2002 6.2 MPI - Cruisers 3470 Express

[crankin12864]

My boat sat for a couple of years during Covid. I changed the oil and primed the engine without starting it. I pulled the plugs and fogged the cylinders with oil. Later, I proceeded to try and turn the engine over by hand at the crank pulley. I would apply approximately 50lbs of force on a 18" torque wrench and then ease off and I continued to do this for 4-5 times until the engine broke free. When the engine did break free, I heard a "ping". I would assume this noise came from a piston ring, although I don't know that for sure. I would like to hear your thoughts on the matter. The engine turns over by hand freely without any unusual noises. Should I be concerned about starting the engine?

[rslifkin]

If it was a bit sticky, I'd probably play it safe. Pull the plugs, put an ounce or so of thin oil into each cylinder. Let it sit overnight, then turn it over by hand with the plugs out to push out any excess and make sure it turns freely. Then put the plugs in and fire it up. Monitor for any unusual oil consumption, etc. after that.

[thesaltytar]

I agree with rslifkin. I had an almost identical scenario last year; the ping likely was a piston ring.

After you hand bar the engine over you can cover the cylinders with rags or cardboard or similar and bump the ignition to eject any excess residue from the cylinders. If you don't cover the holes.... The oil can travel some distance.

Unfortunately in my scenario I also dropped a valve. Knowing this, I would open the covers so I could observe the valves while barring the engine over first and confirm normal operation before lighting off and putting her through the compression strokes.

(Mind you I was also using a 36" pipe wrench...)

[MBWhite]

IMHO, when rings break it is more of a click or snap. A "ping" sounds more like a valve that was stuck open and either is snaps closed when broken free or the head of the valve breaks off and the ping you hear is the valve stem popping up from the guide and hitting the valve rocker.



In your situation I'd disable the ignition and turn it over by hand for 4 or 5 revolutions to make sure it turns freely then use the starter to crank it for several revolutions and once you have convinced yourself it turns freely with nothing binding then hit the starter and let it crank for 30-40 seconds and just listen to it for a constant RPM, if somethings broken you'll hear the change in RPM's while cranking. Use this time to make sure you build up oil pressure so the engine gets pre-lubed but when you get oil pressure and it all sounds healthy enable the ignition and see if she starts and idles smoothly.



If you want to take the time, it is not a bad idea to remove the valve covers and inspect valve operation while cranking and if you did break a valve earlier you'd be able to see which one before damaging the engine further.

[bil56]

yes, sure, good idea to remove the valve cover and look ...