Vit Mk2 Rear Diff Removal

[NonMember]

42 minutes ago, dougbgt6 said:

That's interesting, where does the special order info come from?

Gosh, that's going to test my memory! I'm fairly sure I first saw it in the Courier way back in the late 1980s but I've also seen it in other places. It might be mentioned in the WSM. Probably doesn't apply to Mk3 and might even have been a Mk2 only option.

[Clive]

I have amemory, probably from courier of suchlike, that  Swiss GT6's were supplied with 3.27 (maybe it was mk2? ) so another twist? or maybe just ignore. 

I am not a fan of making teh cars too long-legged. Many owners have 2 obsessions with teh cars. one is to strap performance goodies on (presumably to make the cars quicker) and the other to keep revs as low as possible. Diametric opposites in many ways. I like my cars to rev nicely, and not be afraid.And happily cruise at "speed". But a 2 litre with a 3.27 can feel lifeless. A 3.63 is probably as far as I would go. 2.5 needs athe 3.27, but if used enthusiastically tends to make them fall apart. I broke several....

[johny]

I agree Clive and after taking a few gearboxes apart Im paranoid about remaining in third any longer than I have to! Luckily my engine is running so sweet (at the moment) that I can go down to 1100rpm in 4th and still pull away without pinking?

[Nick Jones]

1 hour ago, clive said:

I have amemory, probably from courier of suchlike, that  Swiss GT6's were supplied with 3.27

Is that not the 1500  Spitfires?  Seems rather odd either way as Switzerland isn't the flattest place around......  Probably a legislation work-around.

Decent 2L will pull the taller 3.63 gearing no problem.  Good for 0 -60 times too as you can get there in 2nd with only mild disregard for the redline.

Nick

[Clive]

Indeed, red lines are there as guidance only...

Pretty sure it was GT6. It may have been in a catalogue. I really can't remember where I stumbled across it, but it did seem odd at the time. Maybe there was only one Triumph dealer over there, and he demanded the 3.27?? no idea. 

[Pete Lewis]

the point missed is to get the car to perform with a high ratio like 3.27:1  the diff has to transmit a lot more of the available torque to the wheels

hence the often occurrence of exploding 3.27 diffs  they have to work harder.

often due to the bigger diameter pinion and a thinner crown wheel    but  triumph  use  a different offset the diff case to accommodate the  3.27 CW 

so up goes the torque input to get the same output  

[Gully]

The German Mk 3 GT6 got overdrive with the 3.27 ratio diff according to the parts book.

According to Richard Dredge's book on the Spitfire and GT6 all Mk 2 GT6s were offered with the 3.27 diff whether or not OD was chosen as an option - with the 3.89 diff as an option for people choosing OD. It was a popular change to improve acceleration so it became the standard set up for the Mk 3 with OD (except Germany!).

Gully

 

[Gully]

When I bought my Mk 3 it had a 3.27 diff and OD. I changed it to a 3.63 which I'm much happier with as a compromise between acceleration and cruising.

Gully

[Peter Truman]

Like yourselves I never understood the 3.27 diff on Switz cars seemed nuts for such a mountainous country!

In the early 70's we did several European Tours in our Mk2 Vitesse, non O/D & the 3.89 was adequate, esp when traversing the St Goddard Pass & racing an Alfa coming down the Como side. When we got to Como brakes were stuffed virtually empty, and the anti roll bar had broken loose off the chassis. I put the car into a garage next to the hotel which happened to service RR to have the brakes refilled an bled and a new U bolt on the roll bar, when I picked the car up I was told NO COST we'll put it on the next Roller!

Same trip I dropped a UJ trying too hard in the Tunnel at Monte Carlo, well it was a week after the GP! Now that did cost a 2.50GBP UJ cost 50. quid installed!

Aah the good ole days when you could have fun!

I must congratulate you all on the alternative method of removing the diff, well explained with good photo's that's what Forums are for, the benefit of ALL. Also the discussion re diff options.

I have removed a diff from a Spit 1500 leaving the spring and diff rear in place just dropping the diff front and removing the input case and diff gears after undoing the drive shafts, worked well.

Good to hear Marcus again his info was invaluable when I transferred the single rail internals into a 3 rail box with J type O/D for my daughters Spit Mk2, mind you his scotch accent made me read it several times before I understood it!

Pic is around 1972 heading up the St Goddard Pass, her in doors was cold, it was warm in the car.

Regards

Peter Truman

Regards

Peter T