Changing/overhauling injectors

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pcatterall

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I’m thinking of getting my injectors overhauled ( Perkins 4108)
We have been getting a dirty transom over the last couple of years.
We are not using any appreciable amount of oil so I guess we are just not burning the fuel completly, being sure the injectors are in good nick seemed a good start.
Whats the best way to do this?

I’m thinking of taking them all out over winter and sending them to a specialist company for overhaul. ( Boat is in the med but I could bring them to uk)
Are there any special considerations connected with taking them out and putting them back?
Is there another way to do this?
Many thanks
 
They rarely go wrong, I suggest you check for other issues first. It's much cheaper to buy a good secondhand set than having yours serviced.

If you have to remove them you may well need an extractor to pull them out, make sure you clean the area round the injector before. There are sealing copper washers, make sure you replace them or anneal the old ones. Plug the holes if you leave the engine without injectors.
 
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pcatterall said:
I’m thinking of getting my injectors overhauled ( Perkins 4108)
We have been getting a dirty transom over the last couple of years.
We are not using any appreciable amount of oil so I guess we are just not burning the fuel completly, being sure the injectors are in good nick seemed a good start.
Whats the best way to do this?

I’m thinking of taking them all out over winter and sending them to a specialist company for overhaul. ( Boat is in the med but I could bring them to uk)
Are there any special considerations connected with taking them out and putting them back?
Is there another way to do this?
Many thanks
Click to expand...
Peter
they are held in by two nuts and years of grime! Take the pipes off, undo the nuts and use a small pry bar or big screwdriver under the ears to ease them out. They seal with copper washers around the nozzle. I used to fettle the nozzles my self or in rare cases replace them. Bring them home and find a good old fashioned diesel shop to do it. If they change the nozzles about £50 per inj, if not, a bit cheaper. Use new copper washers to refit and make sure the holes are clean, any carbon will stop them sealing properly and combustion gas will leak out, phu phut phut!
S
 
savageseadog said:
They rarely go wrong, I suggest you check for other issues first. It's much cheaper to buy a good secondhand set than having yours serviced.
Click to expand...

When I changed the head on my 1GM10 I had the injector serviced by Mcalister's in Cumbernauld. It cost around £30, including VAT and postage back to me (I delivered it).
 
savageseadog said:
They rarely go wrong, I suggest you check for other issues first. It's much cheaper to buy a good secondhand set than having yours serviced.

If you have to remove them you may well need an extractor to pull them out, make sure you clean the area round the injector before. There are sealing copper washers, make sure you replace them or anneal the old ones. Plug the holes if you leave the engine without injectors.
Click to expand...

I had understood that they could just become less effective over the years rather than 'going wrong' as such?....a bit blocked/poor spray pattern etc?
 
Dont buy second hand, unless its to recondition them and then swop with your original injectors.
Fuel injectors do deteriorate with use, but its entirely dependant on the quality and quantity of fuel going through them.
A simple test at a fuel injection specialist will determine condition, for just a few pounds each, possibly even free!
 
pcatterall said:
I had understood that they could just become less effective over the years rather than 'going wrong' as such?....a bit blocked/poor spray pattern etc?
Click to expand...
Think about it. How many hours does your boat engine do? How many hours does a diesel car engine do?
 
pcatterall said:
I had understood that they could just become less effective over the years rather than 'going wrong' as such?....a bit blocked/poor spray pattern etc?
Click to expand...
Peter
I used to service them many years ago, it was part of my job. They nozzle holes get blocked with carbon, the nozzles have a sliding pin that opens and shuts the holes, the pin sometimes seizes, they are controlled by springs that keep the pin in the closed position, the springs go tired the adj hoes out. As others have said, take them to a diesel shop, the best ones are where the guys still wear blue overalls and they smoke a pipe! They will test them for you and tell you what is wrong and whether they are "breaking" at the correct pressure. You can see if they are spraying by taking the injectors out and connecting it back to the pipe out of the engine. Turn the engine by hand and you will see them spraying. You can actually hear the "creak" as they "break". I could hear mine inside the engine when I was turning it with a socket when I changed the cam belt. Caution, the fuel comes out at 200 atmospheres ish! doesnt do flesh much good if it hits it, also turning the engine by hand with the injectors in could make it fire!
Stu
 
duncanmack said:
Did/does it work? :(
Click to expand...

I don't know. Or rather, I don;t know what effect, if any, the injector overhaul had, because I also changed the head which was cracked, rusted through, coked up and had a bent exhaust valve, and also the precombustion chamber in the head. Overall the effects were pretty good: top speed in a flat calm went from 4k to 6kt and speed into a 20kt headwind went from 1kt to 4kt. Starting went from laboured to near instantaneous too.

Having the injector serviced can't have done any harm, I think.
 
JumbleDuck said:
I don't know. Or rather, I don;t know what effect, if any, the injector overhaul had, because I also changed the head which was cracked, rusted through, coked up and had a bent exhaust valve, and also the precombustion chamber in the head. Overall the effects were pretty good: top speed in a flat calm went from 4k to 6kt and speed into a 20kt headwind went from 1kt to 4kt. Starting went from laboured to near instantaneous too.

Having the injector serviced can't have done any harm, I think.
Click to expand...

PM sent.
 
My Yanmar engine had done over 4000 hours when I bought the boat, after a couple of years use in which I had noticed that the hull was getting a black smudge next to the exhaust I asked the man who services the engine to look at the injectors. He took them out and obtained prices for overhaul or replacement with new ones. I cannot remember the cost difference but went for the new ones. No black smudge since! If you think about it 4000 hours in a car at an average speed of just 30 mph equates to 120,000 miles, but my diesel car spends most of its time cruising with the engine turning over between 1500 and 2000 rpm, whereas the boat engine is usually at 2500 rpm so the injector change was probably at the equivalent of a car covering 150 to 180 thousand miles.
 
nigelmercier said:
So what is a reasonable interval to do this at?
Click to expand...


I suppose that as well as hours run there will be other factors like revs run at, quality of fuel etc?
We recently traversed France on the canals at 5kph so that may have been a contribution.

At this time we have ( I suspect but my borescope will prove!) that we have a ‘heavily encrusted prop’ , if we set the throttle for our normal cruising revs/speed we can make niether and suspect that we are failing to burn the fuel being pumped in, result is smoke and black sludge in the exhaust ( not engine oil ).

Air intake has not changed so my ( admtiably simple) mind says do the simple job and change/overhaul the injectors.
 
pcatterall said:
I suppose that as well as hours run there will be other factors like revs run at, quality of fuel etc?
We recently traversed France on the canals at 5kph so that may have been a contribution.

At this time we have ( I suspect but my borescope will prove!) that we have a ‘heavily encrusted prop’ , if we set the throttle for our normal cruising revs/speed we can make niether and suspect that we are failing to burn the fuel being pumped in, result is smoke and black sludge in the exhaust ( not engine oil ).

Air intake has not changed so my ( admtiably simple) mind says do the simple job and change/overhaul the injectors.
Click to expand...

Sounds like classic fouled prop overloading the engine so it can't burn all the fuel the governor is sending. Clean the prop before messing with injectors.
 
I had the injectors on my 4108 serviced last winter. It was a bit awkward getting them out and refitting them, but it just took a bit of patience and some swearing. Of the 4 injectors, one was apparently just dribbling fuel and 2 others were down on pressure. I had them done by colchester fuel injection. It wasn't cheap, but they are a very professional outfit. Unfortunately I didn't get the opportunity to take the boat out much this year, but the main benefit of having the injectors serviced is a much smoother idle - it had been very lumpy prior to having them serviced.

Neil
 
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