rare gt6?
Posted By : William Davies, 16-Jul-2005, 08:56am
I'd be pretty confident in stating that the Triumph 6-cyl engine was never taken out to 3 litres, unless there was a radical developmant project which
hasn't been documented. A 2.5 would be a theoretical period modifcation, but I would doubt very much that it was factory sanctioned.
I think we need numbers...
Cheers,
Bill.
I think we need numbers...
Cheers,
Bill.
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rare gt6?
Posted By : Colin Lindsay, 16-Jul-2005, 09:18am
I think - off the top of my head - the biggest engine I've heard of using the original straight six setup has been 2.6, maybe 2.7 which I think was achieved by boring out the block to about 2188cc then using the 2.5 piston setup (as usual at work with no reference nearby... sorry! Any racers can confirm?) and I reckon if the three litre modification was possible no doubt there'd be a lot of owners doing it and documenting it. The triple carb setup is common enough but unless the engine is from another model I'd doubt if it's three litre. Any chance of more details?
Colin-
rare gt6?
Posted By : Nigel Gibbins, 16-Jul-2005, 02:09pm
Kevin Ginger used to run a GT6 with a reported 2980cc engine in it... !!! Y'know, the fabled Mid-engine GT6.
Dunno what he did to get that but I'll betcha it was expensive
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rare gt6?
Posted By : Colin Wake, 16-Jul-2005, 02:55pm
Are you sure the owner doesn't have an MGC GT????
Perhaps th e dealer fitted one?? or an engine from a Healey??
Colin -
rare gt6?
Posted By : Jason Chinn, 16-Jul-2005, 04:58pm
If anyone would know it would be Tony Lindsay-Dean as he raced with Kevin and they were mates I seem to recall. That GT6 was great - I saw t go round Lydden and qualify with a stuck throttle - brakes glowing red at the end but he qualified!!
2.6 is just a +.60 rebore, 2.7 is Mazda pistons I think (guessing now!)-
rare gt6?
Posted By : Van Hamlin, 16-Jul-2005, 05:45pm
One of my mates from years ago his dad raced a Vitesse in the late 60s. It had a 2.9 engine made by boring out into the water jacket, putting liners in, and using Fiat 130 pistons. This was built very soon after the 2.5 engine came out and if I remember rightly it was a collaborative effort with another guy who had a GT6. So both modified cars would have been fairly new at the time.
He raced it, not sure how long for, and then de-tuned it for road use and he and his wife used it for a good few years before getting a Dolly Sprint. I don't know if the car survives, and I don't know if the GT6 survives either, but it is possible that this might be the car.
Van
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rare gt6?
Posted By : Nigel Gibbins, 16-Jul-2005, 06:02pm
I'm not sure that different pistons will increase capacity? as it's a measure of the swept area of the piston in the cylinder - surely they'd just change the compression ratio?-
rare gt6?
Posted By : Jonathan Binnington, 16-Jul-2005, 06:35pm
yes, I too have investigated this, by using a B2 block it would be possible to re-pitch the cylinder bores and go up a couple of millimetres or so in bore diameter to get another 250cc or so across all 6 pots and that was about that without breaking into water jackets and using liners.
a 3 litre triumph six would be a special beast indeed and not one for the impercuneous triumph enthusiast!
another one of those urban myths
j -
rare gt6?
Posted By : Colin Lindsay, 16-Jul-2005, 08:51pm
I didn't mean different pistons, I meant the longer stroke of 95mm as opposed to 76mm... how big a capacity would you get using the maximum of both boring out the 2498 block and maximum stroke?-
rare gt6?
Posted By : Colin Wake, 16-Jul-2005, 09:18pm
could you fit a longer stroke crank in teh standard block??
They might have done it that way.
I would still put my money on the dealer having fitted a Healey/MGC engine.
Colin-
rare gt6?
Posted By : Robert Macdonald, 16-Jul-2005, 10:57pm
Hi, folks I will try and get more info on the car and engine ect but I can assure this guy has had this car from virtually day one and the car bought and registered by his sister in law there has been only two owners I had a long conversation with him and I am sure he said the car came out the factory like this. i think he maybe a member of this club but does not have access to a pc, also he does not know i have asked questions about the car on here and i would prefer to ask him first if it is ok to make enquiries about the car he treats the car almost like a soulmate rather than something special for people to stand and admire so he may well tell me to mind my own bloody business but i will try and if i can learn anymore i will post it .
regards
Robert -
rare gt6?
Posted By : William Davies, 17-Jul-2005, 00:27am
Hi Colin,
The Healey 3-litre is a huge engine, the MGC's is even bigger - getting either into a GT6 would take some serious engineering. The MGC dispensed with the B's coil sprung suspension in favour of torsion bars, the engine really took up that much room.
