Nigel Clark Posted August 14, 2020 Report Share Posted August 14, 2020 As above, does anyone have 3.27:1 ratio diff, as fitted to non-overdrive GT6s? Condition is unimportant as long as it is suitable for rebuilding. Please PM me if you have a 3.27 diff you would be willing to sell, or if you know someone who does. Thank you, Nigel Link to comment Share on other sites More sharing options...
Steve P Posted August 14, 2020 Report Share Posted August 14, 2020 There was one being offered for free on the CT forum,not sure how viable, as it was "cleaned" with a water based solvent and was rusty.Described as a bucket of bits. Steve Link to comment Share on other sites More sharing options...
Qu1ckn1ck Posted August 14, 2020 Report Share Posted August 14, 2020 Try Tony Lindsey-Dean ? https://www.facebook.com/tony.lindseydean Link to comment Share on other sites More sharing options...
Nigel Clark Posted August 14, 2020 Author Report Share Posted August 14, 2020 Thank you gentlemen, I will follow up. Nigel Link to comment Share on other sites More sharing options...
daverclasper Posted August 15, 2020 Report Share Posted August 15, 2020 Also one currently advertised on TSSC "parts for sale", for rebuild at £100. Link to comment Share on other sites More sharing options...
Nigel Clark Posted August 16, 2020 Author Report Share Posted August 16, 2020 Hi Dave, Thank you for the heads up, don't know how I missed that one! It's got a broken crown wheel and pinion and it's a 4 stud spring mounting (unusual for a 3.27 diff), whereas I need 6 studs for my Rotflex GT6. I'm going to hang on and hope for a better starting point from which to build a new diff. Nigel Link to comment Share on other sites More sharing options...
thescrapman Posted August 16, 2020 Report Share Posted August 16, 2020 Don't worry about rear casing Nigel, there are plenty of spare ones about to allow you to build the diff up before you fit it. finding the carrier may be more difficult. I seem to remember there are. Couple of versions of the 3.27 carrier, the one from the Dolomite being the best. I would check my vague memories first of course. Link to comment Share on other sites More sharing options...
Pete Lewis Posted August 16, 2020 Report Share Posted August 16, 2020 when i reverted a 4 hole swinger to a 6 stud courier i used the clamp plate as a jig and drilled the 2 8,3mm holes tapped to 3/8x 24 unf and it all lined up did on car drilled about 25mm depth , didnt break through to the oily bits Pete Link to comment Share on other sites More sharing options...
Steve P Posted August 16, 2020 Report Share Posted August 16, 2020 2 hours ago, thescrapman said: I seem to remember there are. Couple of versions of the 3.27 carrier, the one from the Dolomite being the best. The 3:27 in my Vitesse was rebuilt by Mike P a couple of years ago with a stronger carrier,i thought he said TR7?. Coould be wrong. Steve Link to comment Share on other sites More sharing options...
thescrapman Posted August 16, 2020 Report Share Posted August 16, 2020 Automatoic 1850 Dolomite or Automatic TR7 with the 4-speed axle rings a bell. Link to comment Share on other sites More sharing options...
Nigel Clark Posted August 16, 2020 Author Report Share Posted August 16, 2020 Thank you chaps. Ideally, I want to be able to drop the 3.89 from my GT6 and bolt in a reconditioned 3.27 as a direct swap. I'm trying to avoid cannibalizing my present diff to build the new one. Life always seems more complicated than it should be, especially when modifying a Triumph! Nigel Link to comment Share on other sites More sharing options...
Pete Lewis Posted August 16, 2020 Report Share Posted August 16, 2020 because the 327 pinion is a larger diameter you either have a thinner crownwheel of a different offset on the diff case CW face the only way you get things to fit in. likewise a higher ratio needs to transmit more torque for the same performance hence more likely to go bang than a lower ratio Pete Link to comment Share on other sites More sharing options...
Peter Truman Posted August 16, 2020 Report Share Posted August 16, 2020 I seem to remember a local chap here who races a very nice GT6 putting the higher ratio 3.45 or 3.27 diff in his car which required a larger crown wheel hence some internal surgery with an angle grinder was reqd to make it fit, it was a discussion over coffee at a club early morning drive. I could ask him for clarification as to what he used and what was necessary if reqd. Link to comment Share on other sites More sharing options...
Nigel Clark Posted August 17, 2020 Author Report Share Posted August 17, 2020 Hi Peter, The 3.27 crown wheel and pinion do require some machining inside the casing to fit, if using the casing from any other ratio diff. I believe the pinion bearings are different too. My plan is to have Paul Hughes at 2Spec Transmissions build it up for me with one of his limited slip diffs: http://www.2specgroup.co.uk/transmissions/triumph/ This is for my 2.5 litre GT6, which I feel will easily pull a much higher ratio. The 3.27 diff is said to be the weakest of the small chassis ratios, but my understanding is that it's the differential rather than the crown wheel and pinion that are the Achilles heel. The 2Spec LSD should get over the weakness of the original differential. I'm not in a rush, so I'm going to keep looking, hoping a 3.27 diff will turn up. In the meantime, 2.5 litres plus a 3.89 final drive does make for amazing acceleration! Nigel Link to comment Share on other sites More sharing options...
