MyE28.com DEV

INTRODUCTION:
This writeup is intended to help in diagnosing, servicing, repairing, calibrating and replacing worn, old or damaged injectors on M21 motors used in vehicles such as the 524td, 324td, Vauxhall Vixen motorhome and the rare Lincoln Mark VII.

HOW DO I KNOW IF I SHOULD SERVICE MY INJECTORS?
Any of the following may be signs of worn injectors if your engine is in otherwise good mechanical shape:

• -Rough idle, idle lope
  -Injector "knock" or "nailing", strange combustion noises. May sometimes sound like piston slap or rod knock.
  -Excessive black or white smoke
  -Loss of power
  -Bad mileage/economy

Injectors are a SERVICE INTERVAL ITEM. They are probably one of the most overlooked parts in diesel maintenance.
Many diesel mechanics and techs believe they should be serviced or replaced every 60,000-80,000 miles.

ABOUT THE INJECTORS:
The M21 engine is considered an IDI or Indirect Diesel Injection motor. What that means is the injectors fire into a precombustion chamber or precup in the cylinder head. As a result, IDI motors typically have higher compression ratios, lower injection pressures and lower power output than TDI or CDI motors.

When an injector is worn or becomes damaged, you must replace the injector nozzle. While it is not necessary, you should replace ALL nozzles at the same time. That way, they will all wear evenly over their service life. The nozzle considered a wear item and disposable whereas the injector body is reusable and must be reconditioned before installation of new nozzles and calibrated after reassembly.

Quoted from a Bosch technical document:

These nozzles are known as Delay Pintle Nozzles, and are nearly always used with the Indirect Injection Engine, and have part numbers like, DN0S"D"299A.--The "D" in inverted commas, refers to Delay type nozzle.

"DN" "0" "S" D "299A"

"DN" referrs to Pintle type nozzle

"0" referrs to the spray angle, whether its defined as a number of degrees or not.

"S" refers to the size of nozzle body.

and "299A" refers to specific characteristics of that particular nozzle ( apart from this number its not possible to find the charaterictics of the nozzle from the makers)

Any letters before the "DN" refer to the maker, eg. B, C, K, R, V are all Lucas / Delphi maker codes, Bosch generally use just the basic number.

As a result, it as been said by many that ALL DN0SD nozzles are interchangable while others state that some nozzles have slightly different dimensions. The M21 uses DN0SD259 nozzles.

DN0SD INJECTOR NOZZLE GUIDE:
This is my interchange guide so far:
DN0SDXXX - [Displacement] / [# Cylinders] / [HP] - Engine model
Known good fitments for the M21 will be in BOLD. Interchangeable nozzles will be underlined.

DN0SD259 - 2.4-6-114 - BMW M21, Fiat, Lancia
DN0SD248 - 6.2-8-130 - Early GM 6.2L
DN0SD265 - 3.0-5-122 - Mercedes OM617
DN0SD318 - 2.5-6-141 - Volvo 940, BMW 525tds, Opel Omega 2.5, Volvo 2.5
DN0SD297 - 1.9-4-76 - Volkswagen "AAZ" 1.9L Turbo
[More to be added, fitments updated]

INJECTOR REMOVAL:
[To be added] Special sockets, injector line care, fuel return barbs, issues concerning #4 "sensor" injector.

CLEANING AND SURFACING THE INJECTOR BODY:
[To be added] Solvent soak, sanding interface surfaces

CALIBRATION, "POP TESTING":
[To be added] Testing Equipment, testing at home v. shop testing, Shims, Pressures, Calibration fluids or different fuel types including Low Sulfer, Ultra Low Sulfer, Bioiesel and WVO and pressures. Spray pattern.

RE-INSTALLATION:
[To be added] Heat shields? Torque specs

OTHER INFO, TIPS, TRICKS, REMEDIES AND FAKES:

Automatic Transmission Fluid Flush:
[To be added]
Lubro-Moly DieselPurge:
[To be added]
Use and effects of Waste Vegetable Oil:
[To be added] Coking glycerin, thinning agents and effects, adequate preheating


----ORIGINAL POST----


Do we have any Bosch gurus here that can tell me if nozzles from any other injectors will fit our injector bodies?

I just got myself a pop-tester to service few cars (VW-TDIs) and while searching for nozzles I noticed a few different options for nozzle sizes. But there aren't any options to increase nozzle sizes for our injectors. And then it hit me. the basic design of a Bosch IDI injector hasn't changed much at all over the years. 300D, 524td, 6.5L GM, etc.. all have pretty similar designs.

So, in my mind.. I am thinking this. If any other nozzles DO fit these bodies, then we could potentially create higher-fueling injectors for the M21.

