Overdrive

[Sideways Tim]

After our little trip to Italy, I've decided to start looking out for an overdrive unit to make cruising a little faster/less frenetic.

What do I need to know in order to pick up the right unit and ancillaries?

[CHRIS211083]

What engine do you have??? 1500 0r 1300???

Chris.

[yorkshire_spam]

Having gone through the same thing myself.... look out for a "reasonably priced" (where that is defined by your pocket!) "full kit".
You want (based on my experience doing a single rail 1500 swap) :
overdrive
gearbox
mounting (incl lower plate)
speedo angle drive and cable
propshaft
gearstick incl O/D switch and wiring

I started to think about collecting the bits over a period of time, but came to the conclusion if I did that I'd probably end up spending more!

[Sideways Tim]

It's a '72 1300, not sure which gearbox, does that matter?

I was thinking a kit would be the way to go, but picking up odd bits now and then could work.

[Clive]

A few things woth thinking about.
either a 3 rail (usually d type) or single rail (1500, all j type) will both fit the 4 cylinder engine.
The 3 rail rail od box will fit using a 1500 spit non-od propshaft (can be very handy)
d type requires a relay and a little more wiring, but easy enough
clutch plates are available to fit either to either engine.

The easiest way forward is to buy a complete setup, or even a whole car (sometimes better value!) But be wary that many gearboxes are tired or worse.

[Blubayou]

I have a three rail Overdrive box in mine, I believe it's the sweeter of the two?

It's without doubt the best change I ever made.

As said above, a complete car is probably the best source, they seem to go for immoral prices nowadays.

Mike Papworth can supply / fit /recon as good as new.

He did mine about 10 years ago after I dropped it off in a pile of bits & it's still tight & quiet.

[Richard B]

2356 wrote:

It's a '72 1300

Should be a 3 rail. My preferred gearchange, I find the single rail a bit clunky.

Look around for a D'type (or a J'Type) unit and then get Mike Papworth to convert your box. Remember your car has 4 sychromesh gears, earlier Spitfires with the three rail box had only three synchromesh gears.

or get a Spare MkIV box ready and have that build up. I'm fairly sure you can build a 3 rail Spitfire box with a J'Type, might need some bits and pieces. Although a 4 pot is well within the power capabilities of a D'Type.

[cook1e]

Canley Classics do a conversion kit, however because you are looking at everything new/recon it's not cheap but would be the easy way out if money is no object. However the picture on thier website is useful for givnmg you an idea of what you need as it's the MKIv D type kit that is shown in the photo ;-)

http://www.canleyclassics.com/?xhtml=xhtml/product/overdriveconversionkit.html&xsl=product.xsl

[Saltddirk]

I see they have added the rear mounting bracket.
It was missing from the kit I bought (years ago)

But yes, as said by Cookie, easy fit and forget kit, even by me....

Dirk

[Sideways Tim]

As ever, great advise. Thanks folks.

[Nick Jones]

Don't discount the single rail box on the basis of poorer gear change.  The best Triumph change I've ever had was the single rail in my Herald (Ex Dolly 1500 and identical to Spit 1500).  That used a Dolly gearlever with the rubber bush in the middle cut out and the two parts welded together.  That made such a big difference I did the same to my Dolly 1850 though the box in that was too far gone to take full advantage.

Biggest disadvantage of the single rail 1500 Spit/Dolly box is weight.  They are HEAVY - and harder to lighten as the factory alloy bell-housings don't (easily) fit them.

Nick

[Freebird]

Nick_Jones wrote:

Don't discount the single rail box on the basis of poorer gear change.  Nick

I would go along with that. The single rail box in my Spit has a much nicer change than the 3 rail in the Vitesse. More direct and the lever moves through a more logical path.

[bob dunn]

I got a running car with an overdrive in it . Its the only way to buy one . buy a wreck from the graveyard.

[Sideways Tim]

What needs doing to my existing gearbox to strap an overdrive on the back of it?

[Richard B]

Its a stripdown & rebuild as the mainshaft needs changing.

O/D unit inc solenoid, O/D adapter, Mainshaft. I've had couple of boxes converted (for one reason or another).

[Sideways Tim]

Thanks!