One for you guys with MAN (mechanical governor) engines

[MapisM]

I've seen a couple of V8 MAN engines (DE2848LE403, I believe they're called) turned on from stone cold, though with an external temperature not too bad, a dozen of degrees or so.
And both were very smokey at first (light greyish/blueish colour), for a minute or two.
Afterwards, they rapidly turned to a much more reasonable smoke level - one for which I wouldn't even bother asking here. And they seemed to run smoothly, with no vibration.
Also, once warmed up, they didn't smoke a lot also at higher rpm (though always unloaded).
Now, I see no reason why the behaviour should be different from any other MAN engines of the same type, i.e. not just the V8, but also V10 and V12, as long as mechanical.
Otoh, the latest common rail electronic engines are still based on the same block, but probably it's not fair to compare them.
Hence the title of this thread - I was wondering if anyone with similar engines can confirm that this is their normal behaviour or not.
Thanks in advance!

 

[Portofino]

Sounds normal
Mine are EDC - not mech injection or common rail .
There s a bit of smoke from clap cold otherwise when warmed up -actually v clean compared with the Volvo,s I used to have ,which used to leave a haze behind on a hot summer calm day when planning
Under water exhausts seem to help with this + prob cleaner engine ?

 

[BartW]

perfectly normal behaviour,
the mechanical governor can not compensate for the too low startup engine temperature,
which is perfectly compensated in a electronically controlled engine,
(the specialists can probably explain in more detail)

my engines have alway's had that,
surprisingly in the season, when engines are used dayly, the start up smoke appears to be a lot less,
It takes more then a day to completely cool down these two iron lumps, and fuel

MapisM its about time to reveal what you are looking at !

 

[Pinnacle]

MapisM its about time to reveal what you are looking at !

+ Lots!

 

[MapisM]

Mine are EDC - not mech injection or common rail.

Since you mentioned, I noticed that MAN made a sort of transition from fully mechanical engines to the electronically controlled common rail (or CRM, in their speech).
In fact, in between, they made some non-common rail but electronically controlled engines.
One example I'm aware of is the 10V 2840LE40x, whereas the x could be either 1 or 3, respectively with mechanical or electronic governor, and an output of 820 vs. 1050hp.
By chance, are you aware of the pros and cons of these early electronically controlled, but not yet CRM, engines?

@ B & P: no worries folks, I'll spill the beans about what I'm up to if and when I'll have something remotely realistic to tell.
At the moment , there's not much more than curiosity behind my thoughts...
In fact, also my previous question on those early 90s MTU engines is already history, in the meantime.
For the records, the boat was a Tecnomarine T62 - btw, chapeau to Poweryachtblog for guessing it based only on the engines model!

 

[Portofino]

By chance, are you aware of the pros and cons of these early electronically controlled, but not yet CRM, engines?
[/QUOTE]
I think it just natural progression -keep up with the jones,s
the only thing that kinda worries me is longevity in the sense where does the HP "arms race " finally stop
In my case the 2876 is a derivative of the truck D28 series ( I think all MAN are used in vehicles as well ?)
wwe have gone from 610 mech to 700 (stroked + EDC ) to 730 to CRM 800 out of the same block in Marine leisure .Guardiene thinks mine are 730 ,s cos of the position of the oil filler cap I will ck the makers plate @ next service
EDC give the MMDS system that shows 18 parameters with 3 levels of alarm
1- error the parameter is outside normal or sensor wire # come loose
2- its really out side normal so engine drops to lower rpm to save damage
3- stop engine to protect
all is stored in the memory so its great for geeks - no need to mess about retro fitting sensors like EGT or L/h

 

[MapisM]

I think it just natural progression

Yep, that's understood, of course.
And in a sense, from a mechanical wear and tear viewpoint, one should think that when you take for instance 1050hp instead of 820 out of the very same block (as in my previous example), the first is bound to be less durable than the latter, even if the first is electronic and more modern...
Anyway, that wasn't my point - in fact, also within all electronic or all mechanic engines, often there are different versions with different outputs, depending on their ratings.

