Thanks for your kind words. Know any good bars in Kansas? (Estimated half way point between us). While I've had occasion to sneak a few peaks behind the scenes over a decade ago, I lay no claim to any expertise. Which means I'll buy the first round.

 

That's interesting. So the AE was originally a reject or marginal AD injector, then they figured out they could repurpose it for cackle reduction?

 

I think I have this narrowed down to (ironically) cylinder 8. It was cyl 8 that failed the CCT and had a high perdel reading. That injector is one of the ones that sounded strong on a buzz test. However, it's barely spitting any oil out of the spout. Since I have the VC off already, the left bank is getting all new injector o-rings being that I already suspected an HPO issue on that side. In retrospect, I should have changed them while the engine was out of the truck to begin with.

 

Right...that's how all Fortune 500 companies develop a product....thru trial and error.

Think about that for a minute. Cat, or Alliant, has a manufacturing facility in which they have processes and process controls to ensure that the product they are making meets the specification.....and if the product doesn't meet the spec, guess what? They go find the problem and correct it.

Any large machine shop has a QC department, and QC believes themselves to be another company within the larger organization. They check things, and inform the production line....before they run a million dollars worth of scrap.

 

What you were told was completely incorrect. The AE or "long lead" injector was an engineered part. It was not an accident or due to machining variances.

Just like the Motorcraft and Alliant reman injectors are also engineered and rebuilt to very specific specs.

 

What you are saying sounds very logical and makes sense in the absence of any other information, but I'm going to have to go with the leader of my group from the International Engine Plant manager's office on this one. He put in 30 years of his life with the company, was getting ready to retire, and had no reason to lie or make it up. We were standing right there in front of the test cells for the 7.3L engines when the topic came up.

I was surprised that Cat culled them too. But I'm not surprised at the existence of a variance in tolerances that still falls in line within "very specific" designed range of specifications, such that a batch of parts can be all be serviceable, and still differ ever so slightly under wavelength scrutiny. That's reality. And this is a truck engine, built to meet a minimum power level for a minimum cost, not a space shuttle. It does not take one being around a mass production environment very long to become familiar with tolerable variances in machine produced parts.

And I think that is the reason why that particular point about the AE injector was shared with me. It was to impress the point that the AE is not THAT much different than the AD. It does exhibit a longer lead time, yes, but there is a measurable variability in the lead time of all the split shot injectors... which of course includes the AD ones.

Now something else does occur to me... this conversation I had occurred when this cackle fix had just been worked out. I can't remember if it was in full production yet or not. It was during the same approximate time period when there was a trial run with PMRs, then a final run with TFRs, then a full commitment to PMRs. It could very weill be that the injectors were culled at that time, and then as the fix became committed to, the AE's then became manufactured separately.

I didn't delve so deep as to try and pin down when Cat did the culling, and at what stage of injector manufacture did the culling take place (after the injector was fully built, or as a subset or individual part was tested for tolerance. In retrospect, those would have been good questions to ask, but would have strayed way too far off topic for the work that was taking place in International's facility at that time... which wasn't building injectors... it was building 7.3s. They had another 800,000 to build at that time. And of far more interest was the new 4.5 and 6.0... some 3 years away from production, which no longer would use a Cat injector.

Anyway, I posted what I learned, from the horses mouth. It isn't conjecture or logic. It just is. Or rather, was. It could very well be that things changed the following year, or the following month. But back then, that is what the manufacturer says happened.

I never did understand why everyone is so insistent on pulling the AE out and replacing it with an AD. I do remember asking if I should pull my AD out of my personal truck and replace it with an AE, and that's when I got the reminder that they are not that different. "Leave them alone", I was told. I guess this turned out to be good advice, as I still have all ADs. But the point about them not being world's different was made.

 

Look at the parts numbers for the piston and intensifier. It appears there is a LL piston & intensifier for both the AD (AE) capacity and AC (AF) capacity injector.

 

It isn't uncommon for new products to be born from "mistakes". It also isn't uncommon for a company to look for, or even create, a market for things that would otherwise be scrap or have to undergo costly rework.

 

I missed this question earlier... and leaving it unanswered may be the reason for the drift summary of the explanation that I shared earlier. So I'm going to put a number on it:

The formerly culled injectors or injector parts (that later were likely purposely manufactured) were NOT rejects. They were functional parts produced within an allowable range of tolerances, only they were biased toward the long side of that range.

