I think we need a bit of clarification when we talk about fasteners used
on the MGB. Some folks are confusing head sizes with thread sizes.
If we are talking about fastener head sizes, there are only a few on the
B which use Whitworth (or British Standard) wrenches. British Standard
head size is similar to Whitworth head size, but differs by 1/16", I
believe. The few fasteners that use these head sizes on the B are the
SU fuel pump banjo fittings, the filler plugs on the shocks, HS carb jet
holders and mixture nuts, and (as Lawrie pointed out) the oil pressure
relief dome nut. I also believe that the distributor clamp bolt (or nut)
is also Whitworth/BS head size, since I have noticed that a standard SAE
7/16" wrench is always a bit tight on the fastener, yet one of my old
Whitworth wrenches slips on like a glove.
Part of the confusion is that the old Whitworth head measurement became
known as British Standard (BS). This is entirely different from the
modern thread pitch known as British Standard Fine (BSF). BSF is for
all intents and purposes the same as the SAE's United National Fine
(UNF). That's why you can go down to the local 'Murrican hardware store
and find bolts whose thread size will work on a B.
Clear as mud? I hope so, because this should be enough BS about BS!
Cheers, PK
|