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MG MGB Technical - LHD Speedo cable

Can anyone describe exactly where the speedo cable, and indeed choke cable run on a left hand drive 3 synchro car, in particular where they go through the bulkhead.

Thanks

Colin
Colin Parkinson

Colin
As far as im aware it goes up through the tunnel on our drivers side by the starter hump then across the car to the speedo but there could also be a special angle drive at the top on some cars.


Ste
Ste brown

Colin,

I feel I can help.
On the joined pic. I noticed the speedo cable hole on the bulkhead for a 3 sync. LHD car. The leftmost hole is dedicated for Tacho cable.
For the choke cable, I send you a pic. noon.
Best regards.
Guy RENOU

Ooops, Picture too large, resized it down.


Guy RENOU

Second pic.
The choke cable passes thrugh bulkead inside the incated gromet, below pedal box.
You can see the relaying and vaccum switch and wiring for the Type D overdrive on the left hand side too.
Hope that help.


Guy RENOU

Thanks for that Guy. I have found choke cable hole, and will check out the speedo cable hole tomorrow. I assume that is on the right hand side of the dash?

The picture showing the pedal box? On the right hand side you have a cable coming through the bulkhead. What is this cable please? Bonnet release?

Colin
Colin Parkinson

Colin,

Quite right the rightmost cable is the bonnet release one, passing inside the inner front wing boxes through the bulkhead. I could add a picture from cocpickt inside if you need it and a pic of dash, please let me know.
Guy
Guy RENOU

Guy I have found the 2 holes. They had plugs in and were painted over!
So where does the cable go once it is through that hole, because it still does not come through the bulkhead.
I am confused!

Colin
Colin Parkinson

The bulkhead is double-skinned, you need to push it exactly square and straight to appear through the second hole (or maybe look from the footwell for light coming through both holes). That's for the choke, the speedo goes down through a hole at the top of the clutch footrest in the right-hand footwell, that's not double-skinned.
Paul Hunt 2010

Colin,

I confirm Paul hunt's solution.
More precisely, on the second sent pic., from the engine bay, the speedo cable output hole is located between overdrive vacuum switch and pedal box, choke cable commes out below pedal box just under brake MC, via the grommet located by a red arrow on the pic.
Guy RENOU

Paul, are you saying that Guy's first pic is showing the wrong hole for the speedo cable?

This is left hand drive.

Choke, that is OK.

Colin
Colin Parkinson

Colin - I'm pretty sure that originally the speedo cable on LHD came up the same hole then crossed over behind the dash, hence the second right-angle drive. I have heard elsewhere that later on it went straight through the bulkhead i.e. didn't need the speedo right-angle drive, but then it still has to turn downwards and go across to the RH side of the gearbox inside the engine compartment, which doesn't seem straight-forward. Both (early and late) Parts Catalogues show one at the gearbox for all cars, and one at the speedo for LHD cars, and other sources indicate one at each end as well. Neither of my (RHD) cars have one but you can get away without the gearbox one with a longer cable, although it isn't such a neat run. There seem to be no less than 13 speedo cables used over the various years and markets, ranging from 3' 9" to no less than 6' (which rather beggars belief) the longer ones could well have avoided the neccessity for an angle drive at *either* end. It all depends how 'correct' you want to be, to be honest neither books nor examples can be taken as gospel, unless the latter comes with a copper-bottomed guarantee that it hasn't been molested.
Paul Hunt 2010

Hi Paul, I am not looking for total originality, and have angle drives for both speedo and gearbox, if necessary.
But I would like to get it right if possible!

Guy, are you saying that the speedo cable comes through the second skin through the large hole directly under the hinge slot? Paul / Ste what do you think?

Colin
Colin Parkinson

Colin
I was with Paul on how it runs until i looked in my reference books and saw a picture of a left hand car with it going through the large hole in the firewall,so thats how it must have gone.

Ste
Ste brown

Colin,

"Guy, are you saying that the speedo cable comes through the second skin through the large hole directly under the hinge slot?"

Absolutly yes, speedo cable comes out the cockpit bulkhead through the arrowed hole on my first pic. and enters into the engine compartment via the large hole in the fire wall. Both holes are aligned. I add one more shot from engine compartment, clearly showing out both aligned holes and below hinge slot..


Guy RENOU

Clausager has a picture of an American 74, could this be the speedo cable (attached)? Can't imagine why any number of Americans haven't chipped in by now ...


Paul Hunt 2010

OK, I see the source of mismatch.
On mk1 pull handle like mine, there is only one large hole below the hinge slot that should be the same on any 3 sync. gearbox cars?
On Paul's picture, we can see the narrow one with the speedo cable and the larger one behind the rear carb air filter entry.
Guy RENOU

Ste and Guy thanks for that. Problem solved. That was until Paul put his pic on!

Paul I do not have that hole on my '65 shell, but I think the speedo cable comes through the big hole if you look closely, and runs across and under the heater hose.
I do not know what the other cable might be, unless it is the heater control cable.

Colin
Colin Parkinson

This thread was discussed between 15/03/2010 and 20/03/2010

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