RayJ

I have to check this on my own, but what Maximo says makes sense to me if I think of the length of piston travel versus crank rotation. Raising the liner does raise the liner equally on the exhaust and intake ports, but the intake and exhaust ports close at different times during piston. The piston travel is not linear in relation to the different points of crank rotation. When the piston reaches top dead center, the crank has to turn alot more degrees to move the piston in comparison to the beginning of the stroke. If all three intake ports and the exhaust port were located on the exact same location on the sleeve the timing changes would be equal. I haven't verified this yet, but it's another way of looking at it.