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Bosio nozzles, good or bad idea?

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monarchd's picture
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In seems I made a mistake. I just finished installing Bosio nozzles in Bruno, my 1982, 300D T. He seems to have much more power, but he's not nearly as quiet. In fact the engine sounds kinda harsh when accelerating... Almost as if the switchover valve has been by-passed, which it hasn't. Is this normal for Bosio nozzles?

Also, when I turn the key off, the engine wont shut down until I press on the accelerator.. I can't find any loose vacuum lines, and the power doors still work......

I'm seriously considering cleaning up the old nozzles, having them pop tested, and re-installing them.

Any suggestions? What's the best method for cleaning nozzles? Will soaking in brake cleaner work?
Thanks in advance.
charlie

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Just now bought a manual

Marshall Booth wrote:
Have you read the engine manual treatment of injector cleaning?

Marshall

No, I don't have a manual and it's not listed in my Haynes,. However, :o I just now bought a manual.

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Marshall Booth wrote:
Read section 7.1-137 in the manual!!

Marshall

Thank you.

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I bought this 1982 300D T about 3 months ago. I changed all filters and fluids, including having the torgue converter flushed. I did a Lubro Moly diesel purge, serviced the ALDA, replaced front brakes, all shocks and tires. The timing chain was tight, but to be safe, I had it changed. At that time I also had the valves adjusted and the thermostat replaced.
All mounts and motor shocks have been replaced all the way back to the tranny and sub frame bushings. I also pulled the dash cluster, replaced the rheostat, dash lights, and re painted the guage hands, etc...

The point is, I'm giving it a lot of TLC.

The engine was very quiet, but even after all of that, it still had a slightly rough idle....Or maybe I unconsciously compared to our Lexus. Maybe I should have let well enough alone, but I replaced the nozzles.

During that process I noticed the #2 injector heat shield had been put on upside down. That is, the concave part was face down. I put the new heat shields in the correct position, put everything back together but it still didn't run right. In fact it's nosier.

This morning I isolated the noise to #2. When I disconnected its nozzle, the noise stopped. Upon opening the injector I noticed the compression spring was about 2mm below all of the other injectors. It seems the nozzle hardly has any load on it and probably needs a thicker shim or another compression spring.

I'm taking it to H & H diesel service tomorrow. They said they'd pop test it and shim as needed. Any other suggestions?

Thanks in advance,
charlie

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:D That's for sure!

Marshall Booth wrote:
A 61x diesel engine will NEVER idle as smoothly as a Lexus.
Marshall

However, something was wrong, and it was/is in the number #2 injector. Had I not changed the nozzles I would have never found it. I also suspect that the heat shield in #2 injector had deliberately been placed upside down in order to put more load pressure on the face of the nozzle. Maybe that's why I only heard the nailing noise after I installed the new heat shield right side up.

Any opinions on that theory?

Some really terrific Mercedes owners/mechanics on another forum urged me to build a pop tester and test all of the nozzles. But I know my limitations... and I'll leave pop testing and adjusting those shims which change nozzle spray patterns to pros who have all of the sophisticated testing equipment such as H & H Diesel Service, etc..

Still, moving into unknown territory is always a challenge, but the learning experience is also always extremely enjoyable. In the 3 months that I've been haunting these fora, I've learned a lot very useful info from a variety of terrific and generous DIY'sers, owners, and mechanics.

However, from the depth of many of your answers, it seems you're probably first a scientist/ engineer and then a gifted mechanic. In that regard, I merely wondered if you, or anyone else, might point out other things that I could do or should have done.
Thank you,
respectfully,
Charlie Munn
Charles

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H-townbenzoboy's picture
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The extra engine noise with Bosio nozzles seems to be a common occurance. It should quiet back down after a few hundred miles or so.

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H-townbenzoboy wrote:
The extra engine noise with Bosio nozzles seems to be a common occurance. It should quiet back down after a few hundred miles or so.

Many thanks Joe, :) I needed that! Still, since the noise seems to be caused by the #2 injector, which has very little load on it , if any, I hope it will quieten down after it's been pop tested and repaired.
Regards,
charlie

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Hi Charlie: Your earlier post stated:

However, something was wrong, and it was/is in the number #2 injector. Had I not changed the nozzles I would have never found it. I also suspect that the heat shield in #2 injector had deliberately been placed upside down in order to put more load pressure on the face of the nozzle. Maybe that's why I only heard the nailing noise after I installed the new heat shield right side up.

Any opinions on that theory?

This morning I isolated the noise to #2. When I disconnected its nozzle, the noise stopped. Upon opening the injector I noticed the compression spring was about 2mm below all of the other injectors. It seems the nozzle hardly has any load on it and probably needs a thicker shim or another compression spring.

