Glow plug tip color: Orange sufficient? (1 Viewer)

[bikemaniac]

Hi,

I am playing around with my L engine (2,2 liter diesel engine with the 7 volt super glow system). I had some starting problems recently and I am trying to weed out the problems.

I pulled out all 4 injectors which allowed me to have a clear view on all 4 glow plug tips while installed. Without starting the engine itself I engaged the glow system with its 2 glow plug relays by just turning the key and watch through the injector holes what the glow plugs were doing.

I observed that all 4 glow plugs turned orange after a few seconds, all with the same intensity. I did the test while it was dark to get a clear view of the color. I was not able to make a good picture but the color resembles this:

Is that color (=degree of heat) sufficient for starting or should it be more bright yellow?

Lucas

 

[Prairie Swamp]

I would say orange is correct. A better method to know if they are good is to measure current when voltage is applied. You should be able to find a spec somewhere or compare to a new known good. And this technique lets you check then without pulling anything.

 

[GTSSportCoupe]

I would say orange is correct. A better method to know if they are good is to measure current when voltage is applied. You should be able to find a spec somewhere or compare to a new known good. And this technique lets you check then without pulling anything.

As current can be limited by poor connections or worn relay contacts, measuring the plug resistance is a better option yet. I=V/R (Amps=Volts/Ohms)

 

[Prairie Swamp]

I've been known to install an ammeter in a car. If it's not pulling 48-50 amps while glowing there's a problem with something..glow plugs, fuse, relay, wiring.

 

[roscoFJ73]

If you touch one when they are glowing you will know its hot enough. It doesnt take a huge increase in combustion chamber temp to help[ a diesel start.
Ive left a 1HZ in the sun in 42c. It cold started before the glowplugs even get hot.

 

[bikemaniac]

If you touch one when they are glowing you will know its hot enough. It doesnt take a huge increase in combustion chamber temp to help[ a diesel start.
Ive left a 1HZ in the sun in 42c. It cold started before the glowplugs even get hot.

Yes, but then the entire engine block is 42 degC. If the entire block is -10 degC and only a small tip is 600 degC (=orange) then its a different story. I think when the tip is bright yellow we are at approx 1000 degC.

 

[roscoFJ73]

Yeah , but people pour hot water on cyl heads and they start in cold conditions.

 

[roalco]

In a Canadian 3B with super glow, the plugs are supposed to be 6 volts, I have tried 7 volt plugs, they worked, but not as well, as they are not reaching the same temp in the same time.
Bosch states the design tip temp of a glow plug should be 850C to 1100C. So as a rough guide, Orange to light yellow, for the correct period of time should give the heat you need to get the atomized fuel to combust in the air charge.

 

[bikemaniac]

I measured 8,5 V across my 7V glow plugs during first period and 4,5V during the second period (after glow period).