About 2 yrs. ago myself and a friend that was doing injectors on the side were observing about a 20% failure rate of the Monark "261" nozzles, within 10K? mi. or less. It was over at least 3-4 sets of injectors so it was more than what could be chalked up to happenstance. Has this improved? In looking at a few different P/N's of Monark nozzles, the markings on them differ between some 220's (possibly older stock?) and the 261's which were bought from the 'bay vendor in Germany 18-24 months ago. I'd think the 261's have more demand than the 220's, which makes me wonder if the supplier or manufacturing facility changed and the supply of old-stock 220's just held out longer before the (possibly) poorer quality ones starting shipping, unlike the 261's. I've built 2 sets with the 220's and the short-term quality was fine, but I can't say as much for the 261's.

Thoughts?

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'82 300CD
"Pearl", the very first turbo diesel 123 coupe
Totaled 11/23/18, rebuild in progress.
'85 300TD, "Artemis".
'78 300D euro, "Ol' Red", mostly retired.
'85 300D, "Gandalf".

Pics for reference.

Attached Thumbnails

   

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'82 300CD
"Pearl", the very first turbo diesel 123 coupe
Totaled 11/23/18, rebuild in progress.
'85 300TD, "Artemis".
'78 300D euro, "Ol' Red", mostly retired.
'85 300D, "Gandalf".

Those nozzles with the logo which is supposed to look like a spray or pop are probably knock offs.

Strange. Those are the ones we had better luck with, the 220's. The one on the far-left looks especially suspicious - only has one row of numbers on it and the Monark logo, no "GERMANY".

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'82 300CD
"Pearl", the very first turbo diesel 123 coupe
Totaled 11/23/18, rebuild in progress.
'85 300TD, "Artemis".
'78 300D euro, "Ol' Red", mostly retired.
'85 300D, "Gandalf".

I rebuilt the Injectors on mine with Monark Nozzles back in 2008-2009 and pulled them out 5 years later and they all tested as good as when I installed them. And, those are the same ones that are in the Car right now. In short I had no issues with mine.

However, I cannot remember what year it was but there was a year when people got some bad Monark Nozzles but after that it seems to have been corrected. There is I think 2 threads on that subject.

The instructions that came with the Monark Nozzles said to clean them before assembling them. When you do that you need to keep the Nozzle Body with the same Pintel/Needle that came out of the body because the are a mated set. If you mix them up they usually won't do well on the pop test but I guess if mixed up parts did pass the pop test that does not keep them from failing early.

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84 300D, 82 Volvo 244Gl Diesel

Please describe how are the Nozzles failing?

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84 300D, 82 Volvo 244Gl Diesel

Makes sense - there was no mis-matching of the pintle to the body on these. Sometimes they were a borderline fail while pop-testing, trying to stream before opening or not atomizing well, so you had to order 1 or 2 extra to be sure you could get a set up to snuff. After that, they would just go downhill and cause rough idle, nailing, and test accordingly on the bench with severe "peeing" before calibrated pressure, etc. Cars driven regularly on good fuel with additives for lubricity. Do you recall if the nozzles you installed said "Germany" on them?

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'82 300CD
"Pearl", the very first turbo diesel 123 coupe
Totaled 11/23/18, rebuild in progress.
'85 300TD, "Artemis".
'78 300D euro, "Ol' Red", mostly retired.
'85 300D, "Gandalf".

All of mine had Germany on them.

My old thread from 2008: http://www.peachparts.com/shopforum/diesel-discussion/219201-installed-injectors-rebuilt-monark-spray-nozzles.html#post1821816

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84 300D, 82 Volvo 244Gl Diesel

Only driven 3K miles since installation but the 261 nozzles on my W115 are running very well. Reduced noise at idle, increased smoothness in low speed acceleration and it just hit the best fuel economy the car has ever achieved (38 US mpg).

Just installed my next set in my OM 617 powered W123 300D NA and the power gain was immediately noticeable with no perceivable reduction in noise. I'll report back if we experience any issues.

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Why I will never do business with "DieselKraut" again

http://www.peachparts.com/shopforum/mercedes-benz-used-parts-sale-wanted/378935-why-i-will-never-do-business-dieselkraut-again.html

I've got two sets of Monark 261s in two different turbo 617s, and set of Monark 314s in a turbo OM603. One set purchased from he-who-must-not-be-named up in WA, back in 2016. Second set purchased from ebay seller in 2019. Third set purchased from greazzer, earlier this month.

I've got about 30K on the first OM617, 20K on the OM603, and the third set about 1000 miles. They're all great, no change in idle quality, power, fuel economy, or smoke since from new.

Wonder when the bad batch was produced. I must have been lucky.

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1983 300D Midnight Blue
4 speed, W115 intake mani, non-EGR exhaust mani, KKK K26, 3 pc Euro bumpers, Lo-spec Euro headlights, AL129X, hubcaps, custom A/C

1987 300TD Smoke Silver
Euro headlights, thermostat relocation, coolant bypass mod, rebuilt Becker + Jehnert + Helix audio, OEM Oris roof boxes and surfboard racks, Euro towbar

1983 300TD Reed (Moss) Green / Dark Olive MB Tex Euro spec

1983 300TD Silver Blue / Blue cloth Euro spec, OM648 and 722.6, 15" hubcaps, W126 S2 brakes

Sounds like a batch of counterfeit goods. Thanks for the heads up. Not you H3ffe but in the OP.

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Te futueo et caballum tuum

1986 300SDL, 362K
1984 300D, 138K

That's what I wondered, or a short-lived change of supplier/manufacturing facility that wasn't up to snuff. Monark had to get their widespread good reputation from somewhere, but we certainly didn't see it in the ones we were trying to run year-before last. I've been using Firad with great luck so far.

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'82 300CD
"Pearl", the very first turbo diesel 123 coupe
Totaled 11/23/18, rebuild in progress.
'85 300TD, "Artemis".
'78 300D euro, "Ol' Red", mostly retired.
'85 300D, "Gandalf".

Nice to hear that vote of confidence. Picked up a set of Firad SD 314's myself that I'm looking forward to install.

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'83 SD, 2x '85 SD
You are entitled to your own opinions, you are not entitled to your own facts.