So this isn't anything like, for example, where a lumber mill that couldn't even give the sawdust from milling operations away in the old days, now makes more profit from the sawdust and chips than they do the timber.

The idea of "rejects" is a misinterpreted topic drift that exceedingly (and inadvertently) exaggerates the message I relayed.

We are not talking about that much of a difference here. To put the difference in real numbers, the maximum measurable difference between an AD and AE is not more than about 0 00196850394 inches.

There isn't enough time between 10 degrees BTDC and around 7 degrees ATDC for significantly longer lead time. But a little bit of longer lead time allows a little more fuel to get in that pre shot before the groove meets the spillway. That little more fuel maintains pre combustion heat and pressure longer and higher, so the cylinder doesn't get the shock of it's life when the other side of the groove closes off the spillway again and the main shot is dropped in.

That IS the so called cackle. That horrific spike of cylinder pressure in #8 when the main shot is dropped in because the pre shot was too cold and under fueled. International figured that if the pre shot were extended a little longer, more fuel in the prime shot would keep 8 hotter and happier to receive the main shot. It can't do this with a regular AD because #6 stalls the initial fill of 8 by firing first, and by further imposing a shockwave on the rail from it's higher pressure spill between prime and main shots.

0.00196850394 inches. 50 microns. That's the simplified, measurable, essential difference between AD and AE.

 

Look at Dan V's post. The chart shows you two completely different part numbers for the intensifier pistons that go into the AD and AE injectors. They know going into the build which injector it's going to be before it's even put together based on which part number they are using for the intensifier piston.

Your evidence is what some office guy told you during a tour? Sorry, but I deal with guys from CAT, Blue Diamond, Motorcraft, etc all the time, and I've heard them say incorrect things many times about the 7.3L, about other PSD's, diesel fuel, etc. That's because most of the guys talking are the ones selling, not actually building them.

What you heard was incorrect. Time to come to Jesus on it and understand that it happens sometimes.

 

He's tenacious Curtis.

He brings up a 50 micron number. 0.00196850394.....yeah I suppose that's the decimal conversion for 50 microns. In the shop we call that two thousandths. Not two tenthousands .0002. I'd like to see the print tolerances for the intensifier pistons.....I've never tried to assemble one, but I do know that you have to have a pretty fair touch to place a z class gauge pin in a hole that is .0002 bigger than the pin (gets easier as the hole gets smaller though). So, a shot in the dark, without seeing the part, whether it's swiss turned or turned then ground after heat treat (if there is any, I assume there is) that the shaft/neck on the piston is +0 -.0002

 

How did they "know going into the build" before building it the first time? Would they commit to an entire production of new parts from only an idea and a CAD rendering? What "part numbers" would they pick from (that didn't exist then) to verify if building them differently would sufficiently address the concern or be worth the inventory costs of maintaining another set of part numbers?

Original manufacturers build things before they become "part numbers", and may build many more things that never become part numbers, out of components that have no part number, until they are verified to be worth producing as a part number. OEMs can also assign and change part numbers before, during, or after production. And testing.

If engineering came up with a theory that a longer lead time on the prime shot of #8 would be worth while trying, what is the most efficient, expedient and immediate way to try it on the engines set up in the test cell? Create and build "part numbers" first? Or call for the culling of all injectors that exhibit a longer lead time than others, and try them out first?

As to your disparaging remarks about "some office guy not actually building them", it sounds like you are asserting unfounded assumptions about a solid man whom you've never met, whose working career and various positions and responsibilities within the company you have no personal knowledge of. According to my Bible, that is closer to the kind of human behavior one might consider "coming to Jesus" for.

Being there, in the context, inside the plant, at the time when various "cackle" fixes were a very hot topic due to the noticeable increase in warranty claim costs from customers complaining about the cackle, especially once split shots went to 50 states, left me with a different impression than you have concluded sight unseen some 14 years after the fact.

This thread is about the AD vs AE injector in Pickachu's troubled truck with a newly rebuilt engine running a post cackle fix pcm with a pre cackle fix injector, and the concern in Question # 1 was about the potential for a misfire with the mismatch.

And my response was to share a point of view that there is not so much physical difference between the AD and AE injectors to cause a misfire. The main injection event will be there by 8 degrees ATDC crank angle, as far as timing. The audible and detectable difference between AD and AE is a change in cylinder pressures during the injection events.