End of Quote:

Once the nozzle holder and the injector body are properly tightened an inverted heat shield will not force the nozzle upwards to increase spring pressure inside the injector.

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New York club member since 1976.

Continuous Mercedes ownership since 1964.

1993 300SD with '99 606 engine. 111,040 miles.
1994 S350   75,238 miles
1995 S350 148,124 miles.
1996 S420 with '99 606 engine  Sold
1999 S600  one of 14 imported  Sold 
1989 Bentley 8  Sold at 40,000 miles.

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jtripp wrote:
Hi Charlie: Your earlier post stated:

Once the nozzle holder and the injector body are properly tightened an inverted heat shield will not force the nozzle upwards to increase spring pressure inside the injector.

Thanks. That makes sense. I guess the previous owner merely erred and put that heat shield in the wrong way.
\
That aside, this morning H & H Diesel Service in Milton WA pop tested the #2 injector, found it had no pressure, increased the shim on the compression spring and brought it back into specs.... It took them about 5 minutes and :D they wouldn't even charge me for it!

The boss, Kevin, smiled and said, " That 300D T will need a lot of service, we'll get even next time."

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I've put about 80 miles on the new Bosio nozzles since repairing the #2 injecter. What a difference! Good, quiet idle, and very smooth shifts. ( I accidentially disconnected a vacuum line. :confused: I may have inadvertantly repaired a slow leak when I stuck it together, hence the better shifting.?) It has plenty of power, and no longer makes that "hot rod noise" when accellerating.
There's no doubt in my mind that replacing those old German nozzles was the right thing to do!

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I bought the set from Russell at dieselgiant.com. His site has a lot of good pictorials, at least for me. I'm a complete novice. ( I've only owned this 1982 300DT for about 3 months, and it needed a lot of TLC. ) I had some questions and sent him an email, about 2 hours later he called me at home ( He's in Geogia, I'm in WA ) and gave me a lot of helpful instructions.

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Marshall Booth wrote:
New nozzles will produce a sharper noise than older, otherwise perfect nozzles.

Marshall

Thank you Marshall. Your confidence in Bosio nozzles makes me feel a lot better!
I thought the engine was running well before I changed the nozzles. However, since the #2 injecter was repaired, and the Bosios installed, the engine is now very quiet and responsive. No more "hot rod noise." In fact I can hardly believe it!

Of course I've also installed the mercedessource.com SVO kit, and it's common knowledge that SVO truly muffles the normal diesel clatter. I'm also getting better mpg with the SVO kit.

Mobil 1 is normal fare for our Lexus, but the mechanics at the Benz connection told me not to use a synthetic because it would cause leaks. However, since reading your discourse on oils, a couple of days ago I switched the 300D T to Mobil 1 for heavy duty diesels.

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Bosch nozzles and cleaning

Bosch nozzles: I think my many rough idle, smoke, and nailing problems for the last four years are primarily due to the Bosch nozzles I've bought from MercedesShop. On their forum you can find all kinds of chatter about the Bosch nozzles, how they're all made in India now and are crap, and people all excited when they hear that someone has some of the now very hard-to-find German nozzles.
Someone please clear this up for me. I am trying to sell this dog because I'm so sick of trying to make it run right, but I need to get it to run right to sell it.
Cleaning: What does section 137 of the Diesel injection chapter say? My FSM CD-ROM skips from 120 to 140. Why did they leave it out? I've monkeyed around with Diesel Purge about 8 times to no avail.
Help!

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Higher opening pressure will result in later injection timing.

__________________

New York club member since 1976.

Continuous Mercedes ownership since 1964.

1993 300SD with '99 606 engine. 111,040 miles.
1994 S350   75,238 miles
1995 S350 148,124 miles.
1996 S420 with '99 606 engine  Sold
1999 S600  one of 14 imported  Sold 
1989 Bentley 8  Sold at 40,000 miles.

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Section 137 of FSM

My year & model are 1979 123 (240D) with 616 engine, 130,000 miles.
My FSM (CD-ROM) is the 123 manual. Don't know why I have no section 137.
Maybe it just goes by a different number in the 123 manual.
I recall seeing a section about using a fine brass wire to clean the tip of a nozzle. Is that the section?
Maybe my Bosch nozzles are somehow getting crudded up, even though I change the filters regularly.
There's a really bad nailing when I start up cold and put a load on it. One cylinder only doing this. Have actually taken a new injector and put it in place of injectors 1, 2, 3, 4, in sequence, and nothing changed.
Am beginning to wonder if it's a cracked piston skirt or dome.

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vlayton wrote:
Where are the Bosio's from?

i bought mine here

http://dieselgiant.com/diesel_parts_for_sale.htm#Bosio%20Injector%20Nozzles

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