Vibration at Idle 300D

After discovering that my (1979 W123 300D) diesel injector pump predates the advent of pumps incorporating a rack dampener adjustment, I was confronted with what to do about the deep, coarse vibration that
was occurring at idle. Adjusting the idle speed did not help, as the engine then idled too fast. Following a posting here, I went ahead and changed the inline and canister fuel filters. That made a remarkable difference. I was then able to set the idle down to where it should be. I am still not satisfied with the level of vibration that remains at idle. I am beginning to question whether my Mercedes shop actually change the engine mount vibration absorbers when they did a complete engine rebuild earlier this year. Changing engine mounts have always quieted my engines down in the past. For instance, my last 300D, I had adjusted so that it was so buttery smooth at idle, it was a pleasure to behold. Then again, that was a four-cylinder diesel, whereas the current one is a five-cylinder OM617.
Does anyone have an opinion as to whether or not this engine might smooth out better once it is fully broken in? The currently has only around 1,500 miles on it.
Thanks!
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Double check your engine mount. I would go back to the rebuilder and have him check out the engine.
How about the injectors... are they rebuilt? Are they balanced?
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

I will. I am taking the car back to the shop in the morning. I changed the filters, and the engine is not sufficiently improved. I will have the mounts changed again. I'm willing to bet that the same injectors went back in after the engine was overhauled.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

By the way, how are injectors balanced? Are they done by a shop that rebuilds injectors?
Thanks.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Yes, the injectors are balanced at the shop that rebuilds them. They make sure every injector outputs at the same pressure rather than just the same size shims to set the pressure.
The pressure varies regardless you install the same parts... so that is why it is painstaking to balance all the injectors. Even Bosch rebuilt injectors are not balanced.... I never tested mine as my new tester was not working and I have to send back the old cores..
Also the orifice does wear out over time so it pays to have new orifice at the same time.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Ah ha! This I did not know. I will look into getting this balancing done immediately.
Thanks.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Motorsforum.com is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here. All logos and trade names are the property of their respective owners.