S7ewie

Hey folks, A friend of mine recently had an idea to build his own log splitter partly because he does a lot of lot splitting and partly because we need a project We're both in farming and have a fair bit of experience in metalwork etc. We have all the tools, but need advice on the parts. He wants to hook it up to his 13 horsepower lawnmower engine. I've seen a lot of figures floating around in my search and was wondering if anyone could help calculate the best size hydraulic cylinder and pump for us to use with that engine? Also any other tips and advice would be appreciated. Thanks