YOUR 1975 MIDGET / BLOCK INSPECTION
Find the block-side
core plugs.
The 1500 parts listing identifies three 1½-inch 144688 core plugs on the block side. The CAD now shows their relationship to the cylinder block, but their positions and condition on this car have not been checked. Use this page to identify the fitted plugs and record what is actually accessible before planning a repair.
Which parts are shown?
| Location | Catalog evidence | CAD status |
|---|---|---|
| Three block-side openings | 144688, nominal 1½ inches (38.1 mm), quantity three | Three separate cups and sockets; center stations and depths provisional |
| Block front face | 144687, nominal 1 inch, separately listed | Not yet modeled; the front plate and access have not been checked against this car |
| Other block and head plugs | Different sizes and positions appear in the wider 1500 catalog | Outside this three-plug study; identify each opening before ordering |
The Midget 1500 parts listing ↗ gives three side plugs. Rimmer's 144688 listing ↗ identifies the nominal diameter; its supersession or current stock may change. A Spitfire MkIV restoration photo ↗ shows three plugs along a related engine block's ignition side. That photograph is a layout clue, not proof of this Midget's fitted casting.
What to record on this car
- 1 · IdentifyWith the engine off and fully cool, locate each visible cup along the block side. Photograph the whole side and then each plug with a nearby fixed feature. Note anything that hides a position.
- 2 · Separate observationsRecord rust, staining, wetness and nearby hose or gasket traces at each location. A wet area near a cup does not by itself establish where coolant began leaking.
- 3 · Measure when exposedWhere a raised metal seat is accessible, measure its outside diameter and projection from the adjacent block face. Enter them for that specific plug in the CAD inspector to reshape only that seat in an owner STEP. If a repair has already required plug removal, also measure the clean opening and removed part before selecting a replacement.
The engine stamp recorded for this car is FP4025UE. Keep a photograph of that stamping with the plug record so any parts comparison can be tied back to the fitted engine. The three virtual centers have not been derived from this stamping.
Before a repair plan becomes a procedure
Confirm which plug is leaking, which adjacent parts prevent straight access, and whether the block-side opening can be worked on in the car. Obtain the applicable North American 1975 factory procedure and its coolant, seat-preparation and installation instructions. The CAD is useful for naming parts and planning photographs; it does not establish a safe extraction angle, drive tool, sealant choice or finished interference fit.
Read the CAD accuracy limits ↗ · Return to the cooling check ↗