Read the drawings
behind the model.

Factory and catalog sources

Spitfire 1500 references: what carries over?

The Triumph Spitfire reference index is useful for checking the shared 1500 engine family. Its engine-number table distinguishes the Spitfire FM and Midget FP prefixes and describes the U/C/E suffix letters. That corroborates the family of the owner-transcribed FP4025UE stamp, subject to rereading its worn digits. Its 1500 general data give a 73.7 mm bore and 87.5 mm stroke, matching the independent Midget factory dimensions already used by the CAD. Those two shared core dimensions are suitable cross-checks; Spitfire body, chassis, fuel, cooling and electrical figures describe a different car.

The index also includes Spitfire torque tables with some rows labeled 1500. They are leads to check against the Midget workshop publication and the actual fitted fasteners, not torque settings adopted for this car. The listed 1975 North American Midget workshop manual is AKM3267; the later Midget manual used elsewhere on this site is AKM4071/B.

The two-page Amicale Spitfire bulletin 62 PDF is indeed a Spitfire 1500 electrical diagram. Its legend identifies an alternator, ignition warning lamp, battery, starter, ballast-resistance wire, coil and distributor, and provides Lucas wire-color abbreviations. It is a 2001 reproduction without a year or market designation on these pages; its legend includes an Italy-only parking-lamp indicator, left-hand-drive-only items, and overdrive circuitry, showing that it covers equipment variants. It is not a wiring diagram for this 1975 North American Midget, and it cannot establish the terminal assignments or wire colors of the remanufactured Bosch AL298X photographed on this car. Use it only to understand component names and general circuit relationships while obtaining the matching Midget diagram and documenting the installed harness.

Check the engine and market on the manual

The file named Triumph-Shop-Manual.pdf identifies Herald, Vitesse 6 and earlier Spitfire models in its title and introduction. It is not a Spitfire 1500 manual. Its dial-gauge/feeler-gauge discussion and timing methods cannot establish the procedure for this Midget merely because the engines share family features.

The Midget factory crankshaft page, PDF p. 4 locates the rear-main thrust washers and calls for an end-float check under operation 12.21.26. The Midget timing-chain page, PDF p. 12 provides operation 12.65.12 for alignment, shims and timing marks. Both pages are labeled Engine—U.K. Specification; confirm the applicable North American instructions rather than importing the earlier Triumph procedures.

The Spitfire 1500 factory manual RTC9237, Italian edition, PDF p. 62 is a genuine 1500 comparison: its footer identifies the publication and operation 12.60.32, sheet 2. It prints a 0.102 mm maximum axial rotor gap, supporting the approximately 0.1 mm scale of the Midget oil-pump scan’s conflicting units. This is supporting evidence, not a correction notice or identification of this car’s pump. Read the pump-source comparison and remaining fitted evidence ↗

Distributor fitment lead

IMG_6967–6970 show a body-mounted rectangular housing and separate vacuum capsule. The Moss Sprite/Midget catalog, printed p. 75 lists a 1975 Lucas Opus 41593 with its amplifier on the distributor, and a later remote-amplifier C.E.I. replacement 41804. The visible layout favors the integral-amplifier form; the fitted distributor number is unreadable and must be checked before parts selection. Open the distributor identification study ↗

Zenith-Stromberg carburetor anatomy

IMG_6958 shows the rounded dashpot and yellow damper cap of the fitted carburetor. The factory Zenith-Stromberg CD4 exploded view, PDF p. 26 identifies the separate cover, diaphragm, piston/air valve, needle and float-bowl relationships modeled in the STEP. Moss explains the model-size designation, giving the 150-series nominal 1½-inch throat. The Midget catalog lists C3754 Federal and C3755 California for 1975–76. The fitted tag and outer dimensions are not verified. Open the car-specific study ↗

Fitted oil filter resolved

IMG_6966 reads ACDelco PF53 on the installed canister. The PF53 product listing supplies outside and gasket dimensions for a closer CAD envelope; these are catalog dimensions, not direct measurements. Rimmer's GFE119 listing warns that aftermarket adapters can use different threads. GFE150 is listed with a ⅝-inch opening and MANN specifies ⅝-18 for its comparison branch, unlike the PF53’s ¾-16. Read the fitment study ↗

Hydraulic reservoir identification

IMG_6960–6961 show a pale LOCKHEED-marked cap beside a black cap whose molded text calls for DOT 3 fluid. The Moss brake-hydraulics catalog and clutch-hydraulics catalog confirm separate master-cylinder circuits on the 1500. The photo-based brake/clutch cap assignments remain provisional until each outlet is traced. Open the photo-led reservoir guide ↗

New identifiers from the owner photos

Read the engine stamp and tune-label evidence page ↗ It compares IMG_6968 and IMG_6957 with the 1975 factory table, and separates the owner transcription from the characters independently legible in the photo.

