I too wanted two horns, but on a Midget rather than an MGA. I got
the second horn mount bracket from a parts car. (I had bought the
bloody thing because the owner would not sell me just the removable
hard top, but that's another story). But in pooling the horns from
my Midget, MGB and this parts car, only two horns worked, both low
notes ! (Sounded kinda funny, too). So, I drilled out the rivets
on one of the high note horns, and "rebuilt" it. This mostly consisted
of cleaning everything, replacing broken exterior connectors, re-
assembly and adjustment. I will now attempt some ASCII art.
(don't try this without adult supervision, kids, it's dangerous) :)
Point Gap ________ Slot in top of threaded cylinder
Adjusting Screw < >
| __ < > __ Lock Nut
v [ >< >< ]
Exterior [ >< >< ] Horn Body
Dbl Spade ---------->< ><----------
Connector | ________>< ><________ |
| T | | { C } [ ] { C } | | |
_____+____|__| | { o } [________] { o } | |_______+____
| ____+____|____| { i } ________ { i } |_________+__ |
| | | | { l } [ ] { l } | | |
| | | u {____} [ ] {____}------------+ | |
| | ----------=------___[ ]___ | |Rivets
v | | ----------=- [_ _] | | v
--- | Contacts [ ] Diaphram | |___
___________________________[ ]__________________________
-------------------------------------------------------------------
--- | | ---
x | | Lower Horn Body w/Trumpet | | x
When energized, the coil draws the diaphram up, causing the shoulder
on the central pillar to open the contacts. The diaphram then springs
back to its original shape, the contacts make contact :) and the cycle
begins again. The threaded cylinder adjusts the 'pull' of the coil,
too much and the horn draws too much current, too little and the horn
will not sound, as the coil cannot draw the diaphram up enough to break
the circuit. Early lock nuts are solid, later ones are folded sheet
metal, and easily buggered up (sp?). The point gap adjusting screw is
hex head, not slotted (IMS) (If Memory Serves). I don't know if MGA
horns are the same, but the horns off my 69 Midget and MGB appear
identical.
John F. Kolb (aka) | Spelling checker by LUCAS.
kolbj@ymv5.ymp.gov | If Lucas built weapons, wars wouldn't start either.
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