If a piece of carbon broke loose from the head or fell into the combustion chamber from behind the exhuast valve....it could get pulvarized between the piston and the PPC and put carbon into the holes...
But sounds like yours are clean ( at least now that you turned over the engine with the injector out )....
The ' mist ' part of the description sounds bad....

And again, no smoke from the tail pipe upon this test. So, this is getting hairy... I guess I've shot down all the easy fixes.

There are about three variations of the PCC's...
the first which fits the old piston style..
the second and third which fit the newer style piston top...
the second and third have more and then larger holes than the first....
this caused an increase of several horsepower in these engines...
I do not know how many of those holes it would take for you to get the spew into the air which you saw...
I do not know how many of those holes would need to be stopped up to cause the original loss of power in that cylinder either...
So, it would still seem easier and cheaper to pull that PCC just to make sure rather than go to the next and way more expensive steps deeper in the engine...

So, with the top of my engine tore to peices, and the pcc clean....next?

I would do a compression and leak down test to try to establish whats happened. Just do the #one cylinder. Maybe #2 to eliminate the possible chance of a head gasket but do not think this applies right now.If you inject compressed air into that cylinder at top dead centre while listening at tailpipe, and inside air cleaner housing it will tell you if you have developed a bad valve and if it is exhaust or intake. Also listen with the oil cap off the valve cover just in case a lot of air is going into the base. But do the compression test first to make sure other proceedures are indicated. Do not forget there is a slight chance the head gasket is gone so check carefully as you go. I am sure you have made sure the camshaft lobes on number one look simular shaped as the other lobes as well. I do not think it is a problem anyways as your problem materialised too fast. The first cam lobe used to always wear down to a circle on the early gas engines but thought not a problem on their diesels. Best of luck.

Unless you have a way to LOCK THE CRANK.... (and you don't )
you need to have the piston at the bottom of its travel....

There are 12 square inches of area on the piston tops...
It is typical to choose something like 100 psi to put into the chamber at the start of the leak down test...

That is 1200 lbs of force on top of that crank throw... If it is not PERFECTLY CENTERED AT THE TOP OF THE STROKE.... it will turn the engine over. And perhaps BACKWARDS.... very bad for the chain ... and specifically forbidden in the Mercedes Factory Shop manual...

I do not know of any reason to use the top of the stroke... as compared to the SAFE bottom of the throw.....

I don't know of any way to lock the crank to be safe at this ... so use the BDC for this test.

OK, So, Grandpa and I turned the engine until both the intake and exhaust valves were disengaged at the top of the motor for cylinder #1. There was no hissing noise noted, BUT my air compressor is not heavy duty. One small concern- when both valves are (shut??) the cylinder should be sealed for compression, right? Well, my technique was-
1) remove the innards from my old injector, allowing unrestriced airflow.
2)connect clear plastic hose to the fuel-line end of the gutted injector, and the other end of the hose to my air compressor.
3) turn it on
4)listen-(air came out of the injection side. I sealed off the overflow connections)
5)screw modified injector into #1 port
6)listen
The interesting thing- the compressor made such a racket that we couldn't hear anything interesting! BUT- the compressor motor did NOT change its note like it was compressing-IE something is releasing the pressure from the cylinder. No compression=no combustion. So, the fuel isn't getting combusted, and is pouring into the hot exhaust manifold and smoking like a trooper(My theory...). I now wonder-valve or rings? I'm pretty sure it couldn't be much else because of the lack of banging/clattering inside her. Rings apparantly don't just break, they wear?-so are we reasonable to say that my valve is toast? Also, there IS some play in the exhaust valve actuator (Sorry, I don't know the right name for that little lever-this is the first time I've worked on an engine-HOWTHINGSWORK.COM is great for morons like me!) not much, about 1mm. Sorry so long, any feedback would be most appreciated!

I was out doing it before I saw your post! But It didn't even offer to turn over

You probably ought to do a search on ' leak down test' ....
I am afraid you are not following all the rules... and are thus jumping to unwarranted conclusions.... which might cost you a lot of money and labor....
without it being necessary....

That is why they call it BLOWBY.

LOL - it'll do it every time.

Sounds like you and Grandpa are putting in a good effort. If you have a spare injector you can gut it and make a compression testor out of it. Make sure the gauge that you use is one that will "hold" the highest indicated pressure. All cylinders should be within 10% of each other. Another thing you can do is have an oil sample done to look to see if there is any metal in the oil. They can tell you what kind of metal it is too.

I hate to be the naysayer here but I think your engine is shot just because of how hard it is to kill a diesel when the fuel system is working properly. On the other hand these engines are pretty easy to rebuild.

__________________
Jim

well a four cylinder running on three is pretty easy to kill in my experience. you do mean stop running right?

__________________
[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

Unwarranted? Um, I don't think that, bc if I don't decide soon on what to do, (shop or scrap) I'l be pressured into scrapping it and buying grandma-ma's CHEVY CAVALIER. NOOOOOOOOOO!!!! I don't want to cruise down the freeway to college in GRANDMA'S CAR!!! Granted, it has functional AC ad a smooth running engine, but Gretel means alot to me (I now know her...intimately...no respectable older woman would let you see her without her valve cover! ) But if I can narrow it down, I can save $$$ in the future if i shop it...or pull the engine myself...hmmmmn....maybe...buy grandma-ma's car...park Gretel at Dad's....work on her when I have extra cash...
But realistically, in the fall I'll go to college and I'll have no money. So as rewarding as engine rebuild sounds, i'm tooting my own horn. A compression test will be run, but again, what realistically do you expect me to find? In all probability, based on all of your kind words of warning and advice, low compression on #1 for some reason, requiring the removal of the head, which requires the removal of my bank card, which only replenishes itself at$7.00 an hour at the outlet mall shoe store. and taps begins to play

If you are fortunate and find that there is only one bad valve (it's possible), you could remove the head and repair this valve for relatively little cost.

You would need a gasket set and the valve, of course, but you could skip the remaining work on the head that would typically be done while it is off.

If pressured, you could reuse the head bolts, although most of us would probably replace them.

The total cost could be about $100. or so, if you just keep to the valve and do nothing else.

Of course, I'm a bit ahead of myself, because you need a proper compression and/or leakdown test to determine if a bad valve is likely. The way the engine just went south in a minute or less leads me to believe that a valve problem is more likely than anything piston related, but, it's not impossible.

This time maybe you should take it to your local mechanic (someone who knows MBZ Diesel) and get a quote, listing what's wrong, what tests they may need to perform, and what it take $$$ to fix it. If it's easy enough, you can do the work yourself, but at least they'll have stuck your nose in the problem.

then self repair is the most likely road for me. there is a shop around here that does foreign cars (MB, BMW, Jags) So I guess I'll take her over there when I get the valve cover and likage back on. See about that comp/leakdown test. What I'm seriously considering if the test is bad, is to park the car and save up the money to buy the parts and tools needed to remove the head. This will, of course, require the purchase of grandma-ma's car for baic transport; I foresee a considerable amount of time that gretel will be out of service, regardless of shop or self-repair. Grandpa is humming Taps and suggesing a part out, but I don't tik I could bring myself to rip apart such a fine old car.