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BMC 1.5 glow plugs


pete.i

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Hi all.

 

Just a general question on glow plugs. I need to change mine and it would seem that I can buy single core glow plugs and dual core glow plugs. The dual core ones are significantly more expensive than the single core. What is the benefit of using dual core ones and would the extra expenditure make any difference to the starting on my 30 year old engine?

 

Cheers for any replies.

 

Pete

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Hi all.

 

Just a general question on glow plugs. I need to change mine and it would seem that I can buy single core glow plugs and dual core glow plugs. The dual core ones are significantly more expensive than the single core. What is the benefit of using dual core ones and would the extra expenditure make any difference to the starting on my 30 year old engine?

 

Cheers for any replies.

 

Pete

 

What engine?

 

That makes little sense to me if its a 1.5, 1.8, or 2.5 but if its a 2.2 these originally had 2v glow plugs wired in series with a resistor but now 12V plugs to fit are available, If thats it I would do away with the resistor and fit 12V plugs wired in parallel - if you can afford it. Otherwise I await to be educated.

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What engine?

 

That makes little sense to me if its a 1.5, 1.8, or 2.5 but if its a 2.2 these originally had 2v glow plugs wired in series with a resistor but now 12V plugs to fit are available, If thats it I would do away with the resistor and fit 12V plugs wired in parallel - if you can afford it. Otherwise I await to be educated.

 

Well it was a general inquiry on dual core glow plugs against single core glow plugs, mainly, because dual core are significantly more expensive than single core. But my engine is a BMC 1.5. My assumption is that instead of having a single heater core the dual core ones have 2 heater cores therefore (I assume) heating up the cylinder combustion space (I know not the technical term but I couldn't remember what it is called LOL) quicker making starting easier.

 

I have to say that I don't seem to have much trouble starting my engine. It starts after a ten second or so blast on the heaters in the summer and it takes around 30 seconds in this cold weather and that 30 seconds was enough even in that really bad winter we had a couple of years ago. The problem with my heaters is that one of them seems to have a loose spindle where the wire connects to the glow plug. My thoughts were that if I was going to replace one then I might as well replace them all.

 

I am aware of the difficulty replaceing these glow plugs and mine have been in for a good few years at least.

 

Pete

Edited by pete.i
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Personally I can not see how they could get two heating elements down the 1.5 pin type plugs. I could see it on the 1.8, modern ones with the larger "bulb".

 

This is why I queried the engine. It could be a 1.8 and without a picture we are unlikely to be sure.

HHMM okay. To be honest I did wonder about that myself. The heater pin is not very fat. The EBay ads say that they are for BMC 1.5 engines and the picture certainly looks like my glow plug.

 

http://www.ebay.co.uk/sch/i.html?_trksid=p2050601.m570.l1313.TR0.TRC0.Xbmc+1.5+diesel+glow+plugs&_nkw=bmc+1.5+diesel+glow+plugs&_sacat=0&_from=R40

 

That is the link to the EBAY page. But I think I am going to go with the cheaper ones.

 

Thanks everyone for the input.

 

Pete

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Personally I can not see how they could get two heating elements down the 1.5 pin type plugs. I could see it on the 1.8, modern ones with the larger "bulb".

 

This is why I queried the engine. It could be a 1.8 and without a picture we are unlikely to be sure.

 

Reading the blurb on one of the offerings suggests its not two heating elements but

 

"

*DUAL CORE TECHNOLOGY USES A COMBINATION OF 2 DIFFERENT METALS IN THE HEATING ELEMENT WHICH ENSURES THAT THE TIP WILL HEAT UP FAST AND HOLD THE HEAT FOR LONGER. "

http://www.ebay.co.uk/itm/DUAL-CORE-DIESEL-HEATER-GLOW-PLUGS-FULL-SET-OF-4-BMC-1-5-NARROW-BOAT-GP302-/151079218065?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item232d05eb91

 

springy

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Ah Okay Springy thanks for that. I didn't read the ads to be honest. Some of them ffom America were priced stupidly in the hundreds of pounds although there were cheaper dual core varieties. I have ordered an equivalent for mine now which is a Durite 0-130-12-12v. £35 plus £3 postage for 4. Not the cheapest but also not the most expensive.

