Nice job Jeremy! We should get together in SR or Napa one day (or the Windsor PNP) Just picked up a '75 w115 300d (nice car for 300.00!) and also have an '84 euro spec wagon and of course my trusty high mileage still beautiful 300sd.

I have a pop tester and have done this job. The injector tips wear out with B100 and I can only imagine what SVO does.

With homebrew B100 or SVO I would clean them every 12K miles. I put in new Monark injector nozzles and saw a huge improvement.

WVO/SVO I can understand... But B100 made reasonably well should have superior lubricity.

In general, IMO its better to run blends anyway...

Nozzle erosion?
 

That is interesting -- commercial or homemade biodiesel? My '87 300D Turbo (W124, OM603) ran on commercial B100 for about 6,000 miles and since then (another 20,000 miles) commercial B20. I noticed no tip erosion when I removed the #14 head.

The nozzles in the #20 head I bought from Sixto were dirty due to the WVO he was experimentally mixing into pump diesel but there was no erosion that I could see, even under a microscope.

I would think that the water in under-dried biodiesel would be the big killer.

Jeremy

To the person marking halves and re-aligning them upon reassembly: old alignment doesn't matter nearly as much as torquing to the right spec. Pop pressure is not so much preserved by the closeness of original shell alignment, but by the spring + shim length w.r.t. inside chamber length.

As people mentioned, when you lap halves you shorten the (internal) spring chamber length, which has the effect of raising pop pressure.

And when you lap halves, any alignment marks made on the two halves are immediately rendered even more meaningless.

Torque to spec, check pop pressure, and adjust shims accordingly, repeat until spec pop is reached. Or, just slap 'em back together and hope they're better than before and if they are, great!

I think it bears repeating that a BRASS brush is used to clean the nozzle area so as not to scratch the metal.

Clarification required: Jeremy did you remove the nozzle pin from the nozzle, then scrub the end of the nozzle, or did you leave the pin in and scrub the lot? And did you do anything special (brass wire?) about cleaning the nozzle pin hole through the nozzle?

thx

Unless I completely misunderstood how the nozzles were made, I didn't find any holes in the injector nozzles of either set of OM603 injectors. (From the #14 head and from the #20 head, the injectors are different.) Even under a microscope the nozzle tips appeared to be solid metal. I did read about holes in the nozzles of OM61x injectors.

I think we need some pictures so we don't talk at cross-purposes. In the 6th picture of my OP, I show all the individual parts. I removed the "nozzle needle" from the "nozzle" and cleaned both, as well as all of the other parts, separately. That included carefully scraping the front surface of the nozzle with a razor blade (after removing the needle), to get the carbon that shows in pictures 3 and 4 off of the nozzle. As you say, it's important to use a brass (soft metal) brush so as not to damage the tips.

When I looked at the nozzle needle under a low-power (20X - 50X) binocular zoom microscope, I could see no holes in the needle. I admit to being somewhat confused because other threads talk about holes in the tip. I concluded that the other threads were talking about OM61x-family engines. Did I miss something?

Jeremy

You're right, let's use same terminology, I'll follow the picture in this thread.

What I meant was, when you take the nozzle needle out of the nozzle, do you plunge anything down inside of the empty nozzle with any cleaning action?

The hole I speak of is very visible to naked eye, it's where the tip of the nozzle needle goes through the nozzle. Do you attack that hole (from the outside) with any brushing action (needle removed) or running a wire through the hole?

That's what I meant to ask.

I get that you removed surface carbon on the face of the nozzle/injector, but it's what goes on in that very tiny region of the hole that matters most.

Clarification
 

OK, I understand now. I cleaned all of the parts for several hours in acetone using an ultrasonic bath (parts in cup with acetone, cup standing in water in the ultrasonic bath). I scraped the carbon off of the face of the nozzle. I didn't do anything special to the hole in the nozzle where the needle seats, didn't even think about it. Should I have? (My first experience with injectors, BTW.) Whatever you stick into that hole has to be carefully chosen so that it removes crud/carbon/whatever with zero risk of enlarging the hole.

Jeremy

There are tools specifically designed to do that job.

Would you mind sharing it with the forum?

That is a lot like asking your dentist if you could borrow his drill so you could fill your own cavity. There is a lot more involved than just having the right tool.

Great write-up Jeremy. I am definitely going to do this on my 84 300D. My impression in the past has been that there are special skills and tools involved. There certaily are some skills here, but I can handle it.

Are those your hands holding the injector or is that a professional model? There is no dirt. Not even under the fingernails. :confused:

Richard

Oh sorry, I mis-read your post. What you meant was ??

"There are special skill and tools specifically designed to do that job"

My hands
 

I wear rubber gloves for the dirty work. Must have removed them for the photos.

Your '84 300D will have different injectors but the pieces should all be similar and likewise the techniques.

Jeremy