Playing with my pop tester

[wolf_walker]

So I've always just bought injectors reman'd and had good luck.
They used to be cheap, progressively not so anymore, and I got a good deal
so I bought a pop tester.

Been mucking around with it, I have a pile of play-injectors and four new nozzles too.

The ole gallon cans of carb cleaner make damn fine injector cleaners if you have a few days to let them sit,
crack em open, loosen the nozzle in the housing (careful tap) and they come out such that the carbon wipes off
with a rag.  Neato.

Now, testing these things.  This strikes me as kind of an "art" and desipite a lot of reading I'm second guessing myself
left and right.

I tried one out of my old TD from many years ago, obvious crap, bad pattern, leaked @1500psi, text book bad.
Great.

I took one of my cleaned bodies, lapped the mating surfaces with 1000 grit till smooth and popped in a new nozzle.
After a couple settling in pops, it sprays well.  I think.  It might be my eyes, and the little cloud of diesel vapor that immediately
obscures one's view after the first spray, but it looks like it's ever so slightly biased to one side of the stream.
Or it might not.  It's pretty damn hard to tell.

It's also popping a hair high, 1900 depending on how one strokes it.
That isn't unusual after lapping, higher pop, I read.

Which is another thing.  It seems to me that the method of articulating the tester handle can effect the
pop pressure a bit.  I can make this injector "pee" if I try to.  Should I be able to?
Is it proper to use short "pops" and kinda try and see where the needle does not climb at
or run through a steady long-pop and see where it holds throughout the duration?
There is variance here I'm not loving.

And the return ports, should they leak?  I was holding pressure, with occasional handle movement, to keep it around 1500psi
looking for body leaks, and it started weeping out the bypass ports eventually. 
Should it?  Kinda hard to throughly check for body half leaks when it's running down from them, I capped them but that wasn't sufficient,
need to cap one and run a drain line on the other I suspect.

Am I being too picky here?



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[TylerDurden]

I believe it is normal for the return ports to weep under pressure... they are lubed and cooled by the fuel, so there is a way for fuel to get around the pintle and up to the port.

In operation, the pintle only sees high pressure for something like 3ms per pump stroke, so not a lot of fuel comes through.

[wolf_walker]

Makes sense.  I think for my OCD purposes I'll cap one and run a hose off the other.

So I can hold pressure on it for a long time and dare it to leak...

[Toby]

If you have to tap on the nozzle to get it out something is wrong. Most likely carboned up because some JO did not replace the heat shield.

If the injector pees it is BAD.

If you are leaking enough fuel out the return port on a leak test to run down the side of the injector, you have a problem.

You need a slow steady pull to check popping pressure. You want to see where it "breaks", not how high you can make the gauge jump. It should have a distinct "pop" when the flow starts. If you don't get that, even if you get a good spray pattern, the nozzle is not right.

[wolf_walker]

The nozzle tapping to remove was on core injectors, totally carboned up.  I bought a dozen or so as cores to muck around with.

I'm still on my first one with a new nozzle, I'll put together another and see how it behaves
in comparison with the pee'ing.  It would only do it if I crept up on the break pressure slowly,
I had to make it do that, it'd never happen in use but my question was should it happen at
all, even when trying to induce it?

The bypass leaking took awhile, the book says 10 seconds or so @1500psi for a body leak check,
I was at more like 45 seconds manually maintaining 1500psi before the bypass wept over and ran down.
So...  Normal?  It wouldn't leak at all in a quick 10 sec check.

I'll fiddle with it some more this evening and work on my lever pulling technique..

[burn_your_money]

I'm still on my first one with a new nozzle, I'll put together another and see how it behaves
in comparison with the pee'ing.  It would only do it if I crept up on the break pressure slowly,
I had to make it do that, it'd never happen in use but my question was should it happen at
all, even when trying to induce it?

Certain ones will pee, it's normal.

[wolf_walker]

That makes sense, excellent. 

[wolf_walker]

Pulled the not very old injectors from my truck, one popped at 1400, rest at 1700 or so. Wish I'd bought one of these sooner.

