Delivery valve O-ring problem; car clacking loud
 

(Edited now that the problem is fixed; answer is on one of the responses below, but here's the original question)......

I have my mobile mechanic here, who's pretty good. He changed out 1 bad glow plug that was toast and the delivery pump O-rings.

I had changed the O-rings about 7 years ago, and he seemed to be doing it just fine. When he was done, we started the car but it's clacking waaaay loud, not the nice purr it's supposed to be, plus the car is blowing smoke out the tailpipe and stalling at times if we let the idle drop.

His professional online source of info said to tighten the splined nuts back to 35 NM. Some members on this forum said 30 NM. I don't know how much make-or-break difference the extra 5 NM would be.

Can anyone think of something we did wrong that would cause such a problem? I'm thinking maybe we got a touch of dirt in one of the valve areas something, but he's a good mechanic and knows to be careful with that. It's possible maybe a bit of the old rubber from the old O-rings got in there. I highly doubt the glow plug is causing such a problem.

1991 300d, 196k

If he failed to replace the copper crush washers with new ones, you may end up with the results you describe. I did my delivery valves on my 96 E300D, and on advice from some of the forum members left the old crush washers in place. Prior to doing the work, the engine ran as smooth as silk. After I did the job, it clacked all over the place. Did the job again, only this time changed out the copper crush washers, and all was well.

You should OUT THEM....
We have a few members.... perhaps six..... who seem to want to recommend procedures BECAUSE they are different from the FSM instructions... just to be contrary.....
and why not ?????.... it won't be any skin off THEIR noses when it has to be redone to correct the situation....
Thanks for sharing that example.....

I believe the correct torque procedure is tighten to 30 Nm, release, tighten to 30 Nm, release, tighten to 30 Nm, and then tighten to 35 Nm. On first start, listen to the injection pump carefully to see if making new noises, as it is possible (but rare) to warp the IP body during the torque process. If you get new noise, re-torque from the beginning of the process. Normal noise is like a sewing machine.

I have not read all of the answers to your thread so this could be a reapeat.

Recheck the Torque and how it is done in the DIY Section.

When the parts are removed to get at the old Crush Washer the Delivery Valve Assembly is a 2 part matched set where the parts are lapped together. If you mix the parts with others they are not going to seat correctly.
The cyldrical part of the Delivery Valve assmely has one or 2 groove around the OD so you know which end the central Delivery Valve is supposed to go into. The Valve is only lapped into one end of the Cylinder.

When you pull up on the cylindrical part of the Delivery Valve Assembly it is possible to pull up the Element Barrel past and out of the slot that lines up with a Pin. If that happes when the Delivery Valve Holder is torqued it is possible to damage the Fuel Injection Pump Housing, the pin or simply push the pin out of the way but the Barrel will not be lined up.

Or it could be nothing. Many have reported after the O-rings and Crush Washers were changed the Engine nailed for a few 100 Miles. No specific cause has been proven but I believe that even when you keep the Delivery Valve Assembly together the central Valve shifts enough that it takes some time to re-seat itself and until then the Engine Nails.

Some pics.

Diesel911, what is the suggested lapping material / compound....?

I did not suggest that someone should lap their Delivery Valves.

I said that the Delivery Valves are lapped to one end of the Delivery Valve Assembly indicating that is why they are a mated set; the lapping is done by Bosch when the parts are made.

When I did that where I worked they had some 1600 grit stuff. But, you have to keep the compound away from the Collar of the Delivery Valve.

For the face of the Delivery Valve that goes against the Element Barrel we used 500 grit.

After that you need to clean off all of the grit.

OK, the proper procedure is to clean the top of the IP surgically clean before starting. Remove the keepers, remove the delivery valves one at a time and only work on one to prevent mixups. Remove the DV, remove the spring, remove the old oring from the delivery valve or from the IP. Use a dental pick to get the Copper washer from inside the hole in the IP. Do not remove the small pin-like piece from the hole, just pluck the Copper washer off the top of it. Use a source of clean diesel and lubricate the new oring and install it onto the delivery valve. Place the new crush washer onto the pin-like piece in the hole, place the spring back on top of that, and place the delivery valve back onto the hole. Before screwing it in, wiggle the delivery valve a bit to ensure the spring is centered. Thread the delivery valve down by hand until it stops. Do that one by one to all of the delivery valves. Then, torque them down. Torque them all to the lower spec, then loosen them all up. Torque them all again to the lower spec, then loosen them all back up again. Finally, torque them all to the higher spec and you're finished.

Some people do report a little more diesel clatter than before the job was done. They also report that it settles back down and sounds like it did before within one tank of fuel (500 miles at the most).

I really hope your mechanic followed that procedure to the T. If not, that's bad mojo. Worst worst case, you crack the pump body. Best worst case, it still leaks.

It's important to replace that crush washer. The 3 stage torque sequence is to set the crush washer up and make sure it makes a good seal. The first stage squishes it and centers it, the second does the same, but the third is a higher torque and squishes it more than the first two stages, sealing the faces.

I think we found the problem
 

We ran Liqui Molly through the system and it really helped out, but it was still loud. He came by today, removed and cleaned out the injectors and it's pretty much back to running normal now. Must just have been some dirt in the injectors.

The dirt in the Injector issue happend to me where I worked one time. It was my fault for not keeping things clean.

What did the Mechanic say about that?

It happens
 

He didn't really say anything about it, though it was obviously his fault for not getting the area clean but even if he had, you can't get them 100% clean. It's just one of those things that happens and you have to take it on the chin.

That is what I had to do when I re-did the job and My Boss did not charge the Guy for me to redo the part of the job I screwed up on.

What I should have done.
Gotten as much dirt as I could before I removed the Fuel injection Hard Lines.

Removed the Fuel Injection hard Lines and put them in a Plastic Bag to keep any dirt out.
coverd the Fuel Injection Pump and Injector threaded ends with Cap Plugs or Tape (Tape works but the Glue disolves and it gets messy so you need to clean more).

when It cam time to assemble. Remove the Hard Lines from the Plastic Bag and hose out the ends with WD-40, Carburator Cleaner, or Brake Fluid. Especially the inside of the Hard Line Nuts.

Blow the inside of the Hard Line Nuts out and the inside of the Hard Line Nuts with filtered compressed Air set them down some place clean.
Remove the Cap Plugs or the Tape and make sure the threads are clean. Crank the Engine and let some Fuel spurt out of the Fuel Injection Pump. After you stop look down at the Delivery Valves and make sure you see no dirt on the inside sealing area. If you do remove it.

Remove the Cap Plugs or the tape from the Injectors. Hoes the inside sealing are out with WD-40 or the other mentioned sprays and check again for dirt.

Install the Fuel Injection Hard Lines. You can tighten the Fuel Injection Pump ends but run the Injector Nuts down all the way and back them off a turn of so.

They you crank the Engine to not only bleed the Air out of the Fuel Injection hard lines but the Fuel coming out also pushes out any dirt that did manage to get into the Fuel Injection Hard Lines or on tope of the Injector sealing area and then tighten the Fuel Injection hard line Nuts.

Anyway that is what I did to make sure and I never ever took a short cut again on a Customers Vehicle.