Which rocker cover
is on this engine?
The red pressed-steel cover is visible in your photographs. A dark cap appears at its opening in IMG_6856; a silver warning-stamped cap appears over it in IMG_6893, but its fitment is unverified. The gasket profile, stud length and sealing hardware are not. Identify those before ordering a cover, gasket or fasteners, and before treating the CAD removal study as a rehearsal for this car.
Parts-plate reference
Moss’s Midget 1500 cylinder-head plate lists these catalog applications. They are a comparison checklist, not proof of what is fitted to this car. Both years retain a separate valve-cover perimeter gasket listing; the later O-rings are listed with the cover fasteners.
| Component · Moss number | Through 1976 | 1977 onward |
|---|---|---|
| Cover stud | 328-675 · 4⅛ in · two | 313-020 · 3⁵⁄₁₆ in · two |
| Fastener and seal | 310-105 nut, 365-720 plain washer and 324-680 fiber washer · two each | 072-019 cap nut, 072-020 washer and 071-092 O-ring · two each |
| Perimeter gasket | 694-100 stock gasket or 694-101 silicone option · one | |
| Oil filler cap | 834-765 original listing; 780-126 replacement listing · one. Compare the actual neck and seal. | |
Moss Sprite/Midget catalog, “Midget 1500 Cylinder Head” plate ↗
The factory exploded parts drawing (PDF p. 63) also shows the cover, fixed studs, separate fiber and plain washers, nuts, gasket and cap. It lists the early hardware separately from the 1977-on North American O-ring arrangement. The drawing identifies parts and order for comparison; it gives no measured cover or stud coordinates.
Make the fitment decision
| What you find on the car | How to use that evidence |
|---|---|
| Engine number, cover number or markings, and conventional exposed studs and nuts | Compare those identifiers and the sealing face with the through-1976 row above. This is a candidate for the early assembly; confirm the fitted gasket profile before ordering. |
| Tube-type nuts, different studs or an O-ring-style sealing arrangement | Check the 1977-on row above. Do not reuse an early fixing list just because the car is a 1975 model. |
| Alloy cover or altered breather connection | Treat it as an aftermarket assembly. Identify the cover maker, its gasket section and stud requirements; check internal rocker clearance and closed-bonnet clearance before fitting. |
| Cover still installed; underside and engine ID unreadable | Keep the variant unresolved. A replacement gasket or fastener choice based only on the red paint or cap shape is premature. |
Capture one useful evidence set
Before removal
Photograph the engine number, cover from directly above and both sides, each nut/stud, the cap stamping and underside, the breather hose and its connection, and every hose or lead near the lift path. Measure cover length, width, height, stud-center spacing and bonnet clearance where accessible. Record measurements in the CAD inspector.
With the cover safely off
Photograph the underside, gasket groove and head sealing face with a ruler in the same plane. Record gasket material and cross-section, stud projection and nut style. Keep dirt out of the valve train. Preserve the old parts until the replacement seal and fixings have been compared side by side.
Keep viewing lift tied to its evidence
In the CAD inspector, distinguish the gap to the fully latched bonnet from available upward travel with the bonnet open. Record the installed cover/cap position, remaining hoses and leads, the first fixed obstruction and measuring method. A direct open-bonnet reading limits the cover and cap together during the rehearsal; the gasket's illustrative separation never exceeds that viewing lift. The closed-bonnet gap is recorded separately and cannot substitute for open-bonnet travel.
Once the cover rehearsal starts, the full-engine explode control is held at zero so the head and fixed studs stay at their assembled model references. A loaded owner build uses its own direct evidence; saved browser notes for a different build do not supply missing clearance. Without a supported direct free-lift reading, movement remains illustrative. One vertical limit does not establish stud release, tilt, sideways exit, cap fit, gasket release or hand/tool access.
The builder retains direct clearance observations alongside a supported direct dimension without changing geometry. Readings of 0–1500 mm are supported as worksheet values, not factory tolerances. An observations-only record does not generate a new STEP. Earlier builds may lack the retained clearance fields; regenerate them from the original measurement log rather than borrowing another configuration's notes.
Then plan the replacement
- Match the observed cover and fixing type to the Moss year rows and a current supplier plate. Rimmer lists standard AJM414, rubber-cork AJM414T, and separate silicone profiles for pressed-steel and alloy covers; the catalog listing alone does not prove which seal is on your engine. Compare gasket profiles ↗
- Trace the rocker-cover breather hose. MGOC says the sealed 1500 system routes cover vapors toward the carburetor through a T-piece; a replacement cover must preserve the relevant connection. Breather note ↗
- Use the sourced valve procedure for removal and refitting. Its factory torque for the two cover nuts is 2 lbf ft. The virtual CAD lift is illustrative until the fitted hardware, obstruction clearance and gasket are verified.