While I don't usually reccomend "fix-in-a-bottle" additives, some of my friends have had some success with something called "Engine Restorer". It's a product that's added to the oil, and supposedly fills scratches, worn areas, etc., in the cylinders, and allows rings to seal more effectively. It's a temporary fix at best, and might squeeze a few more miles out of a worn engine and reduce the oil consumption. Don't add any more cleaners, you'll just create more clearance, and increase the tendency to pump oil past the rings. You're looking at a complete teardown and inspection soon, and probably a rebore job, new pistons, etc.
Cylinders don't wear at the same rate from top to bottom, with the majority of the wear happening in the first inch or so of piston travel at the top. If you re-ring an engine with taper-worn cylinders, the rings must constantly change diameter to try to maintain contact with the cylinder walls. This results in the rings losing their tension quickly, and translates to very short ring life. If the cylinders are worn more than .005" different diameter from top to bottom when you measure them, it's time for a rebore and new, oversize pistons, and the corresponding oversize rings. This straightens out the wear, and gives the new rings a straight cylinder to run in. Years ago, rings wore faster than the cylinders, so an engine could benefit from a re-ring job if the cylinder taper was not excessive. With improvements in ring material and manufacturing processes, I haven't seen an engine made in the past 15 years or so that could be a candidate for a successful re-ring job without reboring. If your engine has the original pistons and rings, it MIGHT take a re-ring job, but don't count on it!
Jerry
