My opinion is --- depends on your skills and personal interests.
If you are sufficiently talented and dedicated, and decide you want to collaborate on an engine, contact me by PM and learn about the engine I'm developing. This engine is fairly far along, several subsystems are complete and work, is multi-platform, very high-performance, and includes some special capabilities that make the engine potentially more interesting than others (if characteristics like "procedurally generated content" interest you).
Oh, and a "game engine" is something like a collection of code libraries (usually shared libraries or DLLs) that does most of the actual work in a game, but only those parts not specific to one game. In other words, the game engine does pretty much everything that needs to be done by more than one out of a hundred games.
Do you have some kind of tutorials on making the game engine
No, sorry but I don't. However, there are a couple fairly good books about game engine design or architecture, which may provide an equivalent (or what you need). But something about the huge size and scope of "a game engine" makes me think "tutorials" isn't an appropriate match. Find the most recent editions of those books. If you're serious, definitely pay for the paper books rather than trying to download for free via some torrent. The authors deserve their cuts.
If you have cool new ideas and you want to brainstorm about them, start a personal conversation with someone who built, or is currently building an engine. And don't worry they will steal your ideas - they won't want to. And even if they do, the work involved to implement their engine, much less your new enhancements is so huge that you need not worry --- and in fact you should be happy if they steal and implement them!