 

Pete

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Well, the metal in that tip is normally very thin. There is a white powder plus the heating wire inside it so it simply can't be that thick. The "normal" plugs have worked well enough for about 40 years so my immediate suspicion is that its another bit of Internet (or more likely Ebay) bull shine. I suppose they might have copper plated the tips but I can't see that making much difference.

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Hi Pete,

 

interesting, I reckon those glow plugs were fitted in December 1992 - diary entry - 29.11.92 - 'removed glow plugs - one broke off ' further entry, 2.12.92, 'removed cylinder head, very cold, canal frozen over'.

 

Tony Brooks offers good advice. hope all goes well. I may have a spare new one somewhere, let me know if you want it and I will start the hunt....!

 

ATB

 

Mike

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Hi Mike

 

Thanks for that but the old ones came out like a dream. Nothing snapped off. I reamed out the galleries with a 4 mil drill bit got a load of muck out using the grease on the bit trick. 2 of the threaded portions on the old plugs were loose and just twisting (yes they were like that before I tried to undo the wire connecting nuts) that is why I wanted to change them. I dont think those two, at least, were actually doing anything and one of the threaded portions just came away.

 

Anyway they are out and I have 4 new ones on order that should be here tomorrow. Thanks for the offer but everything should be okay and you wont have to go digging in those dusty ole ex Keb corners LOL.

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Hi Mike

 

Thanks for that but the old ones came out like a dream. Nothing snapped off. I reamed out the galleries with a 4 mil drill bit got a load of muck out using the grease on the bit trick. 2 of the threaded portions on the old plugs were loose and just twisting (yes they were like that before I tried to undo the wire connecting nuts) that is why I wanted to change them. I dont think those two, at least, were actually doing anything and one of the threaded portions just came away.

 

Anyway they are out and I have 4 new ones on order that should be here tomorrow. Thanks for the offer but everything should be okay and you wont have to go digging in those dusty ole ex Keb corners LOL.

Pete,

 

Good news, I've still got the original propeller, a gearbox coupling and a few core plugs and a couple of thermostats...and a worn out drive plate...........job lot?.

 

M.

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LOL thanks for the offer Mike but I have absolutely no intention of putting the old prop back on. My gearbox coupling is okay. The only core plug that is going to go would be the one that I would not be able to get at without taking the engine out so I fervently hope that a core plug wont go and I have a newish thermostat in. Worn out drive plate ??? LOL. I think the skip is probably the place for that lot but thanks anyway.

 

Pete

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Hi again all. resurrecting this thread for a quick question.

 

I replaced the glow plugs on my engine and everything went excellently, or so I thought. After replacing the plugs the engine started first time and I ran it for an hour. I then shut it down and went home. I didn't go down to the boat yesterday (Sat) so it didn't get started. I went down today started the engine and it started fine. It ran for about ten seconds and then cut out. I have had this once before and it was because the engine needed bleeding. I had had to remove one of the injector pipes to remove and replace one of the glow plugs so that, kind of, confirmed my bleeding theory. Anyway I bled the engine and it fired up first time again ran for ten seconds then cut out. Whilst I was turning the engine over I noticed that there was a tiny spurt of diesel from the pipe that I, earlier, had removed so I nipped the nut down tighter. Whilst doing that I noticed that, what appears to be a lock nut was missing. The other injectors each have a lock ? nut as well as the nut that holds the delivery pipe on. The injector pipe that I removed has lost this nut. Anyway after I nipped the pipe nut up again again I restarted the engine and this time it ran fine for about an hour.

 

So my question is, what is this nut for? I cannot find the other one although if it has dropped off the pipe when I removed it it could rolled under the engine so I will have a good look tomorrow. Is it just a lock nut or is it part of the "sealing system" for the delivery pipe? I can find another nut that will fit on if I can't find the original one as long as there is nothing special about the original one.

 

Any help would be appreciated.

