PeachParts Mercedes-Benz Forum - View Single Post - Delivery valve internal leak as a cause of nailing? Yes? No? Maybe???

Diseasel300 · #30 02-01-2017, 08:57 PM

As promised, I'm following up with this tread. My parts *FINALLY* came in today and I did the job this evening.

First thing I noticed right away is that the DV holders have been off my car before. The gorilla who did it before didn't bother to thread the hold down screws in by hand, so 2 of the 3 were stripped into the IP block. *sigh* Once I got those out and started undoing the DV holders, it became obvious that they were never torqued. I had the torque wrench set on 20Nm and it never clicked once on any of the 6.

I did one DV at a time, and on each one, as I took the holder off I noticed that the whole chamber was filled with some sort of cloudy stuff. Not sure what it was, but it certainly didn't come from outside the chamber (I had the IP well cleaned before I touched anything). I used some clean diesel in a dental squirter to flush out all the nasty crap in the chambers before replacing the sealing rings.

The new springs I installed were easily 2mm longer than the ones I pulled out. A fairly significant difference! The wire size and coil density appeared to be the same, the old ones were just compressed about 2mm compared to the new ones.

Finally got finished and torqued the holders in place doing the 30,30,35Nm tightening routine.

Cleaned everything up and decided to flush the DV's before I put the injector lines back on. Dropped a rag over the DV's, put the accelerator to the floor and cranked through a good couple dozen rotations before putting the hard lines back on, just in case any of that murky crap was still in there it got flushed out.

After putting everything back together, gave the engine a good long glow, pedal to the floor and cranked. After about 4 or 5 compression hits it fired right up. No smoke (which surprised me!)

After letting it idle for a bit, it became very obvious that my loud nailing was gone and the car was new running on 6 cylinders instead of 5 1/2. Went and drove it around town, on the highway, through the country, and all over the area to get it good and hot. Nailing hasn't returned, and my idle is still on 6 cylinders. Idle is still ever so slightly rough (nothing objectionable), but no longer rocking the car and clattering like a man striking an anvil with a hammer.

The biggest change (and this is a big one): no more grey smoke at idle, and no more leaving clouds of smoke when putting the throttle hard down. Was driving it in traffic this evening, and not once did I see a haze behind me. For a car that earned its nickname of "Diseasel" because of the smoke it carried around behind it, that's a MARKED improvement.