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Ive broken my Engine, ideas needed


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I am not very brave when it comes to cracking injector lines, I have heard tales of nasty accidents.

I undo the big nut a little, wrap it well in kitchen roll, then start the engine, run it up to medium revs, then stop and see how wet the kitchen roll is. I am not brave enough to watch the fuel coming out, am I been silly? I did not wrap the union too well on one cylinder and it shot fuel all over the place.

 

 

Ah in that case you're not loosening the nut enough...

 

Shall I come over and see if I can make any difference??

  • Greenie 3
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Ah in that case you're not loosening the nut enough...

 

Shall I come over and see if I can make any difference??

That's a good idea, it can be a bit alarming to see diesel squirting over the top of the engine

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Ah in that case you're not loosening the nut enough...

 

Shall I come over and see if I can make any difference??

Nice gesture Mike,just try and remember that the OP does not want a Trad. sounding single Cylinder engine, he prefers multis!

 

Do not try to do a Samofa conversion

 

CT

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I am not very brave when it comes to cracking injector lines, I have heard tales of nasty accidents.

I undo the big nut a little, wrap it well in kitchen roll, then start the engine, run it up to medium revs, then stop and see how wet the kitchen roll is. I am not brave enough to watch the fuel coming out, am I been silly? I did not wrap the union too well on one cylinder and it shot fuel all over the place.

 

Sub topic, its not bog standard kitchen roll, its Regina Blitz. I used to swear by "blue paper" but I think the quality went right down hill about 10 years ago and I reckon "Blitz" is better than the modern second rate blue paper. Its also of strong non-fibre construction so does not leave little strand behind to get into the fuel system.

 

................Dave

 

 

Obviously do not do it if you are smoking or have naked flames about because although it is unlikely a fuel splash (not vapour) or droplet just might ignite but apart from that the less you loosen an injector pipe the more dangerous the fuel being ejected becomes, and that is not very!

 

The red section above seems to me to be a misunderstanding about not pointing an injector spray at yourself. An injector has a very strong spring in it and an "outlet hole" that in most cases is designed to eject a fine fuel mist at a pressure of around 135 Atm. - 2000psi. It does this by having the outlet blocked by a valve with a very strong spring so the fuel can not get out until it has reached the set pressure. This causes a stream of high speed droplets that are going fast enough to penetrate your skin.

 

When you loosen the injector pipe there is nothing stopping fuel coming out apart from any resistance to flow in the loosened joint so the pressure will be only a little above zero and if you ever see such a joint spraying rather than dripping you will see the fuel is only moving slowly.

 

By all means lay paper towel to absorb any drips but leave the union free so you can see what is going on. Just observe normal rules of cleanliness with diesel to avoid dermatitis and you will not be in any danger.

 

 

 

 

 

Edited by Tony Brooks
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Obviously do not do it if you are smoking or have naked flames about because although it is unlikely a fuel splash (not vapour) or droplet just might ignite but apart from that the less you loosen an injector pipe the more dangerous the fuel being ejected becomes, and that is not very!

 

The red section above seems to me to be a misunderstanding about not pointing an injector spray at yourself. An injector has a very strong spring in it and an "outlet hole" that in most cases is designed to eject a fine fuel mist at a pressure of around 135 Atm. - 2000psi. It does this by having the outlet blocked by a valve with a very strong spring so the fuel can not get out until it has reached the set pressure. This causes a stream of high speed droplets that are going fast enough to penetrate your skin.

 

When you loosen the injector pipe there is nothing stopping fuel coming out apart from any resistance to flow in the loosened joint so the pressure will be only a little above zero and if you ever see such a joint spraying rather than dripping you will see the fuel is only moving slowly.

 

By all means lay paper towel to absorb any drips but leave the union free so you can see what is going on. Just observe normal rules of cleanliness with diesel to avoid dermatitis and you will not be in any danger.

 

 

 

 

 

 

 

Nicely explained Tony. I'd just come back on here to say much the same thing only less eloquently.

 

One other thing to point out is the volume of fuel pushed along the injection line on each firing stroke is tiny, perhaps a droplet of 0.01ml in volume I'd guess, so even a small air bubble in the injection line will compress and prevent the spring pressure in the injector being overcome and the spray sprayed.

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Ah in that case you're not loosening the nut enough...

 

Shall I come over and see if I can make any difference??

Greenie. That's a really nice gesture, and I think he should accept your offer. I feel there is nothing wrong with his pump, it just needs a proper bleed.
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Nicely explained Tony. I'd just come back on here to say much the same thing only less eloquently.

 

One other thing to point out is the volume of fuel pushed along the injection line on each firing stroke is tiny, perhaps a droplet of 0.01ml in volume I'd guess, so even a small air bubble in the injection line will compress and prevent the spring pressure in the injector being overcome and the spray sprayed.

 

Less than the volume of a pinhead at full chat - probably easier for ordinary folk to visualise.

