YOW500 Posted June 20, 2020 Report Share Posted June 20, 2020 Has any member yet fitted the Vitesse Global Ltd Mazda MX5 mk3 gear box conversion. I understand that some TR6 cars have been converted. Has anyone with a TR2 to 3a undertaken the conversion. Are there any issues with over pressurising the MX5 internal hydraulic release unit when using the standard Triumph master clutch cylinder, I understand that similar conversions require that the clutch pedal travel is reduced by the means of a 'stop bracket' fitted to the footwell wall? Also, Does the gear level sit in the original position, and up right, in the case of the TR2 / 3a cars. Thank you. Russell Quote Link to post Share on other sites
stuart Posted June 21, 2020 Report Share Posted June 21, 2020 Why would you? Stuart. Quote Link to post Share on other sites
YOW500 Posted June 21, 2020 Author Report Share Posted June 21, 2020 Ha Ha, straight to the point Stuart. Say just what you mean. LOL Russell Quote Link to post Share on other sites
RogerH Posted June 21, 2020 Report Share Posted June 21, 2020 Hi Russell, I do not think there is an isue of pressure at that is dictated by the diaphragm spring pressure. There could be a problem with travel of the CRB. Not sure of a pedal stop is the answer. You need to look carefully at the dimensions and work from there. Roger Quote Link to post Share on other sites
AndyR100 Posted June 21, 2020 Report Share Posted June 21, 2020 (edited) The installation instructions don’t mention an issue with the master cylinder, it does use a different slave cylinder ...... Andy Edited June 22, 2020 by AndyR100 Quote Link to post Share on other sites
YOW500 Posted June 22, 2020 Author Report Share Posted June 22, 2020 Andy. PM sent. Russell Quote Link to post Share on other sites
AndyR100 Posted June 22, 2020 Report Share Posted June 22, 2020 12 minutes ago, YOW500 said: Andy. PM sent. Russell i have replied...... Andy Quote Link to post Share on other sites
Z320 Posted June 22, 2020 Report Share Posted June 22, 2020 (edited) Hi Russell, this is a very good question and it was the matter of some calculation with our Sachs hydraulic release bearing. First good news is, if Vitesse give you no limitation they did care of that and take a suitable clutch unit for a 0.75" master. Second good news is, "the problem" hits you not by surprise on the street - but the first time you step on the pedal (at your garage)! What's the matter? With the unit on the workbench, or on the gearbox - but not on the engine - the release bearing is fully out, as far the piston can move it out. If you now bolt the hydraulic pipe of a master cylinder on it, and press it, the piston of the clutch unit will flip the unit in pieces and the hydraulic fluid is out. This is why you have to compress the unit when you bolt the gearbox on the engine, only for example for about 11 mm. To get this to the point is an issue of calculation of the construction. On our Sachs unit we calculated the expanse of the piston for about 750 mm² x 11 mm compression = 8,250 mm³. On my TR4A I can press the master for about 34 mm, expanse of the 0.75" master is 285 mm² x 34 mm = 9,690 mm³. So 34 mm of the master moves the piston of the clutch hydraulic about 13 mm out! This does not work when it was compressed only 11 mm! On the first step on the pedal it will flip in pieces and will be leak! In this case a limitation of the way of travel of the master could be: (11 mm - 2 mm safety distance) x 750 / 285 = 23.7 mm. Or use a master 0.625", expanse of the piston 198 mm² x 34 mm / 750 mm² = 8.975 mm way of travel on the clutch unit. Or choose a hydraulic unit with a larger pistion expanse. Or modify the construction to compress the clutch unit more (there are issues why this is limited). I hope this short answer helps, don't hesitate to ask for more details. Ciao, Marco Edited June 22, 2020 by Z320 Quote Link to post Share on other sites
Z320 Posted June 22, 2020 Report Share Posted June 22, 2020 (edited) Sorry me, let me add this: - if I remember correct we compressed the Sachs unit for a mates TR6 with shims for about 14 mm for a 0.75" master? - I use the Sachs unit with a 0.625" master on my TR4A Edited June 22, 2020 by Z320 Quote Link to post Share on other sites
YOW500 Posted June 23, 2020 Author Report Share Posted June 23, 2020 Marco. Thank you for your informed information, it has made the situation much more understandable. Although my original question referred to the Vitesse gear box it also has an influence on your clutch release bearing, and Mazda gear box projects. I look forward with interest for your next thread in connection with the gear box project. Much appreciated Russell Quote Link to post Share on other sites
Z320 Posted June 24, 2020 Report Share Posted June 24, 2020 Hi Russell, you are welcome. With the Mazda gearbox I perhaps modify the Mazda mechanism, this workes lovely and makes the project faster to be finished. But there will be good reasons for Vitesse to use a hydraulic unit? Or is it just marketing, shure they cannot sell DIY style products.... Ciao, Marco Quote Link to post Share on other sites
j-eichert Posted August 5, 2020 Report Share Posted August 5, 2020 (edited) @ Marco Maybe Vitesse uses this hydraulic unit because you get rid of the fork-style mechanism (which is a source of trouble sometimes). Or there is a more technical reaason behind it - just using standard components from today? @ Stuart Having driven a MX-5 (NB-FL) for quite a while: I just dreamed of somebody adapting this gearbox into the TR - so now Vitesse did it. The Mazda gearbox is just great to drive, handle und use - apart from beeing "unbreakable". So IF one day may gearbox will break (again) then this may be an option: selling the broken unit to an enthusiast for rebuilding and buying a Vitesse one. It may not be more expensive overall.... Regards, Johannes Edited August 5, 2020 by j-eichert Quote Link to post Share on other sites
Z320 Posted August 6, 2020 Report Share Posted August 6, 2020 (edited) Hi Johannes, after some peaceful moments with my MX-5 gearbox on my TR4 spare engine I realize this: the Mazda mechanism does not work on a TR gearbox bell because of the position of the electric starter. Or at least it's difficult This is why I'm back (in my ideas) on the hydraulic mechanims for my own MX-5 gb DIY project. Ciao, Marco Edited August 6, 2020 by Z320 Quote Link to post Share on other sites
ianc Posted August 7, 2020 Report Share Posted August 7, 2020 After many many years of struggling to get the TR's clutch fully disengaged (because I have very short legs), I bought an adjustable pushrod from Revington in 2009. Now the clutch starts to disengage sooner because the master cylinder's valve closes after just a short movement of the foot pedal. To stop me ramming the master cylinder's piston hard against the end of its travel, I mounted a wooden block between the foot pedal and the bulkhead. Ian Cornish Quote Link to post Share on other sites
Z320 Posted November 25, 2020 Report Share Posted November 25, 2020 (edited) With regards I lifted this up for Nick Edited November 26, 2020 by Z320 Quote Link to post Share on other sites
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