Hello acy76. At this point, these are the numbers are for the C223's and most likely any other engine that this part number glow plug is recommended for such as the 1.8 Isuzu.....I am setting up a Toyota 2L-T diesel in the next few weeks or months (its a transplant) for a friend and he wants to use the "method" and we will see if similar reads occur.............

I am fairly sure the "method" holds true to any IDI....the actual readings may change with glow plug design and 6 or 12 volt rating........the cylinder temperature relationship should hold true ...........

I do know that a couple of glow plug manufactures have patents on the basic "idea" and some are very old.........some in 2005......

regards,
crossbones

Hi Crossbones

I'm also following this with interest, but I have a different engine (4BD1T).
I already have EGT probes and thermocouple readers. Do you know if the glow plugs are close in performance to a J or K type thermocouple?

Also how do you recognise a dangerzone with a cylinder head temp probe? It is as easy as a max temp like with EGT's?

Forgot to ask about this earlier - have you excluded direct-injection diesels from this statement because so many of them lack glow plugs, or is there something else that renders it ineffective on DI engines? The 4JB1-T I've got is DI, but it does have glow plugs.

Hello all. I do not have exact answers for your questions.......this is what I "assume" at this time and it may change as more information is found.........as long as there is a means to get a temperature relationship from inside the cylinder on a DI, it will work as well......

I use a Type B thermocouple chart as reference for the C223 glow plugs ( I have this information in a spread sheet that applies many other variables to "predict the glow plug reading" or to take the readings and tell me the conditions that are producing the readings......)

What is important is the relationship of the glow plug readings to power/efficiency............It is easy to think that increasing the cylinder temperature gives more power and it does to a point.........the smoke limit is this point where power and efficiency start going in opposite directions very quickly.............

Basically, what I want to achieve is to convert the most heat into power with the least amount of fuel........easy ain't it......

ok, back to the relationship...........now lets say we are driving on level ground at a fixed speed or rpm, the injector pump is supplying a fixed amount of fuel......the coolant system is absorbing a fixed amount of heat....there is a fixed amount of heat going out of the exhaust and a fixed amount of heat converted to power...........

now with all of these variables we have a "total" fixed amount of heat available from combustion......we are now tring to increase the percentage available for power............in order to do this, we have to decrease the available heat for the coolant system and exhaust.............."rob Peter to pay Paul"................

The rules of the "relationship" are very simple: as long as you are decreasing the glow plug readings and the power is increasing you are improving efficiency and water jacket and exhaust temperature will decline...........smoke levels should decline as well...........

Catch 22's: as water jacket temperature decreases you will need to take measures to bring it back up to (top radiator hose temperature of 195?F)

you Must have very clean and set injectors to OEM pop off and they Must not drip at least at 75% of pop off pressure(I personally use 100%) before any timing changes.......................

if you are at the point of changing your timing.........you must pay attention to the way the engine starts.....at the first sign that it is backing up on the starter......you must retard the timing NOW..................

install a temperature sensor in the intake inlet.......a very powerfull relationship there...

I hope this gives you idea's on how to find your relationships...............they have to equal out.....if one goes up, then one must go down.............

please report your findings...

regards,
crossbones

I didn't forget about doing the testing, CrossBones--just haven't had a chance yet. The CSD seems to be fine (according to your test method). Still need to remove the bar between the glow plugs and test them individually.