The Triumph Dolomite Club - Discussion Forum

Has anyone ever fitted a sprint gearbox with overdrive to a 1500TC?

Doubtful!
Certainly not a nuts and bolts type conversion.
Guess you could make up a new rear engine plate, probably need a spacer to get input shaft in the correct position. Clutch plate is different too, again not easy. Could machine the 1500 flywheel to accept a sprint clutch, or there may be an alternative plate that fits (old ford?)

However, the simple solution is the std 1500 od box. They are available, but not as cheap as they used to be.

Or better still if you want teh car to be quicker, fit a slat engine which you can bolt the sprint box,prop and axle to(I have done that, old 1500 was 91bhp flywheel, but they just don't last if used hard. At 15k the cam had lost 2 lobes, and I had been through a few cranks. Change to TR7 engine, not much extra power but it is much quicker, and seems better on fuel)

The last one to try this was carried away by men in white coats

If you want a stronger gearbox for a 1500TC
it is possible to fit a Ford Sierra (Type 9) five speed.

This is popular on Spitfires, Heralds etc.
Basically you use the Triumph bell housing onto the T9 via an adapter plate (from Canley Classics).
The clutch plate is made up of Triumph components (T9 has 23 spline input shaft).
A Sierra speedo cable will fit your speedo but needs careful routing because of the close proximity of the exhaust.
Prop is bespoke. As is the gear lever.
It is better to change the gearbox tunnel for a Sprint version.




Ian.

If you want a (slightly) better gearbox, what WILL fit a 1500 without TOO much hassle is the O/D box from a Vitesse or GT6. These have the D type overdrive which gives a bigger gearing advantage than the J type (25% vs 17%) have a bigger input shaft, closer ratios and (marginally) better laygear bearings and thrusts. This box will accept the 1500 bellhousing without modification so the actual fitting is simple.
The problems come from finding or adapting a clutch to fit and the propshaft length may be problematic! But it's MUCH easier than trying to make a Sprint box fit, that way lies madness!

Steve

Steve, the input shaft on a GT6 type bosx is a fair bit longer than a spitfire/dolly 1500 gearbox, so that needs a custom input shaft or a spacer too. (or if you are an ace machinest, chp the dolly shaft, and the gt6 one, drill both, chamfer, pin and weld. Get to under 3 thou runout.....I know somebody who has, got a thou runout, and done nearly 100k on that box since!)

It's more a case of looking for better ratios for it. Have been looking online at spit boxes with od but they look like they'll need a full rebuild(as in all from scrap yards) and I'd rather adapt my 'box to have od which will be cheaper

You just need a spit or dolly 1500 o/d box. They are quite strong enough.

You can get an input shaft and slightly closer ratios from the Marina or Dolly/Vitesse/TR7 to suit from Canley classics

I reckon the Dolly vitesse ratios suit the 1500 well having driven a mk4 spit so fitted. I'm thinking of doing the same
to my Spit 1500...

Sprint boxes dont really have a backplate/adapter to suit but I guess it could be done as they fit behind the T2000 which
is the same with 2 extra pots.

Jonners

Triumph did something like this with the Vitesse they prepared for Vic Elford for the Spa-Sofia-Liege road race in about 62 or 63. It had a 2 litre engine instead of the stock 1600 and (IIRC) a TR4 O/D gearbox. In the Herald chassis, the TR box needs some chassis relief around the rear and overdrive area. If memory serves, it was doing quite well till a fire ended it's race - and its career! Don't know what happened to it after that, it was probably scrapped or stripped for bits. Reg was something like 6003 VC. Someone in the TSSC has a Vitesse with a T2000 Autobox fitted but not factory I think.

Steve

Boost All The Dollys wrote:It's more a case of looking for better ratios for it. Have been looking online at spit boxes with od but they look like they'll need a full rebuild(as in all from scrap yards) and I'd rather adapt my 'box to have od which will be cheaper

As long as you are aware of the parts you will need.
I remember a chap buy an OD unit at stoneleigh last year (or the year before possibly). Anyway the stallholder sold it, clearly labelled as J type od unit. The chap walked off all pleased with his purchase, telling his mate he was going to fit it on his gearbox in his herald.
I didn't have the heart to burst his bubble.

cliftyhanger wrote:

Boost All The Dollys wrote:It's more a case of looking for better ratios for it. Have been looking online at spit boxes with od but they look like they'll need a full rebuild(as in all from scrap yards) and I'd rather adapt my 'box to have od which will be cheaper

As long as you are aware of the parts you will need.
I remember a chap buy an OD unit at stoneleigh last year (or the year before possibly). Anyway the stallholder sold it, clearly labelled as J type od unit. The chap walked off all pleased with his purchase, telling his mate he was going to fit it on his gearbox in his herald.
I didn't have the heart to burst his bubble.

What's the difference between the J and the D type gearboxes and which will be in my 1500TC

Depends on which gearbox you have, D types are fitted to 3 rail gearboxes (reverse on left) and J types on single rail boxes (reverse on right)
If converting a box to overdrive from non o/d you will need to strip it completely to swap the mainshaft. Much easier to just get an overdive box in the first place.

Steve

Carledo wrote:Depends on which gearbox you have, D types are fitted to 3 rail gearboxes (reverse on left) and J types on single rail boxes (reverse on right)
If converting a box to overdrive from non o/d you will need to strip it completely to swap the mainshaft. Much easier to just get an overdive box in the first place.

Steve

So would it be better to buy a scrap yard spitfire overdrive 'box along with longer speedo cable and a overhaul kit/get it rebuilt by a gearbox specialist?

Have a word with Mike Papworth.

J type overdrives are also fitted to 3 rail boxes in early dolomites and later GT6's.

reverse is next to 1st.

Single rails are all J types.

You can mix and match the bits between cases too. I tend to use TR7 internals as the 4 speed layshaft is cheaper but needs a spitfire reverse
and synchro.

Jonners