Join Date: Jan 2003
Location: Neepawa, Manitoba Canada
Feedback Score: 0 reviews
Re: Best static timing for 7.3 IDI
This info from Ziggster's files....
You need to line up the scribe mark on the pump flange with the scribe mark on the pump gear housing. That's essentially it to start with. Hopefully the gear housing hasn't been removed, 'cause if it has it is possible the pump timing gear has been moved, and it is very difficult(but not impossible) to get it back to the right spot.
On the housing that's mounted on the top front of the engine where the pump bolts into, There is a small line about 1/4" long stamped into the rear/upper face of the housing just where the pump would mate to the housing. Likewise, on the pump almost at exactly the same spot on the flange of the pump where it bolts to the housing is a similar line scribed into onto the top of the pump flange.
The idea is that when you put the pump into the housing on the engine, and if you have those two marks lined up such that the almost form one 1/2" Long line, then the timing will be close enough that the engine should start and run. This is known as static timing.
Dynamic timing via luminosity is done where a probe is put into the cylinder, and actually sees the light from the explosion of the fuel, and the timing is set accordingly.
Some of us set the timing by "ear". This comes from some experimentation and experience.
I like mine so that when the engine is cold, as the cold advance is on, the engine rattles pretty loud, but once the cold advance drops off, then the rattle smooths out and the engine is much more quiet. If you have it too advanced, then it makes that loud rattle all the time, often accompanied by lots of black smoke, and if too retarded, will sound kinda flat most of the time, lack power, and often not smoke at all, or may even smoke greyish/whitish(unburned fuel).
When you are standing at the front of the truck facing the engine, if you turn the pump couterclockwise(top of the pump to the passenger side) you'll be advancing the timing, and obviously clockwise will retard the timing.
If you line up the gear cover and pump top center lines you will be able to start it.
The marks on the pump to housing are only accurate if it is the original pump from the factory. Turning the injection pump 1/16" to either side (measured at the pump to housing flange marks) that's about 4 deg. Turning IP to pax side is advancing timing, to drivers side is retarding, engine off for all adjustments and tighten nuts on IP before start.
6.9IDI ( Navistar method ): 6-7 degrees BTDC
7.3 NA: 8-9 degree BTDC*
7.3 IDI Turbo: 8-9 degrees BTDC*
93 F250 7.3 IDI S/C XLT 4X4 E40D 3.55LS, Captains chairs, Tutone Mocha, Leer 48" Hiboy cap, FR & RR hitches, full DeeZee running boards. Factory ordered/delivered Jan 93
Toys: 2006 37' Triple E Embassy coach (powered by Cummins), 18' Sylvan Pro Fish with Mariner motors.
Proud Canadian BOOB man too!!
Please PRIVATE MESSAGE only!! ...
Please DO NOT.....visitor message me...