Animated movie with a big metal dinosaurs hurling fireballs

Thanks, I've checked some parts of Gurrent Lagen episode 8 on youtube but that's not it. It looks too modern and full of action. As I remember this movie had much slower pacing.

I've looked at parts of random episodes of Evangelion (that I could find on youtube) and it looks closer to what I'm looking for but it isn't that either. I think that this movie was something very simple aimed at kids but not so fast-action paced and violent as some of the newer cartoons are.

Thank you very much for your suggestions anyway.

Last year I've finally found out what the movie was. I forgot to post it here right away but better late then never. It was a japanese movie from 1970 called "Kaitei 30,000 mairu" (english title is "30,000 Miles Under the Sea"). IMDb URL: https://www.imdb.com/title/tt0067286/reference

Thanks again to everyone who tried to help. It took years but it's finally over

CLOSURE!!!
Grats on the find and for coming back to share!