I have a 1990 7.3IDI, Ford recommends 1 degree and International recommends 3 degrees. What timing specs do y'all use?

 

International built the engine, I would go with their specs. That's just my opinion though.

 

8.5


"I'm not a fan of timing above 9 degrees. I've had issues with it and WMO eating glow plug tips. I stick to the 8.5 and even with the newer fuel, I haven't gotten any unfavorable results. The changes in fuel have decreased the energy in it, but not the flash point. If you want more energy, just push your foot down further.

The Cetane rating is Higher thus, it combusts Sooner so theoretically, we should be retarding our timing. Not advancing it, if your trying to compensate."
-Mel (the Moose pump builder,when discussing the new ULSD fuel.)

"The problem with the lumy method is it relies to heavily on the injector, and the readings can be erratic. In theory the method is sound, but in application it falls short. Just ask anybody who has every done both, and your going to hear pulse is the way to go every time. Todd was over my place last night, and I timed his truck to 8.5 PBTDC on the nose. He was 3 degrees retarded. Man that thing will scoot now!"
-Mel

Todds reply:
"Thanks again Mel!
I'll post next week after I run a tank or two through to see how my mileage is. My truck definitely likes 8.5 deg timing!
5.5 degrees was with the marks lined up on the pump, for what it's worth. It seems like 3 degrees has made a big difference.
BTW if you're considering any Moose products, I highly recommend them. The service can't be topped
-Todd

"If you were burning waste motor oil or could (potentially illegally) find leftover old fuel you'd probably want to retard the timing in the general vicinity of the book timing specs and those were 8.5 BTDC at 2000 RPM +-2 degrees with the pulse method or anywhere from 1.5-5* ATDC with luminosity depending on cetane rating. "
-Diesel JD


i had to "borrow" a few posts,as most here so far,use the "by sound" method.-im trying to help discourage that madness lol.engine timing is not hand grenades and horse shoes.

i see this often recommended in searches:
Ferret Instruments V765-01 Injector Tester - Fuel System Tools

oh cool! i found my favorite from Mel:

"Get a meter on it! Why waste your time setting it from one "guess" to another? Glow plug damage, and hammering of the wrist pins can result from too much advance. Not only that, but you will never know if your IP is working properly, because someone who does it properly will know what the timing looks like at idle, and through the RPM range to the target speed. Timing by ear will only get you close. 2 degrees makes a BIG difference, and that is about as close as you can get it by ear... if your good. If you land it at 8.5, it's not because your good. It's because your lucky. "
-Mel

oh double cool! i found the other post i really liked from Mel too,thats good to know:
"It's not a bad idea to have your timing checked every 20-30K miles. It's going to creep in the retarded direction as things wear, and fuel delivery for any given throttle setting is going to decrease. Fortunately as injectors wear, their pop presure lessens so things can sort of stay even, but there are no guarantees. "
-Mel

 

After replacing a head and re-installing the IP, I lined up the marks and it was 8 degrees advanced. The truck blew black smoke whenever I push the accelerator more than 1/4 of the way. I turned it down to 3 degrees, International specs, and it doesn't smoke anymore but runs a little rough at idle.
Does the rough idle have anything to do with the timing?

 

Depends which timing method is used, there is pulse and the lumy method, IIRC pulse is 8.5 BTDC + or - 2 degrees , but timing a 9.7 BTDC seems to help alot better with todays fuel,

IIRC the lumy method is when you time ATDC and its somwere around .5-1.0