Cat C32's running at least 5 deg warmer

[MedMilo]

Cat C18's running at least 5 deg warmer

I have a pair of C18, 1150 hp, engines installed in a 2015 Squadron 65. I did the first two seasons in the Balearics and this summer in the Amalfi area. I did the run from Menorca to Naples in June, mostly at 10 knots speeding up to 20 knots for 20 mins every 3 or 4 hours. As I got to Naples I sped up to 20 knots for the last 45 mins or so and after about half an hour noticed that both engine temps had crept up to nearly 100 deg. Throughout this summer each time we ran the boat at 1800 rpm the temp slowly crept up to about 100 deg.

Given both engines are running warmer than normal I can only think of two possible reasons for the higher running temp - a) the sea is warmer or b) the heat exchangers need to be acid washed etc. I'd be very grateful for any other thoughts on this before I spend quite a few, increasingly expensive, €'s (!) on having the heat exchangers Rydlymed or whatever. The engines are at around 600 hours and around 80% of my time is spent at c10knots/1000rpm.

 

[MedMilo]

Re: Cat C18's running at least 5 deg warmer

Of course I meant Caterpillar C18's, not C32's - getting ahead of my skis! Not sure how to change the thread title...

 

[Deleted User YDKXO]

I had the heat exchangers and intercoolers on my MAN engines in my Med based Ferretti removed and cleaned this season at the insistence of the MAN engineer who did the engine servicing despite the fact that it was only 2 yrs since they were last done. I must admit that I was very reluctant to spend the money again so soon but he was right and I was wrong because they were well fouled. In fact as he pointed out the MAN servicing schedule requires them to be done every 2yrs. I cant say that there has been a huge drop in running temps but they are down a couple of degrees from the end of last season

So what does your Cat servicing schedule have to say about cleaning heat exchangers/intercoolers? Has a Cat technician looked at the engines? Btw the gearboxes might have heat exchangers too so, if so, they will need cleaning too

 

[Portofino]

Re: Cat C18's running at least 5 deg warmer

Yup salted up coolers - they need cleaning
Have you dived under to check the openings on the external strainers --take a knife gave them a good scrape see what crud has developed ?
Have you opened the strainers inside the boat to check ?
Impellers ---age ? --maybe worth an inspection .
100 seems too hot without an alarm , not sure what the trigger temp is 94/95 in VP stuff .

This poolting worried me here too .

After say even just afew week unused in the SoF summer season -sea temp May 21-22 ,August 24-26 my MAN
2876 run will run @ 86/87 for the 1st few days --
My initial thoughts are along the lines like you it's the coolers salting up etc as the years go by ,was 84 so 2-3 degree increase /annum .Or it's the 5/6 degree inc in sea temp from say Easter etc
But what actually happens as I use the boat at planning NOT D is after a few days @ 17-1800 rpm blatting around they drop back to 84 and sit there .
Just finished 1 month stint .August used evey day except two @ planing speed
It was sat unused -July temp as said have come back down ,after 2/3 days

Conclusion
When sat the coolers must pickle in the salty Med ,
But when running 1-1800 rpm the shear force and volume of water kinda -blasts / auto flushes out any salt that WAS just starting to set ,but not quite so it loosens off and temps drop .

Anactdotally
I suspect if your D/P ratio was reversed ie 80 % @ P And no more than 6 weeks "unused " -your coolers would last longer between strips / rydlyme cleans or what ever ?
cos @ the moment they are spending too much time at a reduced water flow .
This means any semi set crud is baking on ,by the time you do the odd 20 min at rated rpm it's baked on -too late to blast it off .So it just builds up layer by layer because it's allowed to .Once a certain thickness there no going back so to speak .



Tickover and marina manourvering mine drops to 81 even after a good blast from 84 ,sea temp 25/26 ish

Does anybody else in Med notice a temp drop after a good blast when they return from a few weeks of inactivity ?

 

[MapisM]

he was right and I was wrong because they were well fouled.
In fact as he pointed out the MAN servicing schedule requires them to be done every 2yrs.

Now, this is very interesting, and I can contribute with my very recent experience:
- 13 years old boat, with 1400 hours clocked on MAN V8
- heat exchangers, believe it or not, never cleaned (!)
- cooling liquid within mid 80s upon sea trial, all other temperatures also spot on
- but, and it's a big but, the sea trial was done with a 14 degrees sea water, as opposed to later in the summer, when it raised by a dozen of degrees

As a result, upon the shakedown cruise at the end of July, cooling liquid temps were getting significantly warmer at P speed, according to the analogue onboard instruments - though no alarms ever went off.
So, having 1200+ NM worth of delivery trip ahead, I decided to have the heat exchangers done before leaving - also because I knew they had to be done anyway, and I was just hoping to postpone the job to the season end.
Living in hope, ain't that what we moboers are used to...?