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Greenie. That's a really nice gesture, and I think he should accept your offer. I feel there is nothing wrong with his pump, it just needs a proper bleed.

 

I have changed the filters many times before and only got air into the injector lines once before, and bleed that out without any trouble so I do know how to do this. I have not succeeded this time which makes me think its not just air. I will try again tomorrow, and have accepted Mikes offer of assistance. We have actually helped each other a few times recently but mostly at drinking beer.

Spent today sorting out alternative battery charging and totally re-plumbing the Alde, and bringing it back into service for the first time in many years. I will need a shower soon as I am starting to smell like a diesel boat.

 

.................Dave

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Obviously do not do it if you are smoking or have naked flames about because although it is unlikely a fuel splash (not vapour) or droplet just might ignite but apart from that the less you loosen an injector pipe the more dangerous the fuel being ejected becomes, and that is not very!

 

The red section above seems to me to be a misunderstanding about not pointing an injector spray at yourself. An injector has a very strong spring in it and an "outlet hole" that in most cases is designed to eject a fine fuel mist at a pressure of around 135 Atm. - 2000psi. It does this by having the outlet blocked by a valve with a very strong spring so the fuel can not get out until it has reached the set pressure. This causes a stream of high speed droplets that are going fast enough to penetrate your skin.

 

When you loosen the injector pipe there is nothing stopping fuel coming out apart from any resistance to flow in the loosened joint so the pressure will be only a little above zero and if you ever see such a joint spraying rather than dripping you will see the fuel is only moving slowly.

 

By all means lay paper towel to absorb any drips but leave the union free so you can see what is going on. Just observe normal rules of cleanliness with diesel to avoid dermatitis and you will not be in any danger.

 

 

 

 

 

 

Thanks Tony.

This makes total sense, I have never really thought about it before, just accepted the warnings about high pressure diesel and tales about it penetrating the skin. Thinking about it these warnings did come from people who did test there own injectors.

I suppose if you were really really unlucky and cracked the union at the very exact instant that it was injecting..........??

...and then all this new common rail stuff does presumably poses a risk. I expect with Brussels dictating what engines we put into our boats we will see common rail on the cut before long. (oooh getting close to politics here).

Will try again tomorrow. Not going to take the injector pump till I am 100% certain that I need to.

 

...................Dave

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Greenie. That's a really nice gesture, and I think he should accept your offer. I feel there is nothing wrong with his pump, it just needs a proper bleed.

 

 

Thank you kindly for the greenie. :)

 

Dave is generally very good at stuff so I'm gonna be surprised if bleeding is all it needs, but on the other hand I've learned in my own sphere of work coincidences are rarer than you'd think. I't highly likely to be connected to the filter change, but possibly not in the most obvious way.

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After everything that has been written about Dave's engine problem, it's too hard to believe that a fuel injection pump dies immediately after a fuel-filter change, there's absolutely no logic in the fact that a perfectly running engine all of a sudden has a dead fuelpump.

 

Something somewhere has gone wrong and my money (too bad I haven't got much) is on air in the system.

 

I would take it all apart again an start from scratch and when it's all properly put together again, some serious bleeding of the system, after which I think that Robert will be your mother's (or father's) brother.

 

Good luck Dave, and happy easter anyway,

 

Peter.

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Thanks Tony.

This makes total sense, I have never really thought about it before, just accepted the warnings about high pressure diesel and tales about it penetrating the skin. Thinking about it these warnings did come from people who did test there own injectors.

I suppose if you were really really unlucky and cracked the union at the very exact instant that it was injecting..........??

...and then all this new common rail stuff does presumably poses a risk. I expect with Brussels dictating what engines we put into our boats we will see common rail on the cut before long. (oooh getting close to politics here).

Will try again tomorrow. Not going to take the injector pump till I am 100% certain that I need to.

 

...................Dave

Common rail stops running if you crack open an injector pipe!! Injectors open by electrickerty on them so they self bleed. They have pressure sensors and all sorts of rubbish on them just more stuff to go wrong

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Thanks Tony.

This makes total sense, I have never really thought about it before, just accepted the warnings about high pressure diesel and tales about it penetrating the skin. Thinking about it these warnings did come from people who did test there own injectors.

I suppose if you were really really unlucky and cracked the union at the very exact instant that it was injecting..........??

...and then all this new common rail stuff does presumably poses a risk. I expect with Brussels dictating what engines we put into our boats we will see common rail on the cut before long. (oooh getting close to politics here).

Will try again tomorrow. Not going to take the injector pump till I am 100% certain that I need to.

 

...................Dave

 

I doubt but am not certain that common rail is any more dangerous than our systems when you loosen a pipe feeding the injectors. Even though the intermediate pump produces a high pressure and more volume once a union is opened there is little to stop fuel leaking out so pressure will not build up so easily. However I think you will get a far greater leakage volume wise. This is not what we are dealing with here though.

