The LD engines' GPs are 12mm dia., (1.25 pitch) on the head end, and 5mm on the terminal end. Some mfgrs supply plain 5mm terminal nuts (usually 8mm across the flats) and a spring washer, others supply a flanged nut, and still others a knurled OD nut that is larger overall.
Manufacturer Part No. MY Range Remarks Voltage Picture Nissan 11065-W2500 1981-83 Beck/Arnley 176-1035 to 12/81 only (1) NAPA Beck/Arnley 176-1036 12/81-on (1) NAPA NGK 3829 (Y204TS-1) 1981 only Non-QGS Type (1)(3) 12v NAPA NGK 4573 (Y204RS) 1981-83 QGS Type (4) 12v NAPA Bosch 80017 1981-83 old #0250202013 6.5v NAPA Champion 189 1981-83 old #CH60 11v NAPA Monark 090507010 to 12/81 for 'Laurel' 2.8D 11v Autolite 1104 1981-83 (2) 11v NAPA Lucas DS016(A) ?????? unverified app 6.5v Beru (PDF) GV 888 1981-83 "Order No." 0 100 220 113 6.5v Delphi (PDF) HDS231 1982-84 prob. 12/81-83 6.5VNote 1: BA & NGK seem to be the only mfgrs to have a separate GP listing for 1981-early-'82.
Note 2: Don't use Autolite GPs. Why? It's been confirmed that the Autolite GPs, when used in the 6.9l/7.3l Ford (IH) engine, swell when overheated, as can happen with certain faulty GP controllers (in the Ford application) or user-installed GP controllers (in all applications). The swollen GP tip then breaks off when removing the GP, and falls into the cylinder where it can ruin the piston if not removed -- and removal of the tip can mean removal of the cylinder head.
Note 3: (from NGK)
Note 4: (from NGK)NGK wrote: Quick-start type
Quick-start type glow plugs are a type of sheathed glow plug that have a heating curve whose resistance changes with the temperature. The resistance is initially low so that plenty of current flows through the heating curve. The temperature increases faster than in standard plugs – and as a result the preheating time reduces.
Generic GP removal advice:NGK wrote: QGS sheathed type
A QGS sheathed glow plug heats up extremely quickly. However, a special QGS control device is needed. There are two different, non-interchangeable types of quick-start glow plugs. The first type has one heating coil with a low resistance which is designed for an extremely high current flow. The second type has both a heating and a control coil. This guarantees that the resistance increases with temperature and therefore provides a certain degree of temperature control. These glow plugs have very short preheating times and improve the cold start performance. Safety information: If the voltage is generated for too long and the temperature is too high, the glow plugs can melt and crack. Therefore the control device or relay must either reduce or completely switch off the current flow as soon as a temperature of about 900°C is reached.
If you are removing a glow plug, and it turns with reasonable torque for a turn or two, but then becomes hard to turn, STOP. Remove that cylinder's injector, bring that cylinder's piston to TDC, then remove the GP. Chances are that the tip of the GP will break off and fall into the prechamber (and then the GP will turn easily again). If the piston is at TDC, the broken-off tip can't fall out of the prechamber and into the main cylinder. With the injector and GP removed, you can now use compressed air (in the GP's hole) to blow the tip out the injector hole, thus avoiding the need to remove the whole damned head.
Don't think you can just start the engine and "blow it out the tailpipe", because severe engine damage can and has been done trying to use that method.