This "solution" applies only to the MGB five main bearing engine and gearbox combination with the tall rear plate. If this engine blows the core plug at the rear of the engine block, the repair would ordinarily require removal of the engine and disassembly of the clutch and flywheel to remove the engine rear plate for access to this core plug. Ah, but the Betson Bolt may come to your rescue.

At 09:49 AM 6/8/05 +0100, Chris Betson of Octarine Services wrote:
>"Yes, I originally came up with the solution to the blown rear plug without having to remove the engine. The BBS faternity dubbed this the "Betson Bolt"!! Although I am sure that others may have also developed this solution since it is fairly obvious if you sit and contemplate the amount of work it saves!
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>Simply take one of the thick washers used to clamp the inlet & exhaust manifolds to the head and tap it out to 3/8 UNF or a suitable metric equivalent. You also need a matching screw (thread all the way to the head) about 1 inch long. Take the washer with the coned side facing the rear engine plate and slide it in till it locates over the hole in the backplate and insert the screw. Tightening the screw will force the washer against the backplate and the core plug into its recess.
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>I improve the design slightly by turning a flange into the washer so it locates positively in the hole in the backplate, but this is not essential."