Hugh Posted June 13, 2011 Share Posted June 13, 2011 Hi all can anyone tell me if will a TR6 2500 cc short end crank will be okay to fit a GT6 MKIII engine please. I think I will also need 2500cc conrods as well as shell bearings. Are there any other parts I will need.Cheers Hugh Link to comment Share on other sites More sharing options...
gallandro Posted June 13, 2011 Share Posted June 13, 2011 I did this with mine. It worked fine but you will need to hammer out the sump. Link to comment Share on other sites More sharing options...
Hugh Posted June 13, 2011 Author Share Posted June 13, 2011 Ok cheers for that . :) Link to comment Share on other sites More sharing options...
Hugh Posted June 13, 2011 Author Share Posted June 13, 2011 Any one out there with a set of conrods please :) Link to comment Share on other sites More sharing options...
thescrapman Posted June 13, 2011 Share Posted June 13, 2011 Are not 2000 and 2500 conrods the same???CheersColin Link to comment Share on other sites More sharing options...
Hugh Posted June 13, 2011 Author Share Posted June 13, 2011 thescrapman wrote:Are not 2000 and 2500 conrods the same???CheersColinColin I am not sure I just thought the throw/ lift would be different but I have never done this before so I am not sure :) Do you have any 2500cc conrods by any chance.Cheers Hugh :) Link to comment Share on other sites More sharing options...
Clive Posted June 13, 2011 Share Posted June 13, 2011 conrods the same, pistons different :) Link to comment Share on other sites More sharing options...
thescrapman Posted June 13, 2011 Share Posted June 13, 2011 I am fairly sure I sold my last set to Dave Picton, but, if you can wait a few weeks I may have some more coming.CheersColin Link to comment Share on other sites More sharing options...
Hugh Posted June 13, 2011 Author Share Posted June 13, 2011 cliftyhanger wrote:conrods the same, pistons different :) Hi Clive can you tell me what the difference is please and is that they the only things required to change my GT6 MKII engine to 2500cc spec.Cheers Hugh :) Link to comment Share on other sites More sharing options...
Clive Posted June 13, 2011 Share Posted June 13, 2011 It is where the gudgeon pin is located. The position is different between the 2 litre and the 2.5.Get a set of TR6 pistons.........and use the 2.5 crank. Job done.This assumes you have the correct head, in which case you will have the dome topped pistons......and you take note of the sump modifying (hammer) etc Link to comment Share on other sites More sharing options...
Hugh Posted June 13, 2011 Author Share Posted June 13, 2011 Thanks Clive can you tell me if I have dome head pistons would I need TR6 pistons will I need a rebore to fit the TR6 pistons. Cheers Hugh Link to comment Share on other sites More sharing options...
Royboy66 Posted June 13, 2011 Share Posted June 13, 2011 Hugh, I can lend a hand with the sump 'dressing' ;) ;D I done it on mine, and have a Large left handed Ommer ! :B Link to comment Share on other sites More sharing options...
Nick Moore Posted June 13, 2011 Share Posted June 13, 2011 The only things you'll need to change the engine from 2 to 2.5 are the crank and pistons. The rods stay the same. To accommodate the longer stroke, the 2.5 pistons' gudgeon pins are nearer the piston crowns.Someone will jump up any minute now and point out that a properly built 2L can produce as much power as a 2.5, and is revvier / more sporting and in character with the car etc. All true but I think you're going the right way Hugh - the 2.5's greater torque makes for easier driving. Roy converted me!And Tim's car proved that a TR5 camshaft is a good match to the engine - I ordered one from the Brothers yesterday.Edit - Jeeze I type too slowly. The TR6 pistons will probably be the same size - but check. As for domed... probably. Best to check the compression ratio afterwards though. Link to comment Share on other sites More sharing options...
Royboy66 Posted June 13, 2011 Share Posted June 13, 2011 I think Roy Sccottie will have a pic of his modded sump! Very nicely done :)BTW Nick great pics from your latest Jaunt 8) Link to comment Share on other sites More sharing options...