IMG_6968 photographs the engine-block stamp, transcribed by the owner as FP4025UE. The Moss Sprite/Midget catalog identifies FP as the Midget 1500 engine prefix; Spridgets.de explains UE as a North American destination suffix. Neither source dates this exact serial or proves that the engine was originally installed in this chassis. IMG_6976 identifies the fitted alternator as a Bosch AL298X remanufactured unit. The fitted alternator record compares the Bosch electrical specification, owner photos, candidate hardware and still-missing measurements. Bosch lists that part number, but the accessible manufacturer page does not provide the dimensional drawing needed to calibrate the CAD. Measure the installed unit before treating the earlier 17/18ACR comparison as a fitment guide.

Current engine geometry references

The Moss 1975–76 manifold plate, PDF p. 47 ↗ distinguishes the inlet and exhaust castings, heat shield and downpipe joint. It establishes the parts and their relationships, not port-center coordinates. The bare 1500-family cylinder-head reference ↗ informs the rocker recess and visible side reliefs. The factory specifications, PDF p. 12 ↗ give the fitted outer spring length and rocker dimensions. The shaft inch and metric figures conflict on that page; the CAD uses the inch range converted to millimetres and records the discrepancy in its data sheet. A square-on recessed head-gasket photo ↗ and a separate supplier bore-size listing ↗ suggest a much narrower 140–150 mm head/deck envelope than the old CAD. A second recessed-gasket set photo ↗ shows the same wider aperture side and off-center bore row. The CAD records a provisional 15 mm crosswise offset and an unclassified hole pattern. This cross-supplier comparison is an estimate, not a dimensioned drawing or gasket template. The Midget 1500 external-engine plate, PDF p. 32 ↗ identifies a separate timing-cover gasket, front engine plate and oil seal. A photographed removed Spitfire 1500 cover ↗ informs the pressed shell silhouette only; it does not establish this Midget’s fitted part or dimensions.

Identify the actual car

The Moss Europe catalog identification page (PDF p. 175) locates the chassis plate on the left inner wheel arch, the 1500 engine-number flange on the left side of the block, and the separate body plate on the left front door pillar. It lists GAN6 as the 1975–79 Midget chassis prefix and FP as the 1500 engine prefix. These range facts do not establish what remains fitted to this car. The stamp visible on IMG_6853’s front panel has not been identified as any of those three numbers. Follow the car-specific identification guide ↗

1975 cooling bulletin

British Leyland’s August 1975 Technical Service Bulletin 75-A-6 describes a coordinated modification for severe overheating on 1975 Midgets and says to rule out ordinary faults first. Its metal expansion tank uses a double-seal cap that is not interchangeable with the original. Compare the bulletin with this car’s photos and start a fitted-parts record ↗

Read the original British Leyland bulletin (PDF) ↗

Bosch AL298X stator comparison

The IAT replacement-stator catalog, PDF page 4 lists stator 07118 for Bosch AL298X at 108.25 mm outside diameter, 73.95 mm inside diameter and 20.55 mm lamination-stack thickness. These are replacement-part dimensions, not a Bosch case drawing or measurements of this car. The CAD uses the listed diameters; its 25 mm visible band length remains an owner-photo estimate because it is a different datum from the internal lamination stack. The same maker’s rotor catalog, PDF page 10 lists an 83 mm Lucas 17/18ACR rotor (17402). It cannot fit the 73.95 mm bore of Bosch-family stator 07118. That mismatch is a useful warning against treating complete-alternator interchange numbers as an internal parts list.

CAD reconstruction research

Explore and download the measured-core STEP assembly ↗ · Part-by-part accuracy register ↗ · Mark a reference and target on a photo ↗

Your existing engine-bay photos (especially IMG_6797, IMG_6853 and IMG_6856) show the red rocker cover clearly enough to use a matching replacement gasket as a scale anchor. AJUSA 11007400, cross-referenced to AJM414, is listed at 360 × 110 mm ↗. The CAD study now uses that footprint for the cover; its height and stamped contours remain provisional. The cap in IMG_6893 is stamped “CAUTION REMOVE SLOWLY,” while IMG_6856 shows a darker cap. Its identity, neck and seal must be confirmed directly; an unrelated 58 mm oil-filler listing is no longer used as a scale anchor.

The Midget 1500 uses the Triumph Spitfire 1500 engine family. The factory Midget manual identifies it as PE94J, with four cylinders and 1,493 cm³ displacement. The shared core makes Triumph drawings useful, but the Midget catalog warns that its FP engine and the Spitfire FM engine differ in fuel pump, distributor and some other fittings. First confirm the engine prefix on this car before fixing a variant in CAD.

