Water in engine!

[a64pilot]

Oil will float on top of the water, at least try to pull out as much of the water as you can, then run it after checking oil level.

[Wotname]

Originally Posted by Captainjohn1975

I can't get the oil out without running the engine for a bit to increase the temp. I'm scared I'm going to do more damage but don't see a choice. It's too thick to go thru hose of vacuums pump

Originally Posted by a64pilot

Oil will float on top of the water, at least try to pull out as much of the water as you can, then run it after checking oil level.

I can't believe what I am about to say but......

Could you add more water to the engine to force out the oil and then use the pump to suck out the water?????

This seems to go against anything I ever knew about keeping water out of the oil and perhaps wiser heads will council against the idea but it seems to make some sort of sense

[model 10]

Thin it with some diesel. I don't know how water can get in the oil. Past the rings? I don't think so, through a valve stem? No. It pretty much needs to be an accessory like the water pump, or a gasket.

[Lepke]

Don't thin the engine oil. Diesels run away easy enough. Old, dirty gas as are sometimes cleaned by replacing oil with diesel and running at idle. Not only can that damage bearings, but easily could lead to a diesel engine running away.
After drawing out the oil thru the dip stick tube - if you can reach the oil pan drain, drain the remainder into a pan, rags, etc., to speed the removal of water.
A couple oil/filter changes will get the water if you run to temperature. An early oil change sometime in the future should finish it. Most filters will hold about 1 once of water. If your engine uses a short spin off filter, replace it with a longer version. Filters are sized by the gasket diameter and threads. Any parts place can look up the sizes. The advantage of the longer filter is the oil moves slower thru the filter so it traps more dirt and water.

But first, determine where the water is entering the oil system.

[Captainjohn1975]

Wanted too update it everyone since you were all so helpful. We've decided to replace our Perkins with a rebuilt Perkins. It's coming from the U.K. After the mechanic tore into the engine he recommended a re manufactured one based on the bad overall condition of it. He said rebuilding it would cost just as much if not more than a re manufactured one. What do you think?

[Cheechako]

Sounds like a good plan. Sometimes it's better to just get one that is completely gone thru rather than minimally "overhauled".

[Captsteve53]

Just remember if your engine dosent start any time with in a a short period then if sea water heat exchanged cooled you MUST close the sea water intake valve until the engine starts to fire then quickly re open the valve,

You are not the first (by a large amount) to not understand that if you crank your engine to long the sea water is building up in your water cooled exhaust system all the time you crank and at some point will enter the engine through the exhaust manifold and open exhaust valves into the cylinder bores, quite possibly leading to a bent rod or off-course seized engine if left for a few days,

Be sure you replace the exhaust riser (as they some times dont come with re built engines) as these quite often are made of cast iron and rot out from the inside again allowing sea water into your engine, cast iron risers can last comfortably 3-5 years or longer (at a risk!), if going to after market stainless steel try to get 316 L Grade as 304 dosent like hot salt water for extended periods, best yet is grade 321 (but hard to find!)- just had one custom made in the UK for a Volvo MD31 and a very nice job

[Captainjohn1975]

So are you saying that by cold starting the engine for some period of time I may have sucks after through the rAw water inlet? Isn't that a closed system.
Can the exhaust elbow also allow water in? Is this created by back pressure being created by the cylinders moving during the starting process. Would you mind explaining how this would work? I just dot want to do it again

[JPA Cate]

If the rebuilt engine is raw water cooled, yes, you can suck in too much.

There is one danger with rebuilt engines that you haven't done yourself: you don't know how thoroughly it was done and how many parts were replaced. Some friends of ours bought a "re-manufactured" engine, not a Perkins, and it turned out to be rubbish, very disappointing for them, and very expensive. I hope yours comes with some kind of warranty.