Peter Truman Posted August 17, 2020 Report Share Posted August 17, 2020 There was a rebuilt 3'27 locally here for sale for quite a while on Gumtree but it wasn't cheap around $1100Aus, haven't seen it advertised for a while. Nigel I never understood why the 3.277 was fitted to the Swiss supplied GT6 models with all them mountains! having driven over them around them and thro them many times in my Vitesse Mk2 with a 3.89 diff the 3.27 long legs just didn't add up! Link to comment Share on other sites More sharing options...
NonMember Posted August 18, 2020 Report Share Posted August 18, 2020 8 hours ago, Peter Truman said: Nigel I never understood why the 3.277 was fitted to the Swiss supplied GT6 models with all them mountains! Almost certainly nothing to do with the terrain and everything to do with some legislative quirk. When I was at Rover they fitted different gear ratios to French market cars because of the way taxation classes were calculated there. Link to comment Share on other sites More sharing options...
SpitFire6 Posted August 18, 2020 Report Share Posted August 18, 2020 On 17/08/2020 at 15:26, Nigel Clark said: Hi Peter, The 3.27 crown wheel and pinion do require some machining inside the casing to fit, if using the casing from any other ratio diff. I believe the pinion bearings are different too. My plan is to have Paul Hughes at 2Spec Transmissions build it up for me with one of his limited slip diffs: http://www.2specgroup.co.uk/transmissions/triumph/ This is for my 2.5 litre GT6, which I feel will easily pull a much higher ratio. The 3.27 diff is said to be the weakest of the small chassis ratios, but my understanding is that it's the differential rather than the crown wheel and pinion that are the Achilles heel. The 2Spec LSD should get over the weakness of the original differential. I'm not in a rush, so I'm going to keep looking, hoping a 3.27 diff will turn up. In the meantime, 2.5 litres plus a 3.89 final drive does make for amazing acceleration! Nigel Hi Nigel, I have a 3.27 in my 2.5. It has amazing acceleration in all gears. What gearbox do you have so I can compare? Thanks, Iain. Link to comment Share on other sites More sharing options...
Nigel Clark Posted August 19, 2020 Author Report Share Posted August 19, 2020 10 hours ago, SpitFire6 said: Hi Nigel, I have a 3.27 in my 2.5. It has amazing acceleration in all gears. What gearbox do you have so I can compare? Thanks, Iain. At the moment, I'm running completely standard transmission, including the original gearbox and D type overdrive. Inevitably, this won't last long with the torque from the bigger engine. As well as the switch to 3.27 final drive with the LSD, Paul at 2Spec will build me a hybrid gearbox, with Dolomite 1850 internals in the original gearbox casing with J type overdrive. Nigel Link to comment Share on other sites More sharing options...
SpitFire6 Posted August 19, 2020 Report Share Posted August 19, 2020 Hi Nigel, Your car with 3.89 Diff & GT6 box: 6000RPM: 1st-39.5MPH. 2nd-58.7MPH. 3rd-83.3MPH. 4th-104.5MPH. Mine with 3.27 & TR6 box: 6000RPM: 1st-39.6MPH. 2nd-61.8MPH. 3rd-93.4MPH. 4th-124.3MPH. Calculated from http://www.mintylamb.co.uk/gearspeed/ You have better acceleration than me. Not by much in the lower gears though. I never had a long life with uprated GT6 boxes. Tr box is stronger & OD on 2nd is useful. Cheers, Iain Link to comment Share on other sites More sharing options...
Steve P Posted August 19, 2020 Report Share Posted August 19, 2020 18 minutes ago, SpitFire6 said: Mine with 3.27 & TR6 box:6000RPM: 1st-39.6MPH. 2nd-61.8MPH. 3rd-93.4MPH. 4th-124.3MPH. I have the Saloon box in my Vitesse as well,pulls like a train but never been near 100mph as it`s scary.Pulls up hills in O/D 4th no problem. Steve Link to comment Share on other sites More sharing options...
SpitFire6 Posted August 19, 2020 Report Share Posted August 19, 2020 2 minutes ago, Steve P said: I have the Saloon box in my Vitesse as well,pulls like a train but never been near 100mph as it`s scary.Pulls up hills in O/D 4th no problem. Steve Hi Steve, What diff do you have? Cheers, Iain. Link to comment Share on other sites More sharing options...
Steve P Posted August 20, 2020 Report Share Posted August 20, 2020 Hello Iain, 3.27 built my Mike P. Steve 1 Link to comment Share on other sites More sharing options...
Colin Lindsay Posted August 20, 2020 Report Share Posted August 20, 2020 18 hours ago, SpitFire6 said: Calculated from http://www.mintylamb.co.uk/gearspeed/ Pity he doesn't have spec for the Dolomite 1850 box; I'd like to see how mine compares in an overdrive GT6 with the non O/D diff. Link to comment Share on other sites More sharing options...
Nigel Clark Posted August 20, 2020 Author Report Share Posted August 20, 2020 3 hours ago, Colin Lindsay said: Pity he doesn't have spec for the Dolomite 1850 box; I'd like to see how mine compares in an overdrive GT6 with the non O/D diff. The Dolomite 1850 has identical ratios to the GT6/Vitesse 2 litre box. Nigel Link to comment Share on other sites More sharing options...
thescrapman Posted August 20, 2020 Report Share Posted August 20, 2020 Same gearset inc. angles in Mk3 GT6 box to 3 rail Dolomite 1850 All earlier GT6 and 2 litre Vitesse have same gearset. TR7 has different angles again, may be same as late 1850 single rail. Link to comment Share on other sites More sharing options...
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