White smoke in reconditioned Bukh engine

[tmtracey]

Oh good. That sounds rather less serious than previously thought.

I did have an issue with the blocked water ‘poker’ last year- maybe some of the salt has blocked some of the cooling passages in the block.
I think my next move will be to fill the block with brick cleaner and see if that clears it up.

 

[tmtracey]

Out of interest, would brick cleaner damage the rubber coolant pipes between the water pump and thermostat?

 

[Charlie Boy]

Oh good. That sounds rather less serious than previously thought.

I did have an issue with the blocked water ‘poker’ last year- maybe some of the salt has blocked some of the cooling passages in the block.
I think my next move will be to fill the block with brick cleaner and see if that clears it up.

Out of interest, would brick cleaner damage the rubber coolant pipes between the water pump and thermostat?

Here’s a pic of my arrangements for the same thing. I used a small, very cheap pump to circulate the diluted Ridlyme (I think it was). I took the thermostat out in an effort to get more fluid through the block IIRC

 

[tmtracey]

Here’s a pic of my arrangements for the same thing. I used a small, very cheap pump to circulate the diluted Ridlyme (I think it was). I took the thermostat out in an effort to get more fluid through the block IIRC

View attachment 124236

That looks a good system. My problem is I think the hose is crimped onto the Y water fitting , so not removable. And I'm not sure I fancy getting the fitting off again!

 

[davidmh]

Reference the rydlyme system. I am sure a previous thread on Rydlyme talked about it reacting with the wet liner seals, any comments,
Also on my Bukh the pipes from the pump to the y piece and from the y piece to the thermostat and from thermostat to exhaust manifold are all car water heater type pipes just a rubber /fabric sandwich construction with jubilee clips. Its worked well for 20 years they just need replacing about every 5-6 year or when they become soft.

 

[Rhylsailer99]

Well, I learnt a few things about the engine yesterday chugging up and down the Deben!

It was a fairly warm day (16-17C) and the smoke wasn’t as bad as I’ve experienced before. On a cold day, it can be much worse.

On start-up, there was big smoke for about 10 seconds and then it disappeared. I let it idle on the mooring for 30 mins (about 900 RPM), and then set off, gradually building the revs over about 2 hours. There was no smoke whatsoever until it reached 1700 rpm when a faint small cloud starting coming from the exhaust. At 1900 rpm it had thickened but was not extending much from the boat. From 2000-2100 rpm, it started to smoke heavily from the exhaust. It was greyish white (mainly white), and extended about 5 feet back from the boat, before dissipating.

I’ve put a video here of it running at 2100 rpm
Engine smoke

2100 rpm is the highest available with my throttle set-up. The company that reconditioned it suggested a cruising speed of 2000-2400 rpm, so I would like to be able to achieve that smoke-free..

Some noticeable things were-

• It took over an hour to get to 60C water temperature and only gradually reach that – is that normal? After 30 mins idling, it was only at 50C. Once it got to 60C, it stayed on that the entire trip. I could only hold my hand on the engine block itself for about 5 seconds,, which seems normal.
• The amount of smoke dramatically increases from 2000 rpm - so once it reaches a threshold, it really smokes.
• However when on the mooring and in neutral, I put the engine up to 2100 rpm. There was NO smoking whatsoever. So something about being under load is creating smoke.

I am fairly sure it was smoke, not steam. As it only smoked on the move, it was tricky to check but I tried holding a rag on a stick in the fumes close to the exhaust – it didn’t get particularly damp (to indicate steam), or absorb any fumes to create a rainbow effect in water, as someone recommended checking. Anyway it certainly looked like smoke to me.

Apart from the slow initial increase in the water temp, the other gauges read normal the whole session. The air filter and exhaust look new and clean. I cleaned the cooling water ‘poker’ last year and flush it every winter. The volume of water coming from the exhaust was good (about 12 L/min when idling after the trip).

Hopefully this helps with understanding the issue - any further advice/comments much appreciated.

i think a temp gauge doesnt work so well with a direct cooled engine . mine is the same as i fitted a gauge and it never goes over 60 deg.

