Glowplugs question

[Sluggy]

Hi Guys and Girls,

I have just received a set of four 102mm glowplugs from the bongo shop - the Blueprint ADK81801 type.

My question is this... are these ceramic plugs? I can find no information either on the factsheet or on the forum to confirm this. I know they are supposed to be ceramic because they come on intermittently whilst driving (so I've been told) and metal ones would not last so long.

[Northern Bongolow]

acording to wickapedia there are no ceramic glow plugs. they are usually made of irridium, or platinum.
spark plug insulators are made of ceramic so this may give us a clue as to why, it doesnt conduct, not sure but it may give you somewhere else to look.

edit-
just reading more on spark plugs, and in fact it is a good insulator, but it can also be a very good thermal conductor,

[teenmal]

acording to wickapedia there are no ceramic glow plugs. they are usually made of irridium, or platinum.
spark plug insulators are made of ceramic so this may give us a clue as to why, it doesnt conduct, not sure but it may give you somewhere else to look.

edit-
just reading more on spark plugs, and in fact it is a good insulator, but it can also be a very good thermal conductor,

http://www.ngk-dpower.com/index.php?id=20&L=2

[Simon Jones]

That link suggests ceramic glow plugs are designed for modern Euro 4 & 5 low emission engines, so would be wasted and possibly ineffective on an engine that is 16+ years old. The ones from the Bongo shop will be absolutely fine

[g8dhe]

There appears to be some confusion here, the heating element of any plug will be made of metal, this may then be encased in ceramic to help protect the metal from the fuel etc. Ceramic itself is an electrical insulator - a very good one.

[haydn callow]

Hi Guys and Girls,

I have just received a set of four 102mm glowplugs from the bongo shop - the Blueprint ADK81801 type.

My question is this... are these ceramic plugs? I can find no information either on the factsheet or on the forum to confirm this. I know they are supposed to be ceramic because they come on intermittently whilst driving (so I've been told) and metal ones would not last so long.

They only come on/off until the engine reaches a certain tempreture. Then they stay off.
You can put a switch in the relay feed to manually switch them off.....normal plugs are fine.

[Sluggy]

Great, thanks everyone for the good advice!

I did presume that the bongo shop would only sell the most suitable ones but I had to be sure

[Northern Bongolow]

acording to wickapedia there are no ceramic glow plugs. they are usually made of irridium, or platinum.
spark plug insulators are made of ceramic so this may give us a clue as to why, it doesnt conduct, not sure but it may give you somewhere else to look.

edit-
just reading more on spark plugs, and in fact it is a good insulator, but it can also be a very good thermal conductor,

http://www.ngk-dpower.com/index.php?id=20&L=2

cheers for the info teenmal, i couldnt find anything on them through wick a wotsit , geoff as per teenmals link and my coments it is a good insulator, this stops the current leaking up the plug to the head (short), but allows the heat generated in the metal core to be passed through the ceramic because it is a good heat conductor. bloody clever these foriegners .

[dave_aber]

There appears to be some confusion here, the heating element of any plug will be made of metal, this may then be encased in ceramic to help protect the metal from the fuel etc. Ceramic itself is an electrical insulator - a very good one.

In an SRC (Self Regulating Ceramic) glow plug the heating element is made of ceramic with a sintered metal heating coil. An HTC (High Temperature Ceramic) or NHTC (New High Temperature Ceramic) glow plug has a heating element and a heater made of ceramic.

Seems technology is still developing in this area Geoff, as NHTC plugs have a ceramic heater & element. I guess there's ceramic and there's ceramic then!

[g8dhe]

I think you'll find that the markteers got at the words

heating element is made of ceramic with a sintered metal heating coil.

Now they do go on to say;

The new ceramic high-temperature glow plug ("NHTC glow plug", "New High Temperature Ceramic") has a fully ceramic heating element.

But they give no clues or better description that I can find, about the only thing that comes to mind is that rather than a coil they may have used a sintered metal inner combined with a sintered ceramic outer body and they are calling that a "fully" ceramic element, but notice the careful choice of words between "Element" the whole thing and "heating coil", I still reckon its markteering rather than technology! But I'll be happy to proven wrong if someone can find explain how they make a ceramic material conduct electricity to the extent required!

[g8dhe]

Well after some more digging it appears that some Ceramics can be made to conduct, but the treatments rather suggest that the final material is not of the usual form that's called Ceramic!
An article here http://www.britannica.com/EBchecked/top ... e-ceramics and also http://www.rsc.org/ebooks/archive/free/ ... -00001.pdf
But as the first article suggests;

Most of these conductors are advanced ceramics, modern materials whose properties are modified through precise control over their fabrication from powders into products.

And this one takes a LONG paragrapth to explain how and why they had to change the definiton of "Ceramic" to make it fit http://www.britannica.com/EBchecked/top ... d-ceramics the new materials So I guess if you change the definition you can make anything fit!