I assume you have done all of the easy fixes - engine is well-tuned, used additives to un-stick rings, cleared all the improtant passages, etc - and have concluded that the problem will require more than a band-aid. My personal preference would be to do a complete overhaul. After all, if the top end is that worn, can the bottom be far behind? In the long run you"ll save money and be happier in the meanwhile. At the very least measure the journal and rod clearances so you know what you"re getting yourself into. That being said, I understand that for a lot of reasons, a top end rebuild may make more sense for you. You can tell if the problem is rings or valves sometimes by doing a compression test before and after adding a bit of oil into the cylinder. If compression improves after the oil is added (oil helps make a better seal at the rings) the rings are implicated; if not the valves are suspect. In the end it probably dosen"t matter. If you"re going to go to the trouble to pull the head and have it re-worked then replace, grind, or at least lap the valves AND replace the rings (don"t forget to hone the cylinder walls). Rings, and valves for that matter, are cheap, it is the time and labor that your machinist will put into the head that will be the big expense. Good Luck and keep us posted.
|