POP testing procedures and tips?

[Deib]

I am pop testing a set of BB codes and I am having some issues.
I have pop tested Gm, BMW and other injectors, most of the problems have always been self inflicted like getting dirt in the injector while cleaning. Sticking a plunger or that type of thing.

I am working on these 7.3 injectors. I took them apart and cleaned them. Put them back together and pop checked them again.
I am getting about 1700 psi, so I ordered some shims.

Now problems I am having.
Injectors should pop and chirp. That is a correctly working injector. They should not drip and should hold pressure.
The spray should be a fine mist.

Now I have about 5 of them that will hold pressure, they open at around 1,700 psi so for the most part they are fine except they do not pop and chirp like I expect.
The stream comes out poorly atomized, but it is straight, not like I would expect form a worn or dirty tip.
But they open and close at 1,700 PSI and seal up tight.

So what is the problem?
Are the tips shot? Do I have some dirt in there yet?
How fast should you be pumping the handle?
The faster I pump the handle the better the atomization is, but they still do not pop.

A couple of them I have cleaned repeatedly. No change. Seems to me if the tips were shot I would get dripping. It the plunger was stuck I wouldn't be able to build or hold pressure.

Any ideas? I have not had bad tips before so I really don't know what to expect. The condition of everything else it seems hard to imagine that is my problem.

Usually I do it like this.
Pop test them.
Tear them down and clean them
Pop test them again.
Shim
Pop test again.
repeat or repair as needed.
pop test.
Install.

Any thoughts welcome.

 

[riotwarrior]

Without having done this personally, I'm maybe speaking out my @$$ here but who knows.

That being said, from what you are describing for your procedure you are on track.

However one thing I've noticed in your thread is a lack of injector CODE stamped on the injectors. What code are your injectors you are popping? What brand? Or do you know? Are they or could they have been modified previously?

In this thread there are a couple of vids showing what these can and do look like

http://www.oilburners.net/forums/sh...quot-best-homemade-pop-tester-quot-with-video

Can you take video and show us what you are saying? That would help

JM2CW

Al

 

[hesutton]

I've pop tested quite a few of these IDI injectors, but I've never rebuilt them. So......... I can't help diagnose why they are doing what. But, I can tell you most will NOT make a pop or chirp even when new/good.

That's never been something I've worried about or even made note of when testing these injectors. The main issues are opening pressure, atomization, pattern, and leaking.

Heath

 

[Deib]

That is great to know.
I will take a couple videos of what I have. That might help, at least maybe it will help others someday because I couldn't find the info I was looking for online.

 

[mblaney]

Did you check out the video link that riotwarrior posted? Very clear picture and sound of mine popping.

 

[Deib]

I did a lot of searching, Not sure if I have seen it. I have found a lot of threads with missing or non working links.

 

[mblaney]

click the link above (riotwarrior) or look for my post about a page down in this forum. I posted it on Monday (yesterday). I just tried the link and it works fine.

 

[icanfixall]

There are three viedos on the link riotwarrior linked too. One is mine and you can clearly hear the poping squeeking on the tips. They are allowed to make a drop on the tips but it must hang for at least 5 seconds. If it will not hang that long the nozzle tip is shot. Each 1 thousands shim is 50 lbs increase in pop pressure.
Al, In the first sentence is the Bb codes posted that are being worked on..

 

[Deib]

Crazy those videos did not load for me earlier. I think a correct on is like the last video.

This first video is always what I thought a correct injector should look like and act like.
http://www.youtube.com/watch?v=i49rOfuE0Xo&feature=youtu.be

 

[Deib]

This second and third video is what I am fighting with these. Pressure is great, no leaks. But not popping or atomization.
If I pump if a lot faster it will start to pulse but still not like the first video.
http://www.youtube.com/watch?v=DjJ4qoUW6sw&feature=youtu.be

 

[Deib]

http://www.youtube.com/watch?v=Q6P06iVzIiM&feature=youtu.be

I think it is still dirty, kind of hard to believe as many times as I have brushed them and scrubbed then and soaked them. But it is the only thing that makes sense, the plungers seem to move free.

 

[Deib]

It looks like it is just dirty tips yet. Or maybe dirt in the bore.
I soaked them again, and brushed them again.
I now have them all working correctly, like the first video but one.

 

[Agnem]

All injectors SHOULD chatter. REALLY good ones will sort of squeal when they pop. The noise coming from rapid opening and closing of the pintle in the seat.

Here is a what it should look like.
http://www.youtube.com/watch?v=-vorzmTWn54

 

[riotwarrior]

Thanks Mel,

Thats a good video and clearly shows a good spray and the NOISE too.

Thanks again!

 

[typ4]

And this is why it takes so long to set/ rebuild a set of these.