See if I have a pic in the below thread.
Result of me advancing the timing to 28 degrees
My Results timing advanced to 28 degrees 617.952 - PeachParts Mercedes ShopForum
There is an emissions sticker on the upper Cross Member in front of the radiator that has the Timing Specs there should be a + or Minus tolerence.
For re-timing a Fuel Injection Pump that has been on a running Engine.
Added: I for got to mention it should be 24 degrees before top dead center on the compression stroke.
Crank the Engine in the direction of rotating and stop at 24 degrees Before Top Dead Center.
Remove the #1 Fuel Injection Line and unscrew the Delivery Valve Holder being careful not to drop the Spring.
Remove the Spring and the Valve in the Center of the Delivery Valve.
Re-install the Delivery Valve Holder and install your Drip Tube.
Put a Pan on the Ground to catch any Fuel.
Start pumping on the Hand primer and observe if any the number of drips coming out of the Drip Tube. You need to check the spec. I don't remember how may drips per amount of time it should have.
It is importent to keep the pressure up with the Hand Primer.
If you have the right amount of drips you do not need to change anything. Reassemble with a New Copper Crush Washer.
For most Timing Chain and Gear Strech or Wear make the timing Late/Retarded. Remove all of the Fuel Injection Hard lines because the Fuel Injection Pump will be too hard to turn with them on.
Before you do anything else scribe a line acrossed the Fuel Injection Pump Flange and the Engine Block. If things get messed up that allows you to return the Fuel Injection Pump to the same spot.
Loosen the 3 Bolts on the Fuel Injection Pump front Flange and the one on the Bottom rear of the Pump.
Here is where people make their mistake. The Fuel Injection Pump needs to be nudged only a fraction at a time. I mean if you rotate your Fuel Injection pump even 1/16 of an inch past your scribed mark that can push you past the sweet spot.
You will nudge the top of the Fuel Injection Pump towards the Engine (this advances the timing).
Stop and carefully pump with the Hand Primer. While you are pumping good and the pressure is up count the Number of drips.
Repeat the above until you get the proper drips per amount of time.
When done snug up all Bolts/nuts that hold the pump inplace and re-check the drips. If OK Tighten the Bolts and Nut more and re-assemble the Delivery Valve and holder with New Copper Crush Washer.
Install the Fuel Injection Hard Lines but leave them a little loose on the Injectors so when you Crank the Air Will bleed out of them.
When you feel enough Air/Fuel had come out from under the Hard Line Nuts at the Injectors tighten them and attempt to start.
If you have had the Pump out of the Engine the proceedure is slighly different.