Luminosity timing

[Diesel JD]

Well everybody, I think I can safely say I figured out what was going on with my machine/ In short it is doing it's thing the way it should and as you would expect given you type in the right offset and so forth. I dug out the snapon manual and figured out how to use any cylinder on the engine by entering a different offset. The thing that messed me up over at Gus's place was that it had been awhile since I brought the meter out, so I had forgotten that advanced (BTDC) readings with luminosity are going to be positive values and larger positive numbers are more advanced. My timing reading is -2.0 to -2.5 * at 1400 rpm. If I understand this meter finally the -2.5 is 2.5 ATDC, it reads around +5.0 at idle, 700-800 rpm, so the more the throttle is pushed in the more retarded the timing gets. Now with Biofarmer's truck I have something like -5* at 1400, fairly retarded but probably ok for now. Gus, you paid me for timing the truck, I owe you, and I have it figured out now. Let's meet sometime soon at an agreed halfway point between your house and mine and we'll time both trucks, it won't take but a couple hrs at most. Somebody who knows for sure please tell me if I'm correct that ATDC readings will be negative and BTDC radings will be positive.....I'm pretty sure that is correct now!

 

[FORDF250HDXLT]

hows this setting been working out for ya JD?
do you happen to know the cetane number rating where you fuel up,and or do you have a hydrometer?

 

[Diesel JD]

Well the truck runs well there with no smoke except on startup and when I get on it, plenty of power decent boost. I thought my fuel economy was low but it sounds like it might be ok all things considered. I'm going to try bumping it closer to 0-1* ATDC but I might just wait until school is out for the semester and I have a chance to do my return lines and pop test the injectors just in case that might be having an effect. No I don't know the actual Cetane rating of this fuel but the cutoff for 1.5 ATDC was 47 and B100 of any quality is almost always this or higher. Also the energy/unit is always lower than petroleum based so these two facts lead me to believe I should go for a more advanced setting. In a way I hate to mess with it, but I also hate that I might be leaving something on the table in terms of fuel economy, or making it run dirtier than it needs to.

 

[FORDF250HDXLT]

Diesel JD,
the more advanced i turn the pump,the the lower the -ADTC reading.
or,the closer to BTDC is goes.
i went as far as -3 and man,it really sounds like way too much.i backed it down so the meter reads -6.what do you think? seems like if i kept it at -3,if i went to cold start it,she melts the gp's lol.
i started with the marks on the stock pump lined up,now it's to the pass some some,but i really feel -3 sounds too extreme,with a lot of rattle going down the road.scared the heck out of me,and i just had to back it back down to -6 ATDC @ 1400 rpm the line is still over nicely at the pass side.
i started out with the lines matching at -9 ATDC @ 1400rpm.
any thoughts?