Nanni 4.390 saga continues (low power low speed)

[freddyuk]

I decided to start a new thread on this as it has got mixed in with other threads.
We now have some data after a test run today and I wonder if anyone has a clue what is wrong.
2 persons on board.
Weather calm with light breeze. No waves just slight chop.
The engine was started up and idled for a few minutes. The bluish smoke from exhaust was minimal and I feel not concerning? See photo. 2

After warming up and leaving the berth within 5 minutes temperature was up to 75c and stopped rising as thermostat opens at 71c.
At 1000 revs we are doing 5kts. At 2000 revs we are doing 8.5kts. At WOT 3300 we are doing 15 kts and just get onto the plane. Official WOT is 3600 revs.
There is steam from the exhaust when going full throttle but I understand these engines do steam a bit.
The temperature was never over 80c and second gauge confirms this.

No smoke just white/grey steam. See Video

I opened the engine cover to check if the turbo wastegate was actually moving but could not see any movement although it was hard to see with vibrations. I could hear a high pitched turbo whistle which you can hear on the very short clip. See video 3 second clip. Does this indicate a turbo leak or dry bearing?? It is so loud it's hard to hear anything.

Fuel is clean. No water or bug.

Photo shows the gauges all looking normal and the speed on the plotter. See photo 1.

I have put video on Youtube so hope this works.
Steaming =

Engine idling =

Whistle =

Any comments welcome thank you.

 

[penfold]

None of the vids are watchable, you need to reset them from private to public.

 

[freddyuk]

Thanks for that they should be there now?

 

[jamie langstone]

Does the waist gate move by hand . Disconnect the rod to the waist gate and see if you can move the waist gate to see if it is stuck. You can get it to move if it is not to stuck by gently working it back and forward.
May be worth having a turbo overhaul. Also 300 revs down have you got a clean hull and prop .

 

[freddyuk]

Hull /prop cleaned and anti fouled beginning of year. Injectors serviced and boat delivered back to me and was told it managed 17kts. I never had that so have my doubts but it is still below targetcruising speed. I did move the wastegate by hand previously last year so its not jammed.
When you throttle up from 1000 revs it does not "come alive" it struggles to get up on the plane and then it is maxed out.

 

[jamie langstone]

Hull /prop cleaned and anti fouled beginning of year. Injectors serviced and boat delivered back to me and was told it managed 17kts. I never had that so have my doubts but it is still below targetcruising speed. I did move the wastegate by hand previously last year so its not jammed.
When you throttle up from 1000 revs it does not "come alive" it struggles to get up on the plane and then it is maxed out.

Does sound like turbo problem . It may pay to
Get the turbo checked . If your confident that
The hull and prop are clean and the waist gate moves as it should then I can only assume that boost pressure is low as it struggles to get going.

 

[sailorman]

I decided to start a new thread on this as it has got mixed in with other threads.
We now have some data after a test run today and I wonder if anyone has a clue what is wrong.
2 persons on board.
Weather calm with light breeze. No waves just slight chop.
The engine was started up and idled for a few minutes. The bluish smoke from exhaust was minimal and I feel not concerning? See photo. 2

After warming up and leaving the berth within 5 minutes temperature was up to 75c and stopped rising as thermostat opens at 71c.
At 1000 revs we are doing 5kts. At 2000 revs we are doing 8.5kts. At WOT 3300 we are doing 15 kts and just get onto the plane. Official WOT is 3600 revs.
There is steam from the exhaust when going full throttle but I understand these engines do steam a bit.
The temperature was never over 80c and second gauge confirms this.

No smoke just white/grey steam. See Video

I opened the engine cover to check if the turbo wastegate was actually moving but could not see any movement although it was hard to see with vibrations. I could hear a high pitched turbo whistle which you can hear on the very short clip. See video 3 second clip. Does this indicate a turbo leak or dry bearing?? It is so loud it's hard to hear anything.

Fuel is clean. No water or bug.

Photo shows the gauges all looking normal and the speed on the plotter. See photo 1.

I have put video on Youtube so hope this works.
Steaming =

Engine idling =

Whistle =

Any comments welcome thank you.View attachment 118712View attachment 118714

Non rngineer question what is a waste gate

 

[burgundyben]

What do you think is wrong with it? All looks normal and going ok?

