Speedo

Chris Blunt · Post by **Chris Blunt** » Mon Apr 28, 2014 3:03 pm

My kilometre speedo reads about 20k too high, that is compared to the GPS, coincidentally my Alfa Spider is exactly same, I am pretty sure the odometer is pretty accurate. My question, is there any adjustment on the S1 cars?

Chris

kingzetts · Post by **kingzetts** » Mon Apr 28, 2014 4:11 pm

Chris,
No adjustment available. But you may find this thread useful
http://www.etypeuk.com/forum/viewtopic. ... highlight=

If your odometer is recording elapsed mileage correctly but the indicated speed is too low, then your needle is probably misaligned. If the speed error is constant (ie is 20k too high at all speeds) this is almost certainly your problem. The needle can be moved by taking the instrument out, removing the bezel and glass, pulling the needle off and repositioning it on its shaft. Not for the faint-hearted or ham-fisted but I've done it and so have others. Or you can send it away for repair.

If the odometer is also in error, and the speed error is proportional to speed, (eg 10% high at all speeds) then you have a gearing error. Check the gearbox angle drive ratio before assuming you have the wrong instrument gearing ( as described in the linked post). Otherwise you have a speedo mismatched to tire diameter and/or final drive ratio in which case a specialist can re-gear the speedo.

christopher storey · Post by **christopher storey** » Tue Apr 29, 2014 7:55 am

To effect the alteration Kingzetts suggests you don't need to take the needle off. The needle is an interference fit on the shaft , so what you need to do is to take the instrument to pieces so that yo can hold the alloy disc which drives the speedo, and then just turn the needle centre hub until you have the adjusted reading. Before you do this, lift the needle over the wire stop at the bottom left and see where it comes to rest . It should be adjacent to a very small white spot about 15 degrees below the stop - if it isn't then it is probably your answer, and you can use the same test after you've turned it to see if you've got it right

Chris Blunt · Post by **Chris Blunt** » Tue Apr 29, 2014 8:12 pm

Thanks for the info, I am away from home at the moment, so will check out all possibilities when I get back in a few weeks, I am sure the tyres are standard size but one important point I didn't add was that this car started off as a RHD MPH and was converted to LHD and kilometers around 1969 when it went to a Spanish owner. Is there any difference with the speedo gearing on the cars that were for the European market?

The idea of getting intricate with the speedo internals fill me with dread, I think the idea of appearing to go faster than I actually am is the better option for the moment

Many Thanks. Chris Blunt

christopher storey · Post by **christopher storey** » Wed Apr 30, 2014 6:39 am

There should be no difference in the gearing of the right angle drive. However, each speedo is tailored to a particular axle ratio revealed by the code on the face of the speedo e.g. 6322/09 . There is a list on the stickys in the technical info on this board which tells you what each speedo is designed for . If, however, your problem is 20kph overread at all speeds, rather than getting progressively bigger as you go faster, then it is unlikely that it is just a speedo mismatch

Edit : here is heuer's original posting on the subject

I found the table below in the Jag-Lovers archive detailing speedometer serial number, turns per mile, axle ratio and tyres. You will see Jaguar produced a wide range of speedos for various applications. The list is missing some TPM figures so if you have one of the listed speedometers and can provide the TPM figure (will be on the right hand side of the needle boss) I will include them.