These dimensions come from factory general specifications, PDF pp. 11–12 ↗. The additional workshop-manual scan, part 3 ↗ shows crankshaft, cylinder block, head, rocker gear and engine mounting procedures in more detail. The factory Spitfire 1500 parts catalog, RTC9819CB ↗ adds exploded block, sump and cylinder-head plates beginning on PDF page 30. Its Spitfire part numbers require a Midget fitment check before use. Download the measured-data JSON ↗

Still needed for an accurate solid model: cylinder-center spacing; block, head and sump exterior dimensions; face and bolt-hole coordinates; intake and exhaust port geometry; mounting points; and verified 1975 North American carburetor and emissions hardware on this car. The available service plates establish construction and many machined diameters, but they are not scaled manufacturing drawings. Those remaining shapes need dimensioned parts, direct measurement, or a scan. The linked measured-core assembly marks provisional shapes and provides an editable STEP file for the next measurement pass. It now has a hollow rocker cover with photo-led sloping shoulders; separately selectable rocker shaft, arms, supports, valve springs and pushrods guided by the factory rocker-shaft drawing, PDF p. 7 ↗; and separate distributor, alternator, 13-blade fan, fan clutch, belt-route, Zenith-Stromberg carburetor and a Smiths heater and separate metal air-cleaner recognition model. The new rocker parts show assembly relationships; their profiles, positions and dimensions remain estimates. The carburetor dome and float chamber are guided by the Moss 1500 carburetor plate, PDF p. 42 ↗, while the fitted carburetor name is visible in the owner photos. The black rear box was previously misidentified as the air cleaner. IMG_6892 now shows its SMITHS marking, round outlet and hose connections; its shape matches the separate 1500 heater assembly, PDF p. 39 ↗. Its heater identity is now supported by the photographed marking and connections, while its exact model and dimensions remain unverified. The earlier unsupported duct to the carburetor was removed. IMG_6885–6887 now show the separate metal air-cleaner case, elbow and black coupling; new photo-led CAD parts depict that actual visible path, with provisional dimensions and placement. IMG_6794 and IMG_6857 show a Cooper-marked cylinder with small hoses. Its form resembles the Moss vapor-adsorption canister, item 72, PDF p. 43 ↗; the hose routing and exact fitted number still need direct confirmation. It should not be used as proof of the carburetor air-filter location. The US air-filter parts plate ↗ depicts a separate intake assembly; the new owner photos locate the fitted air-cleaner case and coupling, although the element and part numbers remain unconfirmed. The earlier four-blade fan model was incorrect. Rimmer lists RKC92 as a 13-blade plastic fan for North American Midget 1500 models ↗, and the Moss cooling plate lists the fan and separate clutch ↗. The RKC92 product photograph informs the revised open mounting spider, rim and swept blades. The CAD uses a rough 280 mm outside diameter and 67 mm adjacent-hole spacing inferred by comparing photo pixels with the listed 1/4-inch fan bolt; these are not factory dimensions. Verify the installed fan and coupling before ordering; the fan inspection and parts plan ↗ separates blade, coupling and ring decisions.

Assembly plates

What the second photo set adds

Browse IMG_6885–6903 with captions ↗. These images show a pressure-warning-stamped two-grip cap on the rocker cover (identity unverified), SMITHS heater casing, separate metal air cleaner and coupling, ACDelco spin-on oil filter, labeled electric fuel pump, and an ignition coil marked external resistor. They improve part identity and visible geometry. They do not give calibrated outside dimensions, hidden geometry, exact replacement numbers or proof of condition beyond the photographed views. The photo locator marks the strongest views; the CAD inspector pairs revised components with specific measurements to take on the car.

How the photos were used

Open the photo locator ↗ to identify visible components in eight views of the actual car and jump to the matching workshop guide. IMG_6895 now shows irregular missing material at more than one fan tip; IMG_6850 and IMG_6854 supply earlier views. Their current condition cannot be established from the photos; inspect the fan cold before running the engine. The locator distinguishes identified parts from visible components whose function is still uncertain; it keeps unresolved locations on a separate checklist. Open the full overhead engine-bay photo ↗ to compare component positions with the CAD, the fan close-up ↗ for tip shape, and the coolant-cap close-up ↗ for the visible 14–17 lb marking. These photographs do not prove the cap’s seal fit or actual opening pressure.

Your engine-bay photographs establish the car’s visible olive paint, red-orange rocker cover, orange ignition leads, pale fan, and intake arrangement. They do not by themselves prove that every component is factory original. The viewer links selected parts to those photographs.

The 3D meshes, separation paths and hidden internal surfaces remain approximations. I have avoided assigning exact catalog part numbers where the chassis and engine plates have not been inspected.