Glow Plug Destroyer - see pics...

[Johnnojack Senior Member Find all posts View Profile Close Johnnojack]

Re: Glow Plug Destroyer - see pics...

Hi Nuddy, so sorry you have to drive a LPG car. Just joking. From laws of thermodynamics (PxV/t =a constant) since a diesels compression is constant and the cylinder volume is constant the heat generated from compression will also be constant or unchanged. The difference comes when an engine is dead cold and the heat generated is instantly conducted into the cold metal of the head and the piston, result- auto ignition temperature isn't reached and the motor won't start. Hence heating is needed by glow plugs or whatever. Once when we camped on the Nullabour I had not flushed the vege fuel for long enough and to add to that next morning we had a frost. No go. I lifted the bonnet and heated the aluminium inlet manifold with a small gas torch, luckily I keep the motor clean so no chance of setting it alight, after about 5 minutes of careful warming we had startup.

[Tony From West Oz Vice Chairperson of WARFA Find all posts View Profile Close Tony From West Oz]

Re: Glow Plug Destroyer - see pics...

Gilfish, yes i think you are right about butane, not propane.
tbird, I think by connecting 2 x 12v plugs in series you create the same effect as a 24v plug, do this on the bench and observe, you can play with as many combinations or single plugs of diff voltage and observe how much they glow, or just get hot and smoke a bit.
To have them in series you would need +ve to terminal on GP #1 , then a wire from GP #1 body to terminal on #2 GP , then _ve wire to #2 GP body.
From what i understand you have done the same thing in the car, just reversing polarity on one plug, using the engine block as a connector, not an earth.Good thinking.

Dagwill, that would be a problem as the engine block is the earth for all sensors and for the alternator and starter motor as well. GPs are available for diesels with 24V electrical systems. The main issue I see is getting a GP with the correct dimensions for your engine.
Tony

[dagwill Senior Member Find all posts View Profile Close dagwill]

Re: Glow Plug Destroyer - see pics...

Hi Tony from what I understood [ thats not much ] tbird used a separate battery +ve wire from that battery going to terminal on #1 GP and _ve wire going to the terminal on #2 GP . The resulting circut is TOTALY independant of the circut involving the battery under the bonnet involving sensors and engine earth.
Current flows to connecting terminal on #1 GP via engine block to body of #2 GP and back via connecting terminal to the extra battery used.
It should work ok ,but i would be a bit afraid of un fussed circuts blinding flashes and blinking eyes.
Testing different GP voltages on the bench and selecting the desired voltage to give a dull not bright red, and go from there, I think is safer.
Yes selecting the right GP dimensions would be important, correct thread pitch and length of element "finger" [ for want of correct name ]

[Tony From West Oz Vice Chairperson of WARFA Find all posts View Profile Close Tony From West Oz]

Re: Glow Plug Destroyer - see pics...

That works for GP 1,3,5 & 2, 4,6 but if one GP failed then there would be a higher voltage across the 2 remaining on that side of the circuit (all 6 shade the block as the common terminal). It would be easy to fuse that arrangement.
You would need a separate charging system (from the earthed alternator) for the GP battery.
If you have a friendly GP retailer, perhaps they could get a selection of GPs of different voltages, which could meet the dimensions, in and return those which were not suitable.
Regards,
Tony

[Captaincademan Senior Member Find all posts View Profile Close Captaincademan]

Re: Glow Plug Destroyer - see pics...

Well I had a few minutes to myself yesterday afternoon and checked the glow plug operation.

runs at 14.0v for a few seconds after glow light goes out (which is quite a long glow).

then the second glow continues until the engine is warm to the point that the coolant starts to register on the temperature gauge, which at idle was a good 5 minutes or more. I should have timed it, but I did not expect it to stay on that long. it kept running at 14.0v.

I will actually time the sucker when I get a chance. probably next weekend now, as the neighbours wouldn't appreciate me dicking around with it at 4.30am.....

[tbird650 Senior Member Find all posts View Profile Close tbird650]

Re: Glow Plug Destroyer - see pics...

