I've got a 25% PSI drop in one cylinder. Only had time to dry test. Will do a wet test to be sure, but I'm leaning towards valve train. I'm losing about a qt of 10w40 Royal Purple every 25-30 hours, which is a week's worth of fishing. Oil pressure is constant at idle and 3000 rpm. The guage jumps a little in transient RPM ranges and bounces at idle, but I think that's normal. Oil pressure is still 35-45. Also have a light knock when under a load, like shifting into gear. The knock corresponds with RPM. It's barely audible in nuetral, but intensifies in gear. I ran some Marvel Mystery Oil though it before I changed the oil hoping that it would free up any build up causing a valve to stick. I'm hoping that a bad lifter is causing all of this. I will know more when I wet test the weak cylinder. I expect that there is a little piston ring wear so I will certanly get an increase in compression, but I am expecting that it will still be weaker than the rest...or I should say, hoping. I don't want to pull the engine and have to replace rod end bearings and all that crap. The noise sounds like its coming from the top end and more on the port than starboard side.
Any thoughts as to how long I should continue to run it in this condition? Maybe it's just an aggrivation I can live with, or is it something that is going to cause the engine to eat itself?
Any thoughts as to how long I should continue to run it in this condition? Maybe it's just an aggrivation I can live with, or is it something that is going to cause the engine to eat itself?
