Chicagoland MG Club
Engine to Gearbox Alignment
Here's a tip for MGs that is seldom mentioned in the workshop manuals (but should be). This one applies to MGA and MGB B-Series engines (1500-1800cc), and possibly AH Sprite and MG Midget A-Series engines (850-1275cc).
I saw a message on the net refering to difficulty in getting the MG clutch splines and bellhousing bolts aligned when mating the engine to the gearbox. This message recommended drilling out larger two holes in the engine rear plate that are "widely held to be mis-positioned by the factory jigs". DO NOT DO THIS !!!
The upper right hole near the engine block oil outlet fitting, and the lower left hole where the exhaust brace attaches are not misaligned, and should not be drilled out. Those two holes will be spot on for location, but are intentionally a smaller closer fit on the bolts than the others. These two holes and bolts serve as locators (similar to dowel pins) to maintain the concentric alignment of the gearbox input shaft to the engine crankshaft. If you just put those two bolts in first (or at least tighten those two first), then the rest will slip right in with your fingers with lots of clearance, and your input shaft and clutch and starter gear will be properly aligned.
Back to MGB Tech Tips