billg Posted February 22, 2014 Report Share Posted February 22, 2014 Hi has anyone fitted a Halda Speedpilot MkIV to a TR3A? The T gear box has threads that don't match the Speedo head cable. Do I need to get a particular gearbox or can I rig something With an new special cable if I can source the right cable ends? Had anyone done this via say Speedy Cables Or Don Barrow? Or so I need a machinist to make me an adaptor? I'm fitting the Speedpilot ins dummy glove box lid. Will try and post a pic when I'm on my laptop. Regards Bill G@NB Quote Link to post Share on other sites
valvebounce Posted February 24, 2014 Report Share Posted February 24, 2014 You need a T-Gear with the correct thread on the union. I haven't done it for a while but most Halda specialists used to offer to swap T-gears to match your car (if you ask nicley). I'd ask Haldaman or Autochron if they can help. Quote Link to post Share on other sites
billg Posted February 24, 2014 Author Report Share Posted February 24, 2014 Hi thanks for the links , will let you know how I get on Regards Bill G@NB Quote Link to post Share on other sites
billg Posted March 8, 2014 Author Report Share Posted March 8, 2014 Hi Valvebounce! Just to say Clive at Autochron was very helpful and Sorted my out very speedily. The right T-gearbox (between the speedo cable and the speedo head)for a TR2/3/3a/4 is a V12N which Has an 8:1 reduction feed to the L-gearbox on the back Of my Speedpilot( it has a built in reduction of 7:1) Thus the revs to the Speedpilot are reduced by a factor of 60. There are screw adjustments. On the base of the Speedpilot To let you calibrate the built in odometer to an exact know distance Ideally a 1mile or 5 mile bit of road that is that exact distance. A SatNav or Garmin might help here and either put a mark On a straight side road or a couple of pegs. Once adjusted for a set of wheels/tyres no further adjustment needed Except when on an actual really as I believe the organisers Will nominate a marked stretch of road to be a particular length. There is another adjuster in the Speedpilot which lets you trim The final calibration to the organisers measured mile etc. Next problem is to find a navigator! It might be easier To find a driver though! Regards Bill G @ NB Quote Link to post Share on other sites
billg Posted March 8, 2014 Author Report Share Posted March 8, 2014 Sorry Lbox has 7.5: 1 ratio Bill G@ NB Quote Link to post Share on other sites
iain Posted April 14, 2017 Report Share Posted April 14, 2017 Hi Bill did you bottom this out? 8:1 Gearbox on the Speedo and 7.5:1 "L" drive on the Speedpilot? That is what I have but am struggling to get it set up. Cheers Iain Quote Link to post Share on other sites
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