I have a 1985 f250 with a 6.9l diesel in it and I need to change a fitting and a line and would like to know if it is possible to inter change parts off of a 7.3 injection pump I think they are the same and I have to drive to go pick the parts up so I just would like to know if they are the same.
thanks.

 

Yes. They are the same. Now there are some minor differences from truck engines to van engines, but as far as 6.9 vs 7.3 AFAIK it's the same. Make sure you have a total of four anti-vibration line clamps attached to the cluster of lines.

JM2CW

 

You need to go read the sticky "top dead center mark"; look for the post by FORDF250HDXLT

I just read through all of that yesterday; somewhere in there, it specifically states not to mix 6.9, and 7.3 injection lines. The way it read, you can swap 7.3 for 7.3, or 6.9 for 6.9, or swap entire set of lines of 6.9 to 7.3, or 7.3 to 6.9.

Apparently though, just swapping a single line will cause that cylinder to not fire properly; perhaps even knock a little. The reason for this is apparently the routing of lines=lengths are different between the two.

 

The 7.3 injector tips were positioned ever so slightly higher within the cylinder head for emissions reasons, and the hard lines were therefore a very tiny bit longer. As I understand it you can interchange 6.9 and 7.3 lines but only as a set, otherwise the the one cylinder will have a different ignition timing and it will not run right. 7.3 pick up trucks had the timing adapter on cyl #1, vans had the adapter on cyl. #4, but they are otherwise the same and are interchangeable.

 

I had no idea it was for emissions. If so, then would that lean towards indicating you'd get a slight bit more of horsepower out of a 7.3, running a complete set of 6.9 lines?

 

The difference would be in the heads. The line length just compensates for the nozzle position. The only thing running 6.9 lines on a 7.3 would do is create a tiny shift in timing. Not enough to notice unless it is just one cylinder firing at a slightly different time, making the engine run rough, similar to unequal injector pop pressures.

 

ok so will it work if I put a full set of 7.3 lines on my 6.9? and is the injection pump the same on the 7.3 and 6.9?

 

As long as the whole set is switched you should be fine. There are differences in the injection pump as well, but they interchange. 7.3's are capable of delivering slightly more fuel, so depending on how it is calibrated you might need to turn the fuel screw down a tad (if you get black sooty smoke).

 

Second the comment to use all four line clamps. Make sure the clamps and the lines do not touch by positioning the rubber dampers correctly. I did not replace all of mine and ended up stranded, performing field surgery, , on the capital beltway.