Do you think I have a chance winning this small claim without these records?

I'm suing a mechanic because he installed a used engine in my car and didn't give me the 90 day warranty that was promised. Within the 90 days it was leaking oil and he refused to fix the leak. Had he given me the 90 day warranty it would've been covered. I reported him to the Bureau of Auto Repair...I thought that he agreed to fix the leak but he only agreed to look at it, then he tried to get me to sign this form that said in fine print at the bottom "no warranty on used engines" but I caught it just in time. We literally fought over the paper and I tore it but kept it for records. I'm suing him for the amount it costs to fix the leak. I paid cash for the most part and he didn't give me receipts but i have records of the portion I paid using my debit card. It's too late for me to subpoena the records of everything from the Bureau, which basically document everything said and done on all parts (me,mechanic and investigator). Do you think I still have a chance getting my judgement? I have the paper he tried to get me to sign to try to refute his 90 day warranty, pics of the leakage, and bank statements showing all that I paid him.