I came up with a formula to compare relative measurements of power and displacement of other motors.. if we take that information and plug it into our engines characteristics, it should give us an idea of what sort of increase we could see.
[Engine displacement] / [# of cylinders] = X [displacement per cylinder] * 6 [# of cylinders on M21] = fueling for "virtual displacement"

Lets just say 300D nozzles fit for a moment.
3.0L / 5 = 0.6 * 6 = 3.6L
Again, lets say 6.5L GM nozzles fit...
6.5L / 8 = 0.8125 * 6 = 4.875L


HOWEVER...if we look at power outputs for these motors things start to make less sense.

I'm going to stick with the 300D and 6.5L motors on this one..

HP (or torque) / [# of cylinders] = X [HP/cylinder] * 6 = XX

300D - 80HP / 6 = 16 * 6 = 96HP - Smaller total volume over stock
6.5L GM - 180HP / 8 = 22.5 *6 = 135HP - Larger total volume over stock

I'm just thinking out-loud here.. if anyone else has better information regarding physical dimensions of M21 injector bodies or nozzle measurements or even flow statistics please share.

If it turns out that other nozzles are interchangeable, it could become a better option than trying to track down replacements from Germany and could be plentiful and inexpensive.

stock m21 injectors can held over 300bhp power.... so why change others..... with different nozzles you can easily make engine running poorly....

like few guys who increased injector opening pressures to higher...

m21 nozzles and mb om603 nozzles are quite similar and many stdiesel owner uses stock injectors with over 400bhp

i can ask few flowing measurements from my ip maker who knows better...

I've only heard about higher opening pressures being used for biodiesel and vegetable oil, to help atomize the fuel better. I was thinking of doing a few tests myself with some clean veg oil and biodiesel on my new pop-tester when it arrives.

If stock injectors can do ~300bhp, then thats great. Availability and cost are then the only issues left.

A set of nozzles for a M21 start at roughly $200 and go up. If you can find them.

By contrast, a set of 6.5L nozzles (8 total) costs about $60.

Here are some part numbers to help..
M21: Bosch #0434250117
GM 6.5L: Bosch#0434250105

These nozzles are known as Delay Pintle Nozzles, and are nearly always used with the Indirect Injection Engine, and have part numbers like, DN0S"D"299A.--The "D" in inverted commas, refers to Delay type nozzle.

"DN" "0" "S" D "299A"

"DN" referrs to Pintle type nozzle

"0" referrs to the spray angle, whether its defined as a number of degrees or not.

"S" refers to the size of nozzle body.

and "299A" refers to specific characteristics of that particular nozzle ( apart from this number its not possible to find the charaterictics of the nozzle from the makers)

Any letters before the "DN" refer to the maker, eg. B, C, K, R, V are all Lucas / Delphi maker codes, Bosch generally use just the basic number.

DN0SD259 is the number for our injectors. The number also comes up with a Fiat and Lancia application.
DN0SD248 - GM nozzles
DN0SD265 - Mercedes OM617 nozzles
DN0SD318 - Volvo 940, BMW 525, Opel Omega 2.5, Volvo 2.5
DN0SD297 - Volkswagen IDI motors


Also, apparently VW guys are using Mercedes and GM nozzles in their older IDI motors. I also saw it mentioned that all "DN0SD" nozzles are physically interchangeable.

btw.... i just heard that one guy who is working in mynädiesel had over 450bhp from hes bmw 525tds m51 engine with mb ip.... but getting more power was impossible.... and reason was that bmws twirl style chambers cant handle more fuel...

so... next idea.... getting mb chambers to bmw engine..... quite lot of work but i think that is possible.....
but maybe in future.....

When my pop-tester gets here I'm going to test all my injectors.. If any are bad I'm going to take the plunge and order some 6.5L GM "Marine" injector nozzles for my 524.. I'll get some good macro shots of the new nozzles compared to the old ones and post them up here.

Anyone want to take a guess at what pressure I should calibrate these to? I'm going to do all my calibrations with biodiesel as a test fluid and checking for proper atomization.

I propose a sticky. (once this is completed)

Anyone want to contribute?

our pop-tester is made from old hydraulic jack
it works quite nicely.... just tested my old injectors and the new ones.... difference is like a night and day

I almost made my pop-tester out of a jack, but I didn't want to leave anything to chance... so I bought one with a nice big oil filled dial and a bleed-down valve.

The first one they sent me didn't work, so they agreed to send me another one. The other one just got here yesterday and doesn't work either.

Hey Beamters, would you please make this a sticky?

Thanks,

//Mark

More info:
Apparently GM injectors (even the "long" ones) are much shorter than our injectors, which makes me question whether or not the nozzles would fit.


DNOSD304 are the short injector variants
DNOSD248 are the longer ones.

It is noted that nozzles between these two injector bodies are not interchangeable.

