KAD 44 - Smoke or Steam

[Dazzajohm]

It looks like the intercooler is not the problem (stand humble to be corrected but this is waht came out of mine as well). How did you actually exclude a loose exhaust bellow. It can look like it is in place when stationary but at speed it might become detatched from the "neck" by the exhaust pressure. If you do not have any overheat, you do not loose coolant and oil levels are stable the serious stuff can be excluded i think. Have you checked that your raw water pump is not leaking and spraying water mist in the engine room. This should show up as salt deposits and later rust on the front of your engine. Also as mentioned before you should check the condition of the rawater-exhaust mixer. On my KAD 42s the head gasket was always leaking despite replacement. This however shoved up as green bilage water.

I must admit, I'm kind of hoping it's not the intercooler as they're bloody expensive to replace!

Regarding the exhaust bellow - when in the marina, if I put in neutral and apply a few rev's I can see the bubbles coming from where I would expect it to on the leg, although that's a good point you raise about it becoming detached at speed.

Other than that, I've got quite a lot a space in my engine bay and I had a good look around over the weekend. Nothing looked out of place or out of the ordinary.

 

[A_8]

Whatever is going on you need to check why the exhaust is all over your behind at planing speeds, most likely the bellow is broken but maybe something else is off. The only way to find out is to lift the boat and check the bellow and drive.

 

[Niander]

Looks like steam to me .
Not a problem is it?

 

[No Regrets]

Looks like Steam. Might be worth trying Rydlyme in the raw water system. It removes all the lime and restores full cooling capability. You need to set up a circulation system without the engine running, for two hours or more. The engines should run a lot cooler after this. Worked for me, total cost £120 worth of Rydlyme, but avoided vast vast bills removing bits and cleaning them, plus it does the whole system, like the water jacket, which you just can't clean otherwise.

 

[Dazzajohm]

Whatever is going on you need to check why the exhaust is all over your behind at planing speeds, most likely the bellow is broken but maybe something else is off. The only way to find out is to lift the boat and check the bellow and drive.

Yes, i thought that and after you guys confirming my thoughts was almost ready to do a lift and hold but went out the other day for a play and it makes no sense.

At WOT no sign of steam or anything. Completely disappeared. But operating at cruising speed of anywhere between 3000 - 3300 rpm its back in abundance. To me that doesn't mak sense as if it was a broken bellow it would surely be worse not better. Again if it was the intercooler then I wouldn't expect it to do that either.

I'm currently in the process of getting a local VP guy out to have a look on a sea trial.

 

[Dazzajohm]

Looks like steam to me .
Not a problem is it?

Only in as much as when the canopy is open it all comes in to the helm and it covers everything in exhaust soot. When the canopy is closed, after a couple of hours the whole transom and canopy are rather gray and it's a pain to clean off!

 

[CX54WEK]

Only in as much as when the canopy is open it all comes in to the helm and it covers everything in exhaust soot. When the canopy is closed, after a couple of hours the whole transom and canopy are rather gray and it's a pain to clean off!

Something clearly is amiss then. It shouldn't cover the boat in soot like that.

 

[Portofino]

You need to hire a competent VP engineer to have a look /examine
could be a multitude or combo of things layered over each other

In no particular order ----

Cracked piston ring (s)
At certain rpm extra heat = expansion =seals ok,
At other lower rpm + temps does not seal so well ,oil blows by = smoke and transom stains .

Is it using a lot of oil ? ,have you done a blow by test whereby you remove the oil filler cap and see what pressure variations through the rev range .Also test the pressure variations of the dip stick tube ?

Or a valve guide (s) on its way out = at certain rpm / temps /expansion or lack of it --oil is sucked in from the rocker box = smoky .Higher rpm kinda self seals ---for now and extra heat burns up any excess oil better than a lower rpm where it gets visibly smokey ?

If it was air filter issues it would just get more smoky proportional to rpm ,ie get worse and poss not reach wot -- which it does .
Could be a fuelling -pump and or injector issue at certain rpm. -intermittent overfuelling ,buts fine at higher rpm,s range and wot

When you have an accurate diagnosis --do tell .

They don,t like heat ,overloading from too much Kg, fowling , engines on the edge re power /wieght ratios -leads to shooting up of Exhaust Gas Temperatures --- High EGT's are a silent marine diesel killer .
Overloading leads to cumulative damage ,ring wear and valve guide wear comes on slowly -eventually the symptoms become noticeable .
What boat are they in and how have you used it rpm wise ? How close to wot have you generally operated it ?

 

[omega2]

the impeller has been mentioned once in this thread, have you done anything to examine it?? if not DO IT NOW.

 

[A_8]

Yes, i thought that and after you guys confirming my thoughts was almost ready to do a lift and hold but went out the other day for a play and it makes no sense.

At WOT no sign of steam or anything. Completely disappeared. But operating at cruising speed of anywhere between 3000 - 3300 rpm its back in abundance. To me that doesn't mak sense as if it was a broken bellow it would surely be worse not better. Again if it was the intercooler then I wouldn't expect it to do that either.

I'm currently in the process of getting a local VP guy out to have a look on a sea trial.

That is indeed strange and don't make sense any way you look at it. There are a bit of piping that actually exits cooling water in the bottom of the transom shield, not sure if there is a bit of exhaust as well.
Have you measured the temperature on the engine and exhaust elbow @cruising speeds?

 

[omega2]

Lots of revs lots of impeller spin thus lots of water, not so many revs not so much water being pushed around by damaged impeller. ?

