Engine overhaul (or not)

[harvey38]

So, we have had the boat for over a year now and only added a shameful 20 hours to each 250hp Ford Sabre engine bringing their total to around 1000 hrs. So much work going on to bring her up to date from the tired Eighties look when we took over ownership preventing us going out much !

The engines run great, oil pressure good, temperatures all good as is turbo boost, good water circulation and apart from the well documented smoking issue when cold/idle, all is good.

There is little in the way of service history which is being rectified by a full service with a change of belts, impellers, filters a etc.

Given the above, is it worthwhile removing the injectors and injector pump and getting them overhauled/inspected or as
everything is fine, leave them alone? Having already spent a considerable amount on the boat, I'm loathed to spend any more just for the sake of it but if the general consensus is it makes good mechanical sense, I'll go with that.

Thanks in advance.

Rob

 

[BruceK]

If it was my boat I would but then I love to fettle, find fault and invariably fix things that dont really need fixing and then wonder why my boat costs me so much. As I wouldn't hold myself up as an example I would probably say let sleeping dogs lie. You'd know for sure if they were duff anyway.

 

[Portofino]

Leave it .
Just do the regular annual oil change / filter and fuel filters .You decide which side of the season .
Add a anti fuel bug treatment over the winter .
Racor filters with clear bowls and WIF s are handy and certainly ease anxiety to eye ball fuel before it goes through , or drain a bit off for curiosity.

 

[kashurst]

Leave it alone. 1000 hours is nothing for the injection system. Just check all the service points are done correctly.
I changed (years ago) the injectors on a Mermaid Marine Ford engine at 1500 hours. Made no difference at all.
If you feel the need to spend some money, get your fuel tanks cleaned out. clean tank = clean fuel = happy engine

 

[Portofino]

The injector thing is quite interesting in terms of the cloudy opinions flying around forums inc this .
I have looked into it and taken professional ( MAN engineer ) advice .

It boils down to the age , ie what type of injectors , the installation ie the weight of boat or a better term the load needed or used to shove it .

Briefly
The simple ones are the basic mechanical spring loaded with just a needle valve tip and one large hole .
The next step may be multiple holes .
Then electronic solenoid opening by now a few holes so multiple .
As above with pulse opening , ie multiple opening events controlled by the ECU
Then CR high pressure , even more elaborate holes , tiny smaller to create super spray patterns even more opening events up to say 5 in a single firing in the search for greater efficiency/ power and a better less emissions burn .Greta likes theses Or hates them the least !

Long slow running this pootling we read about on here means optimal cylinder temps + pressures are never reached .
This mean there’s a build up of algolomations , crap of large un burnt molecules clumping together .
Because the cylinder temps are lower this soot sticks to the injector tips and permanent starts to close those holes .
The spay pattern alters .
Dangerously some tips over heat ,Yeh I know I here you say hang on how come if the EGTs are say 250 *C at pootle D speeds and 600*C when running as designed fast cruise ?
The soot builds up a insulation layer and the metal tip - holes get hot and distortions occur .

Obviously the finer the needle , the finer or increase in holes the finer the so called spray pattern the worse or quicker to knacker the tips will be .

Having said all this the latest CR , ECU stuffed motors can actually tell it’s running at lower rpm and load and phaff about with those 5 events and timings of the discharge and broadly fuel it better to kinda mitigate low rpm running soot build up to a point .

So there are a lot of variables to toss in “ thou shalt remove send away injectors every 1000 hrs “

Its a how longs a piece of string answer .

For me personally the MAN service manual suggests every 2000 hr or maybe 4000 for my age of motor .
Electronic with I think a simple spray pattern quite large holes Iirc ( I have some spare tips in the tool box ) .
I crossed 1000 hrs on the 2003 engine this summer.
Last sumner I had MAN engineers out to replace a load sensor on an injector at 950 hrs .
I did ( bamboozled by the Internet ) ask / enquire about the 1000 hr injector pull floating about on the net .
He connected his lap top up to both engines and we went through ALL the screens showing pressure , times , temps , sequences pump stuff etc .All fell within manufacturers specs and he shook his head “ no need “
I was 1/2 expecting the “ yes let’s send them off for testing “ Kerchung €€€€€ yes please .But Nope .

Thats Ok for my spec as he can hook up a lap top and view stuff to see how far out they are on a screen with OEM data and each other .

