Recently purchased 1999 Pantera w/ t-502's. Original engines in boat were 310's, swapped out in 2000 for 502's. Each of the 502's had one hour. I personally saw the invoice for the swap and the mechanic noted the port engine had noise so he removed the valve covers and the lifters were fixed. He further stated "PROBLEM INTERNAL IN ENGINE, RAN RPM'S UP, NOISE STAYED THE SAME, DID NOT GET ANY LOUDER". The engines now have 135 hours and when starting the port motor there is a definte noise similar to a ticking sound. I posted earlier about the compression readings which were generally 145-160 with the exception of one cylnder which was 135. Leakdown test performed and each cylinder less than 5%. Ticking noise is almost nonexistant after warm up and boat runs 76 on GPS with no problem. This engine has been diagnosed with this problem for 5 years and still running strong. Am I operating a time bomb and any suggestions as to a fix or should I leave it alone. Thanks in advance.

joe

If this problem has lasted 5 years, you could hardly call it a time bomb. If the noise was something big it would have shown itself by now. That said if it were mine I would have had to find the problem by now. Are you planning to keep the boat?. Maybe now would be a good time to pull them apart and freshin them up.

I'd dump a couple quarts of Lucas oil stabilizer in each - won't fix terminal damage but did free up sticky lifter/valve for me at beginning of year.

this may sound very stuid but if you through enough enough s**t against the wall some will stick....how about exaust flapper??? when the rubber burns off it can sound alot like a valve noise!!!!

If the noise is much more pronounced when cold then almost goes away when warm then I would suspect piston slap. Too much clearance between piston skirt and cylinder causes piston to rock and skirt "slaps" cylinder bore every time cylinder fires. As the piston warms up it expands and clearance and noise are reduced. As long as excess clearance isn't from a cracked skirt (which I doubt because of how long you've run the engine without failure) I'd keep running the engine. You can isolate which piston is bad by cutting out cylinders one by one. The tapping will stop when you cutout bad cylinder.

Andrew