 

As I said above the volume displaced by the injector pump per stroke is less than a pinhead's worth at full throttle. This means that even if you did loosen the pipe at the instant the pump delivered fuel the slightest leak or even just the union opening a little to increase the contained volume would drop the pressure to zero. Bleeding the injector main unions is not dangerous pressure wise.

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Can you disconnect the pipe after the lift pump (at the engine end) and put the end in a jamjar? Operate the lift pump and look to see if it is pumping 100% fuel with absolutely no air bubbles? Or disconnect at the inlet to the lift pump and use a vacuum pump (of the kind used to suck oil from the sump) and see if the line is letting air in somewhere?

 

I had a similar problem last week on a Kabola boiler. After remaking all the connections from tank to fuel pump with no success, I eventually found the stuffing box / gland was loose on the red, shut-off valve on top of the filter!

post-25259-0-81138000-1459075496_thumb.jpg

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Thank you kindly for the greenie. :)

 

Dave is generally very good at stuff so I'm gonna be surprised if bleeding is all it needs, but on the other hand I've learned in my own sphere of work coincidences are rarer than you'd think. I't highly likely to be connected to the filter change, but possibly not in the most obvious way.

You will be there to hear Dave explain what he has done. That will probably do the trick

 

Its amazing how many problems I solve while describing them to someone else.

 

Richard

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Any idea why postings in this thread are now running in the Oxford Moorings one?

 

That was my fault for my light hearted post referring to the lack of mooring here due to a row of three broken down boats.

 

.............Dave

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You will be there to hear Dave explain what he has done. That will probably do the trick

 

Its amazing how many problems I solve while describing them to someone else.

 

Richard

 

Done a few more test before Mike arrives as I would look silly if the engine fired up fine as soon as he got here.

Still have a good airless supply of fuel arriving at the injection pump.

But....Fault has now changed a little:......

 

Engine runs on one or one and a bit cylinder and can get up to about 900rpm off load, (1200-1400 is top speed on this engine) but after cracking open ANY injector line the engine will only run at a rough very slow tickover, but plenty of fuel spurting out of the open injector line. So fuel available on all cylinders but cant deliver fuel to more than one injector.

Just digging out my injection pump removal tools????,

 

.................Dave

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I have absolutely nothing to add of any technical worth as i m a numpty . But , having been on the receiving end of a great deal of advice on technical matters thru this forum , often from members participating in thread can i just say how great it is to read of such helpfulness & to say that it is in these situations that this forum shows the very best of itself . I will follow the thread , hopefully to a happy conclusion

cheers

  • Greenie 1
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Mike is a confident bleeder and sprayed diesel all over the engine room, then we had a couple of beers.

 

Its a lot easier/safer bleeding with two people

Mike maybe got a bit of air out, it was a bit inclusive, and the fault improved or at least changed.

We have established that cylinder 3 is running ok, but both 1 and 2 are firing very weakly.

This looks to relate to fuel flow from the injection pump rather than injector issues, though I believe that a stuck open injector can do odd things.

I have repeated everything again this morning and this pattern is now consistent. I spent all afternoon getting the injection pump off. I did this before about 6 years ago and luckily had the various special tools that I made still on the boat. Tomorrow I will get the injectors out and take the whole lot to a Stanadyne agent.

Getting the pump off the drive gear was a bit of a scary experience, The shaft has a taper and I felt I was getting close to the point of stripping threads on the extraction tool and just about to give up when there was a very loud bang as it came off.

 

The engine has done 8000 hours so its probably about time to get the injectors checked anyway.

Have had great help from a couple of forum members, bleeding and loan of a genny from Mike, and a big battery charger and a lovely slide hammer from Dinz.

 

..............Dave

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Hi Dave, too bad that your problem seems to be far more serious then expected straight after a fuelfilter change.

 

Having your injectors serviced after 8000 h isn't a bad thing to get done, although I've had many engines on which the injectors were never serviced and still working plenty good enough after 15.000 to 20.000h.

 

They may have been (maybe slightly) better if they'd had a service/checkup done on them, but as the engines always started very well and never smoked, I didn't see any reason to have the work done, I like the idea of " Don't fix it, if it aint broken".

 

Hope for you that there's only a minor problem that will be cheap to mend on you injection pump.

 

Good luck,

 

Peter.

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Mike is a confident bleeder and sprayed diesel all over the engine room, then we had a couple of beers.

 

 

Lol, if you think I sprayed a lot around be grateful it wasn't RLWP doing it!

 

I estimate we had each injector open for bleeding for between one and two minutes each with the engine running, and that's a LONG time to be catching the spray, and seeing no change in the behaviour. Loosening each of the injectors led to the engine slowing noticeably, but No3 especially so. the volume of fuel issuing from the end of each injector pipe reduced significantly form No3 down to No1, with No1 delivering the least.

 

I'm pleased to report the beer consumption went without a hitch though. We are better at that than fixing engines, it turned out.

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Lol, if you think I sprayed a lot around be grateful it wasn't RLWP doing it!

 

I bet it helped dissolve the spanner-eating sludge under the Gleniffer

 

Richard

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