Wow, this thread is turning out to be such a great discussion. The sharing of ideas and the collective knowledge!

I was encouraged by my test yesterday with the 2 GP's on a separate battery. I'll retest today. By noon forecast temperature will be 10°C. Feeling confident..
Longer term I like the idea of 24V GPs. Agreed finding some of the same dimensions is a challenge. Of all the GP's I've pulled at the scrap yard so far, only one set were the right dimensions but they were 12V and dead. For some reason I'm thinking 24v Landcruiser are close for dimensions,, not sure.

The other way to help cure this problem is to continue improving my fuel. Currently I use about 20% bio in my fuel manufacturing however I haven't made bio since last year due to the price of pump diesel being so low. My diesel distillation cracking plant is in mothballs for the same reason.
BTW, the originator of this thread was running SVO when he had the GP failure. If ran pure bio, I doubt he'd have the same issue.

[dagwill Senior Member Find all posts View Profile Close dagwill]

Re: Glow Plug Destroyer - see pics...

Just sitting thinking about my own setup and how it might be relevant to this thread.
Original GPs 6v Automatic relays would supply 12v for 4 sec. and then cut back to 6v for 30 sec.
Added manual overide push button supplying 12v, so i could give GPs another couple of sec. at 12v ,,,,,BUT,,,, if i got a bit over excited with the button i would fry the GPs Hmmm.
Did away with original relays etc. Using only manual push button and 100A relay to bus bar. changed GPs to 12v so theoreticly I can push button as long as i want without burning them out.
Added a volt meter, reading voltage at bus bar, mounted next to manual button.This V mtr is really handy because it not only tells me yes current is going to GPs but once you are familiar where the needle sits, it also indicates if one or more Gps are faulty as the voltage becomes a little higher as there is less current draw. Now this system worked fine for 1yr or so, good start, no burnt Gps, BUT , one thing i couldnt explain was volt mtr only ever showed 10v , now GPs draw say 50A but this should not drop voltage that much? Well if im only getting 10v maybe 10.5v GPs would be better suited , so i installed 10.5v GPs. Didnt start any better [ was starting ok anyway ] and soon burned out GPs. Went back to 12v GPs and no probs for another yr or so. Not sure of the brand of the 12v GPs but the tips are slightly thinner for the last 4 or 5mm and they have lasted 2 yrs daily drive. PS that volt mtr was only $4 off ebay ,might check it with multi mtr.
If you change GP voltage,experiment etc and still no luck. Look at overfueling, as diesels are revers to petrol engines, too rich and overheat.

[tbird650 Senior Member Find all posts View Profile Close tbird650]

Re: Glow Plug Destroyer - see pics...

I started the van today at noon. It started, with glow time of 30 - 40 secs. It fired pretty good considering only 2 glowies are working. In addition the main battery is on its' last legs. I drove 15km stopped and it restarted after 30 mins with no glow. ... it's all I need it to be and that's with only 2 GP working and at reduced capacity!

Re: overfueling. Yes, that's something I studied a few times. Burned out GP on Google gets lots of hits with 'overfueling'. Certainly you can turn the fuel down, easy done but you also lose power. In my case it didn't solve anything.

Cetane improvement might help GP life. As readers will no doubt already know, cetane is the fuels' ability to have a very low resistance to ignition. Exactly the opposite to what octane is. The thought is, if the fuels' cetane could be enhanced, it would ignite quicker, burn faster and cleaner. Therefore it could equate to less engine deposits. Certainly it's known for its' ability to clear exhaust emissions.
Ethylhexyl Nitrate is widely used but in searching for it, I haven't been able to find a supply that's not stoopid money.

[Tony From West Oz Vice Chairperson of WARFA Find all posts View Profile Close Tony From West Oz]

Re: Glow Plug Destroyer - see pics...