Bottom line, the post-cleaning seatrial is scheduled for mid of next week, so stay tuned.
But I took some interesting pics in the meantime, which I can post later.
M, I half remember that you posted some pics of when you had your stuff cleaned during your stay in CF, but did you take some also this time?
It would be very interested to see the conditions after such a short period, because I'm beginning to suspect that once you begin cleaning the things, they tend to get fouled faster.

Incidentally, the chief engineer of MAN IT suggested me (off the records) to consider a 4 years timeframe, because in his experience the official 2 years is way too conservative.

 

[MapisM]

Re: Cat C18's running at least 5 deg warmer

Conclusion
When sat the coolers must pickle in the salty Med ,
But when running 1-1800 rpm the shear force and volume of water kinda -blasts / auto flushes out any salt that WAS just starting to set ,but not quite so it loosens off and temps drop.

I'm not saying that your train of thoughts doesn't make sense, but I suspect that the effectiveness on an Italian tuning (so to speak) can't be so relevant on heat exchangers.
Once some fouling begins to build up, a good blast has very little effect even on the hull and u/w gear, so why should/could it be more effective inside the exchangers, where the flow difference is bound to be nowhere near as high as on the prop blades...?

 

[Deleted User YDKXO]

M, I half remember that you posted some pics of when you had your stuff cleaned during your stay in CF, but did you take some also this time?

because I'm beginning to suspect that once you begin cleaning the things, they tend to get fouled faster.

I'd want to see some technical justification for that. Its like saying if you never take a shower you dont get any dirtier

Incidentally, the chief engineer of MAN IT suggested me (off the records) to consider a 4 years timeframe, because in his experience the official 2 years is way too conservative

Yup I can believe that for boats which are used regularly and hence the cooling system regularly gets flushed through but for boats like mine which sit unused for weeks and months in polluted Med marinas which are ideal breeding grounds for fouling, I'm not so sure. I wonder whether it can be related to prop fouling in that in those areas in which prop fouling is the most aggressive (eg W Med), cooling system fouling is also more aggressive. I also wonder why engine manufacturers dont have systems for backflushing the seawater side of cooling systems with fresh water. Maybe its because their dealers make so much money cleaning the systems every 2 yrs and selling hugely expensive replacement parts to owners that dont bother getting them cleaned

 

[Portofino]

Re: Cat C18's running at least 5 deg warmer

I'm not saying that your train of thoughts doesn't make sense, but I suspect that the effectiveness on an Italian tuning (so to speak) can't be so relevant on heat exchangers.
Once some fouling begins to build up, a good blast has very little effect even on the hull and u/w gear, so why should/could it be more effective inside the exchangers, where the flow difference is bound to be nowhere near as high as on the prop blades...?

Yes it's all very strange mine cool down with use , after a lay up
When I gave it a "sea trail 1st week in May after it's annual service ,so all as new underwater ,we set off for a 3 hr blast 17-1800 rpm to Imperia from Cannes -sea temp around 20 or lower ?
88 degrees the water temp for the first hour -84 when we arrived .

August sea temp maxed 26 -boat 84 from 86 after 1 month un used .

The water intakes on the mains under the hull are wedge shape and face fwds ,kinda ram water in the faster you go .
Other intakes ,Geny , Aircon , etc are those oval more streamlined normal things


The prop does actually self clean with use too ,infact the hub 1/2 ( not the outer blade leafs ) goes to back polished metal with use and the rudder immediately behind polishes up to the metal with use .

I do give em a snorkel scrape ,but they go even smoother after a few days .I know cos I dive down and ck the prop anodes every now and agian after loosing them last season while I do that I run my hand across the props and they are far smoother than I can get them with a scraper .

I always thought it would be the blade tips moving faster that would clean up before the centre hub ,but it the other way round so there must be a lot of energy transfer going on in the hub region to polish up like its in the shipyard .
Of course parked up 4 weeks they foul up it grows back .

Anyhow back to coolers one day I guess they will need opening ,?

Mike my charge air temps are 16 degrees , @ 17- 1800 rpm not sure how long thay have been @ that or if that's high .
Do you have any data on yours ---- health of the CAC ,s -I think .