Series 1 3.8 - All fitted with 6.40x15 RS5 tyres

Number; TPM; Diff; Calibration

SN 6322/00 ; 1216; 3.31; mph
SN 6322/01 ; 760; 3.31; kph
SN 6322/02 ; 760; 3.31; kph (Germany/Italy)
SN 6322/03 ;1312; 3.54; mph
SN 6322/04 ; 820; 3.54; kph
SN 6322/05 ; 820; 3.54; kph (Germany/Italy)
SN 6322/06 ;1086; 2.93 ; mph
SN 6322/07 ; 678; 2.93 ; kph
SN 6322/08 ; 678; 2.93 ; kph (Germany/Italy)
SN 6322/09 ;1120; 3.07; mph
SN 6322/10 ; 700; 3.07; kph
SN 6322/11 ; 700; 3.07; kph (Germany/Italy)

Series 1 4.2 - various tyres as specified

Number; TPM; Diff; Calibration;Tyre

SN 6322/00A; 1216; 3.31; mph; 6.40x15 RS5
SN 6322/02A; 760; 3.31; kph; 6.40x15 RS5
SN 6322/03A; xxxx; 3.31; mph; 6.40x15 SP41
SN 6322/05A; xxxx;3.54; kph; 6.40x15 SP41HR
SN 6322/09A; 1120; 3.07; mph; 6.40x15 RS5
SN 6322/11A; 700; 3.07; kph; 6.40x15 RS5
SN 6322/13; xxxx; 3.31; kph; 6.40x15 SP41
SN 6322/14; xxxx; 3.54; mph; 6.40x15 SP41HR
SN 6322/27; xxxx; 3.31; mph; 6.40x15 SP41HR
SN 6322/28; xxxx; 3.31; kph; 6.40x15 SP41HR
SN 6322/29; xxxx; 3.54; mph; 6.40x15
SN 6322/30; xxxx; 3.54; kph; 6.40x15
SN 6322/31; 1020; 2.88; mph; 6.40x15
SN 6322/32; 638; 2.88; kph; 6.40x15
SN 6322/33; xxxx; 3.07; mph; 6.40x15 SP41
SN 6322/34; xxxx; 3.07; kph; 6.40x15 SP41
SN 6322/35; xxxx; 3.31; mph; 185x15 SP41
SN 6322/36; xxxx; 3.31; kph; 185x15 SP41
SN 6322/37; xxxx; 3.54; mph; 185x15 SP41
SN 6322/38; xxxx; 3.54; kph; 185x15 SP41
SN 6322/39; xxxx; 2.88; mph; 185x15 SP41HR
SN 6322/40; xxxx; 2.88; kph; 185x15 SP41HR
SN 6322/41; xxxx; 3.07; mph; 185x15 SP41
SN 6322/42; xxxx; 3.07; kph; 185x15 SP41

If you want to work out the expected speed from different axle ratios, gearboxes and tyre sizes, 5Speeds.com has a neat downloadable calculator: http://www.5speeds.com/rpm.htm which is fun to play with! Another online calculator is available here: http://wahiduddin.net/calc/calc_speed_rpm.htm

If anyone fancies a DIY approach to speedometer calibration Mike Frank has an excellent write up on his site: http://www.westnet.com/~mfrank/Speedometer/Smiths.html

The SBM Society also has a good write up on speedo repair and calibration.
http://www.sterlingbritishmotoringsocie ... Repair.pdf
_________________
David Jones
S1 OTS OSB.; S1 FHC ODB #860294

Chris Blunt · Post by **Chris Blunt** » Thu May 01, 2014 5:16 pm

Thanks Chris,

When I get back home in a few weeks the serial number on the facia of the speedo will be the first thing I will look at, then drive the car to see if the error is progressive or constant,
I can compare the speeds with the TomTom, or even the GPS on my bike computer so it should be straight forward

Thanks again,

Chris Blunt

rossbraithwaite · Post by **rossbraithwaite** » Wed Apr 29, 2015 12:39 pm

Hello All,
I realised my speedo was a bit shy when I got caught speeding recently. I downloaded an app that suggests that the speedo is 5-10mph out at 70mph. I checked it over a journey that Google maps says is 28.3 miles. See photos and screen shot here:

https://plus.google.com/photos/10188930 ... 0M3Rnab8UA

The trip meter appears to be accurate but the odometer is way over. It seems odd that one part of the speedo is accurate and the other 2 are not. Does this suggest that the speedo cable is not the culprit? Car has been converted LHD to RHD so that may be the source of the problem although I don't think the diff was changed.

