Weird injector shims?

[3500GMC]

Going through checking and cleaning injectors today. This is the 6.2. Found quite a lot of crud in #4. It's a hard black coke like material, like burnt oil. It was surrounding the nozzle which made it a bear to take apart. There were these .10mm shims stacked on top of the bottom most wavy washer also. Not sure what these do. There are of course the shims of different thicknesses in the top of the injector which load the heavy spring also.

What's a bad injector *look* like? I can see where the steel parts seal to each other. I saw no galling or even wear for that matter.

Also I saw a small shoulder in some injectors and not in others. This shoulder is where the nozzle slips into the injector body bore on down in past the shiny seat area. I will try and get this photo'd.

 

[bk95td]

Mercedes source sells a kit with tools for cleaning the injectors. I'll post a link later when I get home. I have the book that came with the tester I bought from them that might explain where to look for wear and how to clean. I'd have the carboned pieces soaking in lacquer thinner or acetone.

 

[Matt Bachand]

I wonder how one of those sonic parts cleaner things would work. Lemme find a linky.

http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=3305

 

[bk95td]

I might have to get one of those for all the old injectors i'll rebuild.

 

[bison]

Going through checking and cleaning injectors today. This is the 6.2. Found quite a lot of crud in #4. It's a hard black coke like material, like burnt oil. It was surrounding the nozzle which made it a bear to take apart. There were these .10mm shims stacked on top of the bottom most wavy washer also. Not sure what these do. There are of course the shims of different thicknesses in the top of the injector which load the heavy spring also.

What's a bad injector *look* like? I can see where the steel parts seal to each other. I saw no galling or even wear for that matter.

Also I saw a small shoulder in some injectors and not in others. This shoulder is where the nozzle slips into the injector body bore on down in past the shiny seat area. I will try and get this photo'd.

these "wavy" washers are carbon seals,I never seen an extra shim there.Mebby the extra shim was to compensate to keep the nozzles at the right height in relation to the intermediate washer,I dont think it is stock.
Something aint right there IMO

Most of the wear is with the nozzle,occasionally the spring breaks, some times the tread gets damaged if rusted up to much,or the body halves wont seal no more after lapping.other than that these injectors are very rebuildable

 

[bk95td]

Here's the toolkit from mercedes source http://www.mercedessource.com/node/4804 Kinda spendy for what it is but cheaper and easier than trying to find the stuff seperate. Rockauto sells genuine bosch nozzles for $14 each last I checked. Then you just need to set pop pressure. If there is wear on the pintle[needle] or the holder the spray pattern will be effected. Maybe pee a stream instead of a cloud.

 

[WarWagon]

These can be rebuilt by a diesel injection shop for $35.00 each. They will match the pop pressures and all. Your engine will run a lot better when the pop pressures are matched.

You will not be able to see a bad injector unless it is being tested. (Nozzles burn up as stated above and quit spraying: rather inject a solid stream.) I do have a pic of weird carbon build up on my injector #7. Possible leaker there. Otherwise it has to be tested with fuel...

 

[guybb3]

I wonder how one of those sonic parts cleaner things would work.

I have one. They work great. Don't put gemstones in them.

 

[chevyCowboy]

I have one. They work great. Don't put gemstones in them.

do they work good for cleaning up bolts and other small parts? it says its for jewelry why not put gemstones in?

 

[guybb3]

do they work good for cleaning up bolts and other small parts? it says its for jewelry why not put gemstones in?

A) Yes, very well. It works better if you fill it with HOT water (even if the part to be cleaned is submerged in a solvent filled jar). D'ONT put solvent in an ultrasonic cleaner uncovered as it will evaporate very quickly.

B) Some types of stones can crack due to the ultrasonic action.

 

[Slim Shady]

There shouldn't be a shim under the fire ring washer, Hence the carbon build up back in the body of the injector. I would replace the injector completely, there is something wrong with the body or nozzle in that injector. I am guessing someone did that to increase the pop pressure rather than using a shim where it should have been placed. Just my two cents worth.

 

[3500GMC]

So as per OEM, there should not be any shims, other than the one with the arrow below?

 

[Pruittx2]

Shims should ONLY go in the top half above spring.

My guy called the wavy washer a Heat Shield.