Ran with extremely low oil ... What next?

[theredboat]

Coming back to port from a 8hr sail in rough conditions, I flipped on the engine to get into port. We ran it for about 15 mins until my wife went down below briefly and said she smelled burning metal.

Flipped off the engine immediately and a bit of smoke billowed out of the engine compartment. Saw a bunch of oil in the bilge and immediate realized I had been running the engine with almost no oil. it had all leaked out via the oil pressure sending unit.

Next day, crossing my fingers, I added about 3quarts to get it back to full and then started her up with no problems. Motored her around the mooring field a bit. Noticed oil burning out the exhaust, but everything else seemed ok.

Motored for about 30 mins before the oil pressure slowly started dropping over the course of 10 mins. Eventually it dropped to 10 and then to just above zero. So cut the engine and sailed back.

Part of me suspected my oil pressure unit was faulty so I ordered a new one to verify and restarted the engine. Again she started and ran immediately but oil pressure still reads almost zero and now there is a quiet but noticeable squeal coming from the block.

Is this engine shot?

[Marian Claire]

Has the original oil leak been fixed? Have you tried adjusting the oil pressure with the oil pressure regulating valve?
Dan S/V Marian Claire

[theredboat]

Had new pressure gauge wired wrong. now reads 20psi cold at idle which is a good sign. Still burning quit a bit of oil out the back.

Will take it out later under power and report back !

[hanleyclifford]

From your narrative my best guess is that the engine must be taken down. Could be an inexpensive rebuild (rings and bearings). Certainly the engine is no longer reliable.

[ndutton]

If the oil pressure doesn't react to adjustment, I'd take a shot at adding a can of STP aka engine honey to see if it helps, even temporarily. New noises suggest bearing damage and it won't improve over time. Sorry.

For future reference so this doesn't happen again please consider one of the alarm systems offered by our host.

[Marian Claire]

Might be interesting to pull the plugs and see what they look like. Have you noticed any blow-by?
Dan S/V Marian Claire

[Mo]

Sounds like you ran the engine low on oil and the hard truth is an engine cannot take that. If you start the engine...it drops oil pressure warming, then does NOT respond to increased oil pressure with increased rpm...bearings are done. Smoke out the exhaust , under the circumstances you described, indicate that the rings also sustained excessive wear due to lack of lubrication...they are worn and oil is making its way past them. You may also see crud/carbon/sludge build up on the plugs rapidly as well. Hanley calls it as I see it.

Regardless, in this situation she comes out and apart for bearings and rings and cylinder bore check. Sorry to see that this happened, but there's no wishing out of this as it is portrayed. I would consider the engine good enough to get on and off the dock but not as an auxiliary mode of power at this point.

[romantic comedy]

Many times I have found metal particles in the oil of an engine that had bearing failure. I just suck up some oil from the bottom of the pan and see the flakes.
You might thy that and see what you see.

[theredboat]

Yeah as the engine warms, pressure goes from 20psi down to almost nothing now and oil is burning.

Pulled plugs and saw oil on each of them so I suspect rings are bad.

So what are the next steps? If the rings and bearings are bad should I just replace the whole block?. I also had low compression in cyl 3 due to some pitting around the intake valve so I'm almost ready to throw this block out. But let me know if it's worth trying to rebuild with current block as this is new territory for me

Thanks.

[hanleyclifford]

Rings, bearings and valves gone bad are not block defeating. Even if the crank has to go .010 under the engine is very much worth rebuilding. OTOH, you might want to consider an exchange engine from Moyer Marine and get the good rebuild in minimum time. Lot of personal choices here - but don't throw the block out. Edit: Why not call Ken or Don himself and thrash out your situation and get the best opinions?