Mercedes diesel injector SHIM related data - PeachParts Mercedes-Benz Forum

whunter · #1 12-27-2013, 11:45 PM

Don't waste your time and money attempting this DIY without an Injector Pop Tester!!!
Injector Pop Tester, Generic Instructions

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These sizes are a Must have for adjusting "pop" pressure on diesel injectors.

I strongly suggest you have ten each, in hand before beginning:

11.4 mm outside diameter x 0.13mm shim washers (approx 10 PSI each)

11.4 mm outside diameter x 0.16mm shim washers (approx 15 PSI each)

11.4 mm outside diameter x 0.21mm shim washers (approx 20 PSI each)

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All Mercedes (BOSCH) 1961 to 1995 OM615, 616, 617, 601, 602, 603 engine injector shims have the same 11.4 mm outside diameter.
They can be used on other BOSCH diesel injectors besides Mercedes, which use the old indirect mechanical injectors.

The key is using more than one shim to meet the total thickness requirement.
Using a thick shim (typically found in your injector) with 1 to 3 of these thin shims you can make (almost) any required thickness for correct "pop" pressure.

Mercedes diesel injector shim related threads

Diesel Injector Cleaning DIY
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Injector shims sources
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Injector shim sizing
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Injector Shims
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Diesel Injection:
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Injector Shimming and Calibration - TDIClub Forums
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Injector + Heat shield + Nozzle, Prechamber + Collar, and Nailing. LINK THREAD
Injector + Heat shield + Nozzle, Prechamber + Collar, and Nailing. LINK THREAD

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tjts1 · #2 12-28-2013, 02:22 AM

I just sanded (2000 grit) the mating surfaces until i got to the desired opening pressure. Extra shims are a waste imho.

vstech · #3 12-28-2013, 11:35 AM

Quote:

Originally Posted by tjts1

I just sanded (2000 grit) the mating surfaces until i got to the desired opening pressure. Extra shims are a waste IMHO.

... I understand this will reduce spacing, but isn't there a limit to the usefulness of this trick? I'd not want to lap off, .25mm from the body...
and what do you do if the pressure is too high? remove a shim and lap some more?

Diesel911 · #4 12-28-2013, 01:39 PM

Quote:

Originally Posted by tjts1

I just sanded (2000 grit) the mating surfaces until i got to the desired opening pressure. Extra shims are a waste imho.

You can do that but keep in mind that you are doing it for yourself. If you were doing this on the Job the cost of paying someone to lap the surfaces out ways the time spent swapping shims.
If some one is left a lone to rebuild the Injectors as a whole set and has the right equpment and parts (includinga selection of Shims/Spacers) it takes only 10-15 minutes per Injector to rebuild them. Shops used to charge for 1/2 Hour of their labor rate to rebuild the Injectors.

If for some reason you get lucky and most of the Injectors you assemble have good opening Pressures the time can be less per Injector

Diesel911 · #5 12-28-2013, 01:48 PM

Quote:

Originally Posted by vstech

... I understand this will reduce spacing, but isn't there a limit to the usefulness of this trick? I'd not want to lap off, .25mm from the body...
and what do you do if the pressure is too high? remove a shim and lap some more?

Yes, if you lap off too much from the upper face of that intermediate Plate the Lower Spring Seat will rest on that plate instead of the top of the Nozzle Pintel.
However, I have never seen that happen before.

whunter · #6 12-28-2013, 02:42 PM

Quote:

Originally Posted by Diesel911

You can do that but keep in mind that you are doing it for yourself. If you were doing this on the Job the cost of paying someone to lap the surfaces out ways the time spent swapping shims.
If some one is left a lone to rebuild the Injectors as a whole set and has the right equipment and parts (including selection of Shims/Spacers) it takes only 10-15 minutes per Injector to rebuild them. Shops used to charge for 1/2 Hour of their labor rate to rebuild the Injectors.

If for some reason you get lucky and most of the Injectors you assemble have good opening Pressures the time can be less per Injector

How much time for cleaning the exterior injector body?
From personal experience, I plan 0.25 - 0.45 hour per injector = depending upon how nasty (corroded) the exterior is..

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Diesel911 · #7 12-28-2013, 06:32 PM

Quote:

Originally Posted by whunter

How much time for cleaning the exterior injector body?
From personal experience, I plan 0.25 - 0.45 hour per injector = depending upon how nasty (corroded) the exterior is..

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Like I said the Charge was for 30 Minutes per each Injector. Normally that was an easy time to beat. Once in a while you come a crossed that one problem injector that you have an issue getting the opening pressure on if it uses Shims and spacers that throws your time off.

But, we often soaked stuff in the Old Style Carburetor Dip. While it is soaking you just do something else so you don't lose time waiting on it to eat up the Carbon and grease.
We usually only used the Ultra Sonic Tank on DI Injector Nozzles. But that is another throw them in the Tank and go do something else thing.

If you keep all of the Parts from one Injector together the Opening/Pop Pressure will often be close to what you want and that can cut down on the number times you have take apart and re-shim the Injector.

The Fuel Injection Shop was well equipped. I did not have to look for any Tools because they were all behind Me hanging on a Board.
The Bench was in front of and about 10 feet long with a Vice with Copper Jaws in the Middle.
The Bench had Filtered Compressed Air

Where I worked had a big Motor with a 12 inch fine Wire Wheel mounted on it. That is what I used to clean the exteriors of the Injector Body.
If really corroded we had a course wire wheel.
For something extremely bad we had a Glass Bead Blaster.

