Glow plugs Disaster!

[kebo57]

Hi we need to re-group with this,
were all guessing at just what is actually left down the hole if its sheered off then a picture of the end of the plug would put us all out of our misery,
I want to see this engine where are you located

Kevin

 

[Google44]

Sorry for late reply. I am in Derby. How far from Notts are you? Will try to post pic tonight. The very end of glow plug is still left in with about and inch of wire sticking out of it. Where abouts are you?



As you can see on pin the thread is clean and free. You may notice the wire sticking in middle. This wire is stopping me of trying to drill slowly. Guess may try with a very small drill but needs to be very long to get to the end of the glow plug tip.

 

[kebo57]

Hi I might have worded this incorrectly "a picture of the end of the plug "
I was thinking more of a picture the plug its self similar style to the one I posted see below so we can compare the lengths etc.
regarding drilling
I'm an engineer 36 yrs collection of bits & bob's got my own workshop turning, milling, drilling, boring, head skimming etc. thinking of drilling, taping, pulling depending on just what's left down the hole. also if it will tap then a sleeve of 5.04 mm to go over the tip then a screw to flare the tip out against the bore of the sleeve so as to trap the tip in the bore of the sleeve then it might be possible to pull the tip

Kevin

 

[Google44]

It is the tip at the bottom 5.07 mm diameter that is left in - in green on pic. Unfortunetly, I have used the rest of the plug and cut it just underneath the threads to make a block before the long trip abroad in case that plug start leaking but does not come out. The idea was to block the hole. I do have another new identical plug which I can break to serve the purpose. It may be possible to grab the wire with some tool and twist it around but it looks like it needs to get about 10 mill in the hole to grab it. Are you close to Notts?

Apart from having to have a socket and plug in the car all the time and look at glow plug light for 10 seconds after engine start it drives ok and has no side effects.

Thanks for help

 

[kebo57]

Hi that pic you edited is good enough, looks like the whole tip is there just need to establish how much is actually there to get hold of, my warning light is on so I going to pull my plugs so I will find just how much there should be to get hold of
I'm near to Blackburn 102 miles from Derby

Kevin

 

[Alex Crow]

this IS a tricky one.

we have been following this thread for a while now!! if this were my car i would be tempted to fill the hole with compressed 'chemical metal' (a quality one - eg steel stick) to secure the tip just in case, and leave well alone!!! a glow plug could be wired some where external to make the light go out perhaps?

all the above is a compromise, even a bodge, but the engine does not need all 5x plugs to start, as the above posters do realise.

as to what has happened here, it has been suggested that the tip has fused and blown the side out, as can happen. this would explain why it is so tightly jammed and could well make it v.v.hard to extract. of course nothing is impossible however, and for sure the tip could be removed with eg a tiny pin chuck and slide hammer or head removal, but i understand the o/p has already tried various things - further suggesting it is more than just carboned up...

 

[Number_Cruncher]

Going just one step further along, the damage may have been caused originally by the injector not spraying correctly. However, getting injectors out of these engines isn't always easy.

Pragmatically, as has been mentioned, glow plugs have much less of a job to do with any direct injection engine in the climate of the UK, so, the lack of a glow plug on that cylinder won't be causing any significant misfiring from cold, and there won't be lots of unburnt fuel swilling around the bores causing damage. Also, if the fuel consumption and exhaust smoke are acceptable, it may also be best not to investigate the possibility of injector failure too closely.

I think the dummy glow plug, as already prepared and used by the OP is probably a good way to close off the now non-functional glow plug hole.

Perhaps a small square of black tape over the glow plug warning lamp might be appropriate?

 

[kebo57]

Hi all the above could still be carried out
"close off the now non-functional glow plug hole etc"
after a good attempt at getting the tip out in a way that not going to render the closing off procedure impossible.

 

[Alex Crow]

Perhaps a small square of black tape over the glow plug warning lamp might be appropriate?

you surprise me sometimes dr maths.

 

[Google44]

The light is not so much of a problem. It only stays on for around 10-20 secs after engine is started. It is more the fact that I have a socket and glow plug in my car door all the time

It would be nice to have a tool that would go in 5.07 mill hole capable of grabbing that wire and possible twisting it in reversed. I guess if plug was not centered originaly while screwed the reverse action should undo it.

 

[Number_Cruncher]

you surprise me sometimes dr maths.

I'm a pragmatist at heart AP.

In most cases, I've learnt that it is simplest, quickest, and easiest to simply do the job properly, using genuine parts, do it once, and then forget about it. Bodges, and spurious parts have a habit of coming back to cause problems down the line in my experience.

However, as you have said, this is a difficult problem.

The sleeve or sheath of the glow plug isn't actually held by anything like a thread, and it's a long way down a narrow hole. I would be very wary of pushing on it to start to tap a thread, because there's probably nothing much stopping it from falling into the cylinder!, whereas its expanded shape within the cylinder is preventing it coming out.

So, here is where I would draw the line, and start looking for ways to live with the problem unless and until there's another reason for taking the head off.