Ann

[Captsteve53]

John,

Sucking in to much water applies to heat exchanged (fresh water cooled systems especially NOT raw water cooled only as previous thread(yes the fresh water is a closed system being cooled by the raw sea water),Again- if you are turning over your engine (hot or cold) for an extended period for any reason (ie: the engine dosent start right away) then the sea water being sucked in by the raw water impeller is being pushed through your heat exchangers and exits through your exhaust riser elbow into the exhaust system(water lock/mufflers)-If the engine is not running then there's not enough pressure from the cranking speed exhaust system to push the water out of the system,

Therefore it builds up to the point where it back flows through the exhaust manifold and enters the engine through the exhaust valves, this can happen while turning it over or when you stop turning it over, but next time you try and start the engine is full of water (hydro-locked) and probably rusted tight if left more than a few days.

All heat exchanged engines (except for dry exhaust/and above waterline installations) will have a water lock (some refer to as Pong box) in the system, this is designed to let the sea water drain into when you shut down the engine both from the water in the exhaust line before the water lock and especially after the water lock (as these hoses can be long runs before they exit the vessel) The size of the water locks are designed by mathematical formula based on the total length of the hoses/mufflers x there diameter to give cubic capacity, this will then tell the designer how big/capacity the water lock needs to be plus a safety margin.

Again when all these hoses and water locks fill up the water it WILL run back into the engine usually before to runs out the exhaust outlet. You can also get sea water into the engine if your exhaust riser(mixer) has corroded and there's a hole in it (very common) All exhaust risers should be checked regularly and really replaced if older than 5 years- i have seen cast iron risers rot out in three years! Some engines are more prone than other due to the design and thickness of the casting, Many owners prefer to purchase stainless steel after market risers but beware of the type of stainless steel as the more common 304 grade dose not stand up to hot sea water well at all and may not last much longer than the original cast or steel riser, they should be 316 L grade or better still 321 grade(designed to handle hot sea water better).

These inputs are based on my thirty five years as a NZ certified chief engineer (commercial) and Lloyd's certified small ship surveyor currently being a full practicing member of the International Institute of Marine Surveyors (UK)

[Menlim3]

captsteve I have a question. It seems to me that the location of the pong box is crucial (in addition to its size). It needs to be located at the lowest point between the exaust manifold and the exaust/raw water exit point from the boat. Is that correct?

[Cheechako]

Originally Posted by Menlim3

captsteve I have a question. It seems to me that the location of the pong box is crucial (in addition to its size). It needs to be located at the lowest point between the exaust manifold and the exaust/raw water exit point from the boat. Is that correct?

It's good to be as low as possible. But if the boat outlet gets water lapping on it (wind direction at dock etc) it can still flood the engine, it may create a siphon situation, no matter how low the muffler is. It's a good idea to have a vacuum release in the system at the exhaust riser/loop.

[Cherod]

Originally Posted by JPA Cate

If the rebuilt engine is raw water cooled, yes, you can suck in too much.

There is one danger with rebuilt engines that you haven't done yourself: you don't know how thoroughly it was done and how many parts were replaced. Some friends of ours bought a "re-manufactured" engine, not a Perkins, and it turned out to be rubbish, very disappointing for them, and very expensive. I hope yours comes with some kind of warranty.

Ann

Quite , I knew if one " reconditioning " outlet who all they did was steam clean an engine and sell it as recon , it was fully guaranteed in that they would give you another one if it did not work , their theory was that only about one on five reclaimed engines were duds , a real pita for the unfortunate 1 .

[Captsteve53]

Menlim, a couple of further points points here:

1) Water lapping against the exhaust out let should never enter the exhaust system if properly installed and here's why- Immediately inside the hull the exhaust hose needs to rise as high a possible-just under the deck level is the norm- that way even heeled and motor sailing water will never enter(unless your decks are under the water level perhaps in a Chinese Gyve) also many place their mufflers here with the top also just under deck level

2) From that high point under the deck the hose needs to run down hill to the water lock with as straight as possible run and if possible no place for the water to collect until it runs back to the water lock, just to note every bend/elbow etc will make a dramatic rise in back pressure- normally a 90 degree elbow can be the same as 12-15 ft of wet straight hose in back pressure

3) Typically the water lock will be at the lowest feasible point normally just above the hull level from there a nice straight run up to the riser, typically again for the majority of small engines under 100 hp this hose is around 2-3 ft (there are exceptions due to space/hull design etc)

Cheers Steve

[Captsteve53]

Below is the typical engine (under water installation or on waterline)