There is a rotational springiness to the IP timer in the 603. If you hold the IP sprocket steady, you can spin the IP clockwise a little bit. Seems like it would keep fuel timing advanced when you let off the pedal IF the IP has anything of a flywheel. Whatever for?

Thanks,
Sixto
95 S420
87 300SDL

The IP timer is a centrifugal timing device that advances the point of injection as RPM increases. All the 6## series engines have them. It works on the principle of balance weights and springs exactly the same as the distributor advance device on old type gas engines and for the same reason. They very rarely give any problems but don’t pull it apart!

The spill timing at 24º BTDC is just the static setting.

__________________
Beagle

I took apart the timer on one of my OM616 engines a couple of years ago (during a rebuild) just to see how it worked. I was able to get it reassembled without any problems. Did I mess up the calibration by disassembling it?

The engine ran fine after the rebuild

Tim

Tim
It is quite possible you could have altered the setting by stripping it but if you are happy with the performance after 2 years then don't wory about it.
It is not a high-tech mechanism by any standards.

__________________
Beagle

I am switching vacuum pumps on a 1978 300sd to one from a 1980 300sd this requires switching the plates on the front of the injection timer they look like they hold the spring parts in place too. Am I headed for a big can of worms here I am going to start this project in an hour or so sat morning 7 am. I don’t expect to be into the good cars pump till noon any one that knows anything I should be aware of please chime in.
Dave San Jose CA