|
| My last question concerns the speedometer. It reads high, by at least
|15-20%
| although I haven't figured out exactly how much high it is. I mentioned
| that I thought it was high to the guy I bought it from and he said it was
| because it had bigger than stock tires. This doesn't seem right, it should
| read slower, shouldn't it? What can be done to correct a speedometer? Is
| replacement in order? Could it be the cable?
|
| I think speedo shops can change out the speedo drive gears in the
| tranny, or calibrate the instrument itself. I have the same problem
| on my TR-6. Cable is unlikely, 1 rotation in=1rotation out of the
| cable. Bigger tires should make it read slower, yes, but remember
| that if a previous owner installed Webers you may also have a
| non-standard rear-end gear ratio. ( I *think* the MGB speedo drive is
| on the tail of the gearbox; if it's on a wheel disregard all this.)
|
Most britcars use different rear end ratios for overdrive cars then for
"normal" cars. The diffs in overdrive cars are lower speed (higher ratio
numbers) because in fourth/over the drive shaft is going 20 to 30% faster
then the engine. Some one may have put an o'drive diff in your car to give it
jackrabbit start at the expence of top speed. Was it autocrossed? If this
is what's happening. Look up the part numbers of the speedo drive gears,
Both the gear that is on the end of the cable and the one inside on the
transmission tailshaft. If your lucky you may find that both the overdrive
trans and the normal trans use th same gear on the tailshaft but different
gears on the cable end. If so get a gear for an o'drive box, pull your cable,
presto-changeo , your done.
good luck , dickn
|