Hey guys i need some advice on something quick. About 5 months ago i made an online trade with some1 for a car. I traded a rebuilt performance engine and turbo kit for a car. The guy agreed and we made the deal. I had the engine professional built by a shop that has been building engines for 25yrs. I never ran the engine and i gave the guy the receipt when he picked it up. The engine was completely assembled. Now about 6 months later he calls me and has told me that he installed the engine and it is knocking. And he tells me that he has had it looked at by a shop and all this stuff is wrong with it and tells me i had it built by an amatuer. And then he tells me i can either pay for the the engine to be rebuilt or he is going to take me to court. There was nothing wrong with this motor when i sold it to him as it was never even started up. What i would like to know is there anything this guy can honestly do ? I know the guy is full of it and is just trying to scam me for money and i really doubt he can do anything. He also said he has already contacted his lawyers and said that he can file a lawsuit. But how is this my fault he had the engine for 6 months already how do i know that it wasnt installed 5 months ago and he blew it up or broke it. Another thing is im in PA and he is in MD so anyone with some information on this id really appreciate it thanks guys !!!!!