. No forging development,material,strength,mass balance,loaded clearance,working articulation or verified replacement/removal path." }, "4": { "supplier_source": "https://www.sportsandclassics.com/product/146454-triumph-tr250-tr6-spitfire-herald-midget-connecting-rod/", "supplier_image": "https://www.sportsandclassics.com/wp-content/uploads/2023/01/146454-Triumph-TR250-TR6-Spitfire-Herald-Midget-Connecting-Rod-scaled.jpg", "read_scope": "Own146454 product photo visually read: relieved shank with longitudinal edge flanges and rounded pocket ends. Second image is packaging,not reverse-face evidence. Factory Midget p58/107-B80 lists146454 rod and separate119813 bush. No fitted identification or calibrated tracing.", "retained_big_small_centers_native_mm": [ [ 0, -181.25, 122.75 ], [ 0, -35.25, 122.75 ] ], "estimated_relief_y_bounds_mm": [ -145.25, -55.25 ], "estimated_relief_width_mm": 12.5, "estimated_web_thickness_mm": 4.0, "estimated_relief_end_radius_mm": 6.25, "hidden_reverse_face": "Mirrored reference hypothesis;no reverse-face photograph recovered.", "owner_dimensions_applied": false, "removed_native_volume_mm3": 13097.633664120818, "limits": "Shank pocket,width,depth,rounded ends and reverse-face symmetry are construction estimates from supplier topology. Existing factory-center-distance datum and all big/small bore,width,cap split,boss/fixing and installed stations stay. Retained end bore/width values come from the earlier aftermarket H-beam comparison;they are not relabeled as stock146454 or fitted dimensions. No photographed lightening/oil hole,casting mark or number is copied or assigned. No cap,bolt,small-end bush,crank,piston or engine pose changes to force a fit. No forging development,material,strength,mass balance,loaded clearance,working articulation or verified replacement/removal path." } } }