Injector miss match; leak: what to do - PeachParts Mercedes-Benz Forum

coachgeo · #1 05-23-2004, 05:06 PM

Thanks to lietuviai for sending me a spare injector to replace the one I have that is a leaker.

Thought it would be an easy swap. Course not. Murphy don't work that way. The one he sent me is stamped at 135bar. Mine is 115 bar.

Mine wont stop leaking fuel where the injector screws into the injector body. Removed it several times and retourqed countless times. Cleaned it as many times. Ive looked close at the return lines and I swear that is NOT where it is leaking.

Can I take the spring inside my 115 and put it in his or something like that in order to get a better match?

orrr.... should I try my old one again with pipe compound or tape on the threads where it leaks?

I dont want to rebuild them professionaly "yet" cause Im looking to get all brand new ones in the near future. Pageing Gurhka !!!!!!!

langpfeife · #2 05-23-2004, 05:49 PM

For a turbo, it should be 135+ bar...the only difference though is the opening pressures,
it's possible yours are actually rebuilt at 135 bar with 115 bar stamped casings. I wouldn't try swapping
the guts though, they're very sensitive to any adjustments. Even a slightly different torque of the
casings changes them a bit.

Is there a good MB indy in your area? They might have an old bosch tester, and could check/set up
those injectors for ya. You could supply them with new nozzle tips even. IIRC, the specs are
135-143 bar...I set mine at the upper end, with the pump timing at 25 deg...gives 'em a nice crisp
idle, very little smoke, and they run fantastic. (Albeit a bit louder

)

(the cool thing about doing it that way, is that you know they're all set up at the same opening pressure...sometimes with ordering a set of "bulk" rebuilts, the pressure difference betwen them can be a bit high.)

jbaj007 · #3 05-23-2004, 06:02 PM

Don't swap springs, swap shims.

The 115 bar shim should be ~.35 mm. thinner than the 135 bar shim. This won't be exact, but should get you by, until you get them all matched up.

Edit: you WANT a 135, not 115, bar in your turbo (doesn't matter what is says on the outside as most are rebuilt anyway)

coachgeo · #4 05-23-2004, 06:05 PM

Tanks guys I'll compare the shims to help me determin if my 115's are rebuilt to 135.

coachgeo · #5 05-23-2004, 06:45 PM

Quote:

Originally posted by coachgeo
Tanks guys I'll compare the shims to help me determin if my 115's are rebuilt to 135.

hmmmmm..... wish I knew what was up for sure. The 115bar injector that came on the car DOES have a thinner shim than the 135 bar sent me. I swapped shims and installed the 135bar (w/115 shim) into the car. Will see how she runs.

coachgeo · #6 05-23-2004, 08:18 PM

Leak fixed, small nailing started.

could the nailing be from swaping the spacers as described above or would swaping in a wrong spacer cause a different issue?

jbaj007 · #7 05-23-2004, 08:33 PM

Swap in the thicker shim (135 bar) and give it a try. I think with the 115 bar shim in, the "pop" pressure is to low for the turbodiesel and you've got a disturbed burn pattern.

coachgeo · #8 05-23-2004, 08:46 PM

will it be an issue to drive it this way till next weekend?

lietuviai · #9 05-23-2004, 09:57 PM

Coach, I'm glad you got the injector safe and sound. All you need is some patience and some good advice to go along with it. Patience is the most valuable commodity in working on these cars. I came very close to giving up on my car and I'm so glad that I didn't. I have the fine members of this forum to thank!
Without them someone else would have ended up with my car. The new owners would have been laughing all the way to the bank.
Now I've got the bug to get another W123, as soon as I clean out my stable a little and sell off a few of my other steeds.

#10 05-24-2004, 08:14 AM

lietuviai you made my day thanks
Dave San Jose Ca

TomJ · #11 05-24-2004, 09:14 AM

The 115 and 135 bar bodies are different, not just the shim. The top half (that the shim and spring goes in) is actually deeper on the 115 bar, so just swapping shims won't cure the problem.

I've also had some bodies that just would NOT stop leaking, no matter what I did. This also seems to be a new problem as I never remember this kind of things happening with the bodies leaking. I think there's something they're putting in diesel now that does this.

Anyway, if you were closer, I'd suggest having me send you a good-used set that I've balanced till you can get a new set, but....

Don't get the India "new" or rebuilt injectors. Have had NUMEROUS problems with the nozzles leaking and the "new" injectors aren't balanced (maybe to +/- 5bar, but to me, that's WAY too much variance.)