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6.5 Diesel Injector Rebuild

Well I have been wanting to adapt something up on the tester to check the gauge accuracy. This evening while I was at work, I found a hydraulic compression tee that had 1/4" tube on the ends and a 1/8" npt thread with an adapter for 1/4" npt, made up a test line using an old injector line to check how accurate the tester was. Got home and cobbled this contraption together.

I was very cautious applying pressure to it once I got it all together since I don't like compression fittings with this much pressure. slowly applied pressure watching for leaks and standing as far back as my arms would allow!!

watched as both gauges rose noticing right away that the one I added was showing right at 100 psi higher than the tester. this stayed steady all the way up to 2000 psi, both were 100psi apart from each other.

then I attempted to make the injector pop and almost maxed out the little 3000 psi gauge each time while the one on the tester was showing close to 2000psi as the injector chattered spraying fuel.

If I am seeing this correctly, I think the flow is slow to move the tester gauge and the real pressure is shown on my contraption. should I go back removing all shims where before they were chattering at 1200 on the tester and see what this adaptation I made is showing?

What's everyone's thoughts here?

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Went back and redid the 4 injectors I have been messing with and have them all chattering right between 1900 and 2000 psi. had to take a lot of shims back out now that I have this other gauge inline with the tester and the injector. Finally starting to get the hang of testing and setting pressures.

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now with the inline gauge I can see where just a very thin shim raises the pop pressures quite a bit. a 0.1mm will raise the pressure about 100 to 200 psi. This follows along with what others have been telling me where as before I had this second gauge it would take up to 1.0mm to do this.

I will still try to find an adapter so I can replace the India made gauge, but as it is now I feel more confident using the added inline one.

Next challenge I have is trying to get this REALLY varnished injector to come back to life.... I dug through the coffee can I have full of them and pulled this one out that looked the worst.

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I also have the 4 long body injectors I swapped out on the 6.2, these were working when I started the engine on the stand but swapped them for shorter ones since they were up against the turbo side manifold. Once I get well antiquated and more confident on going through them, I will start documenting and posting on those marine ones that both Big T and Will wanted to see.

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dbrannon79 said:
Went back and redid the 4 injectors I have been messing with and have them all chattering right between 1900 and 2000 psi. had to take a lot of shims back out now that I have this other gauge inline with the tester and the injector. Finally starting to get the hang of testing and setting pressures.

View attachment 91376

now with the inline gauge I can see where just a very thin shim raises the pop pressures quite a bit. a 0.1mm will raise the pressure about 100 to 200 psi. This follows along with what others have been telling me where as before I had this second gauge it would take up to 1.0mm to do this.

I will still try to find an adapter so I can replace the India made gauge, but as it is now I feel more confident using the added inline one.

Next challenge I have is trying to get this REALLY varnished injector to come back to life.... I dug through the coffee can I have full of them and pulled this one out that looked the worst.

View attachment 91374
View attachment 91373
View attachment 91372

I also have the 4 long body injectors I swapped out on the 6.2, these were working when I started the engine on the stand but swapped them for shorter ones since they were up against the turbo side manifold. Once I get well antiquated and more confident on going through them, I will start documenting and posting on those marine ones that both Big T and Will wanted to see.

View attachment 91375
Click to expand...
You are making some mighty fine progress.
So, when I checked the first set of injectors after getting them back from the diesel shop, they was popping precisely on 1950 PSI on the India gauge, then they most likely were popping about 2200 PSI.
I never checked them after they came back this time.
The engine does not leave even a hint of smoke when it is started on a cold engine.
 
I read somewhere online that they are supposed to be set slightly higher on the tester so when they are put into service they apparently tend to settle in after use. I have a theory that the pressure will change with heat. as the engine is running the heat changes the spring tension.
 
dbrannon79 said:
I read somewhere online that they are supposed to be set slightly higher on the tester so when they are put into service they apparently tend to settle in after use. I have a theory that the pressure will change with heat. as the engine is running the heat changes the spring tension.
Click to expand...
One of the reasons I used to go 2300 psi. If I remember right
 
Ok guys, I took the really varnished up injector, tore it down, cleaned in the ultrasonic cleaner (30 min run at 140 deg temp), re-assembled as it was without doing anything else just to document everything.

@Will L. @Big T I would like your feedback on the documentation for noting wear and anything else you want to add. I'm doing this before stepping into those marine injectors that you wanted documentation on. all of the photos are from my phone so it's hard to get good zoomed in images, but tell me if I missed anything or if you want more things added.

Here goes.... this will have to be done in multiple posts due to the limit on how many photos I can do at one time.

before teardown...
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Fully dissembled....
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Now the 30 minute wait while it's being cleaned up....
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To be continued....
 
Part 3..

During disassembly the pin or needle within the nozzle was stuck so I dropped it into the cleaner still together. after the cleaning cycle I clamped the end of the needle in the vice and was able to rotate and pull them apart with my hand. I did not put these two pieces back into the cleaner again.

There was still a small amount of varnish on the end of the nozzle which I was able to scrape off with my fingernail (didn't get a pic). Re-assembled the injector as it was by first placing a drop of clean diesel on the tip of the needle, sliding it into the nozzle making sure it was free and smooth sliding.

