A case for running engines off season (not?)

MapisM

MapisM

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Sooo… We flew back home yesterday, eventually. I guess I can't complain, after a boating season which ended by mid of Nov. :encouragement:

But before leaving the pride and joy, I thought to give the (cold) engines a last spin.
Without actually moving her, but better than nothing anyway - or so I believed.
Trouble is, even after 30 mins of so, oil and cooling liquid, and also the blocks themselves, were still almost stone cold.
I left them running for up to 40/45 mins, but the warming up was still hardly noticeable, so eventually I stopped wasting fuel.

With my previous Cat 3116, when I turned them on during winter, they were up to normal running temperatures after 20 mins or so (make it 30 max).
They were much smaller engines, with just about half the displacement of my current 15 litres MAN, but I guess that there must be also other differences in the respective cooling systems.
Regardless, I am now wondering if it still makes sense to run the engines off season without leaving the dock, because my understanding has always been that it's only beneficial for the engines as long as they are brought up to operating temperature for a while...

Both general and MAN-specific views are welcome!
 
Even my comparatively small KAD's will never go above 55C unless under marginal load (in gear at idle) and I see no benefit to running them cold at all. Can be a bit of a pain for me when comfortably at anchor and want hot water for the night. Under marginal load she will reach running temps within 5 minutes.
 
Water temp for me not as relevant as the EGT ( exhaust gas temp )

You are damned if you do you are damned if you don,t
I do .

Rational

I Rev mine to 2000 rpm at the end after gradual temp rise .perhaps up to 20-30 min run time up from idle .
You not said what rpm which is important cos there’s a huge diff between idle and running @ 2000rpm .( wot 2150 in this case )

In no particular order there could be more reasons ?

Spreads fresh oil .
Mixes up a stagnant sump .
Turns any gears .
Exercises springs .
Recoats the inside of the pistons with oil .They dry up .
Oils the valve guides - they dry up too and suffer max wear @ dry starts after 6 months or so .
Removes any surface rust from the cylinders and valves with open exhaust valves = salt air access . [ loads of threads on knackered but infrequent used geny s ] .
Wets any drying oil seals . They shrink when dry = seep / leak .
Shifts any damp if there is any ? From sensitive sensors and other electrotwackerey .
Fuel injection pump gets a run out - seals ,gears springs + fresh static dose of diesel after shut down which will have a fresh dose of good additives to soak inside the expensive internal bits who,s dims are critical .
Injector tips get a run out - spring and any corrosion on the tip from open E valve blown way —- Er for now ! + fresh fuel left inside the canals / pipe work .

Downer
Never reaches best EGT in the 20/30 mins / month so inside the cylinders some agglomeration formation for sure - but then it’s blasted out at 2000 rpm .
Small downer compared to the upside list .


Other stuff beneficial
Secondly
Turn the shafts - quick fwd / rev nudge of the sticks ( slacken stern lines etc )
G box gets a few rotations but not too worried as air tight anyhow and the seals are all ways wet even when stopped .
More helps the shaft seal and Cutlass bearings to give them a few rotations every month n the off season .You can’t do that without an engine start on my boat ,
Why accelerate the demise of the shaft seals with a winter hibernation? If your boats in the water .Realise if stored ashore the decision is removed .

3 rd piece of mind .
When pre booking the annual haul out for early May I at least know it been started only a few weeks before .Not shut down say end of Oct them arrive 6 months later ( never started in this time ) to find dead engines and a yard / lift booked .


4 th
On going prevention nip it in the bud .
Much rather notice a weeping ( but not too catastrophic) fault early rather than the engineer in April / May turn round and say
“ how longs this been going on ? “
“ seems to have knackered the [ insert yourself] because it’s leaked on such and such over the winter “

Remember sods law and boat engines are never far apart the [ inset yourself ] part costs an arm and leg and requires relevant specialist with appropriate specific tools you have not got .