Agian how,s that work ER temp is roasting , outside air temp 30 ,seawater 26 , yet the air cooled prior to entering to 16 ??
Remember this is after being compressed by the turbo @ full spool --

 

[MapisM]

Blimey M, I can't believe that you had that sort of growth in just two years.
The very same components on my boat were fairly cleaner! I'll post pics as soon as I can - out and about ATM.
Did you have also the g/box heat exchanger checked/cleaned?
If not, I'd say it's worth considering, if the engine side is anything to go by...

I'd want to see some technical justification for that. Its like saying if you never take a shower you dont get any dirtier

LOL, yeah, maybe you are right, and the difference has much more to see with regular use vs. boat left sitting for long periods - which does stand to reason.
In this respect, you might wish to talk to jfm and check out what he did on his boat.
To my knowledge, he's the one and only here in the asylum which actually implemented a suggestion I made years ago (which btw was based on an exchange of views I had in the yard where you have been during your stay in CF): connecting the raw water filters to the fresh water tank, through an "L" valve that closes the sea water flow, letting fresh water in, instead.
This way, flushing the engines raw water circuit with fresh water is a matter of minutes.
Well worth doing, when you know in advance that you aren't going to turn on the engines for weeks, or even months.
Not really a backflushing like you suggested, but much better than leaving sea water sitting there!
Btw, I'm not sure that backflushing would be a good idea, because any dirt detached during that operation is likely go straight to the impeller, possibly getting stuck and/or damaging it...

 

[MapisM]

Re: Cat C18's running at least 5 deg warmer

Agian how,s that work ER temp is roasting , outside air temp 30 ,seawater 26 , yet the air cooled prior to entering to 16 ??
Remember this is after being compressed by the turbo @ full spool --

The answer is very easy, methink: a dodgy sensor!
I immediately thought to ask if the 16 was a typo while reading your post, because that sort of number doesn't make any sense.
No matter how efficient the aftercoolers can be, bringing the air temperature so much below e/r air temperature (let alone below sea water temperature!) is physically impossible.
You would need some sort of airco system, to achieve such result - and a pretty powerful one, I guess!

 

[MedMilo]

So what does your Cat servicing schedule have to say about cleaning heat exchangers/intercoolers? Has a Cat technician looked at the engines? Btw the gearboxes might have heat exchangers too so, if so, they will need cleaning too[/QUOTE]

The manual is on the boat in Amalfi and I'm back in London, so will check service schedule in a couple of weeks. Okay, didn't know that the gearboxes also had heat exchangers, thanks for the info! And the genny to I think? Will get Caterpillar in Naples to have a look when they do the service though it's looking as though they may all need doing this winter even though relatively new.

 

[MedMilo]

Re: Cat C18's running at least 5 deg warmer

Yup salted up coolers - they need cleaning
Have you dived under to check the openings on the external strainers --take a knife gave them a good scrape see what crud has developed ?
Have you opened the strainers inside the boat to check ?
Impellers ---age ? --maybe worth an inspection .
100 seems too hot without an alarm , not sure what the trigger temp is 94/95 in VP stuff .

This poolting worried me here too .

After say even just afew week unused in the SoF summer season -sea temp May 21-22 ,August 24-26 my MAN
2876 run will run @ 86/87 for the 1st few days --
My initial thoughts are along the lines like you it's the coolers salting up etc as the years go by ,was 84 so 2-3 degree increase /annum .Or it's the 5/6 degree inc in sea temp from say Easter etc
But what actually happens as I use the boat at planning NOT D is after a few days @ 17-1800 rpm blatting around they drop back to 84 and sit there .
Just finished 1 month stint .August used evey day except two @ planing speed
It was sat unused -July temp as said have come back down ,after 2/3 days

Conclusion
When sat the coolers must pickle in the salty Med ,
But when running 1-1800 rpm the shear force and volume of water kinda -blasts / auto flushes out any salt that WAS just starting to set ,but not quite so it loosens off and temps drop .

Anactdotally
I suspect if your D/P ratio was reversed ie 80 % @ P And no more than 6 weeks "unused " -your coolers would last longer between strips / rydlyme cleans or what ever ?
cos @ the moment they are spending too much time at a reduced water flow .
This means any semi set crud is baking on ,by the time you do the odd 20 min at rated rpm it's baked on -too late to blast it off .So it just builds up layer by layer because it's allowed to .Once a certain thickness there no going back so to speak .



Tickover and marina manourvering mine drops to 81 even after a good blast from 84 ,sea temp 25/26 ish

Does anybody else in Med notice a temp drop after a good blast when they return from a few weeks of inactivity ?