Thanks,
Ross

christopher storey · Post by **christopher storey** » Wed Apr 29, 2015 6:55 pm

Ross : the speed reading and the odometer are by and large independent of each other. The odometer is a purely mechanical device, as is the trip meter. How they respond to the turns of the cable is governed purely by the plastic gears which are fitted . The speedo, on the other hand, is not a mechanical instrument , but is driven by magnetic flux created by the revolving rhomboid shape magnet driven by the speedo cable, the magnet revolving inside the aluminium disc which carries the shaft with the needle attached to it.

Your problem suggests a mismatch of trip and main odometer gears, possibly compounded by a defect in the magnetic part of the instrument, or else ( if but only if the error is constant at all speeds ) the needle having been twisted on the shaft

rossbraithwaite · Post by **rossbraithwaite** » Thu Apr 30, 2015 7:43 am

Thanks Chris.
As I was stationary in both photos of the speedo it would seem that the needle has been twisted on the shaft.
As for the odometer; seems the problem must be internal.
Thanks again.

kingzetts · Post by **kingzetts** » Thu Apr 30, 2015 11:25 am

Ross,
If you were stationary then your speedo needle is definitely misaligned. If you remove the glass, by carefully bending the bezel to allow it and the glass to be removed, you can zero the speedo needle. Look carefully and you will see a small white dot on the face just below the "I" of "ignition. If you carefully lift the needle upwards at its tip so it clears the small pin which it should rest against when stopped, and allow it to find its rest position at which it should point at that dot. If not, pull it off (carefully) and relocate so it does so. Then lift the tip carefully back over the stop pin.

rossbraithwaite · Post by **rossbraithwaite** » Thu Apr 30, 2015 12:16 pm

Thanks John.
That's worth a try for the speedo reading.
As for the odometer; it is out by a factor of 1.47. Is it at all possible that it is reading kilometers instead of miles?

kingzetts · Post by **kingzetts** » Thu Apr 30, 2015 1:11 pm

As Christopher says, the odometer and trip recorder should record the same distances covered. If they are not doing so then they are not geared together correctly and you'll need to find a specialist to help you sort that out - Speedograph Richfield, Speedy Cables, John D Ostick are three that spring to mind.

Post by **Heuer** » Thu Apr 30, 2015 1:23 pm

rossbraithwaite wrote:Is it at all possible that it is reading kilometers instead of miles?

Check the number on the speedo against the list on the previous page.

rossbraithwaite · Post by **rossbraithwaite** » Thu Apr 30, 2015 9:12 pm

Thanks David.
Strangely it seems to be marked SN6322/01 which means it should be kph but it is definitely mph.
Anyway, as the tyres are 185R15 I assume that the tyres and speedo are not matched. I still can't explain the difference between trip and odo with the trip meter being bang on.
Thanks again to all. I will try the speedo calibration soon.
Thanks,
Ross

MLBS3V12 · Post by **MLBS3V12** » Sun May 03, 2015 2:01 pm

Hi there,

what about this supplier:
http://www.speedograph-richfield.com/ht ... meter.html
They repai and/or adjust your speedometer.

Cheers
Michel

Duckham · Post by **Duckham** » Mon May 04, 2015 5:24 am

kingzetts wrote:Ross,
If you carefully lift the needle upwards at its tip so it clears the small pin which it should rest against when stopped, and allow it to find its rest position at which it should point at that dot.

John - at least on my speedo the stop pin is actually a spring wire that can be pushed down flush with the dial, allowing the needle to swing down to the calibration dot.
Joe

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The 'E' Type Forum

Speedo

#1 Speedo

#2

#3

#4 Speedo reads high

#5

#6 Speedo gearing

#7

#8

#9

#10

#11

#12

#13

#14

#15

#16