Engine siezed - what now?

[gavin400]

Went to the boat today and engine (Volvo md1) wouldn't turn over - it appears to be completely siezed and I can't budge it at all.

Last used the boat 3 weeks ago and there were no problems, haven't done anything different from normal.

Any thoughts?

Many thanks

 

[elioti]

I`ve heard some are lucky and unseize it by removing injectors and pour hot cooking oil down the barrel, then try and turn over by hand?

 

[Searush]

Open the valve lifters, remove the fanbelt & the flywheel pulley & put a stonking great socket* on the cranckshaft nut with a long bar. Stand on it. It will move.

Then use the crank handle to turn it over several times. It will then start OK.

Probably what's happened is that you have had condensation in the cylinders that has rusted the rings to the bore at TDC. Mine used to do it most winters whatever I tried to do to prevent it (oily rags in exhaust & air inlets, oild sprays at lay-up, whatever!) The only thing was to try & get to it a cople of times over winter to run it over manually with the cold start button down to get more diesel in the cylinders. Even so, I quite often had to resort to the above procedure if it was left for a long period unused.

* I forget the socket size, but still have it somewhere, possibly something like 36mm with a 3/4" to 1/2" adaptor so I could use a 1/2" tommy bar on it.

 

[Seajet]

Why not hot normal lube oil, less trouble if & when it does fire.

Be careful heating the oil or a seized engine may be the least of worries !

Sounds like water has got in somehow during the 3 weeks ?

 

[gavin400]

Open the valve lifters, remove the fanbelt & the flywheel pulley & put a stonking great socket* on the cranckshaft nut with a long bar. Stand on it. It will move.

Apologies for my ignorance - where are the valve lifters, is this the bolt at the very top of the engine (where the oil fill cap and the compression lever are?)

 

[rotrax]

Open the valve lifters, remove the fanbelt & the flywheel pulley & put a stonking great socket* on the cranckshaft nut with a long bar. Stand on it. It will move.

Apologies for my ignorance - where are the valve lifters, is this the bolt at the very top of the engine (where the oil fill cap and the compression lever are?)

I think you will find the compression lever releases the compression by lifting the exhaust valve, so valve lifter/compression lever is the same thing. Follow the good advice already given and good luck.

 

[RichardS]

Surely it would be unlikely to seize solid in three weeks without some underlying problem?

A friend's diesel car engine seized over a weekend but it turned out to be a blown head gasket which had allowed water to leak into the cylinder and this had locked the engine.

Richard

 

[elioti]

Surely it would be unlikely to seize solid in three weeks without some underlying problem?

A friend's diesel car engine seized over a weekend but it turned out to be a blown head gasket which had allowed water to leak into the cylinder and this had locked the engine.

Richard

thought that too

 

[VicS]

Open the valve lifters, remove the fanbelt & the flywheel pulley & put a stonking great socket* on the cranckshaft nut with a long bar. Stand on it. It will move.

Apologies for my ignorance - where are the valve lifters, is this the bolt at the very top of the engine (where the oil fill cap and the compression lever are?)

It ( only one on the MD1 'cos its only a single cylinder engine) It is the decompression lever on the top cover. Turn it so that the "handle" is pointing upwards
It will hold the exhaust valve open slightly

 

[VicS]

If it has seized due to water ingress, although a head gasket is a possibility, the first thing to check for is the possibility of siphoning through the cooling system filling the exhaust system and then the engine.

Presumably there is vented loop either after the pump or before the exhaust injection point. Check that the vacuum valve at the top of the loop is functioning correctly

 

[Searush]

Open the valve lifters, remove the fanbelt & the flywheel pulley & put a stonking great socket* on the cranckshaft nut with a long bar. Stand on it. It will move.

Apologies for my ignorance - where are the valve lifters, is this the bolt at the very top of the engine (where the oil fill cap and the compression lever are?)

Whoops, I assmed you knew the cold start sequence. OK, here's a summary;

There is a short rod with a 1" ball handle on the end at the top of your engine, lift this vertical & it will stop the exhaust valve seating & allow you to turn the engine easily. There is also a push button at the back of the engine near the throttle control, first set the throttle to fast idle (there should be a click stop setting for this) then push the button down. This increases the fuel supply for starting.

Next (if you have the engine free) you can spin it over quite quickly by hand & get fuel into the cylinder. Next you can spin it on the starter & drop the valve lifter & it should start immediately. Sometimes, if you are fit, the engine is warm or you are lucky, you can spin it by hand & drop the lever to start it by hand. If it doesn't work after 2-3 goes, go for a lie down or have a cup of tea, cos you won't have the strength to try again for about 20 minutes!

Head gaskets can go on these & the waterways also get blocked or rust away. once you get it turning, try the compression. it should be almost impossible to turn the engine over with the decompression lever in the down (off or inactive) postion - unless you turn it very slowly.

TBH, You should be able to get it running, but you should be thinking abot saving upo for a rebuild or replacement. Parts are VERY pricey & if you have to pay someone to do the work, replacement will be a better option.

