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TR6 Shortening TR6 Stroke.....

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Just curious, is there any way to shorten the stroke on the TR6 block? Seems shaving the block and the head and using shorter connecting rods might allow for a shorter stroke, and thus higher rmps. Or is there just not enough meat in the block to pull this one off?


Bill
 
Bill, jooi - why'd you want to do this? It seems like a pretty complicated option compared to fitting a steel crank, or using a GT6 bottom end mated to a TR6 head (7k easy that way but less bottom end oomph).
 
To shorten the stroke you must replace the crank shaft and lenghten the connecting rods. The stroke is determined by the crank.
 
Correct. If you shorten the stroke, you lower the displacement. Displacement is equal to the bore area (pi*r^2) times the stroke times the number of cylinders.
 
I have to hand it to TR6BILL, his threads tend to be among the most interesting ones here. Seriously, his are always a good read.
 
Depends on how much of a decrease you would be looking for. A machine shop could grind the crankshaft offset. Old time racer trick looking for the unfair advantage (depending on which side of the crank was ground). Bob
 
A TR6 should be good for maybe 6500 RPM? Why would you need more rev's? More HP? To get more high RPM HP would require extensive head mods, higher compression, a radical cam, headers, stronger rods, a steeper rear gear to get the car rolling, etc.

I guess you could do it...but a new crank would be about $3K...you might get it done for another $5K....

Rotsa Ruck....!!!
 
There are race prepped 2.5litres spinning to 8000rpm though it takes much more work to get there than YankeeTR mentions. Loads of specialized parts and machining. When all is said and done your looking at $20k-$25k just for the engine for that type of RPM. Even then, it has a limited lifespan. A GT6 crank already has the shorter stroke, but as has been mentioned already, you'll lose displacement for the increase in RPM. TR6's are heavy enough to need that torque from the long stroke and the extra displacement.
 
Hello Bill,

it's not only the GT6 that had a 2 litre engine, The Triumph 2000 sedan also used a 2,000 cc or a 2,500 cc engine depending on which you chose. 2,000 engines are, in your language, 'a dime a dozen' over here. Sourcing and shipping a 2,000 crank and connecting rods would be cheaper than having yours machined, and will fit straight into your block.

One Triumph specialist over here (www.chriswitor.co.uk) prefers the 2,000 as it is livelier and smoother.

Alec
 
[ QUOTE ]
There are race prepped 2.5litres spinning to 8000rpm though it takes much more work to get there than YankeeTR mentions. Loads of specialized parts and machining. When all is said and done your looking at $20k-$25k just for the engine for that type of RPM. Even then, it has a limited lifespan. A GT6 crank already has the shorter stroke, but as has been mentioned already, you'll lose displacement for the increase in RPM. TR6's are heavy enough to need that torque from the long stroke and the extra displacement.

[/ QUOTE ]

Well said...
 
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