I'm just starting a log splitter building project and am planning to put a log lifter on it. Will be happy to share ideas with you. My plan is to hinge mount the lift arm (on operator's side) just below the upper flange of the beam. (Has to be a bit below, because can't interfere with the ram's travel.)
The lift arm will be dimensioned so that, when the splitter is at the operating height I like (it's a 3ph mounted splitter), the arm extends diagonally down to ground level and then out for about 18" so that you can roll the log onto it.
An hydraulic cylinder will be mounted from the lower flange to the inboard portion of the lift arm at a point to minimize the required force and length of travel. Length of stroke will be determined by the amount of extension necessary to raise the lift arm enough to roll the log onto the inboard portion of the arm and thence to the splitter beam cradle.
I don't think that that is going to require a very large bore cylinder. Even a 2" cylinder, operating at 2750psi, will generate over 8600# force, which ought to be more than sufficient to raise the lift arm and even the largest log I could put on it. I haven't calculated the force vectors because it is obvious that that is orders of magnitude more than is needed. Moreover, you only need sufficient force to start the arm moving up since, as the arm raises, the vertical componant increases and thus the required force decreases. I'm no engineer, but I THINK that that's right.
BTW, the splitter I am building is also going to be pretty heavy duty; 8x8 58#/ft H beam, 28gpm 2 stage barnes pump driven by my tractors 22pto hp running through rpm increasing gearbox and pulleys to get pump rotation up to 3500rpm and 30 gal hydraulic reservoir, 5x20x2.5 cylinder, full automatic cycle ram valve with power beyond to operate additional cylinders to adjust interchangeable 4-way and 6-way splitters and the log lift.
If you have "power beyond" on your ram valve, that is probably the best, and safest way to go to run the log lift hydraulics. I'm assuming that you have an open center system. I have a thread started with more detail in the "build it yourself" forum on
www.tractorbynet.com. I go by the same moniker there.
I also assume that you have cutting and welding capability or access to same. I think you'd want to be able to weld and cut 2 1/2 x 2 1/2 x 1/4" angle iron and medium weight expanded steel to form the bed.
Hope some of this helps. Feel free to PM or post further if I can be of help.