I work in Northern Alberta on oilsands operations and cold weather there is really hard on machinery. Most of the big diesels run 24/7 because it is a problem getting them going at -40 degrees. One of the tricks the mechanics use to start small diesels with glow pugs, is to attach a battery and booster cables directly to the glow plug circuit. This ensures lots of power to the plugs.
This works o.k if they are 12volt plugs but a lot of them are 8volt and they burn out. Make sure you know what your voltage is if a tow truck driver wants to boost in this manner.
glow plugs and cold starting
This would work if your GP timer was out. I just cycle the switch after 10 seconds to get a second heating cycle or more if necessary.
One thing to keep in mind is that on the 524 each GP has a seperate circuit from the timer relay and each one has a resistor. The resistor is 5 turns of resistance wire and provides less than 1 volt drop to each plug. If you jump 12v to one plug it will give that plug full voltage but will have to reverse feed through that glow plugs resistor and through the other five resistors to the other five plugs. This puts 5 times the current through the one resistor that is backfeeding and could heat it up and burn it out over time. Plus you would get much less voltage to the other plugs due to the extra current creating a greater voltage drop on the one resistor. I have done this in a pinch when I could not get cranked because of a blown fuse in the GP control and it will get you going but it may do damage over time.
If you jump to the GP relay terminal the GP circuit will work normal but this requires you to remove the cover to the GP control. Use big wire!
One thing to keep in mind is that on the 524 each GP has a seperate circuit from the timer relay and each one has a resistor. The resistor is 5 turns of resistance wire and provides less than 1 volt drop to each plug. If you jump 12v to one plug it will give that plug full voltage but will have to reverse feed through that glow plugs resistor and through the other five resistors to the other five plugs. This puts 5 times the current through the one resistor that is backfeeding and could heat it up and burn it out over time. Plus you would get much less voltage to the other plugs due to the extra current creating a greater voltage drop on the one resistor. I have done this in a pinch when I could not get cranked because of a blown fuse in the GP control and it will get you going but it may do damage over time.
If you jump to the GP relay terminal the GP circuit will work normal but this requires you to remove the cover to the GP control. Use big wire!
So you are saying these are not 12 volt glow plugs?
I need to look into that again.
I at one time had eliminated the controller and used a timer and a starter solenoid to power them. I don't remember if I replaced plugs with a different one or used the factory ones.
I know Kubota uses a 10mm, 12volt glow plug that will work if we need to swap these out.
I need to look into that again.
I at one time had eliminated the controller and used a timer and a starter solenoid to power them. I don't remember if I replaced plugs with a different one or used the factory ones.
I know Kubota uses a 10mm, 12volt glow plug that will work if we need to swap these out.
-
CoyoteStarfish
- Posts: 1016
- Joined: Nov 14, 2008
- Location: Miami, FL
Almost all (12V based automotive) glowplugs are rated @ 10.5VDC.
In my experience a fully charged 12V battery (12.6V) drops to 10.5V when properly loaded with glowplugs according to vehicle specs.
The glowplugs internal resistance drops overall current to this level , thus producing 10.5V since 12V isn't obtainable under load.
THIS BEING SAID, there are also so-called self-limiting glowplugs that decrease internal resistance as they heat up, so they never over-volt or burn out. This is a fairly recent improvement in glowplug manufacturing (last 15 years). I've heard of these running on a bench attached to a 12V power supply for 24+ hours.
Point here is, unless you have self-limiting plugs, if you "juice" them for too long they will either burn out or swell up in the pre-cups making them very difficult to remove.
Old mercedes benz GP relays used a timer schedule to allow the plugs to "cool" between cycles where it would turn them on and off in some crazy order like:
12sec on, 4sec off, 8sec on, 2 secs off, 1 sec on, off. (depending on ambient temperature)
My rule of thumb: if you're going to go manual... Juice it. Count to 15 then let it rest between 5-10, rinse, repeat (if necessary)
In my experience a fully charged 12V battery (12.6V) drops to 10.5V when properly loaded with glowplugs according to vehicle specs.
The glowplugs internal resistance drops overall current to this level , thus producing 10.5V since 12V isn't obtainable under load.
THIS BEING SAID, there are also so-called self-limiting glowplugs that decrease internal resistance as they heat up, so they never over-volt or burn out. This is a fairly recent improvement in glowplug manufacturing (last 15 years). I've heard of these running on a bench attached to a 12V power supply for 24+ hours.
Point here is, unless you have self-limiting plugs, if you "juice" them for too long they will either burn out or swell up in the pre-cups making them very difficult to remove.
Old mercedes benz GP relays used a timer schedule to allow the plugs to "cool" between cycles where it would turn them on and off in some crazy order like:
12sec on, 4sec off, 8sec on, 2 secs off, 1 sec on, off. (depending on ambient temperature)
My rule of thumb: if you're going to go manual... Juice it. Count to 15 then let it rest between 5-10, rinse, repeat (if necessary)