How to clean out a crankcase

[rossl32123]

Restoring my diesel after having seized her I have a significant amount of rust particles that have made their way into the crankcase, despite precautions taken. I have sprayed a good deal of diesel into it through the Conrod ports hoping to flush most of it into the sump, but I can’t get all of it from places like the tops of the cam followers etc. and I can’t suck all of it out of the sump. Any suggestions?

[shakey doug]

First job cover the fuel pump delivery valves.

[a64pilot]

Do what you can, and drain and flush.
Meaning once she is running, let her run for a minute, just enough to suspend as much as possible, shut down and suck out all the oil you can, ASAP then fill, let her run maybe 5 min, repeat. Let her run til hot and last drain.

Get as much off the cam as possible, cause that is the highest loaded place in the engine, greatest pressure. About all you can do without removal and overhaul.

Once she is running, do not baby it, your trying to get the rings to reseat, and that takes cylinder pressure to do that, cylinder pressure is higher of course the harder it’s run. The cylinder pressure actually forces the rings against the cylinder wall and will cause them to wear into each other. If you baby it they won’t really wear in, they will polish each other and you will forever burn more oil that if you had run her hard. It’s called bore polishing, and the major way bores get polished is they get a little rust on them, then the rust is cleaned off of course when it’s run, soon you have worn off the cross hatches you see in the cylinder wall. These cross hatches actually hold a tiny bit of oil and lubricate things, once they are worn away, oil consumption and cylinder and ring and piston wear goes up.

Covering the HP fuel pump cost nothing, is easy to do and may save you a lot of $$$ and hassle.

[rossl32123]

Originally Posted by shakey doug

First job cover the fuel pump delivery valves.

Will do. I had the injectors serviced so I don’t want to pump any crap into them!

[rossl32123]

Originally Posted by a64pilot

Do what you can, and drain and flush.
Meaning once she is running, let her run for a minute, just enough to suspend as much as possible, shut down and suck out all the oil you can, ASAP then fill, let her run maybe 5 min, repeat. Let her run til hot and last drain.

Get as much off the cam as possible, cause that is the highest loaded place in the engine, greatest pressure. About all you can do without removal and overhaul.

Once she is running, do not baby it, your trying to get the rings to reseat, and that takes cylinder pressure to do that, cylinder pressure is higher of course the harder it’s run. The cylinder pressure actually forces the rings against the cylinder wall and will cause them to wear into each other. If you baby it they won’t really wear in, they will polish each other and you will forever burn more oil that if you had run her hard. It’s called bore polishing, and the major way bores get polished is they get a little rust on them, then the rust is cleaned off of course when it’s run, soon you have worn off the cross hatches you see in the cylinder wall. These cross hatches actually hold a tiny bit of oil and lubricate things, once they are worn away, oil consumption and cylinder and ring and piston wear goes up.

Covering the HP fuel pump cost nothing, is easy to do and may save you a lot of $$$ and hassle.

I take your point about the running in. As for the flushing, do I use fresh new oil each time? That’s a lot of oil at 8litres a fill. Can I do the flush with diesel, including running the engine briefly before filling with new oil?

Thanks for your reply.

[Boatyarddog]

You say you " seized " up the engine.
Was this Pistons or bearings?
Was there metal particles in the residue?
If so, be careful as they will scour the new con rod bearings.
Why did you not remove the block?

[a64pilot]

Flush with oil, cheap Diesel oil is fine, your trying to get rid of junk.
Never use Diesel, it could make it run away, and isn’t the best lube either.
It’s not a bad idea to have a book or piece of wood available just in the unlikely event it runs away, just stuff the book over the open inlet and it will starve it for air and it will shut down, do not use your hand, the vacuum can be so severe to really damage your hand.

[Perna]

It's not clear what was seized and what has been replaced but in any case, IMO, absolute cleanliness is necessary for the bearing surfaces otherwise you may get more damage or further seizure, so that's the crankshaft main bearings, conrod big and small end bearings, camshaft bearings and cam follower to cam surfaces and the cylinder bores, pistons and rings.

As for rust particles in the block and sump, there is a new? oil filter for that so although it's not ideal you should get away with it. I would not flush it through but run with clean oil for the first few hours and then change the oil and filter again.

Then you should be good to go.

Good luck.

[a64pilot]

The pistons seized, from having antifreeze in them. Actually of course the rings.
They were broken loose, nothing I don’t think has been replaced, there is probably at least some antifreeze in the crankcase too of course.
He is having his injectors tested and cleaned and I believe has cleaned off the head, and will reinstall everything.
I think.
It ought to work, but will probably use more oil than it used to, how much is based on how bad the rings / cylinders are.
He probably won’t incur any significant damage to bearings etc. I hope, but there is a possibility of course.

[shakey doug]

Is that rust on the Head Deck?

[a64pilot]

I zoomed in to look, and I’m confused.
It seems the pistons are out, and the rods are sticking up above the tops of the cylinders?

This is a five cylinder engine?

[rossl32123]

Originally Posted by Boatyarddog

You say you " seized " up the engine.

Was this Pistons or bearings?

Was there metal particles in the residue?

If so, be careful as they will scour the new con rod bearings.

Why did you not remove the block?

First up I believe only the pistons caused the seizure. Three of them showed signs of scuffing on the skirts in the crankpin area, one was so bad that the rings were partially welded in. The bores weren’t too bad, in fact they are still well within tolerance with just a light honing.

Second, I cannot afford the cost to remove the block from the boat, I am doing it all myself as much as I can to keep the costs down. So I am forced to assume the bearings are all good. I can see that the little end bearings are fine, all within tolerance, so I’m hoping the big end and main bearings didn’t suffer any damage.

I did not get the old oil tested, having found the damage on the pistons I assumed there would be metal in the oil, so what point the testing?

Right now my main concern is to ensure as much as possible that I have a clean crankcase.

[rossl32123]

Originally Posted by shakey doug

Is that rust on the Head Deck?

Yes it is. And some of it has found its way in. It was hard to avoid.

[rossl32123]

Originally Posted by a64pilot

I zoomed in to look, and I’m confused.
It seems the pistons are out, and the rods are sticking up above the tops of the cylinders?

This is a five cylinder engine?

You are correct. 5 cyl air cooled diesel. What you don’t see are the cylinder bores, they are all seperate on this type of engine.

I have replaced the pistons, pins, rings and bores. I have had the heads serviced, including new exhaust valves and new injector valves.

I didn’t need to replace the bores, the old ones were OK, but a rebuild kit was cheaper than 3 new pistons individually, so I went with all new as above.

[rossl32123]

Originally Posted by Perna

It's not clear what was seized and what has been replaced but in any case, IMO, absolute cleanliness is necessary for the bearing surfaces otherwise you may get more damage or further seizure, so that's the crankshaft main bearings, conrod big and small end bearings, camshaft bearings and cam follower to cam surfaces and the cylinder bores, pistons and rings.



As for rust particles in the block and sump, there is a new? oil filter for that so although it's not ideal you should get away with it. I would not flush it through but run with clean oil for the first few hours and then change the oil and filter again.



Then you should be good to go.



Good luck.

Thanks mate, I’ll look for that type of filter. And I’ll try another flush with diesel before I put new oil in to start.

Absolute cleanliness isn’t easy on a boat on a mooring, we are trying our best.