Here is a M21 injector for comparison:

More info..
Injector body numbers:
KCA 30 S 50 - M21
KCA 30 S 44 - Early VW/Audi/Mercedes 115bar
KCA 30 S 46 - Early VW/Mercedes 135bar (turbo?)

More info..

M21 injectors use a copper heat shield with the following specifications:

21.6mm OD X 17.6mm ID X 1.5mm thickness

Copper washer annealing? Pretty neat... I didn't know about this. I'll have to add it.

http://www.motorcycle.co.uk/reference-m ... shers.aspx

Tried it when re-installing my injectors, so far no leaks!

can injectors nozzles be pop tested while engine is out?
also to save money if so if any are bad can I simply take good ones from the bad head engine and swap them out for now?

really got to learn to do some of this on my own..hard to trust fully in mechanics who simply want to get onto the next project

Yes and yes.

Pop testing only tests the pop pressure of the injectors..they can be done to injectors that don't even have an engine.

And yeah, as long as they pop within a certain range +\- of pop pressure you can throw them right in. I like to have all my injectors within 5 bar or less of eachother but most factory manuals allow upto 20 bar tolerance.

I have two pop testers, I can sell you one. PM for details if interested

Does anyone know if the euro injectors are the same?
realoem is saying that they are not until 87+

Euro injectors would have different body styles (due to the lack of a sensor injector)

Bosch DN0SD259 nozzles should fit all M21 application.

I am ordering a set of 6.2L nozzles to see if they fit later this week. I will share my findings.

So has anyone established if there are any alternative nozzles? It would be really helpful to get some update on the possibility of less expensive, easier to find nozzles.

CoyoteStarfish wrote: ... and the rare Lincoln Mark VII. ...

Excellent write up and thread.

Thank you.

Hi
Do you know if the DN0SD286 nozzle will fit the injector body of 524td 1985. this pdf states that the DN0SD286 is the for 524td 1986.
www.cempol.pl/pliki/katalogi/qap/qap_dysze.pdf

What is the different in the engine for 1985 vs. 1986?
I need new nozzle on all my injector so I am trying to find chepest way to them as I am only a poor college student
and found the DN0SD286 at:

http://www.aliexpress.com/snapshot/107242125.html

Thank you
Nick

Hi bacatcha,
I'm familiar with the Lincoln Mark VII version of the BMW engine and cannot answer your question.

What tools is recomended to use when removing the injectors?

Argi wrote:What tools is recomended to use when removing the injectors?

See the Samstag Sales link in this thread: http://www.mye28.com/viewtopic.php?t=88207

You want the diesel injector socket and the diesel fuel injector line socket. You can remove the injectors without these tools but you'll need to modify a regular socket to allow you to remove the #4 injector without destroying the sensor wire.

I'm still trying to find an alternative nozzle.

Here's a 6.5 injector compared the the BMW one. The 6.5 is the shorter one with the thinner needle.











Need one that's 27mm.

I just got a hold of a 1986 324d in great condition. It is a euro only model and was imported to the USA. It has the M21 engine. The only problem is that one of the injectors have a small leak coming from where it goes in the engine. Does anyone have an idea on how I could fix this? I know I should probably replace the nozzles while I am at it. Does anyone know of a reputable place to purchase them online? Thanks, Kevin

I don't know about the availability of injector nozzles in Europe but i just got a set for my 524td from Kerma TDI,they are $200 and it took me quite a while to receive them. Make sure the return lines aren't leaking and making it seem like its coming from somewhere else, that what i would do first. Since im about to do the injectors on my car I read A lot of stuff of rebuilding Mercedes and VW injectors since they are very similar. Before you do any work on the injectors i would high suggest just reading as much as you can about rebuilding them unless you have done it before. Thats my 2 cents, also to get a quicker and easier response instead of posting in an old sticky or thread just post onto the main page of the Turbo Diesel section. here are two helpful links:

http://dieselgiant.com/mercedesinjector ... eplace.htm

http://vincewaldon.com/index.php?option ... &Itemid=28
This link goes into lapping the two halves to prevent them from leaking

Good luck,
Jon

n62motor wrote:Hi
Do you know if the DN0SD286 nozzle will fit the injector body of 524td 1985. this pdf states that the DN0SD286 is the for 524td 1986.
http://www.cempol.pl/pliki/katalogi/qap/qap_dysze.pdf

What is the different in the engine for 1985 vs. 1986?
I need new nozzle on all my injector so I am trying to find chepest way to them as I am only a poor college student
and found the DN0SD286 at:

http://www.aliexpress.com/snapshot/107242125.html

Thank you
Nick

Blast from the past but FYI, I bought both injectors DN0SD286 and DN0SD259 and although I do not have a caliper handy to they appear to be identical except for some minuscule difference in the nozzle, in the last picture the DN0SD286 is on the left, the DN0SD259 on the right. I will measure everything in a couple of days.

AHHHHH!!! look at all that contamination!!! -Paul