Some of you have seen my quest to get my 240D to 40 MPG, highway, and I am wondering if I haven't found the reason why most of these cars are not getting the mileage (and power) that they should be getting.

I have seen another website strongly push Monark injectors. Let me show you the following diagrams, and you tell me what you think. When I saw the spray pattern of the Monark (being wider than the Bosch), it seemed logical that it could be better, until I found out that the injector didn't directly go into the cylinder. Please note first photo PRECOMBUSTION CHAMBER 2


The injection nozzle does not even come close to reaching the cylinder. It stops at the point where NOZZLE REED is pointing to. I want to describe this well, as some may not be familiar with these parts. You can see that the Precombustion Chamber (PC) extends well past the bottom of the injector so it just reaches a little into the cylinder. Note how the piston has a cut out so it does not hit the PC.

Now look at the picture called PRECOMBUSTION CHAMBER Note that the bottom of the PC is closed EXCEPT for the holes on the side.


Now, this last picture put it all together for me. Look at NOZZLE SPRAY PATTERN

This is from the Mercedes manual. Note how concentrated Nozzle A is. This is the correct spray pattern for the 240D and 300D. Now, the Nozzle B look deformed, but that is not the point. Go look at the first photo again. It makes no sense to me to use a wide spray pattern with this PC. Much of the fuel will hit the sides of the PC well before the openings at the bottom. Now look at the Mercedes recommended spray pattern. It is concentrated so that most of the fuel directly reaches the bottom of the PC and the holes on its side. Now, this makes sense to me. Not a wide dispersal pattern. The pattern should not dribble or bounce of the sides of the lower PC.

So, what is at work here? I DOUBT THAT 5% OF THE 240Ds and 300Ds HAVE EVER HAD THEIR PRECOMBUSTION CHAMBERS REMOVED OR REPLACED.

Do you have good combustion? Do you only get 30 MPG on the highway or a little more? I bet this is the reason. Further consider that there are reamers being sold to "ream out the carbon" through the glow plug hole (glow plug is also in Photo PC 2. Consider that this PC is in little cut out between the piston and the top of the cylinder head. Think about 30 years of that kind of abuse. Could it be any wonder that the lower end of the PC could be in very poor condition? I look at these three little holes in the bottom of the PC and it leads me to the conclusion that the harder the spray hits the end of the PC, the better the dispersal pattern will be in the cylinder head. This is what MB designed, and this is what I want.

The only trouble, other than cost? I called Bosch technical services, and I was told that their rebuilds are set to pop at 1450 PSI. This is the minimum standard for Mercedes. I guess I have to rebuild my own using Bosch nozzles at 1650-1675 PSI.

HOW DO YOU INCLUDE PICTURES FROM ANOTHER POST???

See photos post 33 http://www.peachparts.com/shopforum/diesel-discussion/251809-what-type-not-make-nozzles-have-you-tried-3.html (please open in a separate window to see photos, sorry)

30 MPG is good, be happy.

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Cheers!
Scott McPhee

1987 300D

this post sure reads like an ad to try to sell us something.

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79 240D 123.123 daily-driver
03 F250 7.3 PS SD CC (lightly modded)
82 CE 'vette (for sale)
73 dart 318, 73 charger w/'68 383 (both for sale)

I agree surveyguy.

Low to mid 30's is all that can be expected out of a 240D. Anyone that claims higher is full of BS, or it was a one tank fuel that they got that much cause they were traveling down the mountain for the majority of the tank. New healthy injectors will improve MPG, but it's not going to just 10 mpg.

Engine tuning will only account for so much of the MPG. You've got drag from the shape of the body, tire alignment and inflation, etc.

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Precombustion chambers are not cheap and neither are the special tools used to change them out. Put the money on your pocket and be happy with 30MPG. I use the Monarks in my NA 300CD and they were a great addition.

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"Life is tough...it's even tougher if you're stupid." John Wayne


Dave
Pawleys Island, SC

'79 300CD

The tools to pull are not too costly. In any case, it would seem to be worth pulling to at least clean them out.

Daman858, what changes did you see when you put the Monarks in? Any perceptable improvement in MPG? I would assume there were reasons you swapped, so I would think anything new would be a plus, especially with injectors.

And, Surveyguy, it looks like you are the one with something to sell, not me.

Getting much over 30mpg in these cars is verging on defying the physics of how they operate. Injector nozzles are not going to add a magical 5-10mpg. My 300SD got 25 on its original Bosch Nozzles, I currently have Bosio nozzles (for almost 50k now) and get about 24-26mpg.....my dad's SD had Monarks....got about 25-26 also. A 30 year old 4000lb diesel car is already doing really well at 25+mpg.

