from the '93/'94 diesel coffee table book pdf.showing the differences between turbo and n/a fuel components.note,it clearly states for the g codes:not for n/a engine use.



this is cool too.though Gary (icanfixall on obn) didn't have good experiences with the g codes (he prefers bb's)
i put a set of new g codes in my truck,and she loves 'em.
anyway,he did up a couple cool vids.

 

Here's a question:
What is the injector return line for?
Why even have a return port?

And thirdly:
What would happen if you blocked that return port?

 

I can get that one.

The injector needs a return line for the same reason your oil drains into your pan from the bearings. A small amount of fuel passes through the injectors moving parts to lube and cool it. With the return blocked it would quickly stop working.

 

I was waiting for you to bring some stuff over from the other site ... And Let me tell you, I have been waiting for a chance to have a word on Gary's injector vids...

First, whats said about not mixing and matching Turbo/NA stuff is total BS. The Turbo pump is about 5cc more than the N/A pump, and that is why they say don't mix and match. I can only assume that they mean the same with the G-codes, just because its a "Turbo" model stick. I can tell you I have built more than enough E and G codes, I have analyzed the pintles and pop pressures, and there is literally no difference between them. Hell, the part numbers might even be the same on the nozzle assembly (Ill have to check that, and get back to you)...

As far as Gary's videos go, He is comparing the two different brands, and their two different pintle designs. My issue with that, is that the majority of the spray pattern comes from the tip, not the drastic difference in the "upper angles" like is shown. The Cav/Delphi's do spray a tad different than the stanadyne sticks, and personally, I prefer the spray of the Cav/Delphis just superficially.... However, I will say that the quality of the Cav/Delphi stuff is significantly less than the stanadyne stuff. I Have the most trouble finding good Cav/Delphi cores, usually the pintle/bore is hammered on them, and for their age, there is usually more wear on one compared to an equally aged stanadyne injector. I can usually grab a stanadyne injector, and if the nozzle visually checks out, chances are its a good core, I very rarely have issues with them.

 

This.

There is a little seepage past the pintle on every injector, the more seepage, the looser the tolerance on the Pintle/bore...

Its nothing compared to what comes out of the pump return though.

 

Here is a video I whipped out tonight of some brand new G-code injectors I picked up from a friend who needed to sell them.


You always read that G-code injectors pop higher than normal at 2200-2300psi, and that is just completely false. I came to this conclusion some time ago based on all the G-code injectors that I have rebuilt, but its been solidified with this new set straight from Stanadyne.

Another thing you can see is the nice spray pattern these injectors carry. E-code injectors (92.5-94 N/A) have just as nice of a spray pattern. BB code Cav/Delphi injectors have just about the same pattern as well... I have a set of BB codes that are basically brand new (I pulled them out of the box) that I will video as well for comparison.

Anyway, here is to Mythbusting...

 

Interesting that the A code injectors have a higher opening pressure then the B codes, but the B codes flow more, also interesting to note that a A and AA injector are the exact same specs, just different nozzle supplier.

 

Nice post.

I haven't ever had a set of A codes to compare to a set of B codes, so I cant really comment on the differences between them... However, Ill have to check a B code nozzle out again, because ive measured a lot more opening area on the 7.3 nozzles, .039" diameter orifice is pretty small compared to what I have seen.

From what I understand, the early A-code precups actually have larger throats than the 7.3 precups, so the combination of a higher pop injector and larger throat may have been IH's way of tuning the combustion events early on, and shortly after, changed the setup to be more fitting for the application (Making the engine quieter and smoother).

The difference in the double and single letter injector codes is just the difference between Lucas/CAV and Stanadyne injectors.

The one part I did notice though, is they say the corresponding manufacturers parts cant be interchanged, and this isn't true. You shouldn't, but Lucas/CAV (Delphi) parts, at least the pintle and nozzle, disc, will interchange with Stanadynes... Ive also had a number of cores come in with interchanged parts.

 

I've got a couple sets around; D and E code injectors.
They're just like the B codes show here internally -- including the 'spacers'.
Note that when you're adjusting pressures, don't discount your spacer thickness -- on the pile I took apart, I saw .060 - .063; swapping these around can give you that extra .001 or .002 you need, in the absence of a full set of shims.



Which brings me to my own questions:

1. Where can I get myself a selection of shims?

2. When injectors leak or drip, what causes this? Is it usually "nozzle valve/#8" wear? Valve body wear?

3. Is it possible to get replacement "nozzle valve"'s and or valve bodies? And where?

 

1. I'm not sure where you get new shims from, but you can steal them from old injectors and make a stock pile, the Lucas/CAV injectors seem to have the spacers and Stanadyne injectors have a bunch of shims.

2. When the injector leaks its from a worn out pintle (nozzle valve) and nozzle seat as they wear together.

3. From everywhere I've heard, it cost just as much for a nozzle assembly as it does just to buy a new injector, so if they leak, just get new ones.

Also, a certain amount of leakage is acceptable, as long as the drop forming on the tip doesn't fall off before 5 seconds.





Some info on precup sizes

 

The shims really can only be had from other injectors. I have gotten shims from Mcmaster, but they wont fit the Lucas/CAV/Delphi injectors, only the Stanadynes.

The sealing issue is the seat being lifted enough to push fuel past a wore surface. A bad guide can make it worse by hanging the pintle off the seat.

The Nozzle/Pintles assemblies can be had, but they are as much as new injectors, so it defeats the purpose.

 

Ok here is a little meat to add to this thread...

I took a pic of the pintles side by side tonight, as it was convenient, I had 4 sets being built on the bench.

From left to right as seen in the pics, it goes "G" "E" "D" "B" and "BB"... Sorry about the crappy pics, its hard to get this sort of definition, so Ill post three pics..





As you can see, the only differences in the pintles themselves (Aside from the BB code, which is a different brand), is the area below the seat that controls throttling (the "buzzing")... They vary quite a bit over the years/codes. Throttling is what gives the injector atomization...

Now as you can see, the "E" code (92.5-94 N/A) is closest to the BB code in shape.

Now to contrast this a bit, and add a bit of commentary... In all the testing I have done, the three "best" injectors for spray pattern are G's, E's, and BB's, and as you can see, that is about as far of a spread in shape as you can get. This solidifies my view, at least in my head, that there isn't much difference in the function of the different codes, and were, if anything, a consumer based R&D method by the factories.

Now back to being objective.... I hope to get some videos of these different codes as I am popping them, so you can directly see the difference in the spray patterns.

more soon.

 

this is great.thanx for your time showing us the differences and similarities in these injector codes.good stuff.

 

Pop testing a Stanadyne G and D code injector. The G code is brand new fresh out of the box no run time. The D code has about 2000 miles on it.

G code:

D code:

 

I understand this thread is about 7 months old but it is Injector related and seeing as we wanted to keep all of the questions here I figured I would give it a whirl,
Does anybody know the angle at which the fuel enters the combustion chamber on both the 6.9's and 7.3's if there is any difference
Thanks!!