Section : Overdrive

Spitfire Mk3 Overdrive

Posted By : David Crowder, 19-May-2003, 12:32pm

• Spitfire Mk3 Overdrive

  Posted By : Peter Hazlett, 19-May-2003, 01:32pm

  I've never used the clutch when engaging/dis the overdrive. AFAIK there is no need to use the clutch, just flip the switch and off we go...

  • Spitfire Mk3 Overdrive

    Posted By : Nigel Gibbins, 19-May-2003, 03:17pm

    Hee hee - the whole advantage of using overdrive as oppposed to five gears (in retrospect) is you need no clutch as the overdrive has it's own omni-directional clutch which does all the left foot stuff for you.
    
    Keep you foot well in and just flick the switch, wait a brief second and you get a lovely little 'kick' in the back as it slides home - marvelous!
    
    NiG
    http://www.niginthecar.net
    
    PS make sure the inhibitor switch is functioning as using the overdrive in reverse will 'kill' the omni-direction clutch.

    • Spitfire Mk3 Overdrive

      Posted By : David Crowder, 19-May-2003, 04:10pm

      Ok that sounds good but what about my GT6 !! ow and where's that inhibitor switch and how do you test it !!
      DC

      • Spitfire Mk3 Overdrive

        Posted By : Nigel Gibbins, 19-May-2003, 05:25pm

        The inhibitor switch is on the end of the gearbox near the bellhousing. The check if it is working you can turn on the ignition and select third gear. (you don't need to run the engine) You should hear a 'loud' click as the remote switch engages.
        
        Now (with the overdrive still on) select second or first gear - the switch should click off, third/fourth 'click' on, first/second 'click' off. If all this happens then all is well.
        
        The GT6 is just the same even if the overdrive switch itself is in a different position.
        
        NiG
        http://www.niginthecar.net

        • Spitfire Mk3 Overdrive

          Posted By : Adrian Lee, 19-May-2003, 06:28pm

          You may need to check that the solenoid is working properly and throwing the arm far enough when it engages. The check is fairly simple (bit like me). Though I don't know if the test on your o/d will be the same as my '67 Vitesse... It involves taking the small cover plate off and with the solenoid engaged you should be able to pass a 4.5mm drill through the hole in the arm and into a recess on the gearbox housing. I think it relates to how much voltage your car produces. You can then move the adjustment nut either way.

          • Spitfire Mk3 Overdrive

            Posted By : Nigel Gibbins, 19-May-2003, 09:01pm

            I believe Adrian is describing a 'D' type overdrive and the '67 GT6 has the same one. The check is exactly the same.
            
            I think the 'J' type overdrive was used on the Mk3 GT6, though I can't be sure which was used on the Mk2.
            
            The 'J' type is considered to be the better of the two although I couldn't say why (I've only experienced the 'D'), I think it's supposed to be stronger?
            
            NiG
            http://www.niginthecar.net

            • Spitfire Mk3 Overdrive

              Posted By : Adrian Lee, 19-May-2003, 11:22pm

              Jeez... I hope it is cheaper as well as stronger, cost a lot too get it sorted, some imbecile had put slick 50 in my 'box. Sounds vaguely sexual that... not meant.

            • Spitfire Mk3 Overdrive

              Posted By : Graham Reeks, 20-May-2003, 12:47pm

              It's D-type on the GT6 including the Mk3.
              
              Presumably it doesn't matter if the inhibitor switch isn't working, as long as you don't put it in reverse with overdrive engaged. I've been driving like that for a while.

    • Spitfire Mk3 Overdrive

      Posted By : Michael Davis, 20-May-2003, 10:52am

      I find that if you get the revs just right, it doesn't even kick you, all that happens is that the rev counter drops between 500 and 1000 revs :-)
      
      About 2000 revs and 4000 revs seem to be the spots that do it for my car.