While the primary fault fix ( if spotted on a timely winter run up ) cost peanuts and could easily have been a DIY job .

All imho with mechanical toys .
 
What does the manufacturers manual say?

I suspect it says something like put it away nicely. I would be surprised if it says run it regularly

I have never run the engines and in the last 12 or so years of boat ownership never had an issue.
 
Never run mine unless I am running the boat. Was once told that getting them warm-ish, but not hot can lead to condensation that doesn't dry out and does more harm than good.

But I've never managed to get a definitive answer to which is best.

Thousands of boats seem to winter ashore every year without being run for months without issue though, so I'll stick to my version and run the engines if I'm taking the boat to sea, but not otherwise.
 
I was told by MTU not to run the engines for more than 5 minutes at the dock before moving off and not to run them if not intending to get them up to temp, unless unavoidable of course, so that's what I have done. I guess there is a case for and against though!
 
jrudge said:
What does the manufacturers manual say?
Click to expand...
Good question, but I'm afraid I didn't think to check it is the answer. :o
I wouldn't be surprised if it would say nothing on this subject, though.
Did you find it mentioned by VP, and if so what's their take on it?
 
markc said:
I was told by MTU not to run the engines for more than 5 minutes at the dock before moving off and not to run them if not intending to get them up to temp, unless unavoidable of course, so that's what I have done. I guess there is a case for and against though!
Click to expand...
Interesting to hear that, because marinization aside, our engines are practically the same. I'll ask also my MAN chap, the next time I'll talk to him...
 
One thing I do know about engines is that one of the factors affecting their wear life is the number of cold starts so I see no point in starting them just to run them cold at the dock. If you cannot take the boat to sea and put the engines under load and get both the oil and water temps up to to their operating max then I see no point in starting them
 
Our boat is a bit old at something like 35 years... and the longest I've left her without a 15 min run is 1 month.

Never failed to start, but have always been too nervous to leave her more than a month just in case. I believe she gets noticeably more stubborn to start after 3 weeks, but on reflection it could be any number of things such as a cold snap.

Going down the marina tomorrow to give her a bit of attention after she's had 2 weeks alone.

One aspect I'm thinking of now though... she's petrol. Doesn't petrol start to break down after 6 months? Should I be doing anything about that if I'm not taking her to sea through winter?
 
Last March, I thought I'd run our MTUs for a quick warm up.
They hadn't been run for about 3 or 4 months.
That all worked well - no problems.
But then, I thought I'd turn the shafts/props over whilst I was at it.
Again no problem.
Well, until I checked in the engine room - that is.
Water seeping in past the starboard gland/seal.
Panic then set in.
That shaft only has one spare seal left - in the factory, Princess install three seals - one in place and two spares on the shaft.
The procedure is - undo the screws - cut the old one out and slide the new one down - do the screws up - easy!!!
I rushed over to the boatyard where the guys were packing up for the night.
I didn't want to go through the seal replacement without access to a travel hoist.
They said - OK bring her over but you will have to use the builtin boatyard pumps until the morning when we can lift her.
OK - a plan
I would take the boat over - replace the gland and if there was a problem, we could lift her in the morning and put some new glands on.
So off we went.
The boatyard is about 500 yards away but by the time we got there, the leak had stopped.
So, rather than changing the gland (don't mend something the isn't broken!!) we decided to go back to the berth and see if the leak reappeared.
Thankfully, it didn't and the gland has bee dry ever since - even after 1000 miles of cruising this year.
It must have been a barnacle or piece of grit that had crept into the gland.

But the moral to this story is - DON'T JUST RUN YOUR ENGINES FOR THE SAKE OF IT!!!
 
Haha, good point.
An alternative moral could be "if you want to run your engines regardless, do it in the morning!" :D
You made me curious, btw: do you flush the engines and possibly the seals with fresh water, when you know that you are not going to move the boat for some months?
Besides, remind me which shaft seals you've got, PSS?
 
