Preventative maintenance or leave well alone

D

dick_james

Well-Known Member
Joined
31 May 2001
Messages
114
Location
Middlesex, UK
Visit site
My old Perkins 4-108 is just coming up to 1000hours. No smoke of any colour, always starts fine, consumption good. Question is should I have the injectors serviced or leave well alone? I'm tempted to go for the latter but a tiny voice is nagging me. any thoughts?
 
>> leave well alone

My 4-99 was injectopr serviced .... then I had leaks !! Just one injector leaked ... but we tried .... but nope .... drip drip drip !!

I'm a great believer ........... leave well alone ... if its not smoking, little bit is no problem anyway, starts nice etc. etc. - Then you've got a jewel - don't break it.
 
Re: Preventative No, Condition Yes

You can follow three types of maintenance
1) Preventative ( PPM) - based on calender or hours run
2) Condition ( CM) - based on monitoring of performance and overhauling before output becomes unacceptable
3) Strategic (SM) - Posh word for run til bust - used where you can get a new one in a few hours and the downtime does not hurt your business

By looking at your exhaust and observing no smoke you are using method (2). Nothing wrong in that, if your fuel has been to spec then 1,000 hours running is sod all for injectors- mine are on over 3,000hours.
I have never understood (1) ever since I was asked to change the shaft seal on a 3 month old ship on a pump that had only run for 30 days just cause the new fangled for then PPM system said I should.

Now apply the same logic to lube oil changes instead of following the tired ' you must change oil every season' mob and you will be making progress !!!

Brian
 
The engine will tell you when the injectors do start to need seeing to, usually by an increase in black smoke as the nozzels wear, and start to deliver too much fuel or a poor spray pattern.

There is an intermediate way if you are worried: draw the injectors take them to your diesel specialist and have them checked. Most firms do this for free. Then you will know that they are OK. But personally I wouldnt bother - if they work, they work, and they very rarely cause grief once they do start to go off tune.

Oil changes on the other hand are a 'must'. Again apart from being a bit more rattly the engine will keep going, but it will be doing loads of long term damage leading to early failure of bearings etc.

Same with fuel filters: they rarely NEED changing at the service interval. But when they do get blocked - you stop! No 'if's'!
 
I'm not sure that thought will give me much confidence next time I step on an aeroplane.
I shall be thinking " The engineer said it was OK when it arrived, should be OK now"
On the other hand, whenever I've had problems with my car it's usually just after a service.
 
If they are anything like the Volvo Penta (=Perkins in many cases)) block then leave them alone. There is a copper sleeve in the cylinder head that holds the injector. Removing and reinserting the injectors will increase the chance on leakages and if you pull the sleeve out when removing the injector (by accident) you will be in a expensive spot (cylinder head removal).
As been said before, bad injectors will manifest themselves without actual engine failure. It will just start more difficult and produce a lot of smoke. By that time consider pulling the injectors.
It better to spend your enegery on proper oil and filter changes. And use clean Diesel. It'll help preserve your injectors.

Arno
 
Interestingly in formula one, since they have banned mechanics from touching the cars between qualifying and the race, it has been noticable how more reliable the cars have been during the race, indeed everyone finished at Monza !
 
Hi Harry -would agree with you but would add

Oil must be changed before it goes out of spec but the key here is the word before.
I have never changed the oil on my day job engines (currently over 10MW of various types and sizes of engine) just because it was annual service time. The oil is always monitored and the results reviewed. This saves a lot of costs and oil.

I appreciate the costs of an oil analysis has been more than the oil change costs before now for yacht type engines but with the oil change costs my Ford 1.6 now getting over well over £15 perhaps this will change.

Market opportunity for Nigel L to develop a DIY kit?


Filters can block suddenly if the bulk tank is really dirty but normally they block slowly. I came back from the Falklands with a right load of crap MOD fuel heavy oil, fine filters needed cleaning out every day, this was noticed when No1 cylinder exhaust temp fell back as the fuel supply to this unit was first affected by the fuel filter blockage.
Most better installations on bigger yachts and MOBOs have two or more filters, run on one, if the top end performance falls away change over to the clean one and clean /replace the dirty. This works well unless the bulk tanks has a big layer of water/bug produced sludge but if this is case, the crew should have been on top this well before it started to block the filters.

Brian
 
If you do have any concerns about the state of the fuel injection system, a simple remedy (as instructed by a now retired mechanic) is to use one of the many proprietry fuel conditioning liquids. Just follow the instructions on the tin.

Most fuel system problems are caused by dirty fuel, and even when well filtered, crap can and does build up inside the injection pump and injectors. Using a conditioner as part of the service schedule will exponentially increase the life of the individual components.

In the case of your 4-108, if it starts ok, runs ok and has a clean exhaust, then like the other responces, leave well alone. Having fitted a new engine last year, I change the fuel filters annually and the oil & filter twice - once at the end of the season & again mid season. It's a bit of overkill, but I can't afford to replace the engine again!!

Some may say that you only service your car (ie change oil etc) annually so why more frequently on a boat? Simple. Cars operate in a far more friendly environment, get used more regularly and if they do break down you can always ring the AA / RAC!!
 
Market opportunity for Nigel L to develop a DIY kit? >>>>>

There is in fact a field kit .... but you wouldn't like the price !!

You would have to check for :

Viscosity
Density
Water content
Sediments and mechanical impurities
Ash
Sulphur

just of the top of me bonce .... ash and water content will be the hardest to do in DIY form. Density and Visco is not hard ... seds can be done with membrane filtration, but doesn't give you a quantifiable result unless done with lab balances etc.

Possible .... but dangerous in wrong hands ...
 
For the un-initiated how do diesel injectors fit into the head. Are they all interferrence fit (hence your expression "Draw them") or are some screwwed in like spark plugs. Just interested in knowing!
 
H'mm, smoking zorts means injector service. But I have an AD41 which usually potters at 1200 on the river, so how does one define "excessive smoke"? Presumably along the lines of "even worse than usual":-)

Vaguely intend to get the injectors checked this winter as being about 3 years after I bought the engine recon from Coastal Rides.
 
Condition monitoring of oil is the way car engines are going. I think Delco have developed a low-cost module that lives in the sump. Apart from monitoring oil level and temperature, it also looks at the condition of the oil (don't know what!) and tells the driver when its time for an oil change. I recently had a diesel Skoda and thought that as it was coming up for 12,000 miles, it might need a service. In fact, I was a bit worried because the oil looked pretty black and I couldn't find a 1000 mile service stamp in the book. When I asked, I was told "don't worry sir, you should be fine for up to 2 years or 32,000 miles! It will put a light on when it wants some fresh oil. Just make sure you use synthetic oil".
 
You must log in or register to reply here.

Share this page

Top