Section : Gearbox

Single rail Overdrive Gearbox in a 1200 Herald?

Posted By : Phil Kinsella, 04-Nov-2006, 12:02pm

• Single rail Overdrive Gearbox in a 1200 Herald?

  Posted By : John Davies, 04-Nov-2006, 04:51pm

  Phil,
  Have a look at this canley info page: http://www.canleyclassics.com/catalog.asp?category...
  
  I would have thought that a Vitesse propshaft would be right, but maybe not!
  
  The flanges are the discs that terminate the ends, each part of a Universal joint.
  Each has four bolts that fix it to a similar flange on either the gearbox output shaft, or the diff input ditto.
  Trouble is, the flange size isn't constant, and though I can't tell you which size goes where, they will all fit the same type and size of U/joint. Matching flanges is a matter of changing the flange on the U/j.
  
  John
  

  • Single rail Overdrive Gearbox in a 1200 Herald?

    Posted By : Chris Taylor, 04-Nov-2006, 07:37pm

    I think you will find that you need a bespoke propshaft for this conversion. The single rail overdrive box is longer than a 3 or 4 synchro with D type overdrive. The 1/2" difference between the length quoted for that and the length of a non-o/d Vitesse shaft can be accommodated by the sliding spline on the propshaft and the adjustment available on the engine mountings. However the extra length of the longer gearbox cannot be accommodated, and I don't think a Triumph prop of the right length was used on another car.
    You could get any decent propshaft reconditioning firm to shorten your existing shaft to the length shown on the Canley website, or you may be able to buy a shaft from someone like Canley who get them made for their overdrive conversion kits.
    (As an extra check, you could install the diff and engine/gearbox in the chassis and measure the precise length of the shaft required).
    Although the flanges on each end may need changing, they will probably be one of only two sizes used on these cars and should be readily available as used parts. They all fit onto the same universal joint "spider" so it's just a matter of assembling the joint at each end with the correct size of flange and fitting the correct size of bolts.
    I THINK you will need a "small" flange at the diff end (same as what you have now) and a "large" flange at the overdrive end.
    You should get the correct flanges for the shaft BEFORE you get the shaft shortened. Although theoretically you should be able to change these parts at will, these shafts as fitted to "our" cars are very sensitive to imbalance, so it's best to get the shaft balanced after shortening, with the flanges and universal joints you will actually be installing on the car.
    I presume you are aware you will need a special clutch plate to connect to your engine. (Dolomite 1300 I think). If your Herald has a diaphragm spring clutch then it is just the driven plate that is different. If you have an earlier coil spring clutch, then I suggest you change to a diaphragm spring clutch. This will require the clutch, flywheel, release bearing carrier and slave cylinder from a diaphragm spring clutch Herald/Spitfire Mk3 or 4, Toledo or Dolomite 1300. Sounds a lot but these parts should be readily available and will take less than a hour to fit if the engine and gearbox are out of the car.
    Again, this is a well recognised conversion that Canley (and no doubt other suppliers) should be able to assist you with in terms of parts and advice.

    • Single rail Overdrive Gearbox in a 1200 Herald?

      Posted By : Phil Kinsella, 25-Nov-2006, 11:29am

      Thanks gents,
      
      I have also spoken with Derek Giles who says it maybe easier to get shot of the J type, and find a 3 rail D type and prop. Are these about as I have yet to track one down, also, which is deemed the better box?