Mike Terry Posted April 5 Share Posted April 5 Hi, I have a 2003 Caterham with 1800 K series and a 5 speed type 9 Ford box. My speedo is vintage 2002 and not programmable. Now on 13” rims my speedo speed can be well under my satnav speed. I have been in contact with Caerbont Automotive and identified a replacement. The calibration instructions I have been given are: On a prop shaft: - Calibration number = (wheel revs per mile/Km) x (diff ratio) x (number of magnets or bolts). I have a cable drive off the gearbox but at some stage this mechanical measurement gets converted into an electric signal. This is fed into the speedo via an 8 pin plug. I am ok with the first two parts but when is states – ‘number of magnets or bolts’ what does it mean and where would I look? Cheers Mike Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted April 5 Member Share Posted April 5 I'm not sure what you've got... the Speedometer Guide. ... 9 minutes ago, Mike Terry said: I have a cable drive off the gearbox but at some stage this mechanical measurement gets converted into an electric signal. This is fed into the speedo via an 8 pin plug. There are several adapters that fit into a Type 9 gearbox that gives an electrical output. Do you have something that looks like this? Photos, please. ... 9 minutes ago, Mike Terry said: I am ok with the first two parts but when is states – ‘number of magnets or bolts’ what does it mean and where would I look? That would apply to a set-up where the signal is taken from a wheel or a driveshaft, as documented in the Guide. But not to one where it's taken from the gearbox. Jonathan Link to comment Share on other sites More sharing options...
Area Representative Golf Juliet Tango Posted April 5 Area Representative Share Posted April 5 Caerbont recalibrated my speedo about 35,000 miles ago. It now reads about 10% over (at the limit). Link to comment Share on other sites More sharing options...
Mike Terry Posted April 5 Author Share Posted April 5 Yes I have with what looks like a heavy metal cylinder about 30mm in length with wires attached. Ok, so that is where mechanical motion is converted into electrical. From a distance, that does not look easy to get at and not something easy to take apart to check magnet? Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted April 5 Member Share Posted April 5 14 minutes ago, Mike Terry said: Yes I have with what looks like a heavy metal cylinder about 30mm in length with wires attached. Ok, so that is where mechanical motion is converted into electrical. From a distance, that does not look easy to get at and not something easy to take apart to check magnet? I think that access/removal/refitting will be the same as with the original mechanical right-angled cable drive... tight but possible. You can increase clearance by slackening the gearbox mount and yanking the tail to one side. But do you need to do that, or only to change the calibration? That might be possible at the instrument rather than the sender. Could you add some photos of the face and rear of the instrument. That should allow someone to identify how it can be recalibrated. Jonathan PS: The easiest way to establish true speed is now with a GPS device/ app on a smart 'phone rather than with measured distances on the road. Link to comment Share on other sites More sharing options...
Andy135 Posted April 5 Share Posted April 5 35 minutes ago, Mike Terry said: Yes I have with what looks like a heavy metal cylinder about 30mm in length with wires attached. Ok, so that is where mechanical motion is converted into electrical. From a distance, that does not look easy to get at and not something easy to take apart to check magnet? Sounds like a hall effect speed sensor. Where is it located on the car? Can you post a picture? Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted April 5 Member Share Posted April 5 44 minutes ago, Mike Terry said: Yes I have with what looks like a heavy metal cylinder about 30mm in length with wires attached. Ok, so that is where mechanical motion is converted into electrical. From a distance, that does not look easy to get at and not something easy to take apart to check magnet? Ah... I assumed that was describing what's attached at the gearbox where the right-angled drive usually connects. Where is this? Jonathan Link to comment Share on other sites More sharing options...
Mike Terry Posted April 5 Author Share Posted April 5 Hi Jonathan, To answer your question, It is the calibration of a new speedo I am trying to sort out, nothing else. Link to comment Share on other sites More sharing options...
Mike Terry Posted April 5 Author Share Posted April 5 yes it is located at the back of the gearbox on the right hand side when looking to the front of the car Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted April 5 Member Share Posted April 5 Thanks for the photos. Nearly there. Jonathan Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted April 5 Member Share Posted April 5 5 minutes ago, Mike Terry said: yes it is located at the back of the gearbox on the right hand side when looking to the front of the car Thanks Jonathan Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted April 5 Member Share Posted April 5 The settings for that EES3-1A32-00B are in the Guide. I'll see if I've got any more information. Jonathan Link to comment Share on other sites More sharing options...
Mike Terry Posted April 5 Author Share Posted April 5 This is the calibration guidance that CAERBONT sent me for the new Speedo they recommend. Its attached below Guide on Programming new Speedometer PIL042-E.pdf Link to comment Share on other sites More sharing options...
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