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.


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Injector + Heat shield + Nozzle, Prechamber + Collar, and Nailing. LINK THREAD
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