 

[penfold]

Turbos whistle, this is normal.
Steam may be a feature of the product; is there water being ejected at the same time as the steam? If there is and the temp gauge is steady at 80 then it's probably fine, although the steam makes me think the nanni injection elbow isn't much cop and isn't mixing as well as it ought to.
Not reaching 3600 may be caused by many things, dirty bottom, waste gate, fuel, intercooler etc; has anything changed since the last time you had it up that fast?

 

[ChromeDome]

What is your ready-to-go GW? On a planing hull the weight really is a speed killer and factory figures tend to be from the lightest possible config for this reason.

It is strange that you get 15 knots at 3300 rpm when others report 13 knots at 2500 rpm.
Beneteau antares 760 owners
Could your tacho be wrong? Worth checking.
On propellers with rubber hubs (outboards, sterndrives) a defective hub bushing could allow slip but on a shaft boat I've never heard of it. Probably worth the effort to check propeller fitment (key and nut) and at the same time confirm the pitch/dia figures stamped on the hub?

Beneteau antares 760 owners

I have a pair of the same engine (ver. 4.380 / 175 hp) in a different boat, and they behave like yours albeit take longer to reach working temperature. After 20 minutes of flat out operation I get some 85°C, however I never see steam - regardless of hot or cold engines. In my case WOT rpm is 3500 with full tanks and two persons.

Is your sea water impeller new(ish), strainer and heat exchanger clean? A low flow rate could cause steam from the leaving seawater while keeping the engine coolant temp within range.

You can get the 191 page workshop manual here
http://extranet.nannidiesel.com:8081/Joomla/index.php?option=com_content&view=article&id=228:manuels-datelier-t4155-4380tdi-a-4390tdi&catid=72:manuels-datelier&Itemid=97&lang=en
where on pg 159 you see a simple check of the wastegate. Pg 17 states that the pressure delivered by the turbo (aka 'boost') should be 93-103 kpa. To check it under way, the easiest is to use/fit a (inexpensive) boost gauge that will show the actual boost at any rpm/load.


As for the question about wastegate: Simply put, a turbo is driven by the exhaust pushing its turbine. The opposite end of the turbine shaft has a different turbine, pushing air into the intake, enabling more fuel to be burned and more power to be created. Hence will go faster and produce more boost when the engine rpm increases. To keep the boost within range, the wastegate opens a bypass to 'waste' the exhaust gas directly into the exhaust system instead of pushing the turbo.

 

[freddyuk]

The original story is here started by the OP but my post supports his problem: TAMD41P - steam or smoke? Video quiz...
So the steam event started on our delivery voyage after 6 hours of doing 13kts in very rough seas. It was not steaming when we left in good weather as we were taking photos over the stern doing 17 kts (cruising speed) and did not sea clouds of steam. Having just collected the boat I was watching the gauges all the time.
There is plenty of water being ejected at the exhuast.
Eventually all fuel/oil filters were replaced. Both water pumps were renewed. Injectors serviced. Bottom cleaned and anti fouled. Thermostat replaced with correct spec one. Bits of old impeller removed from fuel cooler. Fuel tank syphoned from bottom and checked. Glass bowl filter fitted on tank outlet.
There are 2 persons on board. No heavy gear.
The engine should go to 3600 revs loaded and 4200 unloaded. (factory manual) It does not go to 3600 when loaded. It has gone to 3600 unloaded but I didn't push it further.
The speed should max out at 20+ kts all things being equal and based on anecdotal evidence of other owners of this boat. It is maxed out at 15kts using two GPS units to compare. Cruising speed should be 16/17kts and planing over 14kts. We just struggle onto the plane then that is it, so max revs just keep it on the plane but we are not cruising we are thrashing it.
It is going back to the boat yard on Friday and it will be weighed.
I am planning to measure pressure via the wastegate pipe from the turbo to check if boost pressure is correct. Is that correct way?
There is another vacuum pipe from manifold to fuel pump but what should pressure be in that??
I have not had a compression test or a fuel pump pressure test as I don't have the facilities. I hope to find someone to do this.