 

Pete

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There should be no locknuts on the injector pipes and because of their design I can see no way of fitting one. This goes for all the fuel pipes on the engine. Has the internal flange end broken away from the rest of the nut? Anyway that would only allow it to run on 3 cylinders. It may stop on Idle but with a few revs on it should keep running.

 

There are no locknuts on the leak off pipe unions.

 

The injector pump body bleed just might look like a locknut but it is really the housing for the small bleed screw.

 

There is a locknut on the idle damper which is on the "turret" of the injector pump but the boater should never touch that (and preferably not the bleed screw that is screwed into the top either.

 

I think that you need to look elsewhere for cause of the stopping: fuel level, blockages in the fuel lines/filters, air leaks into pipes etc.

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There should be no locknuts on the injector pipes and because of their design I can see no way of fitting one. This goes for all the fuel pipes on the engine. Has the internal flange end broken away from the rest of the nut? Anyway that would only allow it to run on 3 cylinders. It may stop on Idle but with a few revs on it should keep running.

 

There are no locknuts on the leak off pipe unions.

 

The injector pump body bleed just might look like a locknut but it is really the housing for the small bleed screw.

 

There is a locknut on the idle damper which is on the "turret" of the injector pump but the boater should never touch that (and preferably not the bleed screw that is screwed into the top either.

 

I think that you need to look elsewhere for cause of the stopping: fuel level, blockages in the fuel lines/filters, air leaks into pipes etc.

 

 

HHMM okay Tony. It is an air leak from that feed pipe or at least it was. There was a little spurt of diesel as the engine turned over from that pipe. That stopped when I nipped the feed pipe retaining nut up and the engine then stayed running for an hour or so until I shut it down. The nut that I am talking about is visible on the diagram in the engine manual that I have although the diagram is a line drawing so it isn't that clear. I will take a photograph tomorrow and do a scan of the diagram in the engine manual and then see if I can post it up here. Posting pictures up here might just be more difficult than fixing my engine LOL.

 

Anyway thanks for the reply. I'll see what I can do.

 

Pete

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bmcinjectorfeed_zps02e8cf5f.jpg

EERR okay trying this from my wife's Photobucket. Why the hell can't we just copy and paste the damn piccys Dan??? Anyway here goes

hopefully.

 

Okay Tony those are the nuts that I am on about. One of them is missing from the feed pipe that I removed. I assume that it unscrewed when I unscrewed the feed pipe retaining nut and has dropped down under my engine somewhere. As I said I do have a replacement providing there is nothing special about the original nut.

 

Cheers

 

Pete

Edited by pete.i
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Right.

 

Thats not a lock nut. I is a male-male threaded adaptor that mates the injector pipe union to the injector. It should always stay in the injector until you deliberately take it out. Some more modern injectors do not have them with the injector body being threaded to accept the pipe.

 

I THINK there is a copper washer under the adaptor so you may want to take the pipe off (hold that adaptor with a spanner while you undo the pipe) and then unscrew the adaptor and fish the copper washer out. Please observe scrupulous cleanliness, you do not want dirt or grit in the injector.

 

The fuel in those pipes and that adaptor is at about 2500 psi so I doubt the air is getting in that way, but you can never be sure, especially if the fuel flow into the pump is restricted (but I still cant see how it would).

 

How can you fit the injector pipe if you have not "adaptor" in the injector? There will be no thread to screw the injector pipe nut onto. It may be one of the more modern injectors that do not use one.

 

If the threads fit then you can chop and change those adaptors.

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Right.

 

Thats not a lock nut. I is a male-male threaded adaptor that mates the injector pipe union to the injector. It should always stay in the injector until you deliberately take it out. Some more modern injectors do not have them with the injector body being threaded to accept the pipe.

 

I THINK there is a copper washer under the adaptor so you may want to take the pipe off (hold that adaptor with a spanner while you undo the pipe) and then unscrew the adaptor and fish the copper washer out. Please observe scrupulous cleanliness, you do not want dirt or grit in the injector.

 

The fuel in those pipes and that adaptor is at about 2500 psi so I doubt the air is getting in that way, but you can never be sure, especially if the fuel flow into the pump is restricted (but I still cant see how it would).