I would agree with most of Portofino's points but also add that it is the environment which can cause the most problems and this translates to moisture in the oil which can be excessive after a prolonged stand in a damp environment.
Engine and transmission oils contain something called detergents and dispersants and they work together as the detergents clear any rubbish and the dispersants break them down into the oil, a prolonged stand in a damp environment means the oils need heating up ideally to working temperature for the dispersants to break down any particulate matter and to boil off any excess moisture in the oil. As long as the oil is up to its operating range it is dispersing and boiling off excess water.
 
Mapis, the reason they do this is nothing to do with the engines themselves as the marinised engines are different, most MTU engines are commercial or industrial engines and their differences are more than subtle, to begin with the industrial versions will nearly all have swirl filters or a swirl filter for the air intake and as many operate in less than ideal conditions such as dusty environments the reason they don't recommend idling them for long periods is that they do not pass sufficient air for the swirl filters to work properly. Basically it means that the engines are drawing excessively dirt laden air straight into their air filters and the lack of swirl means they aren't removing the larger particles from this incoming air as they would if they were running within their working range.
 
I wonder what adjacent berth holders feel about running large engines next to them for over 40 mins when it is unnecessary. Fumes and noise is what I am thinking about
 
Returning to attempt to address a few points raised .
The manual is silent on pro longed periods of none use .There is a section on winterisation / storage but it’s not what the OP question was .It talks of system drain down , disconnecting power , flushing , spraying fogging agents etc etc , blocking orarfaces off storing them in a dry environment etc etc. ,removing injectors spraying anti cease products inside the cylinders baring the engine to spead this etc etc .
So I conclude that’s NA to this thread .

How ever the MAN manual does state ( Marc C point ) about never letting them idle for more than 5 mins AND wait until jacket temp reaches above 60 degrees before getting on the plane .

As I said in my opening post it’s important to differentiate how you run them , MapishM still has not made thar clear , I do not idle mine ( never said or implied that ) I get them over 60 easily north of 1500 rpm when the turbos spool up .

Mike F point - sum of cold starts - well I,am adding 5/6 on .
Since retiring we are on the boat the marortiy of a month from May to the end of Sept , this year the longest stint was over 3 weeks and every day we used it ,
Are folks saying “ I,am not going out today because I,am conscious I’ve used up me annual cold start quota “ ?

Theses ( MAN ,MTU CAT and Vp,s D12 ) are marinised industrial units designed basically for heaven use.
That’s not to be confused with the duty cycle s , Again book says something like no more than 1000 hrs / year and indicates what % at various loads .Take a look interesting reading !

My particular instal is certainly no where near the “edge “power / weight ratio wise so in use I do about 80/100 hrs a year in the summer ,with the “ liesure version “ as I have said before I just sit them at 80 % load all day , or lower
So I am only burning up about 10 % of my available hrs capacity per annum mostly north of the av load .
From memory the yearly av load is on paper pretty low - something like 50 % of its time ( 1000 hrs less than 50 % )
So sat at the dock running above 60 or higher once a month is ok in my book as I,am moving my % load aggregate down - following the MAN manual if you like on that number .
Btw We are allowed to run at 100 % load but I never do in the season .I know this thread is not about load but I mention it because it’s hypocritical for folks to say they leave the engines off for long periods in the winter ( closed season ) then thrash the hell out of them in the summer having left them for so long drying up and exposed to damp salt air .Kinda wearing my engine longevity hat .

Another joke is the “ fresh oil at the end of season brigade “
Then what don,t circulate and regularly spread out the very usefull stuff ( various good longevity additives ) that you have replenished about ,buy never running them for months and months .
As said in my opening post you wanna be spattering that stuff about - all around the internal parts not letting them dry up in a damp salty environment.

Ps the geny gets a monthly run out too .It loves boiling a kettle :)with oil heaters on .

Nobody’s mentioned rubber set in impellers yet !
 
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