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-diesel is not just a fuel, its a way of life-
'15 GLK250 Bluetec 118k - mine - (OC-123,800)
'17 Metris(VITO!) - 37k - wifes (OC-41k)
'09 Sprinter 3500 Winnebago View - 62k (OC - 67k)
'13 ML350 Bluetec - 95k - dad's (OC-98k)
'01 SL500 - 103k(km) - dad's (OC-110,000km)
'16 E400 4matic Sedan - 148k - Brothers (OC-155k)

do you have any spray pattern pics from monark nozzles?

the PC is wide in the combustion chamber itself, and there is a ball on a stick, that heats up during combustion that's not in the pc pic. the protrusion into the piston area, is for the explosive gasses after combustion, not for the spray from the nozzle.
also, note the last line in part 3 of the spray pattern photo...

__________________
John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 190D 2.5Turbo
1987 190D 2.5-5SPEED!!!

1987 300TD
1987 300TD
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!

Heck, I'd be tickled to pieces with 30 mpg. I get 24-26 (but drive it hard). I can't imagine higher than 30. Maybe with a constant speed of 50 mph on a windless 65* day.
What are you folks doing to get to 30?

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1983 M-B 240D-Gone too.
1976 M-B 300D-Departed.

"Good" is the worst enemy of "Great".

It is sunny where I am today, I hope the weather where you are is exactly how you like. You are correct. I have things to sell. I am not, nor do I appear to be peddling them outright in an inappropriate manner. Writing the status of our vehicles in our garage is common and appreciated by many.

It appears I'm not the only one that thinks by the way you wrote this post, that you have something to gain by trying to talk others into purchases and upgrades that some people think are unnecessary and will not lead to the outcome you seek.

I hope you get your desired outcome of your original post, and are successful in performing this work yourself; also with your desired outcome. I wish you continued fortune in your business endeavors. My hope for you is that you become more accepting of people's opinion's especially when you ask for them. I am not wealthy, it appears to me you are, and I'm happy for you if so. When you do this work and have this expense, I will be looking on as will others here, of your photos and write-up of your progress/pitfalls/outcome.

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79 240D 123.123 daily-driver
03 F250 7.3 PS SD CC (lightly modded)
82 CE 'vette (for sale)
73 dart 318, 73 charger w/'68 383 (both for sale)

On our 80 240D with the 195-70-14 tires pumped up to a couple lbs less than the max tire pressure. (max 44lbs)
Changed the steel rims to the light alloy 5 1/2" rims. steel 18.75lbs, light alloy 9.70lbs
Changed the Differential from a 3:69 to a 3:58
15/40 synthetic eng oil.

On the highway we are getting a healthy 30+ to 31.8 mpg running at 65 - 70 or so. even intown driving we see 30. every tank will vary depending on the driving conditions, up hill, down hill, head wind, tail wind etc....
we are at 327k, clean filters and valves adjusted. there is only so much the engine can do with it`s 67hp. adding tall tires or higher geared Differential will work to a point. too tall of gearing, the eng will have to work harder to keep up the speed, and the milage will drop.

40 mpg, I don`t know, that would be stretching it a bit.

I didn`t pick up that any one was selling anything here, did I miss something?

Charlie

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there were three HP ratings on the OM616...

1) Not much power
2) Even less power
3) Not nearly enough power!! 240D w/auto

Anyone that thinks a 240D is slow drives too fast.

80 240D Naturally Exasperated, 4-Spd 388k DD 150mph spedo 3:58 Diff

We are advised to NOT judge ALL Muslims by the actions of a few lunatics, but we are encouraged to judge ALL gun owners by the actions of a few lunatics. Funny how that works

I have both types of injectors in identical engines.

Monarks are quieter and smoother. Because they have no pintile holes, they are better for WVO.

The Bosch NOS France nozzles are louder, in a 'sounds more like a tractor' kind of way.

MPG is about the same. 25-27 in the 82 with the 3.07 diff. 28-30 in the 85 with the 2.88 diff.

Power is the same.

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'85 300D, 'Lance',250k, ... winter beater (100k on franken-Frybrid 3 Valve Kit)
'82 300D, 'Tex', 228k body / 170k engine ... summer car
'83 300TD Cali Wagon 210k, wife's car

a pair of members noted that the original post reads like a sales brochure. the way it's worded sounds like an advertisement I guess.

__________________
John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 190D 2.5Turbo
1987 190D 2.5-5SPEED!!!

1987 300TD
1987 300TD
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!

Thanks Dan, I was curious about the pintile and WVO myself. hrmm.... got's me a-thinkin'.

__________________
79 240D 123.123 daily-driver
03 F250 7.3 PS SD CC (lightly modded)
82 CE 'vette (for sale)
73 dart 318, 73 charger w/'68 383 (both for sale)

What we read and comprehend is sort of like what is in my signature.

"I know you think you understand what you thought you heard me say,
But what you think you heard me say, is not really what I ment."

Maybe trying to read between the lines, seeing something that is not there, or maybe is.

Charlie

__________________
there were three HP ratings on the OM616...

1) Not much power
2) Even less power
3) Not nearly enough power!! 240D w/auto

Anyone that thinks a 240D is slow drives too fast.

80 240D Naturally Exasperated, 4-Spd 388k DD 150mph spedo 3:58 Diff

We are advised to NOT judge ALL Muslims by the actions of a few lunatics, but we are encouraged to judge ALL gun owners by the actions of a few lunatics. Funny how that works