{
  "valve_drive": {
    "factory_source": "https://www.spridgets.de/downloads/Parts-1977.pdf#page=62",
    "factory_read": "1500 plate107-B88 visually read: eight143552 tappets and eight157508 pushrods. Neither fitted identity selected.",
    "manual_source": "https://www.spridgets.de/downloads/Midget%201500%20WH%20Teil%201.pdf#page=12",
    "manual_read": "General specification page12/04-2 visually rechecked: tappet0.7996\u20130.8000in/20.30\u201320.32mm and1.75in/44.45mm length;timing chain0.375in pitch,62pitches. Existing follower nominal midpoint and length retained.",
    "supplier_length_source": "https://www.revingtontr.com/product/149513/name/push-rod-tr5-6-cp-pi-811",
    "supplier_length_fact": "157508 listed198mm overall. Supplier explicitly distinguishes overall length from lower-ball/top-cup effective centers; its alternative tubular rod corrections are not applied to157508.",
    "supplier_photos": [
      "https://www.mgocspares.co.uk/ImageHandler/104095w700h700/143552?Sequence=104095&Width=700&Height=700",
      "https://www.mgocspares.co.uk/ImageHandler/104102w700h700/157508?Sequence=104102&Width=700&Height=700"
    ],
    "photo_read": "Both visually read: open hollow follower and pushrod cup/rounded opposite end. No calibrated cavity,seat,wire/shaft diameter or fitted identity.",
    "retained_follower_outer_diameter_mm": 20.310000000000002,
    "retained_follower_length_mm": 44.45,
    "retained_follower_base_y_mm": -67.89937046422807,
    "retained_follower_x_mm": 65.0,
    "retained_follower_z_mm": [
      -137.75,
      -107.75,
      -58.25,
      -28.25,
      28.25,
      58.25,
      107.75,
      137.75
    ],
    "estimated_follower_cavity_radius_mm": 8.0,
    "estimated_follower_floor_mm": 5.0,
    "legacy_pushrod_line_endpoints_mm": [
      [
        65.0,
        -23.449370464228068,
        0.0
      ],
      [
        32.0,
        103.0,
        0.0
      ]
    ],
    "legacy_pushrod_line_span_mm": 130.68451817564159,
    "supplier_pushrod_overall_length_mm": 198.0,
    "numerical_overall_minus_legacy_span_mm": 67.31548182435841,
    "comparison_datums_limit": "198mm overall and the legacy130.6845mm line span use different end datums. Their difference is a documentary/model mismatch,not measured shortfall,adjuster travel or instruction to extend a fitted rod.",
    "detached_comparison_axis": [
      [
        159.99827134242653,
        -88.58333138028758,
        210.0
      ],
      [
        110.0,
        103.0,
        210.0
      ]
    ],
    "reference_registration": "Outside source engine end atZ210mm. Display arrangement only; comparison hidden in normal whole-car view until selected. Eight legacy pushrods,camshaft,block/head passages,rockers and engine frame stay. No longer rod is forced through the existing engine.",
    "limits": "All follower interior and rod ball/stem/cup/flare dimensions,finished end shape and detached placement are estimates. Follower floor is a recognition closure,not a measured spherical contact seat; no lubrication drilling,face crown,material or cam wear established. Factory-sized follower exterior and axes stay. The old pushrod line begins at the follower rim station,not a verified internal seat. The separate198mm replacement comparison does not resolve common cam/head/rocker registration or identify this car\u2019s rods. No cam/head/rocker relocation,length fitting,loaded articulation,valve lash,torque,safe replacement sequence or verified removal path. UK engine operations are not substituted for missing1975 North American pages.",
    "owner_measurements_applied": false
  },
  "units": "mm",
  "source_frame": "Retained engine-local +Y up/+Z front; body engine transform unchanged.",
  "factory_source": "https://www.spridgets.de/downloads/Parts-1977.pdf#page=63",
  "factory_read": "1500 plate107-B90:144973/144974x2/144975 pedestals,144962 shaft,105120x3 coils,105322x2 end spacing springs,146914x2 plain washers,137811x2 plugs,104859 locating screw,PC10 cotter,fourHN2009/WP184 supports. No fitted identity or dimensioned layout.",
  "supplier_photos": [
    "https://rimmerbros.com/ItemImages/Large/144975.JPG",
    "https://rimmerbros.com/ItemImages/Large/105120.JPG",
    "https://rimmerbros.com/ItemImages/Large/105322.JPG"
  ],
  "supplier_photo_read": "Visually read: distinct shaft/stud support architecture,wire spacing coils and split end spring washer. Photos are unscaled and do not locate this car\u2019s fitted parts.",
  "factory_diameter_convention_mm": 14.248149999999999,
  "diameter_limit": "Retain existing inch-converted midpoint14.24815mm from printed0.5607\u20130.5612in. The manual metric pair is inconsistent; no fitted diameter selected.",
  "retained_axis_mm": [
    [
      0,
      104.0,
      -172
    ],
    [
      0,
      104.0,
      172
    ]
  ],
