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MG TD TF 1500 - Speedo correction gearbox

Hello everybody,
Does anyone know a european contact for such a gearbox ? I need one after 4.3 rear end conversion.
Unfortunetely, Declan is still not able to deliver for the moment.

Laurent.
LC Laurent31

Try Speedograph Richfield in the UK.

Tom Lange
MGT Repair
t lange

Laurent
I got a quote from Speedograph Richfield a few years ago of GBP140 for a conversion box to attach to the speedo. They could also offer such a box inserted in a new cable.
However to overhaul the speedo would have been somewhat less at GBP95 - which included recalibration. The prices would of course have changed by now.
Personally I think recalibration is a better solution.
Sorry I have to go and watch the football now!
Tim
TD 1580
Tim Wilkinson

Recalibration could be a solution for the speedometer. But the odometer would still be erroneous.
I doubt they can change the gears inside.

Laurent.
LC Laurent31

Just successfully completed this exercise myself. The odometer can be easily corrected by replacing both ratchet gears. Not difficult once the correct number of teeth are determined and sourced. If you'd like a 'how to' Laurent email me off line. Cheers
Peter TD 5801
P Hehir

Peter,

Do you have a source for the ratchet gears?

Thanks,

Jim
J Barry

Not really Jim. I had a pair made in England but I don't want to divulge the source simply because this is his business and he was doing me a one off favour. I'm still searching for a manufacturer here who is prepared to knock a few up for something less than the price of a sheep station. One clock maker wanted $750 for the pair! Essentially it's a two part problem. The keyed hole in the centre and the teeth themselves. I believe I can get the gears made without the keyed hole at a reasonable price but the other bit is the problem. The English solution was to turn down a 64 toothed gear on a lathe (I have a NOS source for those) and then sweat on the correct ratchet ring. I have another two flat faced speedos that I need to convert to 4.3. One will be my spare and the other I'll sell. Cheers
Peter TD 5801
P Hehir

I found this on line (link below), but I have not contacted them. I had my speedometer calibrated by Nisonger to compensate for the Hi-Gear 5-speed, but they could not calibrate the odometer as the gears were not available. By the way, my push test showed 1165 revolutions per mile (versus 1600).

Jim

http://www.odometergears.com/products/Jaeger-Smiths/All/37
J Barry

Jim the attached pic shows the odometer and tripmeter ratchet gear that needs to be replaced to effect an accurate reading when changing the diff ratio. The other item in the pic is the shaft. The keyed relationship between the two that I mentioned above is clearly evident. I'm unable to comment on the gears shown in the link except to say that I don't recognize them from my flat faced chronometric instruments. The TPM figure I used to determine the number of teeth required on the ratchet gears was calculated by Bud (thanks Bud as the math was beyond me) and I have every reason to believe that his calculations are very accurate. I can say that the 5.125 used 64 teeth and that the 4.8 used 61 teeth. I went with 54 teeth for the 4.3 Cheers
Peter TD 5801


P Hehir

Peter, are those simple ratchet teeth or something more complex? Many years ago Even a novice like myself was able to cut a set like that with a vertical mill and an index head. Shouldn’t be difficult for a machinist with the right equipment.
Is the locating protuberance in the centre part of a circle? If it is it could be fashioned in a blank disc by drilling a suitable offset hole before boring the full hole then soldering in a short length of rod.
Just ideas from a campsite in Somerset with nothing to occupy my hands or brain.
Chris
C I Twidle

Hi Chris. I'm envious. It's bloody cold here. I have no skills in the milling department but what you suggest sounds right for both the teeth and the 'key'. I'd thought that a 100 mm length of brass gear rod of the correct diameter could have the teeth cut and then sliced off like two cent pieces. The bit in the middle (the circle with the protuberance) is more difficult. Can you email me off line? Cheers
Peter TD 5801
P Hehir

A few years ago I installed a T9 gearbox and also made a drawing of a speedo gearbox to be fitted to the speedo, but I can´t find it just now. However, it was a very simple device, mainly two shafts with delrin pulleys, an O-ring and a box with cover also in delrin. By doing so the direction of rotation will be same in as out. Using two gears will change the rotation.
Y Strom

You need three gears ! The centre gear is an idler gear and the number of teeth is not critical.

Regards
Declan
Declan Burns

This thread was discussed between 10/07/2018 and 15/07/2018

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