 

How can you fit the injector pipe if you have not "adaptor" in the injector? There will be no thread to screw the injector pipe nut onto. It may be one of the more modern injectors that do not use one.

 

If the threads fit then you can chop and change those adaptors.

Hi Tony

Thanks for your very promt replies on this. I don't know how the feed pipe has gone on if that is an adapter. Well i do know how it has gone on as the thread is still there. But if that nut holds the adapter in place then that would explain how air is getting into the system. Certainly bleeding that feed pipe union makes the engine work. I do not bleed any of the other bleed points and it was from this feed pipe union that I saw a spurt of diesel coming out whilst turning the engine over.

 

I shall have a look in the morning and endeavour to find the original nut. If not I do have another very similar nut that should fit. Many thanks for your help with this. I will keep you posted as to the outcome.

 

Pete

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Look IT IS NOT A NUT. It is an adaptor with a thread on both ends and a hexagon in the middle. Did you not read the bit where I said some injectors do not use such a device and have the pipe union thread formed as part of the body. If you have a thread stuck out of the injector with no hexagon then its probably one of those injectors. The pipe will just tighten up onto the thread PROVIDING the "olive" on the end of the pipe has not been flattened and it sound to me as if it might have been!

 

I would love to know how an internal pressure of 2500 PSI will allow air into the high pressure system and affect more than one injector. Even the low pressure side is pressurised to about 4 to 6 psi by the lift pump and then the transfer pump raises the pressure inside the injector pump body again.

 

If that union is leaking the engine will run on three cylinders so it may stall on idle but should not when revving a bit, but it would run roughly and jump about a bit. I think you have a crushed "olive" on that pipe that temporally seals when you tighten after bleeding.

 

Take the pipe union nut off and slide nit down the pipe so you can look at the flare on the end of the pipe. It should have nice smooth tapered sides with NO sharp flange around the middle. If there is a flange change the pipe.

 

Bizzard, Tim etc - help.gif

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Look IT IS NOT A NUT. It is an adaptor with a thread on both ends and a hexagon in the middle. Did you not read the bit where I said some injectors do not use such a device and have the pipe union thread formed as part of the body. If you have a thread stuck out of the injector with no hexagon then its probably one of those injectors. The pipe will just tighten up onto the thread PROVIDING the "olive" on the end of the pipe has not been flattened and it sound to me as if it might have been!

 

I would love to know how an internal pressure of 2500 PSI will allow air into the high pressure system and affect more than one injector. Even the low pressure side is pressurised to about 4 to 6 psi by the lift pump and then the transfer pump raises the pressure inside the injector pump body again.

 

If that union is leaking the engine will run on three cylinders so it may stall on idle but should not when revving a bit, but it would run roughly and jump about a bit. I think you have a crushed "olive" on that pipe that temporally seals when you tighten after bleeding.

 

Take the pipe union nut off and slide nit down the pipe so you can look at the flare on the end of the pipe. It should have nice smooth tapered sides with NO sharp flange around the middle. If there is a flange change the pipe.

 

Bizzard, Tim etc - help.gif

EERRRMMMM keep your hair on. I thought I was being polite and I do not need nor do I appreciate you talking to me like that even if this is on a forum. Don't worry I will sort it out myself thank you very much. Thank you for your replies prior to that little outburst

 

Pete

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EERRRMMMM keep your hair on. I thought I was being polite and I do not need nor do I appreciate you talking to me like that even if this is on a forum. Don't worry I will sort it out myself thank you very much. Thank you for your replies prior to that little outburst

 

Pete

Keep your hair on Pete. The thing you think is a locknut is an adaptor to convert the female thread in the injector body to a male thread so that the high pressure feed pipes female threaded nut will screw onto it.

In plumbing parlance the adaptor would be called a ''nipple'' a short bit of pipe with a thread at either end with a short unthreaded blank bit in the middle which is there for pipe grips or stilsons to tighten it or undo it, ''nothing to do with the nipples on a plumbers chest''. Your adaptor is similar but instead of the blank bit in the middle for the pipe grips you have a hexagon nut machined on it for a spanner to tighten or undo it.smile.png

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