The rate shaping of the split shot injector is a physical characteristic of the plunger and barrel, not a PCM or IDM command. The physical differences fall within a range encompassed by the thickness of a human hair.

The rate change can come from the width of the annular groove on the plunger, it can come from the distance of that groove on the plunger body from the working head end of the plunger, and it can come from the location of the spill passage on the barrel. The further away the spill port on the barrel is from the plunger head when the plunger is fully retracted, the longer lead time the prime shot can be injected before the annular groove intersects with the spill port. It goes without saying that all of these parts were machined within known manufacturing tolerances. The net effect of the combined stack of tolerances is what defined the length of time the prime shot had before being interrupted.

Altering the dimensions and/or shifting the location of the plunger groove and barrel spill port mechanically creates the variability in that first shot. As explained to me, that variability existed somewhat within the earlier manufacturing tolerances of the injector assemblies, before it became capitalized on and curated as a solution to the cackle issue. I thought this was an interesting inside tidbit that would never have occurred to me without it being explained by someone in a credible position to know. If I have failed to translate it adequately, chalk it up to MY ignorance, not his.

 

That's what an R&D department does. Somebody comes to them with a problem, and R&D is tasked with finding a solution. R&D will identify an item that they believe through modification will give them the intended result. So if the original P/N is some like T31150, the experimental P/N could very well be XT31150....look the need a method to track the part through the manufacturing process, material, heat-treat, differing operations, differing print call-outs, plating, etc. Without assigning a P/N it's all lost in space. The bean counters are gonna want to who/what to bill the costs to.

If the experimental part, XT31150, does in fact solve the problem, engineering will issue a new P/N for that part and put it into production.

I see it all the time for the Lake City Army Ammunition Plant, whether it's being managed by ATK or Winchester or Remington.

 

Now you are talking about something completely and entirely different.

Yes, I'm pretty sure the engineering process that went into developing the long lead injector resulted in various tests that included different injectors with varying lengths of pilot injection. But what you have been discussing in your other posts had nothing to do with initial development. In essence, you were saying this whole time that the long lead injectors were a side effect of normal manufacturing operations. You even stated specifically that "the AE injector was "culled", not created separately". Which is the entirely why Dan and I both chipped in to correct you.

And this part makes zero sense. You think they just had these lying around for several years wondering what to do with them?

Yes, I am. Because if he told you that exact information that you passed on in this thread, then he is completely wrong. Not the first time it's happened in this industry. I hear stuff like this on a daily basis.

Now if you are making a mistake about what he said, then you are wrong.

Either way, the wrong information was posted, and I'm just trying to point it out. I'm not trying to be a jerk about it. Just stating what's real and what isn't. The coming to Jesus comment was meant as humor. Obviously you didn't quite pick up on it. Not a big deal, it's hard to pass on subtle humor in the context of forum posts.

Not 14 years after the fact. These are still being built.

I know what this thread was about, and I had already answered it as well informing him the same info that the PCM calibration was not having an effect. You were the one who introduced incorrect information about how the long lead injector is manufactured. Dan and I have been trying to point out to you and others how it is incorrect, but you are continuing to argue based on something you "heard" once before a long long time ago.

Not exactly sure where you are coming up with the timing numbers. If you looked at the timing tables in the factory calibrations you would be saying differently.

What you are trying to argue doesn't make any sense. You repeatedly talked about how injectors tested with longer spilt shots were "culled" from the rest, and that Ford after a while figured out how to use them..... when that is clearly not the case..... because an entirely new part number was created for the intensifier piston in order to specifically build an AE injector. Not only that, but it brings up an entire swath of problems regarding build numbers, inventory control, etc.

For real, how do you go in building a batch of injectors not knowing how many AD's you'll end up with or how many AE's you'll end up with? Do you really think that's how manufacturing is done? Basically you're assuming that QC goes right out the window, and that they built injectors hoping for the best.

I'm going to state it again... the AE injector is an engineered part. It was purpose built, it wasn't because some injectors came out bad and Ford figured out a way to put them to use. Was there some R&D to get the correct mechanical pilot injection event? Of course, but it was because of how you were told.

 

Changing the injector o-rings on the left bank seems to have cleared up the hard cold start issue. In the process, I swapped the positions of #8 and #2, and now the temp reading of the manifold at #2 is lower. Unplugging it makes little to no difference in the way it idles, so it looks like a bad/weak injector is probably causing the misfire issue. I'm going to drive it a bit today to make sure any remaining air is out of the rails then I'll check it again.