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2.5 Vitesse?

Dave Bell

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Same block, longer throw crank and different height pistons. 

The very late 2litre(after vitesse, but te last of the GT6's, plus the saloons) even used the same head as the 2.5, but required funny domed pistons.

So there are quite a few 2.5 vitesse's about. Some have PI too.


I ran a 2.5 vitesse for many years. Makes for a different driving experience, definitely need overdrive, and a 3.63 or 3.27 f=diff to make the most of teh engine (i initially used 3.27s, but after breaking the third, changed to 3.63 which lasted well)

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I think he means the engine number matches the logbook engine number, not what the car came from the factory with. 

Seems to be a good car, let down by the stitched (as opposed to moulded) carpet set. The carbs look like late  HS4's? If so are too small. Although they could be a late variant of the HS6. And possibly the 2500s inlet manifold (good thing)

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10 minutes ago, dougbgt6 said:

Stitched carpets? Funny domed pistons? Have you been looking at my car Clive?


Heavens above no. 

But it does seem a shame to have fitted a cheap carpet set when so much was spent elsewhere. Domed pistons never seem right to me. All to save having  the heads machined, so probably saved a shilling a car. (or maybe the factory line were always putting the wrong heads on engines? )


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3 minutes ago, Pete Lewis said:

why has the speedo cable got some sort of correction box on it 

and the front spoiler corner seals are missing 

Those seals are easy enough to replace, but the speedo cable looks to have some kind of geared extension in it; it's certainly a joint of some kind, maybe to extend the cable for the O/D, or to adjust the gearing for the different drive to make the speedo more accurate?

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2L cars go pretty well. The Vitesse (and GT6) Mk2 engine is the best of them.

If set on a 2.5 be aware that they really need longer gearing (as Clive already said) and that the standard transmission, gearbox especially, is already on (or beyond) its torque limit with the 2L and doesn’t last very well behind a 2.5.

That black one looks nice but £15k.....


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Maybe it's the way you use it.     I've had a 2.5 in the race Vitesses for three cars and more engines.    My GT6 gearbox, with O/drive, was built by Mike Papworth (stand up and take a bow, Mike!).

The diff is a Quaife, which is bulletproof, IMHO, when I have had OE diffs explode.   What has failed has been the rear transmission, the halfshafts and rear wheel bearings. 


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The torque of a 2.5 litre engine in a Vitesse or GT6 is very impressive but as has been said, several improvements to the transmission are required.

As a minimum, I would suggest the following transmission upgrades:

- If retaining the original gearbox, fit the larger mainshaft tip bearing (as done by Mike Papworth and others).

- The D-type overdrive is marginal for a 2 litre engine, replace with J-type though this requires gearbox modifications.

- Higher ratio final drive.

The strongest Triumph gearbox upgrade would be a TR/big saloon unit with J-type overdrive, but there's a bit more work involved in this conversion. Ideally, also fit CV driveshafts.

Looking at the photos of this car's underside on eBay, it appears to have a 2 litre gearbox casing but obviously can't tell if it's had the bigger bearing conversion. Also impossible to see of the overdrive is D- or J-type. And I think Rotoflex driveshafts are just visible at the rear.

For the top end £15k asking price, I would want evidence that all the required transmission upgrades are included. Otherwise, the gearbox and overdrive are unlikely to last long. Which is why I'm in the process of upgrading the transmission on my 2.5 litre GT6!



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