Locked solid lump

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rwardale

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Hoping to draw on the collective wealth of experience the assembled forum-ites.

I have an inboard diesel that had the oil drained in October to winterise, but not replaced until March. Previously it has been serviced by me, annually for 7 years, so I know that it is a decent runner. I have fettled the engine over the winter, however now I come to use it, the engine is locked solid. The fettling consisted of replacing the wiring loom and refurbishing the exhaust, thermostat and water pump, none of which affect the engine rotation... The flywheel wont budge...

The facts as I have them, and work done so far:

Filled the engine with oil - which should have happened in October and maybe saved me a load of hassle. I love hindsight.
Engine will not turn on hand start or starter - no not even a little bit.
Flywheel removed and attempted to turn by hand - nothing.
Injectors removed and pots filled with diesel for 3 days before trying again.
Rocker cover off, engine at TDC and conn rods not moving.
Used starter to try to move it, the diesel in the cylinders was ejected over the cabin, but there seemed to be no movement in the flywheel - very weird, as how did the diesel get out of the cylinders...?
Had a chat to David at Bukh Poole, and he is equally stumped.
I am doing this on my own, so I cannot confirm what happens when I hit the starter, as I am in the cockpit.
Am going to involve a diesel "expert" that I am related to, but am not convinced that he will offer anything too different from what I have tried, apart from a lot more grunt to apply to the flywheel...

The engine is a Bukh DV20 installed in a Westerly Griffon. The owner is a 40 something with a fair bit of sailing and engines background, but seems to be lacking enough skills to solve this riddle.
 
Best bet is to use a socket plus long handle on the crankshaft and kick it. Kicking is far more effective than using hands when shifting stubborn car wheel nuts. You might need an extension to the socket to get clear of the engine compartment in which case arrange a solid support (jack or block of wood) under the outer end of the extension.
 
Removing the engine oil to winterise the engine is, as you say, not the best plan ....... but, having said that, I would be surprised if the main bearings would have seized solid over a few months as they would have been well-coated before draining.

The cylinders are obviously not hydrolocked from a leaking head gasket as you have tried turning with the injectors out but it is possible that there has been some water leakage if it is indirectly cooled.

It seems to me that a piston corroded into the bore is the most likely and you have tried the diesel in the bores trick but I wonder if that needs longer to work?

Apply too much force or a shock force might just bend a con-rod so the best way to resolve that would be by removing the head and knocking down the piston with a wood block or similar. Before you take that step, have you tried nudging the crankshaft backwards and forwards a tiny bit at a time with a good lever. Easy provided the crank pulley nut does not come unscrewed too easily. If you can get a tiny bit of movement backwards then forwards you might be able to jiggle the rings free, if that is the problem. However nothing to lose it if isn't.

Richard
 
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Just googled your problem and others have had exactly the same problem. It's nothing to do with the transmissions is it?

"The kill switch shouldn't keep it from cranking but the transmission's neutral safety switch will. Wiggle the shift and try to crank- if it does, it could be that the shift cable or linkage is sloppy/out of spec. It's adjustable, so no big deal. Make sure you clean the battery cables and posts.

https://www.mastercraft.com/teamtalk/showthread.php?t=51018

https://www.google.com.au/#q=boat+engine+won't+turn+

https://www.google.com.au/#q=boat+engine+locked+up+winter
 
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I'm puzzled by this. You say that the diesel was "ejected' from the pots when you used the starter, that implies that the pistons were moving and therefore the flywheel turns. There's no other way for diesel to get ejected (presumably the diesel you put in to lubricate the pots) BUT if diesel was left in the pots even for a day it should have dripped past the piston rings. It sounds as though there has been water in there for some time. I suspect you may need to start removing stuff from the head down until you come up with an answer. Could a valve be stuck open?
 