  "retained_rocker_z_mm": [
    -137.75,
    -107.75,
    -58.25,
    -28.25,
    28.25,
    58.25,
    107.75,
    137.75
  ],
  "historical_support_z_mm": [
    -166,
    -55,
    55,
    166
  ],
  "estimated_supports": {
    "rear": {
      "estimated_shaft_support_center_mm": [
        0,
        104.0,
        -122.75
      ],
      "estimated_stud_axis_xz_mm": [
        17.0,
        -122.75
      ],
      "estimated_head_foot_y_mm": 82.0,
      "estimated_shaft_bore_radius_mm": 7.224074999999999
    },
    "rear-intermediate": {
      "estimated_shaft_support_center_mm": [
        0,
        104.0,
        -43.25
      ],
      "estimated_stud_axis_xz_mm": [
        17.0,
        -43.25
      ],
      "estimated_head_foot_y_mm": 82.0,
      "estimated_shaft_bore_radius_mm": 7.224074999999999
    },
    "front-intermediate": {
      "estimated_shaft_support_center_mm": [
        0,
        104.0,
        43.25
      ],
      "estimated_stud_axis_xz_mm": [
        17.0,
        43.25
      ],
      "estimated_head_foot_y_mm": 82.0,
      "estimated_shaft_bore_radius_mm": 7.224074999999999
    },
    "front": {
      "estimated_shaft_support_center_mm": [
        0,
        104.0,
        122.75
      ],
      "estimated_stud_axis_xz_mm": [
        17.0,
        122.75
      ],
      "estimated_head_foot_y_mm": 82.0,
      "estimated_shaft_bore_radius_mm": 7.224074999999999
    }
  },
  "estimated_spacing_coils": [
    {
      "estimated_centerline_z_bounds_mm": [
        -102.35,
        -63.65
      ],
      "estimated_wire_mm": 0.8,
      "estimated_mean_radius_mm": 8.5,
      "estimated_turns": 9,
      "rocker_indices_from_rear": [
        2,
        3
      ]
    },
    {
      "estimated_centerline_z_bounds_mm": [
        -22.85,
        22.85
      ],
      "estimated_wire_mm": 0.8,
      "estimated_mean_radius_mm": 8.5,
      "estimated_turns": 9,
      "rocker_indices_from_rear": [
        4,
        5
      ]
    },
    {
      "estimated_centerline_z_bounds_mm": [
        63.65,
        102.35
      ],
      "estimated_wire_mm": 0.8,
      "estimated_mean_radius_mm": 8.5,
      "estimated_turns": 9,
      "rocker_indices_from_rear": [
        6,
        7
      ]
    }
  ],
  "estimated_shaft_inner_radius_mm": 4.0,
  "estimated_end_spring_z_mm": [
    -151,
    151
  ],
  "superseded_engine_source_parts": [
    "rocker_pedestals_provisional",
    "rocker_support_fasteners_provisional",
    "rocker_shaft_provisional",
    "cam_followers_catalog_reference_provisional"
  ],
  "owner_measurements_applied": false,
  "reference_pose_changes": "Four supports follow retained valve-pair centers rather than old arbitrary block positions. Stud axes move fromX0 to estimatedX17mm to express the separate shaft/stud architecture. Neither relocation is a fitted hole map; original head/rocker/valve/cover geometry is not moved or drilled.",
  "workshop": {
    "source": "https://www.spridgets.de/downloads/Midget%201500%20WH%20Teil%203.pdf#page=7",
    "printed_page": 80,
    "operations": [
      "12.29.54",
      "12.29.55"
    ],
    "market_label": "ENGINE\u2014U.K. SPECIFICATION",
    "scope": "Visually read for architecture only: cover/four pedestal fastenings;front cotter and rear locating screw;remove rockers/pedestals/springs/spacers preserving order;clear shaft/rocker oilways. UK torque,locking compound and sequence are not presented as verified applicable1975 North American instructions. No actual extraction path verified."
  },
  "limits": "All support contours,offset,stations,bores,stud/nut/washer dimensions,shaft bore,plug/cotter/locating sections,coil diameter/wire/count/pitch,lengths,end-spring shape and static spacing remain estimates. Four pedestals represent different catalog roles with one generic casting profile,not exact144973/4/5 machining. Inherited rocker bodies and valve positions stay; the revised support order is a reconstruction hypothesis,not a measured installed stack. Springs do not simulate preload or axial control; plain/end washer positions are unverified. Hollow shaft and blind locating recess do not reconstruct pressurized lubrication or oil drillings. Head receiver/stud engagement,threads,locking,wear,rocker handedness,contact/alignment,cam timing,valve lash,cover/head fit and tool room are unverified. No shim,external oil-feed kit,working articulation,strength,torque or safe/verified removal path is inferred. Whole-car inspection separation is illustrative; historical233-part engine core stays as fallback.",
  "viewer_coil_mesh": {
    "method": "Analytic circular tube on the same constant-pitch CAD helix",
    "longitudinal_sections_per_turn": 36,
    "wire_ring_vertices": 12,
    "estimated_maximum_chord_deviation_mm": 0.05,
    "scope": "Viewer representation only; STEP retains swept circular sections."
  }
}