Okay here it goes...... I bought a car yesterday from someone I know or thought I knew. I drove the car up and down the person's rd. Then went straight home. Less than 5 miles. No problems. Parked the car for the night. Woke up this am excited about getting it legal. Drove it into town to handle insurance, registering it, tags. During doing these things probably within 15-20 miles it started making a knocking noise mostly when pushing gas at first. When rpm were up right before it changed gears. Checked the oil a lil low but not too low. Then progressively started making the knocking noise continuously Im thinking around 40 miles or so. I had someone listen to it and they think its the rod bearings need to be replaced. It's BAD. I put a lucas oil treatment in it and some thicker oil. Still knocking BAD. I just wanted to know if someone could have done something to engine because it was not knocking when I bought it. It made one strange noise when the person cranked it to let me drive it but the noise stopped immediately. If they could of done something how can I find out for sure. Any help or advice would be greatly appreciated. Thanks, Joy