Alrighty Fellas I got a 6.9 in my 87 F250 and I yanked the engine to repair oil leaks around timing covers, valve covers, and of course IP Gear Housing. I marked my gears and tried to line up the timing marks but i think i might have advanced it one tooth. If I retard the pump as much as i can it bellows black smoke and sounds like a power stroke. - sounds like a advance pump to me. If I advance the pump to were it was originally it sounds very muffled with a knock or two every second.? not quite sure what that means. Maybe its just not firing on all cylinders? Also while I had pump off I Pulled injectors even though it ran fairly good and took them to school to test them and one fell apart as i pulled it fr. the head. So i replaced the injectors. Any how is there any way to retard the pump more(assuming thats the problem) before I pull the pump housing off. I havent been through engines or fuel systems yet so I am trying to learn. I would take it to school and dynamically check the timing, but I hate to drive it 80 miles like this. Thanks for everything!

 

Visit ........ http://www.members.shaw.ca/k2pilot/Timing%20article.htm for the recovery proceedure. Which way are you turning the IP, to drvrs side is retard to pax is advance, 1/16" is about 4*.

 

Thanks for the article I have read it before and i just couldn't find it. I didn't see it under the articles, maybe I should look again. But I loosened the lines on rear of the IP so I could rotate it some more and I think it is actually retarded now but atleast I can drive to work or school so I can properly time it and know I'm not going to blow through a piston going 70 down I-90. Thanks again.

 

That helps a lot. Where will the timing usually be if a person lines up the marks on the pump and adaptor housing as a starting point?

 

That info should be on the passenger side rocker cover.

Stock spec is 3.5 degrees ATDC for 43 to 46 cetane fuel plus or minus 2 degrees.

It should run a bit better a little more advanced than that though.
I am running about 7 degrees BTDC on mine.

 

Thanks again! Using your information to determine that the IP timing on my truck is currently set from 6* to 10* ATDC could explain a lot of my problems and provides a great starting point for improving engine performance. The rebuilt engine doesn't have any information on the rocker cover and the traces of yellow paint I uncovered lead me to think she may have originally been a bus or heavy truck engine.

I originally set the static timing mark to about 1/16th inch pax side of the index mark and she ran fairly cool with acceptable power. At that setting She pulled Galena Summit's 8% grade with 5000 lbs of camper and gear towing nearly 8000 lbs of horses and trailer and she didn't start to get uncomfortably hot untill just before we reached the top. After the dynamic tuneup the mark is 1/16th inch drivers side of the mark and she burns 15% more fuel and get's hot going 70 down a flat freeway with just the camper on. I'll go back to my original setting, check performance and then start fine tuning from there for optimal performance.

How should the timing be advanced or retarded to compensate for higher or lower cetane ratings?

 

If we constantly run additives in our fuel does it really change timing specs? I always put cetane boost - white jug- in my fuel it does wonders for it.

 

I wouldn't even worry about cetane ratings as most stations run the same. Any fuel remaining in the tank would mix and change cetane again so forget it, use some additives.

The 6.9 used the luminosity timing which visualizes the firing of the fuel in the cylinder on compression that is why ATDC, the pulse method uses BTDC. Pulse timing measures the injection pressure of fuel in the line before the piston reaches the TDC so firing off of the cylinder is at the correct time.......let's not mix the methods up

 

That was my fault, I am running a 94 7.3 turbo fuel system on my 6.9.
I forget sometimes.

 

The rocker arm cover off the original 7.3 engine reads. " timing marks aligned. refer to manual for dynamic timing settings" and the manual says 8.5* BTDC @ 1875 rpm.

This leaves me a little confused about the proper static setting. If static timing is set to 7.5* BTDC (acknowledging the +/- 2* possible variance) will the timing advance or retard as the engine comes up to speed and can an approximate estimate be made of what the timing would be at 1875 rpm?

Last question. Following the threads and writers comments it appears trial and error can produce excellent performance in these engines but how expensive is the timing equipment for these engines and would using it necessarily produce any better results than those obtained adjusting the timing and fuel settings through trial and error?

Thanks! Don

 

There is an excellent article by Mel of TDS and OBN fame........ take out the stars.

http://oil*****burners.net/brian/idi...nServicing.htm

It's long but the timing info is in the last paragraphs.......