Gearbox to clutch housing fitment.

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I spent the day working on Harry's race car which had been black flagged at Castle Combe for dropping oil on the track.

The oil was coming from two places. The cover over where the petrol pump normally sits on a Jav and through the clutch operating spigot.
The first was fixed by making a more substantial plate.
The leak from the gearbox was more problematic.
Firstly the lug on the casing had been welded which meant the face was not flush. Some filing did reduce this but not enough so a shim washer was inserted so as not to strain the case.
Second the gasket had been fitted under the input shaft cover which meant the bearing circlip was not properly clamped so the bearing had moved out towards the engine by the thickness of the gasket.
A new gasket was made to go around the cover but this still allowed the oil to escape as now the input shaft cover was not clamped against the bell housing. It was flush with the bell housing when inserted into it. The original brass cover will protrude by .2mm to accommodate a thin gasket.
So to achieve proper clamp on the bearing no gasket should be used with the assembly sealed just using silicone everywhere.
The thick gaskets supplied by JCS should not be used. A thin paper gasket may only be used if the input shaft cover protrudes from the bell housing by the thickness of the gasket.
Make sure the bearing circlip is hard against the gearbox face and the input shaft cover fits tightly over the bearing and is hard against the gearbox casing.
The input shaft cover on this gearbox was not standard as a double lip oil seal was fitted.

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