 

[gavin400]

Many thanks for all the help - usually start it by hand cranking without any problems.

Will give some of the suggestions a try.

Don't think it is water siphoning into the engine via the cooling system/exhaust as there is a vertical exhaust elbow with the water connection at the bottom - so the water would have to traverse quite a significant vertical distance.

 

[ianat182]

Possibly think in reverse re the water ingress. There should be a swan neck shaped exhaust pipe to the exhaust outlet. If the exhaust outlet is at /close to waterlevel height , it is possible in rough water for sea water to backflow down the exhaust,possibly producing a hydraulic block/ingress to the engine.Try removing the exhaust pipe and draining it into a bucket as a first check,but rust may have already started its corrosion of the rings/bore.

Hopefully the engine may have stopped at TDC and the near limit of the piston stroke, so previous advice re the crankshaft pulley and levered socket may free it. ColdStart fluid not recommended, hot oil sounds better.

Are you sure your Dynastart is operating correctly,you shouldn't have to handcrank it if the batteries are fully charged, and if you're using the coldstart button each time.

ianat182

 

[gavin400]

Possibly think in reverse re the water ingress. There should be a swan neck shaped exhaust pipe to the exhaust outlet. If the exhaust outlet is at /close to waterlevel height , it is possible in rough water for sea water to backflow down the exhaust,possibly producing a hydraulic block/ingress to the engine.Try removing the exhaust pipe and draining it into a bucket as a first check,but rust may have already started its corrosion of the rings/bore.

Hopefully the engine may have stopped at TDC and the near limit of the piston stroke, so previous advice re the crankshaft pulley and levered socket may free it. ColdStart fluid not recommended, hot oil sounds better.

Are you sure your Dynastart is operating correctly,you shouldn't have to handcrank it if the batteries are fully charged, and if you're using the coldstart button each time.

ianat182

Thanks Ian,

Yes there is a swan neck in the exhaust system - this was replaced new this season as it was corroded through, but everything was replaced like for like so don't think the problem is coming from here and the engine has been running fine since this work was done.

The dynastart is new, have been operating without electric start for a few seasons hence the handcranking - the engine always fires easily when handcranked.

I can almost imagine the engine seizing during the close season, but can't understand why it should happen mid season when nothing (to my knowledge) out of the ordinary has occurred - especially as it has never missed a beat during the 10 years I havevhad the boat.
Maybe its time is just up after 45 years?

 

[Avocet]

If it has seized due to water ingress, although a head gasket is a possibility, the first thing to check for is the possibility of siphoning through the cooling system filling the exhaust system and then the engine.

Presumably there is vented loop either after the pump or before the exhaust injection point. Check that the vacuum valve at the top of the loop is functioning correctly

That happened to Avocet some years ago. Same reason. Just rotten luck that it happened to stop with the exhaust valve open that day!

 

[VicS]

Yes there is a swan neck in the exhaust system

But is there an antisyphon device in the cooling water system? If so has it failed and allowed the system to fill with water.

 

[SAMYL]

The most common mistake people make with a seized engine is to try to turn it by force.

If moderate pressure will not free it DO NOT FORCE IT.

Turn it BACKWARDS to see if there is any movement that way. If so then you can rock it back and forewards and eventually free it completely. If you try to force it you may just compound the problem and jam it harder.

Deisel fuel through the injector hole is as good as any for easing the pistons but don't overdo it, a squirt or two is sufficient otherwise you will get an hydraulic lock forming.

 

[RichardTaylor]

I once saw a guy claim his Volvo was seized, when in fact it was a stuck solenoid was the problem which was quickly resolved by a sharp tap with a mallet.

 

[Searush]

I once saw a guy claim his Volvo was seized, when in fact it was a stuck solenoid was the problem which was quickly resolved by a sharp tap with a mallet.

OP has a hand start on his engine, I'm sure he will know. But the hand start is geared & the crankshaft nut (55mm - I've just checked) makes it easy to apply the effort direct to the crankshaft. Rocking it to & fro is a good idea, but if the decompressor lever is up there should not be a hydraulic lock. Err unless it isn't lifting the valve!

I found my MD2b did this regularly for a few years before I replaced it & the socket on the crankshaft worked every time. I only ever had to do it at the start of a cruise, once freed off it would run fine until next time it was left for a while. In the end I got fed up & spent some redundancy money on a Yanmar.

 

[gavin400]

But is there an antisyphon device in the cooling water system? If so has it failed and allowed the system to fill with water.

Vic,

I don't think there is an anti syphon device - (have tried uploading a photo but the file size is too big).

The seawater enters the pump/impeller housing at the back of the engine, and is then delivered to the front of the engine via a 12mm dia. plastic hose, it exits the engine via the same diameter hose and is fed into the bottom of the exhaust swan neck.

I suppose the water could syphon back via this hose, but it would only go back into the cooling system?

To syphon into the exhaust side of the engine it would have to climb the swan neck (which is much larger 38mm dia. and is matbe 200mm high)?