ENGINE STUDY / BELOW THE CRANKCASE

Follow the oil
from the sump.

The interactive engine now shows the pump housing, cover, two rotors, three mounting bolts, pickup tube and strainer as separate pieces. Open a piece to see what it does and which real hardware needs checking.

Explore the pump in 3D ↗
3PUMP MOUNTING BOLTS AND WASHERS · WORKSHOP PAGE
0.1 mmINNER AND OUTER ROTOR END FLOAT LIMITS · UK WORKSHOP PAGE
0.25 mmROTOR LOBE CLEARANCE LIMIT · UK WORKSHOP PAGE
0.2 mmOUTER ROTOR TO BODY DIAMETRAL LIMIT · UK WORKSHOP PAGE
Shape and location remain provisional

The factory workshop PDF, p. 10 shows the pump removal and overhaul sequence and the limits above on an Engine—U.K. Specification page. A Midget 1500 replacement listing and replacement pump photograph help explain the visible body and pickup form. They do not identify the pump fitted to your North American car. The CAD pump position, rotor profile, bore, shaft length, bolt centers, tube bend and strainer clearance are estimates. Its shaft is not connected to the distributor drive in the model.

Explore each connection

Pump housing and cover

A hollow body surrounds the two rotors. The separate cover exposes the chamber in exploded view. Neither face is a gasket or machining template.

Select cover ↗

Inner and outer rotor

The inner shaft is driven from above; the outer rotor turns around it. The teeth are illustrative, so use the manual’s measurement method on the actual pump.

Select inner rotor ↗

Three retaining bolts

The workshop establishes the count. The Midget 1500 parts listing gives a ¼-inch UNF × 2¾-inch bolt and ¼-inch spring washer; the CAD scales the shank accordingly. Centers, head and fitted engagement remain estimates.

Select bolts ↗

Pickup and strainer

The pickup is drawn low in the sump to make the oil path legible. Its real mesh, connection and floor clearance need direct inspection.

Select strainer ↗

When the sump is already coming off

  1. Photograph the sump and drain plug, then record the gasket and fastener pattern on the fitted engine.
  2. After following the applicable workshop procedure to remove the sump, photograph the pump, pickup, strainer and drive engagement before loosening any of them.
  3. Record the pump casting or part number, three mounting-bolt positions, pickup attachment, strainer form and clearance to the sump floor. Keep washers and other hardware identified by location.
  4. If inspecting the pump, use the applicable manual and measuring tools for rotor end float and lobe/body clearances. Treat the UK values above as source comparisons until the correct North American specification and fitted pump are confirmed.