Differences between engines. Concern or not?

[MapisM]

These things would explain different fuel burn rate for the same rpm and also the different turbo pressure

They would, if the boost pressure would be lower, but it's actually higher!?

 

[Divemaster1]

I'm sort of a KIS(S) kind of person....

a) a diesel engine (in tune) will burn x L / hr based upon Hp Load
b) in this case I'd guess it is an issue about loading...(someone once told me that in a twin engined, outward rotating props config, the SB engine would work harder than Port... not sure why, but it was true on our installation then, so had different loaded props...).

If you are serious and worried, do an oil sample analysis followed by a compression test to assess if it is a serious issue, tuning or loading....of course we also assume that fuel filters are clean... if not that could explain the differing fuel pressures...

 

[splosh]

splosh, the engine nos are 3 digits apart so I guess that means the engines were nearly but not quite sequential. No, the F53 is one of the few Ferrettis that has straight shafts and not V drives which is good because there's one less gearbox to worry about and also the V drive boxes must consume a little power

Okay, shaft drive, so as you say no real loss of h.p. How many hours the engines done? and in particular a question as to if the engine hours are the same for both or different?? If engine hours are different then what engine and by how much. This will start pointing towards your diagnosis imo.
If your set up is the same as mine (C15) then you will have the dash hour meters and seperate control panel on each engine with hour meters there - check both! as if there is a difference then there you are to start asking some questions.

If serviced by Caterpilar then the are quite transparant and should talk to you if any probs were previous and logged as they are proud of their products and are quite aproachable.

I would honestly sea trial yourself before purchase and have your own independant cat report, but then looking at your amount of posts you have been here a while so it's unfair for me to tell you what way to go. Relying on someone elses report in your hands is okay for them and thus lead you to query.

 

[aquapower]

mike have sent you a pm

 

[Deleted User YDKXO]

Report also gives % load factors at max rpm which are 95% port and 93% starboard. Dunno whether they should be exactly 100% or whether these factors are within normal range given that prop design is not an exact science. Mind you this is Hull no 59 so Ferretti should have got it right

 

[Deleted User YDKXO]

Sat Dome is KVH Tracvision G4 which means nothing to me. Is that OK? $64k question is will I be able to watch England beat Italy in the World Cup Final in July whilst loafing on my boat?
Btw if this deal goes through, it looks like my stay in Sardinia is short lived as the F53 is based in N Adriatic and I'd certainly want to 'do' Istria and Dalmation Islands whilst I'm there

 

[omega2]

Do not know if this will help, but a mate of mine had a similar anomoly, on a Yanmar set up, we put it down to the gearbox arrangement, in that they were running handed props, but were identical gear boxes one was running in reverse for forward motion, and other running as it was built to do. They were ZF'S the manufacturer stated that it was permissible to use them like that but there would a slight difference in ratios, but not enough to worry about. I am dead sure they were not Borg Warners as they will definately not work like that.

 

[mjf]

Teaching Grandmother maybe.....my thoughts are props then cutlass bearings

 

[jfm]

They would, if the boost pressure would be lower, but it's actually higher!?

Oops, yes you are right MapisM. Note to self - rtfq!

Mike, this is strange. All the suggested theories on here realting to loading (busted prop, mismatched props, unmatched gearboxes, innate imbalance on a twin screw boat, tight cutlass) would be plausible if the port engine was using less fuel AND had lower boost pressure. But it is using 10% less fuel and 5% MORE turbo boost. That is wierd. I'm inclined to rule back in my suggestion higher up, which is that the starboard turbo is busted/tight bearing. That would account for starboard engine using more fuel and having less turbo boost pressure

I'm not going to mention the channels you'll (not) get with a G4 cos I dont want to spoil your (son's) day :-/ It's a 40cm dish.

 

[Nick_H]

$64k question is will I be able to watch England beat Italy in the World Cup Final in July whilst loafing on my boat?

Very unlikely i'm afraid, but nothing to do with satellite coverage.

The G4 is roughly equivalent to the current M3, which is the yellow line on this map. The map tends to be a bit optimistic, so you may struggle in Sardinia, but should have no probs in N Adriatic. That's assuming you want UK progs, there's a chance you'll pick up the world cup final on a foreign TV station on a different satellite with full coverage wherever you are.

 

[omega2]

the gearboxes referred to are ZF'S and if run at the same revs one engine would be working harder than the other. There fore it was suggested to balance the boost pressures rather than the revs. Hope this helps.

 

[Marsupial]

I'm looking at a technical report on various tests carried out by a Cat dealer on two Cat 3196 engines in the same boat. These tests were carried out during a seatrial and there is very little difference between most of the parameters measured except in one area. At max rpm, the port engine appears to be consuming about 10% less fuel in terms of litres/hour than the starboard engine. In addition, the measured fuel pressure in the port engine is abour 10% higher than starboard and, similarly, the turbo boost pressure is 5% higher. The measured rpm of both engines at max speed were virtually identical.
Is this variation acceptable or should I be concerned? Could the variation be caused by differences between the props?