 

[Rhylsailer99]

smoke worse on a cold day = steam

 

[neil_s]

Here’s a pic of my arrangements for the same thing. I used a small, very cheap pump to circulate the diluted Ridlyme (I think it was). I took the thermostat out in an effort to get more fluid through the block IIRC

View attachment 124236

I use Fernox DS3. I hang my bucket under the exhaust on the transom and run a pipe back to the engine's own pump. The engine gets a good warm up before operation commence so that the thermostat is well open. Hot DS3 is much more effective! A run at fast idle seems to do the trick.

 

[Charlie Boy]

That looks a good system. My problem is I think the hose is crimped onto the Y water fitting , so not removable. And I'm not sure I fancy getting the fitting off again!

It’s crimped on the side that goes to the thermostat for sure. Mine isn’t on the input side although for all I know it may be different on the DV24. I’d be surprised if it was, Bukh certainly like to reuse all the old drawings again if they can!
Next time I do it I’ll crimp the pipe that goes to the thermostat to ensure the acid goes right through the block and doesn’t slip away through the ‘stat housing.

 

[jamie N]

Not wanting to be silly, but the best way to ensure cooling, is that the block is free from constriction, which is where the largest deposits are going to inhibit. Remove the block; head off, block off, clean the passageways with perhaps a screwdriver as there'll be sh1te there that'll want to come off. Doing this will restore the block to 'nearly new' condition. It's not the most difficult thing to do at all, and costs virtually nothing along with giving an opportunity to have the injector serviced and a new gasket; £60? Good value I'd say, and doesn't require special tools or knowledge in this Google age.

 

[Rhylsailer99]

thats how i do it remove the thermostat and block the bypass and run a bilge pump to pump the solution through the block i used fernox or barnacle buster.

 

[Rhylsailer99]

thats how i do it remove the thermostat and block the bypass and run a bilge pump to pump the solution through the block

there is no worries of it going into the engine as its strictly thrrough the water ways of the block

 

[LittleSister]

thats how i do it remove the thermostat and block the bypass and run a bilge pump to pump the solution through the block i used fernox or barnacle buster.

How did you block the by-pass?

 

[Rhylsailer99]

I use Fernox DS3. I hang my bucket under the exhaust on the transom and run a pipe back to the engine's own pump. The engine gets a good warm up before operation commence so that the thermostat is well open. Hot DS3 is much more effective! A run at fast idle seems to do the trick.

I would pinch the bypass pipe with mole grips or block it to push all the fluid through the block .

 

[Beneteau381]

Out of interest, would brick cleaner damage the rubber coolant pipes between the water pump and thermostat?

It wont damage the coolant pipes

 

[Birdseye]

I was wondering if it's worth trying some cheap and easy solutions first before taking the thing apart

Absolutely. Its too easy to start by imagining the worst most complex and expensive problems first. Bukh engines are often called "steamers" anyway. So start off by checking the basics from water pump ( overheating?) to injectors. Its easy to take an injector out, turn over the engine and check that the injector is working OK. Air filter clear? Seawater inlet clear? Fuel filter clear? Try some fresh fuel.

Only when you are sure that everything external to the engine and auxiliaries is OK do you contemplate stripping the engine

 

[Beneteau381]

Absolutely. Its too easy to start by imagining the worst most complex and expensive problems first. Bukh engines are often called "steamers" anyway. So start off by checking the basics from water pump ( overheating?) to injectors. Its easy to take an injector out, turn over the engine and check that the injector is working OK. Air filter clear? Seawater inlet clear? Fuel filter clear? Try some fresh fuel.

Only when you are sure that everything external to the engine and auxiliaries is OK do you contemplate stripping the engine

Its steam, so start from there

 

[tmtracey]

Thanks for the help everyone.

What sort of top crusing RPM do you get with your Bukhs? When does the steam usually kick in?

I'd like to add that the engine is great value for the money, it sounds great and runs very smoothly. As an ex-lifeboat engine, one can assume they were designed to absolutely reliable while not necessarily needing to perform at high rpms. Bukhs do have a habit of steaming. It sounds like the cooling passages may be slightly furred up so will flush through over the winter.