How hard is an engine rebuild DIY?

maybe watch youtube

 

I did a home rebuild on my Caterpillar, with no diesel engine training, but I have a good history of mechanical work. There are some specialty tools and depending on what is damaged inside, you may need some machine shop work. One possibility is counter bores being cut.
As mentioned, YouTube has the Adept Ape. Very good Caterpillar mechanic and has very informative videos.
Being meticulous and clean is very important. The guys on the site helped me a ton and I am pleased with the results.

 

I rebuilt my Cummins 444xt a few months ago. No real mechanical training but I’ve been working on vehicles since my teens

There area few special tools I either bought, borrowed, or made. Used a chain hoist to flip the block and put the crank in then flipped it back over

I did the whole thing on a flatbed trailer parked in my shop. When it was done I towed it back to the shop where the truck was and they dropped it back in

 

Buy an engine manual for the engines you are wanting to rebuild. Read them extensively. I have no idea how common those engines are? Can you find videos on YouTube about them?

I rebuilt my cat basically by watching YouTube and finding specs online. I've been playing with wrenches my whole life and fixing things around the farm. Had torn a few blown engines apart but never put on back together.

Really I didn't feel it was complicated. Just take your time and pay attention to details. Use paint markers to make sure everything goes back the same way it came apart