which ones should i get

 

motorcraft, IH, buer, or wellman.all 4 good plugs.
buer makes motorcarft and ih i belive.

 

Bosch and Beru are good ones. Just make sure to use proper applied torque.
To much torque closes the top gap and causes plug fail.

 

do not use bosch in the 6.9. same with ac delco. they are prone to swelling and tips breaking off.

 

Plugs are very seldom cause of failure:


Heater element with folds and hollows
Causes
Open circuit coil due to

•Operation at too high voltage, e.g. on jump starting
•Excessively long current feed due to sticky relay
•Incorrect post-heating with the engine running
•Glow plugs that can be post-heated not used (type GN)
Rectification

•Only jump start with 12 V electrical systems
•Check the pre-heating system, replace automatic pre-heating relay
•Fit glow plugs that can be post-heated


Heater element melted or burnt away
Causes &
Overheating of the heater element due to:

•Injection starting too early
•Coked or worn nozzles
•Dripping nozzles
•Engine damage e.g. due to piston seizing, valve damage, etc
•Seized piston ring
Rectification

•Adjust injection timing exactly
•Replace complete injector


Connecting bolt broken off, hex head damaged

Causes

•Connecting bolt broken off: the connecting nut was over tightened
•Damaged hex head: usage of inappropriate tool; due to deformation the plug has a short circuit from the housing to the circular nut.
Rectification

•Use a torque wrench to tighten the connecting nut, tightening torque for M 4 thread: max. 2 Nm, for M5 thread max. 3 Nm; do not oil or grease thread.
•Tighten plug with suitable torque wrench; observe stipulated tightening torque exactly (can also be obtained from the vehicle manufacturer's information). Do not oil or grease thread.


Tip of heater element damaged

Causes
Overheating of the heater element due to

•Injection starting too early resulting in the heater element and heater coil being overheated; the heater coil becomes brittle and breaks.
•Annular gap between plug housing and heater element reduced, as a result too much heat flows from the heater element, the regulator coil remains cold and permits too much current to flow through the heater coil that then overheats.
Rectification

•Check injection system, adjust injection timing exactly.
•On fitting a glow plug, it is imperative that the tightening torque specified by the manufacturer is observed.

 

yes, the 6.9 glow plug system is a bad design. thus the reason alot of us switch over the the 7.3 idi glow plug system.

the stock 6.9 system will overheat the plugs,(bosch,acdelco) and cause them to swell.

motorcraft, buer, and ih rarely swell when left on to long.

wellmans are a different game, they are dual coil, thus taking a little longer to warm up, so not getting as hot witht he stock setup.

 

thanx guys

 

my first set of motocraft lasted exactly 1 day.. replaced with bosch and they worked for a year, and still good now.

they are 6v plugs and they are fed with 12v so they heat up instantly, it's also why the controller timing is so critical.

 

all the plugs for 6.9/7.3 idis are 6 volt.

 

you can swap in a 12v plug I remember reading, that way it's hard to burn them up once your controller goes bad for the 10th time and you wire them to a pushbutton