Retro fit overdrive gearbox to Mk2 1969 Vitesse

[Hazzard]

Hello everyone, I require some advise please. I have the option of buying a Mk1 Vitesse 6, 2 litre overdrive and gearbox with the prop shaft and the overdrive switch and steering Colum cowl. But will it fit into my Mk2 2litre 1969 vitesse please. all advise very much appreciated as I am new to triumphs. hope someone can help me out.

[johny]

You really need its serial number stamped on the top face of the main case. Vitesse 1600 not same as the 2L - the latter is same for both 2L models...

[Colin Lindsay]

I'm open to correction about the early Vitesses but given that most Triumph gearboxes for our small cars use the same case and fittings then would it fit the 2 litre bellhousing? (I've no idea of how, if at all, the 1600 bellhousing differs from the 2 litre) If so then it may be a straight swap, just use the clutch plate that suits the gearbox. Propshafts etc are easily modified as are the flanges, electrics are simple, so it all comes down to gearbox fit against the engine.

[johny]

It would probably fit but the gear ratios are different Colin so not good for 2L☹️

[GFL]

The Early Vitesse 6 gearbox is a lot weaker than a 2 Litre box, I have a feeling the input shaft is different too, although I'm not 100% sure on this.

The Prop shaft flange will also be square type and the smaller 5/16" bolt size too.

Gary

[Pete Lewis]

3 hours ago, Hazzard said:

will it fit into my Mk2 2litre 1969 vitesse

its a simple yes  its fully interchangeable between mk1 and mk2 

ref the comments about the 1600  yes it will fit if you drill the flywheel to take a 2ltr diaphragm clutch and you need to swap to the 2ltr throw out bearing and carrier 

the dowel positions change between coil clutch and the diaphragm clutch covers  the bolt holes are the same 

Pete

[Hazzard]

Thank you to all that have replied I am very grateful. Further infor gained re the Donor Box. Its a D type gearbox. Serial number HC20138 with a Laycock overdrive. Hopefully this information will bring better confirmation and clarity to my question. Would just ask also if the gearbox and overdrive are good choices to go ahead with this upgrade for my car.

thank you all again H. 

[johny]

Yes thats a gearbox from a 2L mk 1 or 2 vitesse. Its a good modification by all accounts but does bring extra complication with associated risk of unreliability plus a suspected reduction in gearbox durability.

The chances are your purchase will be pretty worn so will probably need dismantling for restoration....

[daverclasper]

1 hour ago, johny said:

Yes thats a gearbox from a 2L mk 1 or 2 vitesse. Its a good modification by all accounts but does bring extra complication with associated risk of unreliability plus a suspected reduction in gearbox durability.

I have read that it's the layshaft that may suffer with an overdrive box?. If this may be the case, then, could, only using OD in direct drive 4th gear, maybe reduce possible wear?.

Also, if this is correct about OD's causing GB wear, would this still be the case, even if the OD was never engaged?.

Just interested, if anyone has ideas about this?.

Thanks

[johny]

The thinking Ive read is that the mainshaft is shorter and not so rigidly supported in the od as in non od box which puts more load on the tip bearing at the other end. The tip is too small as we know so suffers even more plus it may also put more load on the layshaft. Unfortunately all of these needle roller bearings run directly on the shafts and gears so the lack of changeable bearing races makes repair more complicated☹️

[Pete Lewis]

the only effect on the layshaft mythical wear  can only be down to  hard use ,a good clog down in 3rd and give the OD a flick  to maintain the torque band ,in all my years the layshaft spindle is aged worn , or  poor manufactured repair there were a lot of soft shafts about a few years ago

but the mainshaft tip is the weak point be it OD or Non OD 

even most giving it some Jeronimo  the OD is pretty bullet proof

nothing lasts for ever and correct oil and levels is a must  low oil  levels is a good killer

Pete