Hugh Posted June 13, 2011 Author Share Posted June 13, 2011 Nick_Moore wrote:The only things you'll need to change the engine from 2 to 2.5 are the crank and pistons. The rods stay the same. To accommodate the longer stroke, the 2.5 pistons' gudgeon pins are nearer the piston crowns.Someone will jump up any minute now and point out that a properly built 2L can produce as much power as a 2.5, and is revvier / more sporting and in character with the car etc. All true but I think you're going the right way Hugh - the 2.5's greater torque makes for easier driving. Roy converted me!And Tim's car proved that a TR5 camshaft is a good match to the engine - I ordered one from the Brothers yesterday.Edit - Jeeze I type too slowly. The TR6 pistons will probably be the same size - but check. As for domed... probably. Best to check the compression ratio afterwards though.Thanks Nick Yeah I was in Roy,s car the other night and I thought afterwards that the torque of the engine would lend it's self to a more relaxed form of driving for me when I get back to driving that is :)Yes a highly modified 2000cc would produce as much power as a 2500cc engine but I don't want to go down that route. :) I might put triple weber's on it just to listen to the induction roar I am not after out and out power just a small increase in power and more tourque. Link to comment Share on other sites More sharing options...
James Posted June 13, 2011 Share Posted June 13, 2011 I don't get it.Even a standard 2 litre should be relaxing and enjoyable to drive- you don't need to hammer it everywhere?The stock 2 litre in my heavy saloon would make her whoosh along at a decent rate. Link to comment Share on other sites More sharing options...
Clive Posted June 13, 2011 Share Posted June 13, 2011 James, if you have to ask then you don't understand. The 2.5 was fitted to the TR's so is a great sportscar engine :PNow, pistons are the same bores, so if you have std pistons now you need std TR6 ones. If you have +20, then likewise you need +20. Sorry if stating the obvious, but needs to clear to avoid costly mistakes.Head. Hmm, engine number would be an indicator, as would accurate depth of head. And don't forget induction. A nice pair of HS6 carbs required and the manifold opening up a bit to match, plus file the carb mounting holes. Roy will guide you on that :)Off to bed, gotta go to work tomorrow :'( Link to comment Share on other sites More sharing options...
Hugh Posted June 13, 2011 Author Share Posted June 13, 2011 jcarruthers wrote:I don't get it.Even a standard 2 litre should be relaxing and enjoyable to drive- you don't need to hammer it everywhere?The stock 2 litre in my heavy saloon would make her whoosh along at a decent rate.James I started this thread to discuss what I need to change my 2.0 to 2.5 . There have been lot's of thread's on one engine over the other and I would like to keep this thread on 2.0 to 2.5 because I am trying to look at ways of having a more relaxed more torque engine which I hope will help me drive my car after I recover from my injuries.So please engine over the other just what is required to go from 2.o to 2.5 thanks.Hugh :) Link to comment Share on other sites More sharing options...
Hugh Posted June 13, 2011 Author Share Posted June 13, 2011 cliftyhanger wrote:James, if you have to ask then you don't understand. The 2.5 was fitted to the TR's so is a great sportscar engine :PNow, pistons are the same bores, so if you have std pistons now you need std TR6 ones. If you have +20, then likewise you need +20. Sorry if stating the obvious, but needs to clear to avoid costly mistakes.Head. Hmm, engine number would be an indicator, as would accurate depth of head. And don't forget induction. A nice pair of HS6 carbs required and the manifold opening up a bit to match, plus file the carb mounting holes. Roy will guide you on that :) :)Off to bed, gotta go to work tomorrow :'( Thanks Clive I have HS6 carbs on my car now and your right Roy and Tim set me right on them ;) Link to comment Share on other sites More sharing options...
