I just ordered some Monark replacement nozzles for my '92 300D, is a pop-off test required before installation in vehicle??

For all practical purposes, yes. The probability that all injectors will be within specification is extremely low. I have replaced dozens of nozzle sets and have never had a single set test even close to spec prior to adjustment.

Even a set that is within +/- one bar with the original nozzles can be all over the board with new nozzles.

I pop tested my old (original) injectors, and they were surprisingly not too badly off the mark. Only one was a low popper. Half of them had bad sprays as well.

I obtained a pop tester and shim kit with my Monarks, and set them all to top of range 145 bar. Plus or minus 10 psi kind of thing.

What surprised me was what little relationship there was to the previous nozzle in the injector to what its replacement needed to be shimmed at.

If all your previous nozzles were bang on, there is NO guarantee you'll be within spec on your new nozzles.

While they're out, it's so easy to do. Do it.

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Cheers!
Scott McPhee

1987 300D

Diesel injector nozzle POP test pump
http://www.peachparts.com/shopforum/general-information/213112-diesel-injector-nozzle-pop-test-pump.html#post1759285

How to build a diesel injector pop tester
How to build a diesel injector pop tester







Have a great day.

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1985 300SD
1983 300D
1984 190D
2003 Volvo V70
2002 Honda Civic

https://www.boldegoist.com/

If you do not Lap the precision surfaces inside of the Injector there is a chance they will leak between the Nozzle Nut and the upper Body.

Red Arrows show the surfaces. The part with the double Arrows need both sides lapped.

Attached Thumbnails

 

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84 300D, 82 Volvo 244Gl Diesel

yes, always whenever anything inside the injector is changed.

When CSEANWATTS installs new nozzles, does he pop-test them? I'm sure he does since he has such high ratings. He did a set for me about 8 months ago...

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Regards,
Ian White

1995 E300 Diesel w124 OM606
2014 E550 w212 M278 biturbo

2001 BMW 740i E38 M62 (past)
1981 300SD w126 OM617 (past)

I just got a new injector set from C sean Watts, they were all pop tested, Shipped nicely too in a nice padded container

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hum.....
1987 300TD 311,000M Stolen. Presumed destroyed

I believe I have read on this forum that C Sean Watts used to pop test new Monarks, and now does not anymore. He said that they are always right on from the factory.

I may be wrong, however.

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----Adam

1985 300SD 322,000

Nah, Utter Rubbish!

Done hundreds of injector re-builds, its all in the Cleaning of ALL the parts and Exactly HOW you do the injector up on final assembly!!

--There is a Knack to it!

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http://i190.photobucket.com/albums/z...0TDnoplate.jpg

Alastair AKA H.C.II South Wales, U.K. based member

W123, 1985 300TD Wagon, 256K,
-Most recent M.B. purchase, Cost-a-plenty, Gulps BioDiesel extravagantly, and I love it like an old dog.

W114, 1975 280E Custard Yellow,
-Great above decks needs chassis welding--Really will do it this year....

New nozzles and new injectors are two very different different concepts.

Cool!

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84 300D, 82 Volvo 244Gl Diesel

C Sean Watts also sells completely new Monark Injectors. I believe those were the ones he was speaking of that are always righ on from the factory.

We PMed each other several months ago and on his rebuilds; besides Pop Testing he also laps those precision surfaces.
He also has an Ultrasonic Cleaning Tank.

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84 300D, 82 Volvo 244Gl Diesel

Yes, yes and thank you. I've been busy the past few weeks. NO manufacturer, I've ever heard of, makes nozzles (to be installed in injector bodies) that DO NOT need to be tested - did that make sense? All new nozzles installed should be pop tested when installed, regardless of make. Monark's NEW, ready to install complete injectors are set from the factory. I check them at random (about half) and none have ever been off. As for the servicing - I stick to MB's FSM, "Dress the surfaces {see red arrows in photo above} before reassembly." FWIW, this also applies to VW, Volvo and a fork lift I once worked on. For the benefit of any new folks, when we say, "lap" or "dress" we DO NOT mean removing measurable amounts of metal, leaving any new machining/sanding marks or rounding the edges in any way. Your objective should be leaving a shiny, clean mirror finish. Also, when we say, "clean" the injector parts we mean thoroughly, completely and as much like a NASA satellite assembly room as you can possibly get. It is not unreasonable to spend up to 30 minutes on ONE dirty injector.

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1987 300D (230,000 mi on a #14 head-watching the temp gauge and keeping the ghost in the machine)
Raleigh NC - Home of deep fried sushi!

So what is an average price for 5 injectors ready to go into my 300sd? and did you guys see big improvements after changing these?

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83 300SD Dark Silver Dark brown inside