Remember I was in S California back then and now. Not a lot of People owned Mercedes back then and due to the Weather in my area they were not likely to be severely corroded.

The other Injectors we got were from Commercial Vehicles where how the looked was not as important as the Cost to rebuild them. So if the bluing was a little patchy it did not matter.

We had filtered compressed Air and Air Guns with different sized Needle ends on them to quickly blow out tiny passages.

We did have some Cold Bluing that could be applied but that was not routine. The Cold Bluing was mostly reserved for Detroit Diesel Injectors and sometimes the Cumins Injectors.

Depending on the Injectors some of the Parts could go on the Lapping Machine.
On Mercedes Injectors both sides of the Center Plate can be lapped on the Machine; all of them can be done at the same time.

I generally lapped the upper body by Hand.

We used 500 Grit Lapping Compound. I have read that some People disagree with that but I know it worked for the 5 years I worked in that shop.
We used the same to lap the tops of the Elements and the bottoms of the Delivery Valves when we a Fuel Injection pump was overhauled.

If you need to take an Injector apart to change the Shims you measure the shim Pack or Shims and measure what you put in. Note the Pop Pressure you got and from there you now have a formula for that Injector and if you have to change the opening pressure you know how man thousands of an inch you need to change when you select another Shim.
If you have a good selection of Shims you will only take the Injector apart one more time.

That is part of what I can remember about doing the Job.

Rebuilding Injectors is the job that they start the New People out on.

whunter · #8 12-29-2013, 12:51 PM

Quote:

Originally Posted by Diesel911

Remember I was in S California back then and now. Not a lot of People owned Mercedes back then and due to the Weather in my area they were not likely to be severely corroded.

The other Injectors we got were from Commercial Vehicles where how the looked was not as important as the Cost to rebuild them. So if the bluing was a little patchy it did not matter.

I wish corrosion was not a major factor in my area.

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tjts1 · #9 12-29-2013, 01:01 PM

Quote:

Originally Posted by Diesel911

You can do that but keep in mind that you are doing it for yourself. If you were doing this on the Job the cost of paying someone to lap the surfaces out ways the time spent swapping shims.
If some one is left a lone to rebuild the Injectors as a whole set and has the right equpment and parts (includinga selection of Shims/Spacers) it takes only 10-15 minutes per Injector to rebuild them. Shops used to charge for 1/2 Hour of their labor rate to rebuild the Injectors.

If for some reason you get lucky and most of the Injectors you assemble have good opening Pressures the time can be less per Injector

I took mine from 1900psi to 2100psi with about 1 minute of sanding. It doesn't take much.

jt20 · #10 03-20-2016, 04:29 PM

Quote:

Originally Posted by whunter

These sizes are a Must have for adjusting "pop" pressure on diesel injectors.

I strongly suggest you have ten each, in hand before beginning:

11.4 mm outside diameter x 0.13mm shim washers (approx 10 PSI each)

11.4 mm outside diameter x 0.16mm shim washers (approx 15 PSI each)

11.4 mm outside diameter x 0.21mm shim washers (approx 20 PSI each)

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There is a really large difference between "PSI" and bar. I think you are mistaken.

jt20 · #11 03-20-2016, 05:04 PM

e300 e300d om606 injector shims are 9.8mm x 3.0mm

Diesel911 · #12 03-20-2016, 11:29 PM

Quote:

Originally Posted by jt20

e300 e300d om606 injector shims are 9.8mm x 3.0mm

I believe most of the info on Injectors is not from 606.*** Engines.

If the 606.*** Engine Service Manual is the same as the 617.952 and older Engines then there is a spec in the Manual that gives the aproximate amount of bar change results from a certain thicknes of Shim.

yuke · #13 03-21-2016, 08:14 AM

I am going to rebuild my injectors soon in my 617. What pressure are they supposed to pop at? I do not have bar on my gauge only psi. At this point I do not have any shims where is the best place to get some? If I do sand one person mentioned 500 grit lapping compond what grit sandpaper would you use 1000-2000? What part of the insides would you sand? How do you know if your injector is no longer any good and needs to be replaced?

toomany MBZ · #14 03-21-2016, 08:47 AM

A non turbo is a 617.91x a turbo engine is 617.95x, hope this helps.

You need proper pressure and a good spray pattern. You can use shims to get the pressure right and if you have a bad spray pattern, replace the nozzles.

Once you have the injector apart, lap the mating surfaces, this helps in sealing the two halves when reconstructed. Item number 5 & 7 in last pic.

BillGrissom · #15 03-21-2016, 03:04 PM

1950 psig. Best they can probably be trimmed is +/-50 psig.
Lookup my post. I gave McMaster-Carr PN's for steel shim washers that worked for me. As I recall, 0.1 mm shim gave a 100 psi increase. I never lapped the parts and never had leaks (both cars).

I suspect that spray pattern and lack of dribbling is more important than pop pressure. I say this because I found 3 of 5 injectors in my 1984 300D popped at 1600 psig and were for a non-turbo engine, yet changing them made no noticeable difference.

Fuel seems to make a big difference. I run Diesel HPR (only in CA) and when idling at a stoplight, the other cars can barely tell I have a diesel, with their windows down. It sounds as quiet as the newer M-B CDI diesels.