Very good morning to all. I answer this issue since I have a minivan super carry Chevrolet Motor Suzuki F10a in which my engine occurs the same fault.My works have been to disarm and assemble 5 times in a year and with this experience and multiple consultations that I have made I conclude that there are problems of the ring that is of poor quality, the oil. It influences. It has the complete work of camera: change of guides, vasas and gums of valve. My engine after repaired it lasted only 1 month and began the spark plug couple. Right now, I greatly appreciate that you and others can help us in the final solution of this problem. I am in Venezuela Barquisimeto Edo Lara my telephone is 04245236829.Saludos