Just sitting thinking about my own setup and how it might be relevant to this thread.
Original GPs 6v Automatic relays would supply 12v for 4 sec. and then cut back to 6v for 30 sec.
Added manual overide push button supplying 12v, so i could give GPs another couple of sec. at 12v ,,,,,BUT,,,, if i got a bit over excited with the button i would fry the GPs Hmmm.
Did away with original relays etc. Using only manual push button and 100A relay to bus bar. changed GPs to 12v so theoreticly I can push button as long as i want without burning them out.
Added a volt meter, reading voltage at bus bar, mounted next to manual button.This V mtr is really handy because it not only tells me yes current is going to GPs but once you are familiar where the needle sits, it also indicates if one or more Gps are faulty as the voltage becomes a little higher as there is less current draw. Now this system worked fine for 1yr or so, good start, no burnt Gps, BUT , one thing i couldnt explain was volt mtr only ever showed 10v , now GPs draw say 50A but this should not drop voltage that much? Well if im only getting 10v maybe 10.5v GPs would be better suited , so i installed 10.5v GPs. Didnt start any better [ was starting ok anyway ] and soon burned out GPs. Went back to 12v GPs and no probs for another yr or so. Not sure of the brand of the 12v GPs but the tips are slightly thinner for the last 4 or 5mm and they have lasted 2 yrs daily drive. PS that volt mtr was only $4 off ebay ,might check it with multi mtr.
If you change GP voltage,experiment etc and still no luck. Look at overfueling, as diesels are revers to petrol engines, too rich and overheat.

Dagwill,
There will be voltage drop between the battery and the GP Busbar due to the wiring resistance and the current flowing. With 6 GPs at 50A, the total draw is 300A from the battery. To drop 3V that would only need a resistance of 0.01 ohm (which is pretty low resistance) in the cabling and battery. I would be happy with 10.5 V at the Busbar.
Back on P1 of this discussion, there was an explanation by Bosch(?) that the burnt GP was due to over fueling.
Regards,
Tony

[Qwarla Senior Member Find all posts View Profile Close Qwarla]

Re: Glow Plug Destroyer - see pics...

With 6 GPs at 50A, the total draw is 300A from the battery.

I think you are a bit off with 50 amps per glow plug.
In my experiance I have measured a current draw of 10 amps until the plug is red hot where it then reduces to around 6 or 7 amps.

[Tony From West Oz Vice Chairperson of WARFA Find all posts View Profile Close Tony From West Oz]

Re: Glow Plug Destroyer - see pics...

I think you are a bit off with 50 amps per glow plug.
In my experiance I have measured a current draw of 10 amps until the plug is red hot where it then reduces to around 6 or 7 amps.

took the 50A figure from the post I quoted.
If the current is actually 10A per GP, then the total current is 60A. The resistance which would cause a 2.5V drop with 60A flowing is 0.42Ώ. This would include battery internal resistance, contact resistance and wiring resistance.I hope this helps,
Tony

[dagwill Senior Member Find all posts View Profile Close dagwill]

Re: Glow Plug Destroyer - see pics...

Thanks for info tony , 50A for the Gps was an off the top of my head figure for Total GP current draw. I just assumed with that current the voltage would still be up around the 12v mark. seems its not the unsolvable problem i thought it was, Thanks

[craigcurtin Senior Member Find all posts View Profile Close craigcurtin]

Re: Glow Plug Destroyer - see pics...

Thanks for info tony , 50A for the Gps was an off the top of my head figure for Total GP current draw. I just assumed with that current the voltage would still be up around the 12v mark. seems its not the unsolvable problem i thought it was, Thanks

You probably know this buy you can get self regulating glow plugs that will do an extended glow at a lower voltage - Bosch Duratherm is the make for my car.

Craig

[hobie1kanobie Donating Member Find all posts View Profile Close hobie1kanobie]

Re: Glow Plug Destroyer - see pics...

when I was running svo in my hilux, I would go thru plugs at a rate of about 20000 kays. probably due to evilbay plugs. but at 40 for a set of 4 I didn't worry too much. Hilux is long gone now. and as far as I know its still running.

[tbird650 Senior Member Find all posts View Profile Close tbird650]

Re: Glow Plug Destroyer - see pics...

Update: I've been continuing to use my glow plug set up outlined upthread and it's working nicely. Still waiting for some 24v GP's to show up at the scrap yard but there's no hurry, what I got is working.