[Healeys] Speedometer gearing

[John Vrugtman]

If you will check the parts manual, it will show a rear end ratio of 
3.545 for non overdrive cars and 3.90 for those fitted with overdrive.

John
64/66 BJ8s

On 5/15/2011 4:25 PM, Per Schoerner wrote:
> Hi
> I'm trying to figure out the speedometer drive gearing inside the 
> different gearboxes. I'm helping a friend with his speedometer. He has 
> a 100-6 which was delivered without overdrive. My own car is a 3000 
> mk2 with overdrive. The rear axle gear ratio on these cars are the 
> same, as far as I understand, according to Clausagers book. But the 
> speedometers are different. The 3000 speedometer needs 980 revolutions 
> per minute to show 60 (MPH) and advance the odometer 1 mile in one 
> minute. The 100-6 speedometer needs 1575 revolutions per minute to do 
> the same thing. Note that both cars are imported from the states, so 
> both are speedos are in miles.
> Does anyone know what the difference is? Well, I can calculate it of 
> course, but I thought asking on the list would be safe in case I have 
> got something wrong.
>
> Best regards, Per from Sweden.