Technical question regarding 7.3 idit injectors/heads

[idi_Marty]

I was reading an article and it stated that injectors were retracted .060" from the combustion chamber on 7.3 heads. In regards to the 6.9 configuration, and that this was done for emission reasons.
My question is, that is it possible and would there be any benefits to milling the injectors hole .060"? Purely hypothetical, and just curious as to the effects that it could have in regards to the precombustion chamber, and fuel combustion. Thanks in advance for any info.


1994 Crew Cab F-350, 7.3L idi Turbo Diesel, 4x4, auto, DRW, Tollesboro, Ky

 

[OLDBULL8]

Personally, I don't think there would be any advantage to mill/counter bore the injector bore them that .060 deeper. My thought is that, that .060 gives the spray more distance to spread out for better combustion (emission). I wouldn't believe any more HP or torque would be gained. If it did how would you know the difference?

 

[79jasper]

Which "article?"

R&D was just talking about that....

 

[icanfixall]

Thats really old news. R&D is a little behind the curve. I designed a special ball end mill to open up and clean the precups in the heads. They are really ruff cut oem too. When I did this to my offshore heads I sunk the cups the 60 thousands in the heads. I felt this was a simpler method instead of machining both the cups and the injecter seats. Russ aka typ4 has borrowed my ball end mill to do this to his cups. Can I know for sure it changed anything.. Nope but I know it did not hurt anything too. What you don't want to do is change the precup bowl. There is a lip built into them that works to increase the swirl. You can open up the throats but doing to the same to all 8 precups requires a comparator bench. I did that because I had one available at the time. No longer have that bench because I retired from the machine shop ...

 

[idi_Marty]

I appreciate that insight, I just really wonder how that .060" related to emissions and what the purpose was behind their reasoning as to how it made them more environmentally friendly


1994 Crew Cab F-350, 7.3L idi Turbo Diesel, 4x4, auto, DRW, Tollesboro, Ky

 

[idi_Marty]

Different subject, but I could really use some of your combined knowledge, my question pertains to the camshaft, the very front love behind the timing gear, it's eccentric, but would anyone know where the largest part of that lobe falls in relation to the timing mark for the injection pump timing mark? The reason I asked is because I am "that guy" who took the injection pump, gear and all off, lol yep, that's me. I think that I can realign the marks using that lobe as a reference for the marks. Thank you for educating me, continuously


1994 Crew Cab F-350, 7.3L idi Turbo Diesel, 4x4, auto, DRW, Tollesboro, Ky

 

[idi_Marty]

Figured out I could edit the above post

 

[79jasper]

That won't help you.
It's just the fuel pump lobe, which doesn't need timed.

There are several threads here that talk about lining it back up. Can't tell you the title's though.

 

[idi_Marty]

That's what I was thinking it was, and it's on the camshaft, which is timed and if I can figure out where the lobe is in relation to the timing marks I can roll it around to get me close, or am I overlooking something?


1994 Crew Cab F-350, 7.3L idi Turbo Diesel, 4x4, auto, DRW, Tollesboro, Ky

 

[icanfixall]

Heres a pick of the timing marks on the injection pump gear and the cam gear. Notice the DOT at the bottom of the crank gear and the DOT at the bottom of the cam gear. When your gear timing these idi engines never align the "Y" on the injection pump gear to the DOT on the cam gear. Thats a common mistake and your timing will be 180 degrees out.

now loking at what I pictured you see all the marks correctly alined. See where the drive pin in the injection pump gear is. If you removed all the wrong stuff from your engine then hopefully you were at top dead center. If you were not timed to the zero mark on the dampner and the tab you have some work ahead of you. What you need to do no matter what has been done is seperate the pump grom the gear from the housing. Now lay the gear flat and scribe a mark from the "Y" all the way to the other edge of the gear. Finding top dead center is the next job. Only if you know the engine was at top dead center can you now set the gear down in the hole where it meshes with the cam gear. Now use a square placed on the timing cover top lip and make sure the line you made on the gear it directly up and down. Not off to either side. The gear will roll from side to side but you will see what I'm talking bout when its correctly gear timed to the cam gear. When thats done install the housing. then the pump. You will be correctly gear timed if you follow these insturctions carefullly. Generally speaking you can't see the "Y" mrak and the "Y" mark on the cam gear because its so far down. Those "Y's" have to line up perfectly or your screwed without a kiss. The engine will run but poorly.

