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  #1  
Old 01-28-2020, 12:00 AM
cmac2012's Avatar
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Quote:
Originally Posted by cleeves View Post
You're saying the injectors nozzles should be like new if they've run 135K miles? I don't agree with that. Mine were in deplorable condition at 135K on a 1-owner well maintained example. 3 out of 5 were shooting a straight line of fuel and the remaining two weren't far behind. All had cupped, concave nozzles.
Here are mine. Your description of cupped, concave nozzles caught my eye. Mine don't seem to have any of that, but these are the first MB injectors I've seen. What do you think?





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1986 300SDL, 362K
1984 300D, 138K
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  #2  
Old 01-28-2020, 10:34 AM
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Originally Posted by cmac2012 View Post
Here are mine. Your description of cupped, concave nozzles caught my eye. Mine don't seem to have any of that, but these are the first MB injectors I've seen. What do you think?
Mine were definitely worse looking. It's kinda hard to see from the lighting. My fingernail would easily get stuck on the lip of the cupping. Now that you have them out, pop-test them. If only you were in Atlanta, I'd lend you my pop tester.

-Henry
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  #3  
Old 01-28-2020, 11:28 AM
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Originally Posted by cleeves View Post
Mine were definitely worse looking. It's kinda hard to see from the lighting. My fingernail would easily get stuck on the lip of the cupping. Now that you have them out, pop-test them. If only you were in Atlanta, I'd lend you my pop tester.

-Henry
Thanks! Nah, Atlanta's a bit far.

I hitchhiked through Georgia in Dec. '73. Camped out at a rest stop. Maybe the starriest night I ever saw.

I'll take them to my buddy, pretty sure that's the sort of device he has. Will get a kick out of seeing it. He wants to keep me happy. If I ever get rich and famous I'm going to have him put in new seals on my SDL tranny. He wants to do it. Says he can stop all the leaks. Might do it myself someday. Whoa, big job.
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Old 01-28-2020, 01:31 PM
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Do not waste the opportunity to inspect the glow plugs heating up with the injectors out. The tips should get really hot visually. If they do I would not put in a new set. As you would have no ideal on most acquisitions of the time they have been in service. They could have been replaced not that many miles ago for example. Also have a look for possible carbon buildup in the pre chambers. Many of the aquisitions have not seen highway service for years.

Of note was one poster on this thread mentioned that every thing he did seemed to make some difference. I have advocated going through the fuel system at least partially on any new acquisition for years. How extensive depends on your 0-60 times for the version you have.

At a minumim enough to reduce the chances of an issue while away from home. It is usually very cheap to do yourself. All my versions of 123s are on the faster side of most other similar ones I have driven. Especially the 240ds.

I have another bone to examine as well. I expect these engines to light off as soon as they start to turn over. If they do not something is not right. In reasonable temperatures of course. If they will not do this they are going to be harder to start in cold weather if you need that ability.

A road breakdown can be expected to become ever more expensive to deal with. Every year. Many mechanics have no working experience on these engines. Plus there are other factors that can impact the situation. You want to reduce the probability as much as you can yourself. Doing it all cost less than all the components of just one road breakdown. When far from home.

We are also driving cars that a wait for parts of even just a secondary filter or belt can take time. Mind things like your lift pump is bad. To me it is simply preventative maintenance on antique vehicles.

Our 77 N/A 300d even is not too bad for what it is. The 84 300d has passing ability like a gas car. Or at least feels that way to me. It does so well in that area I am almost positive that the whole system must be functioning like new. I call it just making certain that all components of the system are working well. Not a true restoration .Expected Zero to sixty times are well documented in the archives on each version.

Last edited by barry12345; 01-28-2020 at 01:49 PM.
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  #5  
Old 01-29-2020, 12:14 AM
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I love going up to Berkeley and seeing all the diesel Benzes driving around. I used to live across from Fat Apples...uhm 30 years ago.

Good luck with the search. I was amazed at getting my 300d back to making power. It wasn’t any one thing that was robbing power. It was half a dozen things each eating a few HP and once I went through it all it finally ran properly.

Putting a boost gauge (just a T, some hose and a cheap air gauge) on my ALDL line gave me an idea just how much boost I was getting. I had a lot of goo on the inlet side of my turbo.
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  #6  
Old 01-29-2020, 03:57 AM
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Originally Posted by ykobayashi View Post
I love going up to Berkeley and seeing all the diesel Benzes driving around. I used to live across from Fat Apples...uhm 30 years ago.

Good luck with the search. I was amazed at getting my 300d back to making power. It wasn’t any one thing that was robbing power. It was half a dozen things each eating a few HP and once I went through it all it finally ran properly.

Putting a boost gauge (just a T, some hose and a cheap air gauge) on my ALDL line gave me an idea just how much boost I was getting. I had a lot of goo on the inlet side of my turbo.
Is that something that needs attention?

Speaking of goo, I pulled the ALDA line from the manifold, that was on advice from this one:

Quote:
Originally Posted by Maxbumpo View Post
This is a great point, the pressure line fitting at the intake manifold and the over-boost control valve can get plugged up with soot, and then you get a sluggish engine. You said you can barely blow through it, to me that means a fail. I'd recommend you remove the fitting from the manifold and spray it out with brake cleaner and maybe push a bit of wire in / out.
Oh man, not sure I'd call it soot, but it was black and residue like, that's certain.



I got the right size drill bit (loose fit) and cleaned the junk out of the long skinny part, then used WD-40 and brake cleaner to clean the rest and the line as well. Blew compressed air through it. Good thing I found that. My fix of the other broken line probably wouldn't have gone so good.

One thing I wonder about is the little relay hub where the lines converge. Tonight, to take off the manifold banjo bolt I took the hub/junction off the firewall as I couldn't see where that hose hooked in. I noticed an electric line coming off of it. I'm curious just what goes on in that little hub thingy.
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  #7  
Old 01-29-2020, 09:49 AM
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Post Overboost Protection Valve

That's the one we've been telling you to clean out, it must not have any resistance to being blown through .

Get the proper de greaser, not brake clean and drill bits .
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  #8  
Old 01-29-2020, 09:54 AM
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Quote:
Originally Posted by cmac2012 View Post
One thing I wonder about is the little relay hub where the lines converge. Tonight, to take off the manifold banjo bolt I took the hub/junction off the firewall as I couldn't see where that hose hooked in. I noticed an electric line coming off of it. I'm curious just what goes on in that little hub thingy.

that's overboost protection valve.


if it gets continuity through the pressure sensor on the intake manifold it then vents this line to atmosphere therefore limiting fuel by not sending pressure to ALDA
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  #9  
Old 01-29-2020, 10:29 AM
cmac2012's Avatar
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Quote:
Originally Posted by barry12345 View Post
Do not waste the opportunity to inspect the glow plugs heating up with the injectors out. The tips should get really hot visually. If they do I would not put in a new set. As you would have no ideal on most acquisitions of the time they have been in service. They could have been replaced not that many miles ago for example. Also have a look for possible carbon buildup in the pre chambers. Many of the aquisitions have not seen highway service for years.
This is the first time I've had injectors off of one of these motors. Looked like a fair amount of carbon buildup down in there but what do I know.

Even though it's low miles, pretty sure it was mostly city miles. So just as many startups as a car with say 400k and lot of highway miles. I've already ordered the glow plugs, a little over $60. If I'm going to take them out and ream them (have a reamer on the way) I may as well put new ones in. Would be interesting to test them though.
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