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GT6 GT6 Crank in a TR6 Block

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bobh

bobh

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Have any of you ever heard of putting a GT6 crank in a TR6 block? One of the local club members who owns a TR6 said he was running a GT6 crank. I'm not intimately familiar with the GT6 engine other than knowing it is a 2 liter 6. Isn't the TR6 engine basically a stroked 2 liter 6? The stroke was increased aproximately .75 inches?
I don't know the details of the changes to increase the stroke. I know in my Ford Flathead it involved a different crank and different pistons.
Do the engines share the same block? If so wouldn't his engine now be 2 liters? (not including an over bore during the rebuild)
 
Basically the 2.5 is a stroked 2.0, your right about that. The 2.0 is a bored out version of a STANDARD (referring to the company that bought the Triumph name following WWII, Thus 'STANDARD-TRIUMPH') 1600cc I6 which I bellieve developed from an earlier STANDARD I4. (the Spitfires 1500 block is also a direct relative)

The blocks are inherently the same but the 2.5 blocks did need some clearancing to allow for the increased throw of the stroked crank. The later 2.5 blocks also had some buttressing added for strength. As long as the GT6 crank matchs the needs of the TR6, as in long or short nose to match the flywheel, I can't think of any reason that it couldn't have a GT6 crank.

It would lessen the displacement but it would also be capable of higher rpm with less harmonics. The resulting engine would also generate less torque, which is part of what makes a TR6 so fun to drive. So my question would be why? /ubbthreads/images/graemlins/confused.gif

Stroking GT6 engines to 2.5L for GT6's, Spit6's and 2000 Saloons has been pretty well documented when those owners want more torque and power but a well tuned 2.0L in the lighter cars can be very fun to drive and very smooth revving.

/ubbthreads/images/graemlins/cheers.gif
 
I am not an expert on the subject, but I think putting a shorter "stroke" crank into a long-stroke block is going to significantly reduce your compression, perhaps to a point where it may not run. Does that make sense?

Rob.
 
Not if you use pistons with the correct compression height, Rob. If you were to reuse the stock TR6 pistons, then they would be significantly down in the bore at TDC.
Jeff
 
Yes - that makes sense. Either the pistons would need to be longer or the con rods to get you back to the correct compression..
 
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