 

[markc]

Just a few observations - if there was a boost leak, wouldn't there be black smoke from the unburnt fuel? The steam does not look worrying - you can always use an IR thermometer to check the temp of various components . Feels to me that the most likely culprit is lack of fuel - does this engine have LDA adjustment on the fuel pump? Perhaps the end stop for the fuel pump needs adjusting?

 

[paradave]

The original story is here started by the OP but my post supports his problem: TAMD41P - steam or smoke? Video quiz...
So the steam event started on our delivery voyage after 6 hours of doing 13kts in very rough seas. It was not steaming when we left in good weather as we were taking photos over the stern doing 17 kts (cruising speed) and did not sea clouds of steam. Having just collected the boat I was watching the gauges all the time.

As the OP of that link, I don't think your issues are related to mine. For your info, the majority seemed to think the steam coming from my TAMD was normal and certainly over the next 100hours of use we had no issues. A couple of months back I noticed a lot more steam coming out, on a warm day and at 7knots and asked Volvopaul to check it out - it appeared my elbow is corroded and on its way out - he cleaned and decrudded it and then the steam all but disappeared. Think we'll be replacing it this winter however as obviously not fit for another season.

Throughout this, I've not really had any performance issues. I cruise at 16knots on the plane and can hit 20knots flat out with a light load. Mine won't rev past 3200 however and yet is supposed to get to 3600. Whether this is an inaccurate rev counter or prop I'm not sure - I don't think it warrants further investigation at this point though.

 

[freddyuk]

We did have black smoke when it was tested after long layup during lockdown. We had replaced both water pumps and thermostat to cure overheating (impeller bits left in cooling system?) . It was getting towards 95c so thermostat was replaced and we found the Nanni experts supply an 85c stat whereas Nanni specify 71c. I supplied my own and sent the other one back. Then tested boat and it did not overheat but revs issue was still there and pushing it to the limit gave us less steam but black smoke so we backed off. It was then sent for engine service and injectors were refurbed and one was "not seated correctly". I did not get any other info except it was returned to me and they said all was normal except it didn't go over 17 kts. I could not get 17kts at all. I have checked fuel quality and it is not contaminated. When we go to max revs now there is no smoke.
The fuel pump has not been messed with since purchase when it was surveyed and sea trialled and it was all good. The actuating rod goes all the way to the stop. I am not aware of any other adjustment - this is a non ECU engine.
To test fuel supply pressure you need to know pressure at the injection pump so special tools and skills??

Remember this issue started on delivery voyage which was very rough. I do not think the boat was ever used in heavy weather before as we were getting leaks through the wiper spindles which would have been fixed if it happened before as this dripped onto cabin bunks.
Steam was apparent after we went from beam sea to following sea as that is when you look behind!

 

[freddyuk]

Thanks Paradave - I was not suggesting the issues were related just that I had a steaming issue and was investigating at the time. You do say you can get to 20kts at max 3200 which highlights my issue of 3300 with 15kts!! Something isn't right. If I remove the exhaust elbow it may help with the steam but I cannot see how it will increase engine power? Also I need to get hold of gasket to do this. It seems as if my gearbox is slipping so not driving the prop at full speed??
I do not know how the gearbox works to be honest.

 

[paradave]

I’m sorry I can’t help anymore, it must be frustrating, but my mechanical knowledge is basic.
I can’t remember if we’ve asked this already - have you checked the prop size to see if it’s been replaced with an inappropriately pitched prop?

 

[Jamie Dundee]

You do say you can get to 20kts at max 3200 which highlights my issue of 3300 with 15kts!

Different engine and gearbox though.

 

[freddyuk]

I believe the boat has not been messed with so everything is original however when it is lifted out tomorrow I will get the prop checked. It should be dead calm when I take it and I will be one up so maximum performance can be established as it stands.

 

[freddyuk]

Just been to check out the gearbox and confirm it is an "auto box" ZF45A. So what if the gearbox is screwed as in clutches slipping at higher revs. Would this not cause my symptoms? It certainly would in my car.

 

[Jamie Dundee]

Just been to check out the gearbox and confirm it is an "auto box" ZF45A. So what if the gearbox is screwed as in clutches slipping at higher revs. Would this not cause my symptoms? It certainly would in my car.

If the clutch was slipping I’d expect a screaming engine and nasty burning smell.