Advice Sought. Engine Seized after installing Injection pump

[jimbunyard]

What did you find when you took the valve cover off? Did you remove or loosen the rocker gear? If you have access, sometimes you can get better leverage with a big screwdriver or medium prybar at the ring gear when you remove the starter. Care should be taken to avoid breaking teeth.

Wouldn't put anything in the gear oil.

[CliveCollett]

I once had a Perkins 4108 start, run fine and then stall and refuse to turn over. No bang, no nasty noises. Would not turn over at all in either direction. Ended up taking the engine out and stripping.
Turns out a too long bolt had been wound into an unused hole low down in the block to stop oil coming out. The bolt, over time, had vibrated in until it made contact with No1 big end bearing, just a glancing blow that bent the bolt. This in turn siezed the bearing solid.
As soon as the bearing was loosened the engine turned over. New bearings fitted and rebuilt. All good.
I hope your problem is not the same as lifting the engine out is never easy. I think your suggestion of removing the gear cover would be my next move before taking off the head.
Good luck and keep us posted.

[Jack C]

Originally Posted by P8R2012

Maybe it is hydrolocked , drain all fluids and see if the engine spins.

Fluids drained, injectors out. No engine spin

[Jack C]

Originally Posted by CliveCollett

I once had a Perkins 4108 start, run fine and then stall and refuse to turn over. No bang, no nasty noises. Would not turn over at all in either direction. Ended up taking the engine out and stripping.
Turns out a too long bolt had been wound into an unused hole low down in the block to stop oil coming out. The bolt, over time, had vibrated in until it made contact with No1 big end bearing, just a glancing blow that bent the bolt. This in turn siezed the bearing solid.
As soon as the bearing was loosened the engine turned over. New bearings fitted and rebuilt. All good.
I hope your problem is not the same as lifting the engine out is never easy. I think your suggestion of removing the gear cover would be my next move before taking off the head.
Good luck and keep us posted.

I agree. Gear cover next. I think I inherited a problem like a loose something that got jammed.

After an hour to try and get the alternator belt off because the belt is too small, I am getting the feeling that an amateur worked on this engine previously.

And when I do get the engine moving I will need to work out how the fuel is getting into the oil.

Will keep all posted. This is a deep detective story.

[Jack C]

Originally Posted by jimbunyard

What did you find when you took the valve cover off? Did you remove or loosen the rocker gear? If you have access, sometimes you can get better leverage with a big screwdriver or medium prybar at the ring gear when you remove the starter. Care should be taken to avoid breaking teeth.

Wouldn't put anything in the gear oil.

The valves and push rods look fine. Cylinder 2, valves fully closed, rocker moves sideways, space above valves. Injector hole for cylinder 2 shows piston at top. Pistons 1 and 3 down. Each has one valve open.

Are you suggesting leverage to free the piston? A breaker bar on the crankshaft bolt does not work. Why lever the flywheel?

Do you mean not to dilute the gear oil with acetone?

[jimbunyard]

Originally Posted by Jack C

The valves and push rods look fine. Cylinder 2, valves fully closed, rocker moves sideways, space above valves. Injector hole for cylinder 2 shows piston at top. Pistons 1 and 3 down. Each has one valve open.

Are you suggesting leverage to free the piston? A breaker bar on the crankshaft bolt does not work. Why lever the flywheel?

Do you mean not to dilute the gear oil with acetone?

If the valves are stuck, and they can get stuck in any position, they will prevent the engine from turning. Since you have to take the rocker gear off as a prelude to removing the head anyway, it's best to eliminate that possibility first.

Yes, as you noted previously, clockwise rotation of the crank bolt only seems to tighten the bolt, CCW rotation just loosens the bolt. Rotation from the flywheel eliiminates that problem. The small movement obtainable by individual teeth, combined with the length of the levering bar (should be at least 18" to be effective) will give you tremendous rotational force. Though, again, you must be careful and ensure that your 'prying' is concentrated at the root of the tooth.

Yes, no need to dilute the gear oil. If something is stuck (which seems highly unlikely as you can rotate the gear at the output flange) it will be so mechanically, i.e. something physically between the gears after the input shaft gear. Since you've not likely dropped anything into the gearbox, there's nothing to jam those gears. Really the only other thing could be if a spring or some other part of the drive plate broke off and lodged between the flywheel and the flywheel housing, which can happen, though I don't think that is very likely in these circumstances. Would be pretty anti-serendipitous...and adding acetone wouldn't do anything if that were the case anyway.

[Shaneesprit]

It’s unlikely to be stuck valves as normally you could rotate backwards, away from the valve.
Strange for anything to seize while stopped with that amount of diesel in the fuel.
Only really 3 ways to get fuel in the oil
1) Lots of low load running - Common but not to the extent you are reporting.
2) injector stuck open - Misfire
3) fuel lift pump - Common on Yanmar

Sounds like an Engine out job - to be honest you have it all apart anyway so will probably be quicker and easier.

