Noise-Lifters or Injection Pump

[HGV]

I have an annoying noise coming from the engine of my 1987 300TD with 200K miles. At first I thought it was a bad injector but I swapped the injectors with my 87 300SDL. No difference on either car. I ran two cans of diesel purge with no impact. I recently did a valve job and had all the lifters replaced, so I doubt it is the lifters. It sounds like I need to rebuild the injection pump. What is athe typical life expecting from the injection pump? The car has power but smokes and runs rough when cold.

Henry

[Alastair]

Have you had the cam chain replaced recently? It could be that yur injection pump timing is a little over advanced, causing a valve lifter type noise, this is good old fashond Diesel Knock,and sounds like lugging a gas engine. What colour is the smoke?, Is the smoke worse when hot or cold? If black, its a bit advanced. If blue/white and oily, its retarded, but quiet. At this milage its best to change the chain anyway, and set up the timing at the same time

Hope this helps.

[psfred]

There is another source of injection knock -- sounds like someone is tapping on the block with a steel hammer, or driving a big nail into a block or oak -- leaking pressure valve seals.

These usually cause rough idle, smoke, and loud knock. Engine will run fine at rpms above 1500. Easy fix, but you need a special spline socket for the pressure valve holders in the pump.

Pump noise is rare -- usually the engine runs badly if the IP is bad. You can determine the source of the sound as follows -- take a chunck of dowel rod, put one end up to your ear (any thing similar will work -- avoid sticking anything IN your ear!), then put the other end on things you thing may be making the noise. You won't have any trouble determining where the noise is coming from.

If the noise is in the engine, try loosening the cap nut at each injector one at a time. If the noise stops, you've found a bad injector, unless you also get good fuel delivery with the capnut loose, but a loud knock with a good injector. In this case, the seal is leaking at the IP, or you have a bad pressure valve. The diagnostic here is the good injector with proper fuel delivery with the capnut loose -- if the injector knocks, the IP isn't delivering fuel under pressure, so the seal or pressure valve has to be leaking. Seals are $7.60 for both copper and o-rings for all six pressure valve holders.

Peter

[HGV]

Great advice. I thought it could be the ball check. I thought that once you removed the splined nozzle out of the injection pump, it needs to be recalibrated. I never beleived it nd I remember changing out leaky o rings on my 220D when the sulfer content changed in diesel fuel. Of course that IP had a stndard bolt pattern. Howeasy it is to change the ball checks in the pump?

henry

[psfred]

Henry:

You will need to get new clips for the injection lines -- they are plastic and will usually break when you unclip them.

Unclip the plastic clips, take the capnuts off, then take the injection lines off the pressure valve holders. Next, remove the lock rings on the holders.

You will need a special splined socket for the holders themselves, there is no substitute. Remove the holders, careful not to use the spring on top of the pressure vavle. The copper seal is on top of the seat inside -- lift off with a pick or small screwdriver, replace spring and holder, and torque to 20 lbs two or three time.

Re install locking rings, injections lines, and and retaining clips and start.

Pretty easy, and the seals are $7.60 for both copper seals and new 0-rings.

Peter

[HGV]

Any suggestion where I might find the splined socket?

Henry

[Alastair]

If you have a disused pump--or a friendly diesel shop near, get three or four retainers from the top of Inj.Pump and weld them together, on top of each other, Place them on a splined shaft or delivery valve holder, while you weld them up--alternatively, you could drill and screw them together. Place a short piece of steel tube over free end, and weld into place--One new tool to clutter up the workshop!

The 603.96X engine has hydraulic lifters. When they collapse, they can be quite noisy. I had one that got stuck once. It was very loud. I gently warmed it up and after driving a few minutes it pumped back up.

[sixto]

"Seals are $7.60 for both copper and o-rings for all six pressure valve holders."

Peter,

Job 07.1-210 says to replace the springs as well. Any comment?

Alastair,

I'm going to need a picture because I can't envision what you're recommending as an alternative tool.

Thanks,
Sixto
91 300SE
87 300SDL
81 300SD

[Billybob]

I read an earlier post of Alastair's regarding making this tool an it sounded like a pretty good idea! You obtain 2-4 of the retainers, place them in place on the splined nut on the IP or on an extra splined nut off the IP, so as to hold them in the proper aligned position, and fasten them together (welding seemes the best, but bolting would probably work) then fasten a handle of sorts, again welding a handle would be best but a small od pipe bolted and epoxied should work I'd think! Here's a pic of the retainers, the flat steel pieces.

[sixto]

Gotcha! Now to figure out whether it's cheaper for me to just buy the $45 tool.

Sixto
91 300SE
87 300SDL
81 300SD