 

[idi_Marty]

That's what I was thinking it was, and it's on the camshaft, which is timed and if I can figure out where the lobe is in relation to the timing marks I can roll it around to get me close, or am I overlooking something? And I've read the articles on reinstalling, yeah never gonna do 180 degree timing lol, but I DID forget about the dampney timing, set it to 0 and check the marks, I commonly over think things. Thanks for getting me back on track.


1994 Crew Cab F-350, 7.3L idi Turbo Diesel, 4x4, auto, DRW, Tollesboro, Ky

 

[icanfixall]

We have two ways on knowing if the storke is coming up to tdc. An injecter or a glow plug must be removed. You crank the engine and watch for a BLAST of air come out the hole in the head. Be real careful because thats coming out under great pressure. Its enough to harm your eyes or stick carbon in your fingers if you have one plugging up the hole waiting for the pressure increase. The other way is to remove the passenger side valve cover and watch the valves close and hear compression eacaping from the glow plug ot injecter hole. Then hand crank it till the timing marks on the dampner and the tab down there line up. The zero mark is under all the dirt at the short flat probe location. Not the tall skinny probe location. Roitwarrior has a great pic of this zero mark.

 

[Goose_ss4]

Think over on FTE they were comparing 6.9 and 7.3 pre cups and heads, and there were some differnces and the injector clearneces. the idea was to swap the 7.3 pre cups into the 6.9 heads to get the injector closer.

 

[riotwarrior]

Different subject, but I could really use some of your combined knowledge, my question pertains to the camshaft, the very front love behind the timing gear, it's eccentric, but would anyone know where the largest part of that lobe falls in relation to the timing mark for the injection pump timing mark? The reason I asked is because I am "that guy" who took the injection pump, gear and all off, lol yep, that's me. I think that I can realign the marks using that lobe as a reference for the marks. Thank you for educating me, continuously


1994 Crew Cab F-350, 7.3L idi Turbo Diesel, 4x4, auto, DRW, Tollesboro, Ky

That's what I was thinking it was, and it's on the camshaft, which is timed and if I can figure out where the lobe is in relation to the timing marks I can roll it around to get me close, or am I overlooking something?


1994 Crew Cab F-350, 7.3L idi Turbo Diesel, 4x4, auto, DRW, Tollesboro, Ky

That's what I was thinking it was, and it's on the camshaft, which is timed and if I can figure out where the lobe is in relation to the timing marks I can roll it around to get me close, or am I overlooking something? And I've read the articles on reinstalling, yeah never gonna do 180 degree timing lol, but I DID forget about the dampney timing, set it to 0 and check the marks, I commonly over think things. Thanks for getting me back on track.


1994 Crew Cab F-350, 7.3L idi Turbo Diesel, 4x4, auto, DRW, Tollesboro, Ky

It may be a good idea but why reinvent the wheel?

You already have enough to deal with having to get it timed correctly and it's actually not that hard if you have the #1 Glow plug out and a remote starter switch. A comp tester would be helpful too perhaps?

You can BUMP the engine over, one hand above GP hole, while watching timing marks on the harmonic and if you feel air rushing out as the engine is coming to TDC and the timing marks line up on crank to 0 deg then you should see the timing mark on the top of the cam gear and align your IP gears mark to match it should be timed. Check with a small mirror or dental pick to see/feel if the cam gears mark.

Between Gary's pics and just being methodical and careful it won't be that bad.

JM2CW and I'm likely in left field with this or worse outta the park but this would be what I'd do myself if I effed it and pulled the gear cover. (which I would never ever do BTW)

Al

 

[icanfixall]

The only time I would remove the gear, pump and housing is when I wanted that from a wrecker engine. Then its just 4 9/16 hex bolts and 8 5/8 hex hard line nuts. Then lift off and walk away with the "kit"...