Does this website have working plans on how to build Mr. Dingel's water-powered engine/car?

No, this website (or for that matter, any other website or source - offline or online) does not have working plans that will allow one to replicate Mr. Dingel's invention. As it is, his invention has not yet been patented or even released to the public domain. Mr. Dingel is still in active negotiations with various groups. Any claims by any party that s/he or they have the plans are false.