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[wolf_walker]

Spray pattern is some sort of trap for the OCD....

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[srgtlord]

Well then, did you find the pop tester, or did the pop tester find you 

[wolf_walker]

Well then, did you find the pop tester, or did the pop tester find you 

I thought I heard it chuckle at me earlier.. 

[wolf_walker]

Well one out of the four new Indian Bosch nozzles doesn't spray well so far.  I don't think I'm surprised.  Debating weather to order more or try the Chezch made Meyle brand.

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[wolf_walker]

From the dept of post-apocalyptic fixes:  I was able to make that bad spraying new nozzle functional by lapping it internally with, since it was the first thing
in arms reach, auto paint polishing compound.  It actually has as good or better pattern than any of the other three now, but the whole spray is canted about 2 degrees
off to one side.  I can just barely perceive it but it's there.  I'd use it if I had to.  I'm tempted to try such on the others and see how they react.

I also have decided that the Mk1 eyeball is only marginally capable of discerning small differences in spray pattern.
I'm comfortable with my pumping technique and have a good feel for the procedure now, but it is damn hard to see
anything that isn't a glaring fault with spray pattern.  This leads me to believe that there is some leeway in such,
since I'm pretty sure I've spent a hell of a lot more time lapping parts and fine tuning break point and doing back to back
comparisons of spray patterns than 98% of shops do for the money they charge.  It's no damn wonder the assembly line built Bosch
remans are so-so at best.  It also occurred to me, as I was watching a spray pattern across it's length of five or six inches, that it never sprays
that far in-motor (duh).  So trying to observe just the first inch or two makes it even more difficult.  I suppose the pattern further down from the nozzle
is indicative of what's happening up close.  Maybe.  I'm also faced with the fact that I'll not be happy till I run a set for a bit, then pull them and pop em
again to make sure they wore in correctly.

What I need, is a high speed video camera for real comparison work. 
I have used one for checking the gas system action on AR's (bolt bounce and such).

Have 4 more India Bosch on the way for comparison and further fiddling. 

[wolf_walker]

So.  Some initial conclusions.

Diesel alone isn't sufficient to lube the body threads.
There was some jerking reaching final torque that I didn't care for.
Test 1 they wept still, three out of four.
Test 2 after using some handy royal purple oil to lightly lube the threads and mating surfaces and
going to 65 instead of 52, no leaks.
Pop pressure was not discernibly changed with the increase in torque.

The india Bosch nozzles, 2nd set that I opened now (first set came with the tester I bought and two were open)
pop tolerably for normal use, no dribbles, nothing crazy.  Not a one of them sprayed what I'd call nice.
Sample size of 8 but nothing really surprising.
They were all sort of a elongated oval if viewed from above or below, if that makes sense.
I really don't think it'll make a damn since the pattern is gone and burning an inch away from the nozzle
and my eyes can't tell dick about the pattern when it's that tight happening for a split second other than
if something really nasty is going on with it.  I strongly suspect there is some leeway there given proper pop
pressure and not leaking.  I still wish I had a high speed camera but I don't know what I'd do with the data
once I had it.  I might play with hand lapping my older nozzles that still sprayed pretty well later.

Truck runs well but honestly, I can't tell much difference.  It ran really well before, runs really well now.
One injector was low, hundred PSI or so, but they sprayed fine. 
I think it's slightly more clattery now,
which is odd since I set them to 1925 give or take 50psi, so if anything it should be retarded on the timing
now.

Didn't smoke in the slightest before, doesn't smoke in the slightest now.  Up hill lugging it, no smoke.
Weird.  It's still a hell of a lot stronger than a stock 1.6.

This weekend I'll see if the smoke screw works I reckon.


I'm a little annoyed they leaked the first time around, but I think I understand why.
I'd like to procure some of the famed Monarc German nozzles and see how they spray/run.
I have a crap load of injector bodies to do something with now.

[92EcoDiesel Jetta]

The threads on the injector body halves do not provide the seal.  The mating surfaces on the intermediate disk do.