Just as a side note, I can barely quench my curiousity as to how it seems all of these (99-03) trucks sound different from one another. Even stock for stock. Every time I hear one out in public idling, that is the first thing I notice. But there are so many possible variables in play that is makes it very hard to come to a conclusion.

 

Many swear up and down that adding about 40:1 two stroke oil to the fuel makes theirs quieter. From recollection it was mostly Excursion owners, maybe 'we' think they should sound more like a soccer mom car than the bad azz heavy hauling diesel truck that it is. I tried this and checked it with a DB meter app on my phone as well as my ears and found no change. I then added WMO at about 40% oil/fuel mix and found no change, other than a bit more smoke on a cold start. The WMO I used wasn't truly WMO, it was mostly used hydraulic oil and ATF along with a little bit of old cheapo 2 stroke oil and some other unused motor oils that I had no use for. But still quite different from #2 diesel fuel so I expected a change.

My IDI might be a little less clattery on 100% WMO vs. diesel fuel, but that's an extreme change in fuel for maybe a minuscule change in sound. Neither engine shows a discernible change in power between the fuel types. I don't do great MPG monitoring so I don't have hard numbers between the fuel types, but that also doesn't seem to change.

 

BTW, running a heavy mix of oil on a cold day with old dirty in-tank filters makes your fuel pump sound very unhappy.

 

1. sure, but for there to be no "crushing" taking place all those surfaces would need to be machined both perfectly flat and parallel with each other and at a perfect right angle to the injector bore. to machine all 6 surfaces that precise would be both unlikely and cost prohibited. any minute deviation creates a high/low spot and now that causes never tension and acts as a spring. during the heat cycles the relatively soft ( compared to the injector tip and head ) cup and washer go through plastic deformation and become the shape of their mating surfaces, as that process happens the springiness goes away which would reduce the torque value of the bolt.

2. I think they used copper for the same reason brake calipers and other banjo type fittings use copper washers, because it deforms easily and conforms to the shape of the matting surfaces making it a good gasket. if you used steel in all of those surfaces it would require a greater degree of precision to make them all perfectly flat and parallel.

then again, its just my observation and a theory based on the design and materials I see and the challenges the engineers faced to make it seal and still be reasonably inexpensive to manufacture,

 

Fair enough. No right or wrong here, just sharing personal experiences and results.

I wouldn't, denatured alcohol is toxic. I use Isopropyl with the concentration over 90%, then blow tho holy snot out of it with air.

 

It seems like 95% of 7.3s in the wild get by to a zillion miles or more even though many of us might say they could use a retorque. Mine probably would have gone another zillion miles. I retorqued mine when I shimmed my armature plates and didn't tell my girlfriend to expect anything different. I was satisfied by the quieter running and she mentioned it the first time she rode in the truck afterwards. Maybe she knows more than I give her credit for or maybe retorque helps.

 

You make some very good points.

The cups I just installed are the machined stainless ones from Clay. They are significantly more rigid than the stock brass cups. I am hoping this results in less loosening.

 

I'm just going to throw my two cents in here. I've owned one 7.3 in my life and changed the injectors once. So you definitely wouldn't describe me as very experienced.

Here's what I did: I torqued them down to 120 in-lbs with the existing hardware. The holes had oil in them and I figured that was good enough to lubricate them to ensure a reasonably accurate torque reading. No loc-tite! That just seems like a really bad idea to me. Then I ran the engine for an hour and torqued them down again (the "hot-torque"). They all took 1/4 to a 1/2 turn to return to spec - this is why loc-tite is a bad idea! The looseness wasn't because of the bolts backing out, it's because the injector has to seat itself into the bore, and the 60 minute vibration and heating cycle solves that. If you use loc-tite, you're just ensuring that the now-loose injectors won't back out any further, but you still aren't using the correct torque values.

Then I put everything back together.

This was in March 2017. Fast forward to late last year and 30,000 miles later. I was fixing a glow plug problem and had the driver's side valve cover off. I checked the torque on all four injectors on that side and two of them moved a tiny bit. The other two didn't move at all before the wrench clicked. I'm 100% satisfied that the injectors are torqued correctly and will stay that way.

I have an inexpensive set of Tekton torque wrenches. No idea how accurate they are as I've never had them checked.

 

So what I take from this thread is I should have used a torque wrench when I put my injectors in. oops

 

I am sure as many or more people screwed this up USING a torque wrench as those who did not.

10-12ft lbs is not very much. I’d say you are gonna be FINE!

 

Hmm, food for thought here. I will soon be doing injectors, glow plugs, gaskets w/harnesses. The shop manual only says torque to 10 lbf/ft and nothing else.

 

That is all 99.9% of people have ever done. Re-torque is only discussed on this forum.

Please be aware that torque wrenches can be up to 20% off at the extremes of their range and parts store and HF torque wrenches are not reliable in any torque range.... I know of a few people who broke bolts using a tq wrench and there are stories in this thread where people appear to have not gotten them tight enough.

10ft lbs = 120in lbs

 

It's really surprising that no one really talks about re-torquing or hot-torquing injectors outside of this forum, given: 1) how much the injector "settles" in the bore, reducing tension on the hold-down bolt, and 2) how important Alliant says injector torque is.

 

I would really like to know how they put them in at the factory. They must have tooling that allows them to insert the injectors with a higher and more controlled force, before even installing the lower hold-down bolt, initially seating the injector better than we can. Particularly when we're trying to re-install the rear injectors while the engine is in the truck.

 

Nope. Every factory injector hold-down bolt I've ever tested was below 100 in/lbs of torque - sometimes as low as 80. That's going all the way back to 94.5 7.3L