Wrong Speedo reading

[LOZZA s1]

Hi troops , Have fitted a Speedo and a T/case out of a 2A to a 1957 series 1, have found that the speedo reads 50mph at 60km and 60mph at 70km, I thought matching speedo and t/case out of same veh would have gave correct reading , or is the series gearbox a different ratio, is there a easy fix or live with it.

[JDNSW]

The Series 1 and 2a transfer case are interchangeable, but in any case the speedo takeoff is at the back of the case and unlike the coil sprung Landrovers, there is only one type of worm and gear takeoff. Over reading grossly like that would be most unusual - 50mph is 80kph! More usual is under reading or erratic readings due to the worm on the output shaft not being secure.

However, you should also be aware that there are two* different speedos, which depend not on the Series, but on the tyre size. Those standard on the short wheelbase are set for 6.00x16 tyres, and those standard on the lwb are set for 7.50x16 tyres - but the larger tyres and hence speedo were optional on the swb 2a. They can be distinguished by the very small numbers at the bottom of the dial, but I don't know the numbers (revolutions per mile or km). And at this length of time since manufacture, heaven knows where the speedo came from!

* There are actually a lot more - trip meter or not, km or miles, warning lights incorporated after 1967, higher maximum speed on sixes etc as well as the ratio set by tyre size.

A changed diff ratio will also change the reading, but such changes are fairly rare for Series 1 and in any case would cause the speedo to under read, not over read.

The only remedy I can think of would be to have the speedo refurbished.

John

[LOZZA s1]

As my ser1 runs 7.00x16 tyres, the speedo is smooth when working , not eratic at all, has been fitted for a couple of months now, I did not know they came with different speedos, I thought it was a gearbox/diff ratio change

[gromit]

Here is an old thread on speedo gearing.

http://www.aulro.com/afvb/series-land-rovers/156644-series-speedo-tyre-sizes.html

Colin

[wrinklearthur]

Over reading is caused when the speedo cable inner end float isn't free to move into a float position and pushes the spinning driver plate inside the speedo head further into the driven plate .

This is usually caused when the square hole that drives the inner at the transfer box has a broken 'inner' piece, or rust, or dirt inside it.

That obstruction prevents the 'inner' seating into the shaft which causes the other end to project further into the speedo head.

I have found with a poorly made, new speedo cable, the 'inner' square has needed easing slightly by a subtle grind on it's squares, to make it a sliding fit in those square holes.

.