Hugh Posted June 13, 2011 Author Share Posted June 13, 2011 thescrapman wrote:I am fairly sure I sold my last set to Dave Picton, but, if you can wait a few weeks I may have some more coming.CheersColinThanks Colin seems I only need piston's but thank you for your kind offer Cheers Hugh :) Link to comment Share on other sites More sharing options...
thebrookster Posted June 14, 2011 Share Posted June 14, 2011 I likes!! Like various others here, I prefer the longer stroke engines for the torque characteristics, hence I am building a 1500 for my spitfire. I shall watch your build with interest Hugh, right up my street :)Seeing as you say you are only after a moderate power increase, concentrating rather on the torque, then a simple crank/piston change is ideal. Only other things I would consider is a mild cleaning up of the ports (I really have got the bug here) and a decent manifold if you don't already have something (if you can get one, and don't mind the price GT's 6 cylinder jobby really seems the biscuit, a simple bolt on that will give nice improvements). If you decide to play with the head, give me a shout and I can send some stuff your way that can help, nothing major just simple work that can be done at home to improve flow.This is one of the reasons I like Triumphs so much, you can get amazing gains for so little work.Thinking on the torque side, anyone ever considered putting a small turboed diesel into a Triumph :P That could result in some interesting results!!Cheers,Phil Link to comment Share on other sites More sharing options...
Richard B Posted June 14, 2011 Share Posted June 14, 2011 908 wrote:just a small increase in power and more tourque.Oh, you'll get more torque :)If your existing headgasket has a tag at the back the you will have recessed bores and (probably) domed pistons. The other way to check is the head height. If the head is 3.400" then it is the same as a 2500, if the head is 3.300" then it is a flat piston 2litre head and unsuitable for a 2.5. (unless you can open out the combustion chamber lots...)ps. You made need to adjust your final drive as a 2500 will not rev as much as a 2000. I have a 3.63 + J'Type with 14" wheels on my Spitfire.pps. Post the number stamped on the head and I'm sure it'll be identified.ppps. if you have the HS6's and a MkIII GT6 then with a bit of milling the 2500S inlet manifold can be fitted. This has long tracts and flows better than the standard (cramped) GT6 manifold. Link to comment Share on other sites More sharing options...
Hugh Posted June 14, 2011 Author Share Posted June 14, 2011 Richard_B wrote:Oh, you'll get more torque :)If your existing headgasket has a tag at the back the you will have recessed bores and (probably) domed pistons. The other way to check is the head height. If the head is 3.400" then it is the same as a 2500, if the head is 3.300" then it is a flat piston 2litre head and unsuitable for a 2.5. (unless you can open out the combustion chamber lots...)ps. You made need to adjust your final drive as a 2500 will not rev as much as a 2000. I have a 3.63 + J'Type with 14" wheels on my Spitfire.pps. Post the number stamped on the head and I'm sure it'll be identified.ppps. if you have the HS6's and a MkIII GT6 then with a bit of milling the 2500S inlet manifold can be fitted. This has long tracts and flows better than the standard (cramped) GT6 manifold.Ok Roy came to see me for a chat and a coffee today he also measured the head depth it's 3.42 with tag at the rear so it must be domed head pistons fit ? So reading your comment above I guess that I just need to change my pistons and crank to achieve a 2500 engine? Hope I have got this right :) Link to comment Share on other sites More sharing options...
Richard B Posted June 14, 2011 Share Posted June 14, 2011 What cam are you running?Not sure, but will you also need a harmonic damper pulley from a 2.5?I would be tempted to uprate the timing chain to duplex as all the 2.5's had.and don't forget to panel beat the sump around No.1 & 2 conrods. Link to comment Share on other sites More sharing options...
Hugh Posted June 14, 2011 Author Share Posted June 14, 2011 Richard_B wrote:What cam are you running?Not sure, but will you also need a harmonic damper pulley from a 2.5?I would be tempted to uprate the timing chain to duplex as all the 2.5's had.and don't forget to panel beat the sump around No.1 & 2 conrods.Right I am going to run a TR5 cam and a duplex chain plus the damper. :) Link to comment Share on other sites More sharing options...
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