 

[Google44]

According to the above pic the tip is 5.07 in diameter and is a lot less then a hole it is stuck in. However, I got the original plug that was in. When you look at it carefully I can see the carbon only on a very top bit which is a lot less then 5.07 diameter. This makes me think that it cannot drop in cylinder as the head is designed to hold it. The opening must be less then 5.07. Otherwise, I would se carbon traces on the '5.07 part' of the tip. This explains why tip is stuck in that little narrow hole at the end - probably at the very end of it due to not being perfectly shaped.

I have event tried bending the middle wire (with engine off ), one way then the other hoping it will release the bottom tip from its grip but no lack. The wire behaves like a spring. The wire is only around 10 mm down from the top of the hole.

Somebody even suggest to weld on a top of the wire. I've ruled that out because there must be an easier way, at least I hope so.

I will wellcome any good ideas that expose small or very little risk of pushing it in.

Alex

 

[Number_Cruncher]

>>This makes me think that it cannot drop in cylinder as the head is designed to hold it.

That's not necessarily the case.

If your engine was an indirect injection type, the furthest the glow plug sheath could fall would be into the pre-chamber, but, in your case, it could fall into the cylinder itself. If there's a piccie of the cylinder head of a CDi engine showing the valves and the protrusion of the injector and glow plug into the combustion chamber, it would become clear.

When everything is new and clean, the last thing that makes contact between the glow plug and the engine is, on your piccie in post #44, the large diameter taper to the right. The sheath is free, and normally, there would be clearance between the 5.07mm diameter part and the head. When you remove a plug, as the clearance is small, it tends to wipe itself clean as you remove it, leaving only carbon on the very tip.

With use, carbon builds up, bridging the gap between the sheath and the head, and in your case, the end of the glow plug has blown which has further tightened the fit.

This may be helpful;

http://www.beru.com/download/produkte/TI04_e.pdf

 

[Google44]

In that case if I would be designing the engine heads and glow plugs I would make the tip to go from higher diameter gradually to a smaller. In that case it would be impossible to have a glow plug in cylinder.

What is realy interesting that before this plug got stuck I have successfully removed the plug that was in for nearly 8 years. This tip was in for only a day. What I will do is measure out the resistance of the wire towards the ground. If it is 0 then plug tip must be damaged inside. I have check every plug before it went in and it was between 0.5 and 1.0 ohm.

If plug is ok then may apply some voltage on wire and heat it then let it cool down to release the carbon around it.

How does that sound?

The wire supplying the 12V to it must be very strong so it does not heat the wire rather then the plug.

 

[kebo57]

sheered of heater plug

Hi as I said earlier that my glow plug light was on so
I extracted four with the extraction tool that I made earlier it worked a treat.

BUT I sheered one glow plug of just below the threads see picture ended up taping it out to 6mm X 15 deep, had problems with the electrode it didn't sheer off but managed to rotate back & forth till it did sheer off, near to were it enters the tip
then drilled down to the start of the tip (4.8mm drill)
then cleared the inside of the tip out (2.0mm)
next was to tap 6mm X 15 deep
then turned a taper on the end of a 6.0 mm bolt & relieve the thread back so that the taper would be forced in to the the tip, didn't plan for the next bit as the taper sheered off but could have been to my advantage.
then turned some spacers & extracted using a 6mm bolt.
it was tight getting it out near to the limits of a 6mm bolt but it came out it was fouling on the o/d of the plug not so much on the tip location its self

Kevin

 

[Alex Crow]

good work!! those wires don't always break off where you want! had one the other day and expected a nightmare trying to drill the wire out, but it went ok. luckily i was able to get it out with a freeze spray and good old carb cleaner, followed by one of those tapered square extractors. if that had not worked i would have gone with the m6x1.00 tap and home made extractor, but i am sure it would not have been as neat as yours!!

 

[kebo57]

Hi thought about some resin in the gap between the electrode and the plug body so as to steady the electrode whilst you drill it for the tap
I still reckon that the tip could be removed
I noticed that the tip is only a press fit in the plug body no crimping etc so I could under cut the plug body inside the bore where the tip would end up to leave a step and then flair the tip end in to the under cut creating some interference fit, using the long screw with the slow taper to flair the tip in to the under cut, make it long enough to leave in and use the other end to jack the whole thing out.

Kevin

 

[exeng]

I have machined a cdi head in half to show a cross section of the glow plug hole but its to large to attach but if you like it i can e mail it to any intrested parties.It shows the taper seat and the smaller 5 m/m hole to the cylinder

 

[kebo57]

I have machined a cdi head in half to show a cross section of the glow plug hole but its to large to attach but if you like it i can e mail it to any intrested parties.It shows the taper seat and the smaller 5 m/m hole to the cylinder

Hi steve
yes I'm interested I would like you to email it to me.

Thanks Kevin

 

[kebo57]

machined a cdi head in half

courtesy of exeng www.extractengineering.co.uk
Thats great steve you know what coming now ! more pics could we have one of the valves etc

Thanks Kevin