Perkins M90 hydrolocked, what to do?

[svparamita]

Engine ran perfectly two weeks ago. Tried to start it this morning - starter not turning it over; tried to rotate crankshaft via nut manually: impossible. Checked siphon at exhaust - valve was plugged. I assume seawater flooded cylinders via exhaust manifold. Does anyone have had this experience, and what is the best way to proceed? I hope the engine is not toast...

[skipperpete]

Hi svparamita and welcome to the forum. Find a diesel mechanic as soon as you possibly can, failing that, get the head off ...and check the sump for water. It’s very important to deal with this TODAY, try to get it to roll over after you get the head off and put enough oil in the cylinders to cover them completely. All of the above suggestions only serve to stabilize the situation and make it easier to pull the engine down for a proper inspection and overhaul. There will inevitably be someone who posts that they were able to get their own flooded/hydrolocked engine to turn over and run happily, ignore that, I can accept that it’s possible to get an engine to recover if you act quickly in maybe the first 24 hours but with an engine flooded with saltwater for 2 weeks, there are no shortcuts.

[svparamita]

Well, thanks for your input. Got up at 4 am yesterday, pulled the injectors, sucked out all the water in the cylinders, and sprayed RostOff via a tube into the chambers. Let that sit for an hour, then tried to turn the crankshaft. After an hour of trying, it finally turned a few millimeters, another hour it turned well enough to dare engaging the starter. Did this three times, using about 1 liter of RostOff,- Then let it sit for an hour, replaced the atomizers, started the motor, - starter overloaded. Pulled injectors again, cranked while plugging each cylinder in turn, and maged to vaporize residual oil inside. The boat inside was a cloud of oily mist - luckily my wife was not onboard... That nedded to be done also three times, then the motor sprang to life, and purred away. Ran it for an hour, changed the oil ( colour was slightly opaque, it was fresh oil with less than 30 minutes on it) and ran it for two hours. Inspected oil filler cap every 10 minutes, - a little condensation, lessening over time. The mess inside the boat and engine room is indescribable - but the motor runs smooth now, and sounds like new. Checked the oil this morning, no water or milkiness on the dip stick. Will change the oil once again today and keep running it a few more hours on the dock, before we take the boat offshore. The motor has less than 1800 hours on it, but I have been using Lucas Oil additive for several years - I wonder if that offered some extra protection. In any case, there seems to be no damage, and excellent compression, which is amazing. I still cannot believe it quite yet, and will keep monitoring oil and sounds for the next several hours. Thanks all.

[senormechanico]

The boat interior notwithstanding, you dodged a pretty big bullet !

[bstreep]

Well done. What you did was what I would have done. If this worked, you dodged a serious bullet.

[svparamita]

Originally Posted by senormechanico

The boat interior notwithstanding, you dodged a pretty big bullet !

Yes, with the help if a local mechanic they call God, no kidding! I will do a few more oil changes, and hope for the best. Someone mentioned to keep an eye on corrosion on valve springs, and to rebuild the top end at the first sign of it. Any other ideas?

[fredNerk]

Originally Posted by svparamita

Yes, with the help if a local mechanic they call God, no kidding! I will do a few more oil changes, and hope for the best. Someone mentioned to keep an eye on corrosion on valve springs, and to rebuild the top end at the first sign of it. Any other ideas?

Rust on the springs. I had never previously thought of that issue. If rust on the spring coils started to pit the surface. It could/would be a potential stress point

[Searles]

Yes the micro pitting of valve springs happens verry quickly,have seen multiple early failures ,of s/w flooded engines ,due solely to valve spring failure ,drops a valve into a running engine ,believe it or not one was an M90 low line Perkins .⚓️⛵️⚓️

[svparamita]

Thanks for getting back;

Four oil changes later, and no moisture visible after the second change. Motor runs smooth and as it should. But checking the valve springs I do notice some pitting on two springs, at the very bottom. Not sure if that discoloration is actually pitting, or if it was there before the water ingress.
See IMG_1916.jpg. Not sure if this attachment opens, [IMG]IMG_1916.jpg[/IMG]
What do you think? Thanks

[Searles]

The simple answer is ,not if but when, new valve springs will give you peace of mind ,they maybe ok but probably not,l would not hesitate ,do it now ,you may really dodge the bullet .⛵️⚓️

[svparamita]

Thank you all for your help and advise.
We have taken off, ran the engine for 7 hours, and not a trace of moisture under the valve cover, or in the oil. The valve springs look clean, except for the two springs as shown in the photos, which have lost some of their shiny (chrome? some other finish?) on the bottoms of the springs. May have been there before the mishap. maybe just worn off. I may be dreaming...
I looked at a new valve spring set from Parts4engines, and they dont have any coating on them. Anyway, thanks again.