Hydrolocked 3gm30F

[Örjan]

Please help.

I have also done it.

When priming the fuel lines I had the raw water cock open and subsequently flooded one cylinder with saltwater.

The engine now only runs on two cylinders.

So my questions are as follows.

1.what can happen when hydro locked ?

2.Can you hear if a valve/s is bad.

3. Can stuck ring/s be enough to cause the compression loss so that this cylinder does not fire?
4.
does a bent conrod create enough compression loss?

I didn't like the sound so I tried the decompression levers to see which one did not fire.

when i turned the levers for number one and two (closest to the bow)
there was a clear change in rpm and a "ohhfing" noise from the air intake.

Doing the same on the cylinder closest to the stern the rpm did not change an the only difference was a bit more "ticking" from the valves "rockers"

my conclusion was that it did not fire.

I also get raised oil level in the pan.
No water in the oil but I suspect diesel.
(the oil is black but thinner) no greying or signs of water.

the engine run 3600rpm under no load.
(I guess i should avoid doing that until it fires on all cylinders)

What should I do next?
Compression/leak down test?

Should I try some "decarbon-derust-magic marvel oil fixit all additive" if the rings are stuck?

Or should I just take the top of and see what has happened?

Appreciate any help that might solve my problem
Thanks

örjan

[r.furborough]

You have probably bent a connecting rod and lost compression on that cylinder if it was hydrolocked. Water cannot be compressed and therefore the connecting rod bends. A normal wet/dry compression test should be able to determine this followed by removing the cylinder head.

I would think you could ultimately be looking at a bottom end rebuild.

[Chief Engineer]

Looks like teardown time...complete rebuild.....If it hydrolocked, you have probably damaged a rod...might as well take the head off and see if there is any difference in the pistons at TDC on each cylinder.

BUT!!!! befor you do that pull your injectors and check them out.

[Örjan]

Thanks for the input !
I guess i will have to take the head off and see.
I guess you could change piston and rod and rings in the boat on that cylinder to get me through the summer or is that a bad idea?
Would you take the piston out from the top or bottom?
Or does it matter?

[Örjan]

Fuel in the oil suggests leaking rings or can it get down there in any other way?

[Örjan]

The con rod is fine! .......

[roverhi]

Did you check the injector?? Depending on how long the water was in there, it could have ruined the injector. You say the con rod is fine, how did you check it. I assume you got the engine started without using the compression release levers. If that's the case, the water in the filled cylinder had to go somewhere or something in the engine had to give, either the con rod bending, the rings deforming or the head gasket blowing out. The valves shouldn't have been effected. A compression check will tell you if the problem is in the engine rather than the injection system. All a diesel needs is air, fuel at the right time, and compression to run. It's probably one of the latter two issues.

I managed to get a Volvo MD2b started that was water locked. A new con rod later, it was as good as new.

Aloha
Peter O.
Pearson

[unbusted67]

Originally Posted by Örjan

When priming the fuel lines I had the raw water cock open and subsequently flooded one cylinder with saltwater.
örjan

Yikes, I am a real beginner when it comes to engines but have bled the fuel lines on my 3hm35f with the raw water intake to the engine open a hundred times. Is this going to happen to me?

[Cheechako]

The lower piston land was problematic on my 3GM30, is it possible you broke the piston lower ring? The engine would run ok at high rpm unloaded, but had no power.....

[Örjan]

Originally Posted by unbusted67

Yikes, I am a real beginner when it comes to engines but have bled the fuel lines on my 3hm35f with the raw water intake to the engine open a hundred times. Is this going to happen to me?

I bled the fuel lines by moving the engine by hand so there was no exhaust pressure to blow out the water in the exhaust hose. It filled up and then it went in to the exhaust valve . We noticed it commig out of the air intake.
I then shut the raw water cock and continued to move the engine around by hand with the decomression levers on so that the valves were open.
when I thaught it was empty I tryed starting it and it came to a complete stop .I guess it only did a couple of revolutions or not even a full.
There was obviously some water left.

So next time I will shut the raw water cock.............
Hopefully one learn something every day.

[unbusted67]

So whenever I bleed my fuel lines should I close the raw water seacock? I have an electrical fuel pump hooked up so I don't have to manually pump the fuel through a secondary filter and then all the way through the system. When it gets to the injectors I usually go up and run the starter and the engine fires up. Is this the right way?

[Örjan]

Originally Posted by roverhi

Did you check the injector?? Depending on how long the water was in there, it could have ruined the injector. You say the con rod is fine, how did you check it. I assume you got the engine started without using the compression release levers. If that's the case, the water in the filled cylinder had to go somewhere or something in the engine had to give, either the con rod bending, the rings deforming or the head gasket blowing out. The valves shouldn't have been effected. A compression check will tell you if the problem is in the engine rather than the injection system. All a diesel needs is air, fuel at the right time, and compression to run. It's probably one of the latter two issues.

I managed to get a Volvo MD2b started that was water locked. A new con rod later, it was as good as new.

Aloha
Peter O.
Pearson

I trusted my own logic to much so I pulled the head only to find that the piston and rod was fine (a compression test would off course told me this before I pulled the head).

[Örjan]

Originally Posted by unbusted67

So whenever I bleed my fuel lines should I close the raw water seacock? I have an electrical fuel pump hooked up so I don't have to manually pump the fuel through a secondary filter and then all the way through the system. When it gets to the injectors I usually go up and run the starter and the engine fires up. Is this the right way?

I think key is that turning the engine slowly(by hand )does not create any exhaust pressure to blow out the water in the exhaust hose. It will pump up water and fill the exhaust hose which will then overflow in through the exhaust valve at the lowest cylinder. Shutting the raw water cock prevents this.

I was new to the process and took a long time..........
I think I had the decompression levers on also (valves open).

[Cheechako]

So whenever I bleed my fuel lines should I close the raw water seacock? Its all a matter of how much you are cranking and how much water your exhaust system/waterlift muffler can hold. I've never worried about it and never had a problem, but rarely needed to bleed a system unless I've had the engine apart.... I expect it to start immediately or start looking for issues. By my way of thinking you shouldnt get much air in your system changing fuel filters and I always bleed if needed while the engine is running. Too much cranking with the seacock shut could wipe out your impellor... especially if the engine starts up! I suppose that is the lessor of the evils though... A better setup would be to have a drain spigot on your waterlift muffler to open while cranking....

[Örjan]

Originally Posted by Cheechako

So whenever I bleed my fuel lines should I close the raw water seacock? Its all a matter of how much you are cranking and how much water your exhaust system/waterlift muffler can hold. I've never worried about it and never had a problem, but rarely needed to bleed a system unless I've had the engine apart.... I expect it to start immediately or start looking for issues. By my way of thinking you shouldnt get much air in your system changing fuel filters and I always bleed if needed while the engine is running. Too much cranking with the seacock shut could wipe out your impellor... especially if the engine starts up! I suppose that is the lessor of the evils though... A better setup would be to have a drain spigot on your waterlift muffler to open while cranking....

Your right. It usually is not a problem .
Having the decompression levers turned did not help either.
You learn something every day.....