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  #1  
Old 02-27-2010, 06:15 PM
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Pintle on new Monarch nozzle broke ????

So I was lapping down the shim of on an injector that was at 124 bar and making good progress using 600 grit wet/dry paper. I took down the shim bye .0762mm and the pop pressure went down to 117 bar. So I decided to take the shim down another .0254mm. A few minutes of lapping I got to my desired thickness and reassembled the injector. The pop pressure increased to 131 bar what the heck? How can reducing the size of the shim increase the pressure? So apart comes the injector to see what in the heavens happened.

The end of the pintle, that the thrust pin sits against, sheared off right where the pintle increases in size. The metal at the shear point is wavy looking. I believe the part that sheared off turned slightly and with the metal being wavy increased the actual length of the pintle thus increasing the pop pressure. My reasoning is there is now shiny metal on both the pintle and the part that sheared off of the pintle on a portion of the high spots of both pieces and not the dull Grey/rough parts that are at the bottom of the waves.

Of course the place that I purchased the nozzles is closed on Saturdays so my car will be down for another week at the minimum .

Has anybody have a similar experience with the pintle breaking at the same spot? I wonder if this nozzle was made 5-minutes to quitting time before a long weekend or if there was a whole batch of inferior metal and or some kind of error in the manufacturing process when this nozzle was made?

More than likely I did something wrong, I can't figure out what I did wrong. The whole process is pretty straight forward and simple.

Anybody got a single new monark nozzle for a om615/616 lying around?

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  #2  
Old 02-27-2010, 07:54 PM
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If the thrust pin was not positioned properly, it could easily place a side load on the needle valve when the injector was reassembled.

Quote:
Originally Posted by holdthewind View Post
I wonder if this nozzle was made 5-minutes to quitting time before a long weekend or if there was a whole batch of inferior metal and or some kind of error in the manufacturing process when this nozzle was made?
My money is on operator error. But not at the Monark factory.

Last edited by tangofox007; 02-27-2010 at 08:02 PM.
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  #3  
Old 02-28-2010, 02:04 AM
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Quote:
Originally Posted by holdthewind View Post
So I was lapping down the shim of on an injector that was at 124 bar and making good progress using 600 grit wet/dry paper. I took down the shim bye .0762mm and the pop pressure went down to 117 bar. So I decided to take the shim down another .0254mm. A few minutes of lapping I got to my desired thickness and reassembled the injector. The pop pressure increased to 131 bar what the heck? How can reducing the size of the shim increase the pressure? So apart comes the injector to see what in the heavens happened.

The end of the pintle, that the thrust pin sits against, sheared off right where the pintle increases in size. The metal at the shear point is wavy looking. I believe the part that sheared off turned slightly and with the metal being wavy increased the actual length of the pintle thus increasing the pop pressure. My reasoning is there is now shiny metal on both the pintle and the part that sheared off of the pintle on a portion of the high spots of both pieces and not the dull Grey/rough parts that are at the bottom of the waves.

Of course the place that I purchased the nozzles is closed on Saturdays so my car will be down for another week at the minimum .

Has anybody have a similar experience with the pintle breaking at the same spot? I wonder if this nozzle was made 5-minutes to quitting time before a long weekend or if there was a whole batch of inferior metal and or some kind of error in the manufacturing process when this nozzle was made?

More than likely I did something wrong, I can't figure out what I did wrong. The whole process is pretty straight forward and simple.

Anybody got a single new monark nozzle for a om615/616 lying around?
When this happend to me where I used to work it was because I happend to put the Thrust Pin/Bolt in upside down.
After that I developed a habit of tightening the Injectos nut down as much as I could by hand and eyeballing it to see if it was screwed in enough before I torqued the Nut to the Body.

Another possible is that there is 2 types of Injectors and they do not have the same dimensions inside or out side; including that Thrust Pin/Bolt.

If you have both types and mixed the parts up it can do what happend to you as one of them has a Shorter Spring but a Longer Thrust Bolt.
(As complete assemblies both Injectors can be used on an Engine but the parts between them cannot be mixed.)

See the PIC.
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Pintle on new Monarch nozzle broke ????-2-injectors-compared.jpg  
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  #4  
Old 02-28-2010, 01:42 PM
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Most likely a slight misalignment.

When you reassemble, turn BY HAND and try to 'get a feel' for the spring action. If it get harder to turn something might be off. If it stops all together, it should be good. PM sent.


**NOTE** Not all internal injector parts are interchangeable. EVEN IF THEY ARE THE SAME PRESSURE(S) and made for the same engine(s)
As "911" pointed out.

BTW Monark makes them by CNC machine, so unless the machine was going out to a night of beer and pretzels it's not likely to be a manufacturing flaw.
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Last edited by C Sean Watts; 02-28-2010 at 01:51 PM.
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  #5  
Old 02-28-2010, 05:22 PM
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I was just trying to... well save face bye hoping that it was a manufacturing defect and not my thick fingers coupled to my even thicker brain that was the culprit of the SNAFU.

I already assumed it was my fault by saying : "More than likely I did something wrong, I can't figure out what I did wrong. The whole process is pretty straight forward and simple."

All the injectors match as far as i can tell the #'s on the side of the injectors are:

KCA30SD27/4 130 115atu
KCA30SD27/4 423 115at
KCA30SD27/4 130 115atu
KCA30SD27/4 226 115at

After I had the pintel brake I adjusted another injector with out issue to ~the correct pressure. So now its just waiting for a replacement nozzle.

I need to change the seal in the diff anyway, so I geuss i have time before a replacement arrives.

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