The raw water inlets are a bit crudded up but not too bad and I recently cleaned the strainers which weren't too bad either. Despite getting to about 100 deg the alarm hasn't gone off which surprised me too tbh. I'm not sure whether the regular slow running could be contributing to the problem - one thing's for sure, the boat gets quite a lot of use and even though the winter I take it for a decent run about every six weeks! Perhaps I should try doing a long run at planing speed and see whether the temp drops after a few hours....

 

[MedMilo]

and it's a big but, the sea trial was done with a 14 degrees sea water, as opposed to later in the summer, when it raised by a dozen of degrees

Yes, this is what I'm wondering. It must be logical that if the water doing the cooling is warmer it will cool less! So if it's 5 deg warmer one might expect the engine temp to run 5 deg warmer too. But it surely can't be linear or else the Swedes would be running their engines at around 60/70 deg in the winter. Maybe they do?!

 

[jfm]

My c32s now 4.5 yrs old and c650hrs show 80 degrees on the gauges from the day they were brand new till now, and whether P, D summer or winter. I'm just back from a big cruise in 27deg seawater and they showed 80deg throughout. I'm therefore surprised to hear all these stories of differing temperature readings in different conditions.

And yes I have freshwater flushers to all heat exchangers. Both engines and gearboxes, both gensets, and the airco system. Easy job and I'm surprised it isn't much more common. If I'm leaving the boat more than 2 weeks I flush.

Also allows me to run genset in shipyard

On my next boat I think I'll hard plumb this, with electric valves and a panel full of LEDs, so I can do it from helm almost automatically.

 

[jfm]

Yes, this is what I'm wondering. It must be logical that if the water doing the cooling is warmer it will cool less! So if it's 5 deg warmer one might expect the engine temp to run 5 deg warmer too. But it surely can't be linear or else the Swedes would be running their engines at around 60/70 deg in the winter. Maybe they do?!

Absolutely not Milo. The cooling should be overspecced, so that the thermostat is always restricting its effect. Then you have the same jacket water temp whether summer, winter, running fast, running slow.

 

[BartW]

FWIW,
I look very much to the engine temp meters since the big overhaul

for a while I had too high temp ~90°C readings (intermittantly) on the FB helm station on both engines,
it appeared to be a corroded connections (ground?) in one of the multi connectors to the dash.
discovered pure by accident

now with all new temp sensors on the engines,
my old VDO gauges are reading between 83 and 85°C,

cooling water temp measured with a IR gun close to the VDO sensors measures 77...80°C

(engine temp rises for a while when accelerating going on the plane)
probably none of the meters are accurate within 1°C

Medmilo FYI from Monday i'm a week on the boat

 

[vas]

My c32s now 4.5 yrs old and c650hrs show 80 degrees on the gauges from the day they were brand new till now, and whether P, D summer or winter. I'm just back from a big cruise in 27deg seawater and they showed 80deg throughout. I'm therefore surprised to hear all these stories of differing temperature readings in different conditions.

And yes I have freshwater flushers to all heat exchangers. Both engines and gearboxes, both gensets, and the airco system. Easy job and I'm surprised it isn't much more common. If I'm leaving the boat more than 2 weeks I flush.

Also allows me to run genset in shipyard

On my next boat I think I'll hard plumb this, with electric valves and a panel full of LEDs, so I can do it from helm almost automatically.

Reading your thread I also installed truedesign 3way valves and the relevant pipework from the tanks (1,25inch) so I can also flush the engines. Last year I completely forgot to do it... An El. Setup would be nice indeed. Still I can run the engines on the hard without all the mess of opening the strainers push pipes in, etc...

V.

 

[jrudge]

Having mine cleaned knocked 8 /9 degrees off and. It cost euro 800 so not so bad to be honest.

 

[MapisM]

Absolutely not Milo. The cooling should be overspecced, so that the thermostat is always restricting its effect. Then you have the same jacket water temp whether summer, winter, running fast, running slow.

True.
But what can and does happen is that if you have the heat exchangers fouled, the oversizing bit gets "eroded", so to speak - to the point that also with the thermostatic valve constantly open the cooling is just enough.
In such conditions, which I think is what happened when I seatrialed my boat with 14° sea water, it's only logical that as soon as you have a 10+ degrees difference in the sea water, that's bound to be reflected in higher temp of the closed circuit.

 

[MapisM]

And yes I have freshwater flushers to all heat exchangers. Both engines and gearboxes...

Well, of course also g/boxes, they come with the territory, I reckon.
Aren't they on the same circuit, right after the engines, on your boat?

I like your thinking on electric valves for automatic flush, IIRC we actually debated also that option back then.
But... you might as well get rid of all those valves, installing a huge w/maker, and cooling the engines with fresh water 24/7!