Volvo MD30 - sitting idle for 8 years - partially seized

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Trying to help a friend out....
Volvo MD30, been laid up for 8 years (don't know if properly winterised etc.).

Tried to crank it by hand just now on the crank nut. We get 2/3 - 3/4 of a turn and then a sudden seize. It turns both ways fine. It's not a gradual seize, the engine turns fine by hand and then a sudden stop (both ways).

We opened the oil cover and I can't see (one of) the middle valves moving, nothing at all.... I can't see further down.

I know this is an open-ended question, but where would you start looking next? Open the rocker covers? Remove the injectors?

When we crank the engine the props aren't moving (they are free) so we know we're in neutral.

Many thanks.

 

[Jcorstorphine]

First thought it could be a hydraulic lock caused by water ingress but if that were the case then the engine would be 100% seized so dont think that is the problem. Most likely would be one of the cylinders is corroded through the engine "breathing" through an open valve.
Take off the three inlet air filters and spray in lots of penetrating oil like plus gas while the engine is being rotated clockwise and anticlockwise.
Otherwise remove the injectors and dribble in penetrating fluid and leave for a few hours

The other thing you should check for is a seized valve so whip off the three valve covers and see what is moving or not.

I would caution against using brute force as might be a problem with the injection pump operation.

 

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Many thanks. It's just one rocker cover on these. I think this is the next step.

After that, remove the injectors and see what is going on down there - not sure if a puller is needed for these.

 

[scottie]

Previous #2 is referring to Md3
A sudden stop after free movement sound more like hydraulicing or hitting a stuck valve
Removing the rocker cover will allow visual confirmation ov valve movement and the chance to free stuck valve/s
Other than lessening compression I would think that taking the head off is not much more than injector removal and let's you see properly what is happening
Removing injectors is likely to disturb the sleeves and that required the correct tools and actually best left to a workshop

 

[Jcorstorphine]

Many thanks. It's just one rocker cover on these. I think this is the next step.

After that, remove the injectors and see what is going on down there - not sure if a puller is needed for these.

Senior moment on my part. I was thinking of MD3B which is the 3 pot engine used in sailing boats. Think your engine is based on a Peugeot block but same advice applies

Edit Double Senior Moment, Think engine is built by Volvo and not based on Pug unit.

Just one last thought.. Could someone have done an over the top job of winterising the engine 8 years ago by Pouring in a lot of oil and giving a hydraulic lock which I had dismissed as thinking of a water hydraulic lock. As Scottie said "off with the head"

 

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I'll mention the starter to them - easy access to it. I did a bit of Googling and someone mentioned it could be seized to the flywheel.
I will also mention the rocker cover - also easy to do, and I think a good idea.

Another wild idea I had is... what is the UJ's were seized... allowing certain movement, but no more? Or is this totally unlikely?

I would get a pro to remove the injectors, and see what's going on there.

 

[Croftie]

A sudden stop after free movement sound more like hydraulicing or hitting a stuck valve
Removing the rocker cover will allow visual confirmation ov valve movement and the chance to free stuck valve/s

Suspect you may be right with stuck valve. OP said

We opened the oil cover and I can't see (one of) the middle valves moving, nothing at all.... I can't see further down.

 

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Stuck valve on cylinder 2 and seized piston 2, suspect broken con-rod.

Economic write-off, I suspect. If I was in UK i'd give it to volvopaul. Not sure if worth trying to re-build, or even if parts available.