Champagne Murphy said:
I'm puzzled by this. You say that the diesel was "ejected' from the pots when you used the starter, that implies that the pistons were moving and therefore the flywheel turns. There's no other way for diesel to get ejected (presumably the diesel you put in to lubricate the pots) BUT if diesel was left in the pots even for a day it should have dripped past the piston rings. It sounds as though there has been water in there for some time. I suspect you may need to start removing stuff from the head down until you come up with an answer. Could a valve be stuck open?
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That's a good point. What I suspect is happening is that operating the starter on an engine with one or more seized pistons generates a huge load ..... enough to bend a solid metal conrod.

That jolting load might send sufficient shockwaves through the conrods to generate enough movement (probably nearer vibration due to slight deformation of the conrod than movement) to expel the diesel. My real worry is that the slight movement has actually come from a permanent deformation of a conrod. :(

I would certainly not operate the starter again until I have identified the source of the problem.

Richard
 
I think you need to get the head off before going much further.....
My initial guess would be rings stuck with a little rust, but this would have occurred even without leaving the engine without oil.

I would be very interested to know how the diesel was exiting the bores through the injector ports when you tried the starter if the pistons were not moving......?????? The logic just does not fit.

If the pistons are stuck..... a block of wood on the crown and a good sharp whack with a hammer will dislodge them. Soaking in diesel is a good thing to continue to do.
 
RichardS said:
That's a good point. What I suspect is happening is that operating the starter on an engine with one or more seized pistons generates a huge load ..... enough to bend a solid metal conrod.

Richard
Click to expand...

Sorry Richard I cannot see how a starter motor would have enough torque to bend a conrod os a hydraulic locked engine.

I had a hydraulic lock due to water in the cylinders on my engine once and the starter motor just stalled. Removing the injectors turning over the engine with the starter ejected the water and the engine started straight away after refitting and bleeding the injectors.

The OP said "it appeared the flywheel had not moved" and he is turning it over from the cockpit so could not see the engine/flywheel turning over.

I think the OK needs to confirm if the flywheel turns over when the starter is operated and that the valves rockers operate correctly providing the starter does not stall during operation.
 
Alpha22 said:
I think you need to get the head off before going much further.....
My initial guess would be rings stuck with a little rust, but this would have occurred even without leaving the engine without oil.

I would be very interested to know how the diesel was exiting the bores through the injector ports when you tried the starter if the pistons were not moving......?????? The logic just does not fit.

If the pistons are stuck..... a block of wood on the crown and a good sharp whack with a hammer will dislodge them. Soaking in diesel is a good thing to continue to do.
Click to expand...

Id not remove the head just yet

Id want to be more certain that one, or both, pistons is seized first. As you say the logic does not fit
 
Hi, surely the flywheel is bolted directly on to the end of the crankshaft, I believe it is on my DV10, so how could the piston move without the flywheel? When I bought my E30 she had been in Gosport boatyard for several years and the DV10 was completely solid. We got it turning by putting oil in directly in the cylinder, not diesel, however after a couple of years it was evident the years of neglect had left the cylinder lining damaged and we had to take the engine out and rebuild.
 
Rogershaw said:
Sorry Richard I cannot see how a starter motor would have enough torque to bend a conrod os a hydraulic locked engine.

I had a hydraulic lock due to water in the cylinders on my engine once and the starter motor just stalled. Removing the injectors turning over the engine with the starter ejected the water and the engine started straight away after refitting and bleeding the injectors.

The OP said "it appeared the flywheel had not moved" and he is turning it over from the cockpit so could not see the engine/flywheel turning over.

I think the OK needs to confirm if the flywheel turns over when the starter is operated and that the valves rockers operate correctly providing the starter does not stall during operation.
Click to expand...

I agree that if the engine is already totally hydrolocked and the starter motor hasn't had any chance to turn the flywheel at all then it is probably more likely to burn out the starter motor electrics than bend metal. However, if the engine has turned for a second and built up some momentum then the huge gearing difference between the starter pinion and the flywheel can certainly bend a conrod as a worst case scenario.

A hydrolocked engine can indeed sometimes turn over with the starter motor ..... but very slowly. It's all a question of how much combustion space has been occupied by water. If the engine does turn over slowly I would still refer to it as being hydrolocked although, I suppose, it should be called hydro-restricted or something.