1. What HOURs are on each engine? has one done more than the other - you dont say

2. Is there a exrtra piece of equipment on one of the engines, a high output alternator, hydraulic pump or similar that's not on the orther one?

3. Is the hot water calorifier connected to only one engine?

These are the sort of things I would look at to try and explain small differences like the ones you describe. WHY? Because the throttle opening of each engine is difficult to access, just because each engine is doing the same RPM it doesnt mean they are both producing the same amount of power. The differences in the power required from each engine to achieve the same RPM would explain the small differences in the reading you have obtained.

 

[PowerYachtBlog]

As I said in PMs Mike I seatrialled a couple of Ferretti 53s and even on hull number 3, they where very close if not identical.
I also asked a guy who has a 53 from 2002 and he said, that at 1900 RPM the speed he cruises lph are in most cases the same or a differences of a 2 LPH the most. The difference increases a bit but not more then 5 LPH if you have a beam sea on that side engine.
Check well those props too. as a couple of years ago those Rolla costed 8000 EUROS each.

 

[jfm]

As I said in PMs Mike I seatrialled a couple of Ferretti 53s and even on hull number 3, they where very close if not identical.
I also asked a guy who has a 53 from 2002 and he said, that at 1900 RPM the speed he cruises lph are in most cases the same or a differences of a 2 LPH the most. The difference increases a bit but not more then 5 LPH if you have a beam sea on that side engine.
Check well those props too. as a couple of years ago those Rolla costed 8000 EUROS each.

Why does material like that get said in PMs when this forum is about information sharing?

I completely agree your general point PY that differences should be in the order of 1-2 litres/hour. Engineers aren't so bad that they make engines 10% different

 

[MapisM]

Mike, what speed did the boat reach at WOT?
2330 rpm and a load below 100% on both engines would lead to think that BOTH props are slightly short.
Anyway, I still think that the weird numbers are on port engine.
The "peak" at 2190 doesn't make sense. Regardless of whether the props are optimally tuned or not, the "prop demand" consumption curves MUST steadily increase, tending to match the "max power" consumption curves at WOT and max rpm.
Besides, even a rough multiplication of the rated max consumption (125 l/h @ 2300 with 100% load) by the 93% load of stbd engine gives exactly the 117 reported, whilst the same calculation on port engine gives 119, instead of the 101 reported.
I know that electronics are generally reliable these days, but if max speed is fine I would tend to think that there is simply a faulty consumption reading on port engine for some reason.
You might be interested to look at Cat specs for further details.

 

[MapisM]

I'm not going to mention the channels you'll (not) get with a G4 cos I dont want to spoil your (son's) day :-/ It's a 40cm dish.

Nothing to worry about. Lippi will take care of spoiling Capello's day anyway...
G4 and similar dishes are actually very common in Adriatic, it's only south of Dubrovnik (roughly) that they begin to show their limitations.

 

[PowerYachtBlog]

Why does material like that get said in PMs when this forum is about information sharing?

I completely agree your general point PY that differences should be in the order of 1-2 litres/hour. Engineers aren't so bad that they make engines 10% different

Sorry JFM don't mean to hide any information to you. But Deleted User asked some information about the 53 to me by PM a couple of times, so it was fair to respond him that way.

I think once you have a double digit problem it is a problem somewhere.

 

[splosh]

Also check this out on those model engines with Cat prior to purchase as there were some probs with intercoolers and is public knowledge if you do a search!

This is a snippet from the internet:

I haven't yet seen the final class notice. Revision 2 of the class notice states: "You are receiving this notice because you have been identified as an individual or entity that has been an owner of a boat with a Caterpillar engine, including a 3196, C-12 or other Caterpillar engine, containing the aftercooler model numbers in issue".
"Plaintiff is pursuing this action on behalf of himself and all other persons who own or at any time owned a boat powered by a Caterpillar marine engine equipped with any version of aftercooler model/part numbers 138-2571, 161-9898, 210-5631, and 216-5147". Aftercooler serial number: 216-5147-04 is the latest of eight iterations.

 

[MedDreamer]

I know that electronics are generally reliable these days, but if max speed is fine I would tend to think that there is simply a faulty consumption reading on port engine for some reason.
You might be interested to look at Cat specs for further details.

Assuming the boat has seperate fuel tanks, is it worth asking the current owner if he keeps a log of how much fuel each tank takes when filling up? If its consistent with the data reading then its a real issue, if the amount of fuel per tank is similar its an instrument problem.

Alternatively look at the fuel tank gauges now (assuming not full). No-one part fills one tank so if they show a difference consistent with the 10% anomoly then it looks real

Apologies if this is too simplistic to be useful Mike but just ways that non techies like me would seek to verify the data.

 

[jfm]

fuel tank gauges ...

beware though that the genset likely draws from one tank, and with med airco it'll be a 4 litres an hour job