Do you have any end float?
Does sound like a piston seized due to lack of lubrication, so bore is probably damaged - you need a borascope or to he move the head - my guess is probably see Aluminium scrapes on the cylinder bore.
But also think do ensure the box didn’t lock up - can you rotate the prop?

[FlyingScot]

IIRC the alternator OEM belt for 3YM30 is too tight for the normal rotational adjustment to get it on and off. You have to loosen the other mounting points.

[kapnd]

How about the torsion dampener between the engine and transmission?
I’ve seen those come apart to the extent of locking up the motor.

[Jack C]

Originally Posted by FlyingScot

IIRC the alternator OEM belt for 3YM30 is too tight for the normal rotational adjustment to get it on and off. You have to loosen the other mounting points.

Many thanks, nice to know its a Yanmar screw up not a previous owner. So replacing a belt is not a 5 minute operation, especially at sea.

What additional mounting points do you mean? I have loosened all got a tiny amount of slack. Either I remove the pivot side by removing a front bracket or lever of the belt with screwdrivers. Or as I plan to remove the crankshaft pulley anyway, maybe start with that.

The problem is that the bolt holding the slotted adjustment guide to the engine stops the alternator from fully slackening the belt.

[double u]

another wild shot (considering your situation in Israel with many enemies):
is your fuel-deck-filler accessible to anybody, unlocked?
Jokers have been known to throw sugar into dieseltanks...

[RaymondR]

"Many thanks, nice to know its a Yanmar screw up not a previous owner. So replacing a belt is not a 5 minute operation, especially at sea."

Well it is if you are willing to surrender your misdirected propensity for finessing and revert to a more appropriate response based upon brute strength and ignorance.

[skipperpete]

Originally Posted by Jack C

Keeping up with daily doses of liquid wrench.



In a few days I will try transmission oil with acetone, 50% each.



By taking out the idling gear I should have problem isolated to pistons or seized crankshaft bearings.



Or seized gearbox. ??

JackC, is there any rotational movement at all when you try to bar the engine over? Even as little as .010” would indicate that the lockup is somewhere other than along the crankshaft.
Trying to turn the engine via the gearbox is problematic because a 2:1 reduction box becomes a 2:1 multiplier using the output flange as the input.
Try undoing the little bolts on the circulating pump pulley, loosening them often allows enough slack to peel off the vee belt ....and removing the pulley completely makes it even easier.
How diluted was the engine oil compared to straight diesel fuel? If it was really thin, the possibility remains that the oil pump never actually picked up the oil from the oil pan suction and the engine ran with zero oil pressure. Did you see the oil pressure on the gauge or hear a low lube oil alarm ?
Pete.

[Jack C]

Originally Posted by skipperpete

JackC, is there any rotational movement at all when you try to bar the engine over? Even as little as .010” would indicate that the lockup is somewhere other than along the crankshaft.
Trying to turn the engine via the gearbox is problematic because a 2:1 reduction box becomes a 2:1 multiplier using the output flange as the input.
Try undoing the little bolts on the circulating pump pulley, loosening them often allows enough slack to peel off the vee belt ....and removing the pulley completely makes it even easier.
How diluted was the engine oil compared to straight diesel fuel? If it was really thin, the possibility remains that the oil pump never actually picked up the oil from the oil pan suction and the engine ran with zero oil pressure. Did you see the oil pressure on the gauge or hear a low lube oil alarm ?
Pete.

Pete, thanks for the encouragement.

I am using a socket with the standard 12" ratchet for testing if the engine is freeing up. Its what I used when turning over the engine to set the timing.
I plan to try a longer breaker bar today. If the pistons were seized it will take some force to get them moving. I'll add force after I have checked the gears.

I am sure I can get the belt off. I'll buy a longer belt for when I re-install.
Once the belt is off I can pull the crankshaft pulley and get to the gears.

Oil dilution. The dipstick showed 1.5 of full. According to the manual the dipstick shows about 1 liter of the 2.5 liter capacity.
After I added 1 liter oil to the totally drained engine, nothing shows on the dipstick so that makes sense.
To answer your question, I estimate 0.5 liter of extra volume. So 0.5 added to 2.5 liter gives 0.5/3 = 1/6th dilution.

There is no oil pressure gauge and there was no low oil pressure light or alarm.

I am thinking that the high no load revs loosened something. Then it fell into somewhere after the engine stopped and jammed something.

[double u]

(digging around further in my memory....)
on the job (charter fleet)~94, 95:
Volvo 2003T (I think), suddenly stopped after ~3000h
upon opening discovered:
on one big-end: one bolt gone, lying in oilpan, second bolt 1/2 open & bent
boat on our base for last2 years, engine never been opened before, afaik
riddle unsolved...