Hi everyone,
Looking for some help - I don't own a Rover car but rather a 2002 Range Rover P38 with the 4.6L Rover V8. Obviously there are some differences but the core block and valvetrain I believe are very similar to the original 3.5L V8. Anyway, I have an exhaust lifter (tappet) which has stuck down on cylinder #4. I believed that was the source of my rapping / tapping sound and replaced the lifter and pushrod. Upon startup, the engine ran smoothly and quietly but after about 20 minutes, particularly with some light revs, the engine is right back to where it was before - rapping! Additionally, since this vehicle is new enough, there is a misfire on this same cylinder, which I believe was due to the stuck lifter no opening the exhaust valve enough. Spark plug was very dirty black on this cylinder. Final thoughts are that when I removed the original stuck-down lifter, it was very difficult to remove from the bore. I used locking pliers and wriggled it out. There is some light scoring in the lifter bore. The new lifter dropped right in. I did take the new lifter apart and put some oil in it and squeeze it before install.
Any idea what could cause a second almost immediate lifter failure? Could the light scoring on the lifter bore create the problem? Could the problem be in the valves themselves or similar? I also changed the oil - I have tried very light oil (0w40 all the way to thick oil (20w50) and no difference.
Thanks for any help,
Tyler in USA
Looking for some help - I don't own a Rover car but rather a 2002 Range Rover P38 with the 4.6L Rover V8. Obviously there are some differences but the core block and valvetrain I believe are very similar to the original 3.5L V8. Anyway, I have an exhaust lifter (tappet) which has stuck down on cylinder #4. I believed that was the source of my rapping / tapping sound and replaced the lifter and pushrod. Upon startup, the engine ran smoothly and quietly but after about 20 minutes, particularly with some light revs, the engine is right back to where it was before - rapping! Additionally, since this vehicle is new enough, there is a misfire on this same cylinder, which I believe was due to the stuck lifter no opening the exhaust valve enough. Spark plug was very dirty black on this cylinder. Final thoughts are that when I removed the original stuck-down lifter, it was very difficult to remove from the bore. I used locking pliers and wriggled it out. There is some light scoring in the lifter bore. The new lifter dropped right in. I did take the new lifter apart and put some oil in it and squeeze it before install.
Any idea what could cause a second almost immediate lifter failure? Could the light scoring on the lifter bore create the problem? Could the problem be in the valves themselves or similar? I also changed the oil - I have tried very light oil (0w40 all the way to thick oil (20w50) and no difference.
Thanks for any help,
Tyler in USA