 

[n.herring]

There is nothing strange about a diesel engine smoking under load, once it is up and flying the smoke disappears, as I said a week or more ago this is a job for an expert on things like injectors, bore wear etc.

 

[Dazzajohm]

You need to hire a competent VP engineer to have a look /examine
could be a multitude or combo of things layered over each other

In no particular order ----

Cracked piston ring (s)
At certain rpm extra heat = expansion =seals ok,
At other lower rpm + temps does not seal so well ,oil blows by = smoke and transom stains .

Is it using a lot of oil ? ,have you done a blow by test whereby you remove the oil filler cap and see what pressure variations through the rev range .Also test the pressure variations of the dip stick tube ?

Or a valve guide (s) on its way out = at certain rpm / temps /expansion or lack of it --oil is sucked in from the rocker box = smoky .Higher rpm kinda self seals ---for now and extra heat burns up any excess oil better than a lower rpm where it gets visibly smokey ?

If it was air filter issues it would just get more smoky proportional to rpm ,ie get worse and poss not reach wot -- which it does .
Could be a fuelling -pump and or injector issue at certain rpm. -intermittent overfuelling ,buts fine at higher rpm,s range and wot

When you have an accurate diagnosis --do tell .

They don,t like heat ,overloading from too much Kg, fowling , engines on the edge re power /wieght ratios -leads to shooting up of Exhaust Gas Temperatures --- High EGT's are a silent marine diesel killer .
Overloading leads to cumulative damage ,ring wear and valve guide wear comes on slowly -eventually the symptoms become noticeable .
What boat are they in and how have you used it rpm wise ? How close to wot have you generally operated it ?

I'm currently awaiting some good weather to get a VP engineer on board and take out for a sea trial so he can see exactly what's going on. I would like to add that I don't believe it to be smoke but steam.

As far as I can tell, apart from the steam, everything else is working fine, temp is where it should be etc.

It's a Princess 266 with single kad44. Usually operate at 3000 rpm when cruising. Wot is abour 3900 rpm.

 

[Dazzajohm]

the impeller has been mentioned once in this thread, have you done anything to examine it?? if not DO IT NOW.

When I spoke to a VP engineer we spoke about this. He said if it was an impeller problem I'd see the temp raise significantly.

 

[n.herring]

Steam is not going to plaster the back of your boat in gunge, white/grey smoke will be unburnt diesel, grey/black smoke will be oil

 

[derekh]

I have a beneteau 1080 with steam at 3000 rpm. The temp is running 85-90'. I am told it is normal. Dropping back to low speed temp drops to 60'. I have had new impellers fitted over the winter. I'm on. Shafts with exhausts above the waterline when cruising.

 

[Dazzajohm]

I have a beneteau 1080 with steam at 3000 rpm. The temp is running 85-90'. I am told it is normal. Dropping back to low speed temp drops to 60'. I have had new impellers fitted over the winter. I'm on. Shafts with exhausts above the waterline when cruising.

Thanks for the info, do you have a kad44?

Who told you it was normal?

Cheers

 

[Colin K]

Hello,
My old tub has TAMD 41b's and I have just found a couple of videos of looking astern on the plane and yes there is a mist/steam coming from her. Also found on You tube some others which seem to do the same so I am hoping its normal.

Cheers, Colin.

 

[Dazzajohm]

Well, by way of an update, I had the dealer I got the boat from come and do some checks. The problems have been there since before the warranty expired so he's been really good at keep returning. I believe most of what has been suggested on here was checked and the only thing to be a cause of concern was the aftercooler which was replaced. Problem still not resolved and now the engine has developed a significant oil leak. The guys troubleshooted this but have not been able to locate it so the dealer now thinks it best to swap the engine out for another he has in the workshop. Whilst I'm really pleased I've been offered this option as my current engine does seem fraught with problems, my concern is that the replacement is a KAD 42 and not a KAD 44. I'm wondering how much difference the lower HP will make to the performance.

Anyone got a KAD 42? If so what is it in and how does it perform?

Cheers

 

[Portofino]

Refer to post # 48
Now it's blowing out oil from downstairs -so pressure is getting past the ring (s)

You need more Hp not less
As they age engines loose % power
So start as high as poss to keep the load as low as poss or turned around as far away from 100 %
For longevity

It takes a different mind set to understand diesels particularly marine D
Most lads are brought up with petrols 50 cc bikes toys cars your first car that you modded with a better air filter or exhaust pipe and new alloys etc

Forget all that marine diesels are glorified air pumps that heat air by way of approx 2x compression ratio of volatile petrol --- and you squirt oil into the compressed air
Any oil P nut , chip oil -or diesel it all burns
Prob is HEAT load s of it far more than a petrol
It's getting rid or not allowing that heat to build up for too long
That's the prob
Road versions if the same block are detuned
Eg MAN 12 L block in a truck 380-480 Hp
In a boat 800. Hp
Over loading with an outfit on the edge being too heaven amassed cruising stores and foul led
The pump just keeps squirting fuel in , unburnt. Leads to Black smoke and if over loaded a rapids rise in EGT
It does not go bang -just wears -burns rings piston crowns and exhaust valve s
Shortens life in a boat
Meanwhile the same equivalent block in a vehicle passes the 1 million Km mark uneventfully because it's got a gearbox and never really is subjected to overload + it's 1/2 the out put so less heat more unlikely to damage it's internal components

A truck diesel will last for ever a boat diesel needs TLC
Do not overload it ---by accident