For balance on an American forum this gets done to death .One guy said if you do not regularly remove them the sealing o ring cease up and this can make removal problematic, poss head off or new head etc .
I put this to my MAN guy .In other word let just remove them to put anti cease and a fresh o ring on them and while they are out send them away like everyone else seems to doing .
He said his has never had issues removing them and the o ring or what ever the sealing ring never ceases up .
Again I felt a victim of internet lore .

Sorry I cannot say yeh or neh to your specific “ 1000 hr pull em Q “

It depends on too many factors .
I would leave it well alone for now but if you can speak to Sabre engineers .

A lot of pooling will bring the pull sooner . A lot of overloading will burn the tips too = excess EGTs - that old chestnut

Run the boat as it was intended will extend life .

 

[Elessar]

So, we have had the boat for over a year now and only added a shameful 20 hours to each 250hp Ford Sabre engine bringing their total to around 1000 hrs. So much work going on to bring her up to date from the tired Eighties look when we took over ownership preventing us going out much !

The engines run great, oil pressure good, temperatures all good as is turbo boost, good water circulation and apart from the well documented smoking issue when cold/idle, all is good.

There is little in the way of service history which is being rectified by a full service with a change of belts, impellers, filters a etc.

Given the above, is it worthwhile removing the injectors and injector pump and getting them overhauled/inspected or as
everything is fine, leave them alone? Having already spent a considerable amount on the boat, I'm loathed to spend any more just for the sake of it but if the general consensus is it makes good mechanical sense, I'll go with that.

Thanks in advance.

Rob

do the injectors IMO. A good engineer will have a spray pattern and pressure tester - to check they open and close at the right pressure. You only need to overhaul the ones that fail. Do a compression check when they are out. All 12 of mine needed refurbing though. Leave the pump alone.

 

[scottie]

do the injectors IMO. A good engineer will have a spray pattern and pressure tester - to check they open and close at the right pressure. You only need to overhaul the ones that fail. Do a compression check when they are out. All 12 of mine needed refurbing though. Leave the pump alone.

I would agree for this vintage of engine that pop test is adequate and proportion response but completely inappropriate for later electronic injectors and in fact can be misleading they require proper bench test

 

[ChromeDome]

"If it ain't broken..."

I too would be tempted to take them out - otoh a fellow boater took them out of his AD41 (for a good reason) and sent them off for a clean & check. Noting major but "while they were out anyway" ended up with new injector tips, sleeves, shims, gaskets, some lines and check/reset of injection pump timing. Some DYI, some by a certified technician with a bill to match.

 

[Scarron]

I would say no, leave the pumps and injector alone, they would probably benefit from running under hard load for a few hours to get cylinder temps up and the injector tips flowing well.

But what you must do instead on your Sabre 250s is a full strip down and ultrasonic cleaning of your intercoolers and the heat exchangers.

The intercoolers on the Ford Sabre are the weak point on these engines specifically the undersized O rings that seal the end caps on. When they leak, and they will if not rebuilt every three years then seawater will be ingested by the engine and it’s full rebuild time. I have just had to do that with one of mine!

I cannot emphasise highly enough that this preventative maintenance is essential to avoid meeting Mr Big Bill.

Stephen Atkins of Seahorse Marine carries the spares including new tubestacks. (I have just replaced all of mine) and Abbey Heat in Eastleigh can clean and pressure test tube stacks and casings/end caps.

 

[Bandit]

Injectors worth doing, then you have eliminated a “is it an injector or a fuel pump problem” . Also if boat is 30 years old it’s not the hours buy the years, lack of use , and shitty old diesel that is.
I would thoroughly clean through fuel system including the tank there will be 30 yrs of crap, bug, sediment and water in it. Then refill with filtered or new diesel and that religiously withMarine 16 or Grotamar at every refuelling.
I am a fan of Racor pre filters worthwhile fitting oversized.
investigate the condition of your fuel tank .
what are your stern seals, when we’re they last maintenance or replaced, also cutless bearings.
I would also have coolers removed, inspected and cleaned with Rydlyme. Examine mating faces carefully.
Drop me a pm if you want to talk Aqua-stars and maintenance.

 

[ChromeDome]

I decided on Racor R25 prefilters which are finer than that the usual recommendation. Engine filters are OEM.

The setup works very well - judged by the used filters when cracked open, the diesel I get is consistently clean.

If you want a fuel polishing system could be considered.