In the OP's case I don't think hyrolocking is the problem but is more likely to be a small head gasket weep causing the rings to rust onto the bore. However, in either case, I would not use the starter at all until I was sure the engine was free as something expensive is likely to result one way or the other! :(

Richard
 
So an update after today's shenanigans...
Loosened the flywheel bolts, so that there was a bit of rotation in the flywheel and rotated it to jar or shock the crank. No joy.. The hand start goes through a gearbox to spin the engine so I am against putting too much weight into that. I prefer the direct drive approach on the flywheel. Not a lot of space to grab to move it.
Looking back at a photo when I started the strip down, it appears that the flywheel has rotated about 30 degrees since strip down. This can only be from the starter, and may explain the diesel decor. Yes, the logic did not work, as the pistons had to be moving to spit the diesel out. The pots were full and the injector port is small, so that is why the fuel went so far. Tapped the end of the crank shaft to try to shock the bearings. Was told by Bukh that there is a thrust bearing on the crank. This may reduce the effectiveness of this percussive approach, but running short of sensible ideas.
Left the pots with more diesel today and will get some long bolts to replace the flywheel ones to get a long lever in play. Also put a pint of diesel in with the engine oil in the sump, the thinking being that it may lift the level of the oil to soak the big end bearings. Does diesel mix with oil, or one fluid float on top of the other??
 
Thanks for the many responses, I will change the order of things tomorrow... A bit more info, the rocker cover has come off, and all the valves are moving, as I can just about push them against the return springs. The Bukh has 6 M10 socket head bolts holding the 35kg flywheel onto the end of the crank, so I cannot get a socket in to it to spin it up, but what I will do tomorrow is bolt a bar using these bolts and try to ease the flywheel around.
I also found out that there is a shaped washer at the bottom of the injector hole, as it was spat out with the diesel when I span the electric motor. This "injector washer" for want of a more intelligent name, forms a seal with the bore. The washer from pot 2 shows signs of corrosion, when compared to the washer from pot 1.. Water in the bores, or at least pot 2..?
Alpha and Murphy, I agree that the diesel ejected from the bores has to be down to the pistons moving, and looking back at a photo, pre fettling it seems that the flywheel has rotated 30degrees, but is still rock solid. This must have happened when cranking on the starter. I have now marked the flywheel and a point on the engine.. The fact that it has rotated at all is cause for celebration, a rum for the owner and savlon for the knuckles...
RichardS, I am taking it very easy with the starter, short bursts if no more that 1second, as I have just rewired the engine and really do not want to fry the shiny new cables.. The engine is not hydrolocked as the injectors are out, but what it could well be is the weeping gasket that you mentioned. I am reluctant to take the head off unless I really have to.
Will let you know more if I can skip one of the 2 rugby coaching sessions tomorrow and get to the boat..
Richard W (OP)
 
rwardale said:
Am going to involve a diesel "expert" that I am related to, but am not convinced that he will offer anything too different from what I have tried, apart from a lot more grunt to apply to the flywheel...
.
Click to expand...

He can do one thing you cant on your own - he can watch the flywheel whilst you operate the starter and confirm that the flywheel is actually moving. Mind you diesel cannot be ejected from the ports if the flywheel isnt moving.
 
No mention yet of decompressing the engine using the convenient lever on the rocker cover or using the starting handle.

Standing on the latter (properly engaged) whilst operating the former might achieve some movement.
 
pvb said:
Wasn't hand-starting mentioned in post #1?
Click to expand...

Ah yes. Sorry. Eyes skipped past that.

A further thought... When the water pump was reinstalled, was it properly engaged? That is, did you check the engine would turn over (by hand) and rotate the pump spindle as you would expect? I wouldn't have thought it possible to jam it but...
 
Whatever you do DO NOT try to turn it by force, you will only compound the problem and end up doing some form of expensive damage.

As RichardS says try turning it BACKWARDS but yet again without force.

If still no luck identify the cause of the problem before causing any further damage.
 
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