Whatever this car turns out to be, I think the BMC engine is to all intents and purposes impossible,
Cheers,
Bill. -
rare gt6?
Posted By : Jonathan Binnington, 17-Jul-2005, 08:55am
loger stroke will need offsett grinding on the crankpins to get say a 3mm increase in stroke and say the bore was increased by 3mm over the oversize
74.7mm bore x 95mm stroke might go to 78mm bore x 98mm stroke (with special pistons)
such an engine would be of displacement
1/2bore x 1/2bore x pi x stroke x 6 = 2810cc oh dear!
ok, fitting wet liners isn't really a goer because the three pairs of cylinders are siamesed, so might have to go the longer stroke route, to get an engine which doesn't like high revs unless instead of just having a special crankshaft made you buy a set of carrillo rods as well as special pistons
HAVE WE GOT A BUDGET TO KEEP WITHIN HERE?????
looks to me like the 2.5 is at it's design limit for displacement
jonathan
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rare gt6?
Posted By : Colin Wake, 17-Jul-2005, 09:13am
Lets assume you have a Formula 1 budget, maybe more Minardi than Ferrari, but money is no object. Could it be done within a standard block???
Colin-
rare gt6?
Posted By : Robert Macdonald, 17-Jul-2005, 10:40am
Hi, folks another bit of the conversation I had with the old guy has came back to me he mentioned the gearbox had no syncromesh, I am hoping somebody out there can make sense of all this because not having enough knowledge of the internal combustion engine I cannot by the way the old guy is an engineer.
regards
Robert-
rare gt6?
Posted By : Nigel Gibbins, 17-Jul-2005, 03:26pm
The box is probably a 'dog box' then and that would make the car a racecar (usually). You won't find any sychros in there.
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rare gt6?
Posted By : Jonathan Binnington, 17-Jul-2005, 04:22pm
with a special crankshaft with extra throw to get a longer stroke by say 8mm and previously mentioned increase in bore to 79 mm
we get
3029cc
special crankshaft one off say &163;5000
set of special rods say &163;2500
set of special pistons say &163;500
special head gasket say &163;250
plus sundry engine building bits
say &163;10,000
plus a special gearbox for 250+ bhp &163;2500
plus fueling system of your choice PI/efi/webers say &163;1500
plus big radiator &163;500
not much change from &163;15,000
then the jalopy to put it in...
not in my budget!
j-
rare gt6?
Posted By : Colin Wake, 17-Jul-2005, 04:47pm
Mine neither, but it is possible.
Now to solve how it was done back then.....
Any one contacted Tony LD yet???
Colin
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rare gt6?
Posted By : William Davies, 17-Jul-2005, 01:05pm
Hi Jonathan,
I've got a 2.5PI engine which came from an abandoned project. This has had plenty of work done, though the engine was never completed and lacks pistons. It's been overbored +0.060, which I calculated some time ago as taking it out to something around 2.7 litres (correct me if I'm wrong). My piston supplier shows this oversize as a standard off-the-shelf item, presumably this capacity shouldn't require any substantial re-engineering.
Cheers,
Bill.
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rare gt6?
Posted By : Andy Cook, 19-Jul-2005, 01:23pm
Jason,
Here's a piccy of Kevin's GT6 racer for nostalgia!!
This was taken at the TSSC International when it was at Cranfield (before it moved to Stafford), about 1987 I think. They had a demo of TSSC race cars at speed on the runway and also a fairly quick auto test on the runway for anyone who wanted to take part that year. I remember it well as I broke the gearbox on my 1500 spit taking part in the auto test by chipping teeth off the layshaft cluster 1st gear and reverse cog when I wheel spun it in reverse.
Regarding large capacity Triumph 6 cylinder Engines. My mate Colin Geer had a 2.7 Litre 6 cylinder Triumph Engine in his Turbo charged GT6 in one of it's incarnations, this was built by Steve Phillips who used to do a lot of Triumph Tuning work. I believe Colin's GT6 ended up being reduced to 2.3 litre in a later version though as the shorter stroke engine revs better and was more suited to the turbo arrangement. That was before Colin fitted the current Seirra Cossie Engine and box!! Saw him over the weekend and his GT6 is currently being converted to a Sierra Cosworth LSD rear end which is a body off job. he expects to have it out and about again next year including Stafford.-
rare gt6?
Posted By : Jason Chinn, 19-Jul-2005, 04:14pm
Nice one Andy - I'd forgotten just how fat the rear end of that GT6 was!
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