That's a different size speedo... it wouldn't fit in your dash. I think the
gear trick would be a lot easier -- Moss shows a 20 and a 21 tooth pinion
for this application, so you have a choice. I think Skye's site has a chart
of speedo variants. A long time ago we had a correspondence regarding the
effect of different pinions, and calculated some possibilities. But I'm
afraid we didn't consider your case -- we both have 66 Bs.
At least, I don't think you have to dismantle the tranny -- it just goes in
where the speedo cable inserts.
on 5/21/02 6:43 PM, James Schulte at schultejim@prodigy.net wrote:
> Listers
> Does anyone have a 1250 speedo off a 1967B laying around they would be
> willing to part with? Has anyone tried this move to rectify the problem?
> Jim
>
> Larry Hoy wrote:
>
>> All cars after 1973 had 1000 tpm speedos. So afer 1973 they used the
>> gears at the transmission to compensate for OD or Non-OD cars. Your 73
>> OD was set up for a 1280 TPM speedo. It would be easy to swap 73 speedo
>> for the 78 speedo...if they were the same size. So you could look for a
>> 1280 speedo from a 1967 car.
>>
>> There are some transmission speedo gear issues you could deal with but I
>> don't have all that information off the top of my head. Perhaps someone
>> else does.
>>
>> Good luck.
>>
>> Larry Hoy
>>
>>
>>> Listers,
>>> Sent my 1000 Smith Speedo for my 78B to Niosenger's 5 weeks
>>> ago to have it calibrated. Got a call on answering machine
>>> to call. Did that this morning and to my total surprise,
>>> they can't calibrate it. Dan said that the late speedos have
>>> cheap plastic gears and they can't be fixed. I have a 73
>>> engine and O/D in my 78B. When I did the rolling test he
>>> recommended, counting the turns the speedo cable makes with a
>>> paper clip attached, it came out really high. As in 19 and
>>> 1/4 revolutions. He
>>> said it should have been around 14 and some. How could it be so far
>>> off? I have 185/70 R14 Firestone tires on rothstyle wheels.
>>> The speedo reads 80 when I'm actually doing about 60 mph. Is
>>> the gearing in the O/D
>>> that far off? Any suggestions?
>>> Jim
>>> 78B for sale
>>> 70B
>>> seeking MGCGT when 78B is sold.
>
--
Max Heim
'66 MGB GHN3L76149
If you're near Mountain View, CA,
it's the primer red one with chrome wires
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