There's another thing instead, which as I'm told is peculiar of MAN engines: a VERY expensive maintenance schedule every 1000 hours, where according to the builder all injectors should be replaced, among other stuff. And while I was also told (but don't take my word for it!) that this is not true anymore with the CRM engines, I don't know if it's still true with pre-CRM engines with electronic governor - as is yours, if I understand correctly...?

 

[Portofino]

The 1000 hr I understand is pulling the injectors and testing them adjusting if neccassary - ,- hopefully replacing -- not replacing with new .
And adjusting the valve clearance .Being of modular design each head is seperate so will need its own rocker box gasket .
The cost will be labour intensive -depends on No of cylinders .
Apart from that other stuff in a leisure boat is the same as other marques ,eg impeller , coolant , belt , heat exchanger and intercooler strip /clean ---- as and when I guess .
Iam on 690 hrs at the mo .
Two issues if you like idiosyncratic to MAN ,s
1- the closed coolant circuit is v high pressure -there are two "radiator caps " on the header tank .Its tempting as a keen DiYer or attentive owner to open these to check the level of coolant .-Thing is they are a tight fit ( of course ) and the rubber gasket can "set" or bit of crap -when refitting prevent a good seal .
What happens is sometime maybe 1hr into a cruise an alarm goes off "low coolent pressure " -cos it's not quite sealed .drops from 700 to around 450 see pic below

A temp solution is use a supermarket bag as a membrane to reseal under the cap - when it's safe to remove it .
You end up buying another -keep as spare €80 a pop .
It's no biggi -just don,t fiddle opening the expansion tank and rely on Mk 1 eyeball for coolant in the bilge if any leaks and the MMDS -

Second poss issue is turbo whistle
They whistle a lot high pitch when accelerating -more than other marques .
Uk folks that use trains will know the "whistle " sound ,it's when motorised train units accelerate out of the station .
A good sound insulated engine room is essential or you can get Walker Air Step -air filters which claim to reduce it .
Personally I like it ,hearing em spool up as the boat takes off
If an air filter drops off you will know as its 10x louder
Hope this helps

 

[MapisM]

All interesting stuff, thanks.
I suppose that with an Itama you don't have a lot of pootling experience, hence with the engines at very low rpm/low load, right?
Just wondering how well they withstand that kind of usage - i.e. temperatures & pressures, smoke upon accelerating after long(ish) time at D speed, or anything else noticeable...
BartW might have more experience on that, I suppose.

 

[Portofino]

I was messing about -as I said the MMDS is a geeks paradise
The load here is 60% I was doing 10 knots which is just above D speed .
825 rpm is my pref D speed about 9 knots

As you say only done a bit of D really to keep cool just want to get some air flow over us .Or plan on arriving at destination tea time not just after breakfast
Nothing noticeable -but I do give the last 1/2 hr a "Italian tune up " if we have been at D most of the day .
Water temp drops to 78 at D (sea temp 24-26 ) and risers to 82 at P .
Generally we go @P 1750 rpm is something like 28 knots - but sometimes even faster to piss off other boats
Here we are passing a Leopard with Arnesons he's was doing30 knots speeded up to34 as I creep up behind coming back from St Trop one day - so thought -right I,ll have him

So went past @ 36 knots @2010 rpm with a bit left over
Nice problem to have

EGT drops ,in fact most measurements drop a bit at D .
Bart as you say prob knows more about long time @D speed

 

[BartW]

There's another thing instead, which as I'm told is peculiar of MAN engines: a VERY expensive maintenance schedule every 1000 hours, where according to the builder all injectors should be replaced, among other stuff. And while I was also told (but don't take my word for it!) that this is not true anymore with the CRM engines, I don't know if it's still true with pre-CRM engines with electronic governor - as is yours, if I understand correctly...?

