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GT6 TR6 in a GT6

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hymodyne

hymodyne

Senior Member
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If a TR6 crank, conrods and pistons will fit in a GT6 engine block; and with the adding of a TR6 head you get the benefit of the extra 500cc's of displacement, what keeps folks from just putting a TR6 engine in their GT6? I'm imagining that the gearbox and bell housing being different has something to so with it, but I just wanted to ask the question.

Hym
 
I understand the TR6 is also taller. But I may be wrong on that and I am sure someone will correct me.
 
I don't know about overall height of the engines, but the sump is quite different on the GT6. From what I've heard, one needs to use the GT6 sump when doing this swap...but one also has to perform some selective, er, reshaping of said sump to clear the rods/crank. :hammer:

The TR6 gearbox can be made to fit and is probably a good idea. The GT6 differential might hold up with the extra torque...or it might not. Meanwhile, many say that the 2.0L revs much more nicely than the stroked 2.5L....
 
A LOT of work for relatively little gain, I believe. More displacement means more torque, which the relatively weak GT6 drivetrain doesn't handle well, and the TR6 gearbox won't fit between the frame rails wthout substantial modification. But the TR6 motor doesn't breathe much better than the GT6, so max power is almost the same (both were rated 104 bhp in US trim, I believe). The TR6 lump is also heavier, so takes more power to accelerate and makes the car more nose-heavy.

GT6 intake manfold tilts down; the carbs won't fit under the hood with a TR6 manifold.

BTW it's the crank that increases the displacement; not the head.
 
Check to see if the exhaust for a TR will fit the GT body
 
Good advice above, as usual. I'm with Randall, unless you're seeking some highly specific reason for 500 more ccs under the bonnet, the GT6 engine does practically everything the 2500 will, and it will rev higher, too.

I know some folks yearn for tons of HP, but a GT6 with approx. 135 or so HP is fast as lightnin'! :shocked: And, you can fetch 130 or so HP out of the GT6 engine using period-correct parts and relatively minor mods (i.e., cam; headwork; 6-3-1 headers and less restrictive exhaust, etc.).

Save yourself the trouble and stick with the 2000cc GT6 powerplant. If you're rebuilding, make sure the key components are balanced, the rest is easy.

Good luck, let us know. And, please post photos!
 
My racer sources say that the tr6 crank must be put on a major diet before it
will make any rpm's at all.Perhaps while this process is happening you can get clearance with the sump and get the best of both worlds.You will want to get better rods though.....cast iron doesnt like high rpm.
MD(mad dog)
 
If I recall the discussion correctly, Kas Kastner said just the opposite. He found that the TR6 crank flopped all over the place at higher rpm, and needed more weight in strategic spots to help strengthen it. They measured something like 5/8" deflection at the rim of the flywheel, at 7000 rpm.
 
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