Once it was back together as it came apart I torqued the housing together at 54ft.lbs. I can't really find any real documentation on what this torque spec should be, but from what I have read online it should be somewhere between 51 and 65 and seems to also have a slight effect on fine tuning pop pressures when the smallest shims would be too much! Please add knowledge here if there is a set torque spec for this.

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And last but not least, here is the results on the tester.....

For your viewing pleasure, I recorded a 20 second video of it chattering between 1700 and 1800 PSI.

 
So far what I have found is that so long as all the parts come clean, lapping the bodies and whatnot, they all seem to function and be usable again. Its the "will they last" if they are put back into service question!

some seem to chatter at a higher pitch than others but all will spray nicely once cleaned up. it's the spring within that seems to loose it's tension leading to lower pressure over time and use.
 
One thing I can't really test is leak-down. I think if I had a way to pressure it up just before it pops and isolate the tester with a ball valve I could watch them for leak-down along with dripping fuel while under pressure. I would assume if the leak-down occurs where fuel comes out the return line, it's "OK" but when it leaks from the nozzle, then it's a real problem!
 
is it normal for them to be able to pressure up over what they pop at when pulling the handle slowly then piss a stream once the spring gives in from that pressure? everyone I have messed with does this but videos I have found online seem to all just pop once the set pressure is reached.
 
Well all except for this one gummy one I just cleaned up. it doesn't seem to leak from the nozzle nor anything come out from the return ports, but pushing slowly on the handle it will piss a stream right at 1900, any more and it starts to pop even when going slow.

maybe this is where lapping the tip of the needle in the nozzle comes into play. just guessing.
 
Yes- just time spent is a learning curve. Keep it, it’s like using a feeler gauge- you will get the feel for the speed and listening to the sound.

I did at one point rig up a spare db2 and powered it from an old compressor motor.
That allowed me to examine spray patterns better.

When doing the pressure- think of it as if they are alphabetical letters not numbers. Don’t focus on a number. Learn to get them all to pop at letter H. Then test them in the truck and find out your’s does best at K.
Obviously using the numbers makes the reference point easier- my example is to not get caught up on being at a certain number.
It takes a bit of practice to get your skills dialed in to make them do what you want.

Like Les mentioned just use practice to stop ot from popping close to the pressure. Like if they pop at 1700, go to 1500 and let it sit a minute. No drop forms then move on.

I hadn’t spoke up so far because everything you are doing is on point. Wanting to see the part numbers is more of reference point to compare in the future for people learning and so we can see what you have vs what else pops up to compare.

Nothing wrong with how you added the gauge. Good solution.

Something to play with:
Pump as slow as you can and record pressure in slow motion. Upload to YouTube and you can slow down even more.
Pump as fast as you can and do the same.
You will see a major difference.

People argue as to slow vs fast pump. Think about how fast the injection pump is doing it…

This is another reason I use the alphabet example. Imagine two identical trucks. Person A pumps slow, person B pumps fast. Both can produce same power but person A will say it’s at 1700 and person B says at 1950 because of the difference in speed of pumping the jack handle.

We had 3 of the Kent Moore tools and two were pretty identical, a third was maybe 10% difference. I swapped gauges and that wasn’t it. Something in the tool. Eventually we just use the two identical ones and returned the third.
 
You are doing good.
I wondered about if the injectors were cleaned how well they would perform.
I could not see how the nozzles could wear out within 100,000 miles.
Maybe its the pintle to nozzle thing that wears, like that flat spot on the pintle.
I also was puzzled about the injector squirting like that.
I also wonder how critical that would be once the injector is attached to the IP.
IP builds approximately 3000 or so PSI, when the rotor turns and opens that gate, its not like its building pressure slowly, its like bam the pressure is immediate and explosive. So, I question how critical it would be if the nozzle squirts like that on the tester.
People a lot smarter than I can come in and explain the real whyfores.
 
I messed a little more with that last one that was really varnished up. tried lapping the nozzle tip and with that have come to the conclusion that is not needed or doesn't help anything. maybe hurts it. I also ran it though another cycle on the cleaner which got it much nicer looking.

added a 0.2mm shim and got it to precisely 1950 in a consistent form. I pumped the tester several times and at first it didn't want to spray or chatter correctly but after a bit of pumping, the tone in the injector changed and it began spraying and chattering good and consistent. it stayed at 1950 the whole time. I think after lapping the tip it must have settled and sealed up making it work correctly.

Something I noticed that I didn't see before was on each of these Bosch made nozzles the tips all have a tiny flat spot machined into them that seem to cause the spray pattern wide in one direction but narrow in another. kinda like how a power washer sprays. the china made nozzles which don't have this flat spot in them will spray in a circular pattern. I thought this was interesting to see.
 
Here is one of the marine injectors I started on. I did put all of them on the tester to see if there was a "smokin gun" as to why Big T's burb was smoking while running. I think there is a video he posted here in the forums on it. all seems to hold pressure and not leak. so I tore one down and took some photos. one thing I did note is when seperating the body on this one is that it was torqued to 70ft.lbs. I kept increasing the torque setting while trying to loosen the body, every time it flicked I would move it to the next setting until it loosened.

Here is some photos of the tear down and a short clip of it on the tester.


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