every 1000 hours replacing injector nozzles seems normal / appropriate, at least that is my and the previous owner experience. I'll asc the MAN man I see him later today,
I can imagine / understand that these older engines have a less perfect combustion than modern CR engines, and that the nozzles suffer from that
you don't need to replace the complete injector, but just the nozzle, and this costs 75 euro pp,
so I would not say that it is really expensive
also the work,
acces to the injectors is easy, depending where you are, can't be a huge cost.
imo MAN engines are one of the cheapest re maintenance, in that power segment,
parts are easy to get and not overprized,
and know how and experience is widely available around the med
(US owners tend to say the opposite )

regarding behaviour / smoke when accelerating after D speed,
tbh never gave much attention to that, but never noticed any abnormal smoke.
The only moment that these engines have a lot of smoke, is when starting from cold, during 10 minutes or so.
I have alway's been adviced from different sources, that these engines are perfectly OK running at lower rpm (1100)
without any constraint.
I notice a small increase of cooling water temp, of about 3..5 °C (tem gauges are not very accurate)

 

[MapisM]

Thanks B for your comments, and also for any others you might fetch from your MAN guy.
While you talk to him, I'd be interested to hear also about usage at RPM even lower than 1100 - say around 800/900, and obviously with very low load.
In fact, in some boats powered by those engines, that's already enough to reach a D speed of 9 knots or so...

 

[BartW]

Thanks B for your comments, and also for any others you might fetch from your MAN guy.
While you talk to him, I'd be interested to hear also about usage at RPM even lower than 1100 - say around 800/900, and obviously with very low load.
In fact, in some boats powered by those engines, that's already enough to reach a D speed of 9 knots or so...

according to Ilko, it doesn't make any difference as long as your oil pressure is high enough minimum 1.1bar.
at slow rpm you can sail around the world with this engine he answered ;-)

the only problem (according to him) is at high rpm 1800 and up, and high load, you might stress the engine,
this engine doesn't know / feel exactly how much load there is on it...

 

[MapisM]

Understood B, thanks again.
I suppose what Ilko means is that if for instance you hammer the throttles with a very dirty hull, the engines try as hard as they can to comply, but as a result you could keep them running for long periods at very high load even below the max rpm, which is possibly even worse than running them at full load/max revs.
In this respect, I suppose electronic engines have much more sophisticated ways to keep all running parameters monitored, and activate some protections if/when necessary.
No big deal for myself though, because IF (and it's a big if!) I will eventually choose to join the P boaters club, I'd be definitely more concerned about engines underutilization, rather than the opposite scenario...

 

[Portofino]

You will be fine going D with MAN ,s ---- oil Pressure is 2.7 normally rises to 3.2 at 1750 rpm
Temp is actually 84 -bad pic

Also it's very quiet @ D - folks can kip

 

[Deleted User YDKXO]

imo MAN engines are one of the cheapest re maintenance, in that power segment,
parts are easy to get and not overprized,

Agree with that. I've been surprised how reasonable parts prices are for my MAN engines

 

[BartW]

I suppose what Ilko means is that if for instance you hammer the throttles with a very dirty hull, the engines try as hard as they can to comply, but as a result you could keep them running for long periods at very high load even below the max rpm, which is possibly even worse than running them at full load/max revs.

thats exactly what he said ;-)

 

[PowerYachtBlog]

I run a boat with R6 from 2005 800hp, no smoke and whatsoever. I am sure electronics have a bit to do about this.

I also ran a few times a Pershing with DE2848, 800hp and they do smoke a little bit when cold though as you say after a mins or 2 it is all over.
All normal in my book.

Just beware you have no Ambientalist near you when you start cold

 

[PowerYachtBlog]

Agree with that. I've been surprised how reasonable parts prices are for my MAN engines

I am surprised about this remark, cause I always think Cat prices are much cheaper. New Volvo engine parts though on the other hand are something else even to Man engines.

 

[MapisM]

I also ran a few times a Pershing with DE2848, 800hp

The 2848 in 800hp flavour is exactly the DE2848LE403 that I mentioned at the beginning.
Aside from smoking upon cold start, if you have any other remarks/experiences on them, I'm all ears.
I guess that on a Pershing they are bound to be stretched quite often...