Yes, certainly if you increase the stroke, the torque will increase as a result of the longer lever arm. However, increasing the stroke also increases the engine displacement which will result in a torque increase. To determine the effect of stroke we must keep all other engine parameters constant.
For example, Case 1) if we consider an engine with a 4.0 in bore and a 4.0 in stroke the displacement is 50.27 cu in per cylinder. The cross sectional area of the piston is 12.57 in sq. Lets assume a cylinder pressure of 100 psi and that the force acts at a right angle to the crankshaft throw. The resulting torque is 209.5 ft-lb, (100 psi x 12.57 in sq x 4 in / 2 x 1 ft / 12 in). Case 2) if we consider an engine with a 5 in stroke the bore must be reduced to 3.578 in to equal 50.27 cu in per cylinder. The cross sectional area of the piston is now 10.05 in sq. Again, assume a cylinder pressure of 100 psi and that the force acts at a right angle to the crankshaft throw. The resulting torque is again 209.5 ft-lb, (100 psi x 10.05 in sq x 5 in / 2 x 1 ft / 12 in).
Yes, I do agree a short stroke engine with a larger piston can produce the same torque as a longer stroke engine with its smaller piston, as per the above example.
This is why I maintain stroke does not determine engine torque.
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