Well here is my problem, I have to add like a half quart of motor oil every 3 days or around 300 miles. smoke comes out of my exhaust everytime i step on the gas. I check the engine and there is no leak so it is coming straight out of the exhaust. I use mobil1 5w30 and my motor is a usdm B18c5 swap in a del sol. The motor has about 70,000 miles. People say that i have bad pistons? anyone know what might be the problem.