what to clean out injector chambers?
 

I am having problems starting my TD and so I pulled all the injectors. I know I will need new heat shields, so I have a set coming from phil... (is that 2.25 each shield or for a set?) anyway, the injectors and everything in the injector area are covered with a pretty good coat of carbon. what should I use to clean them up? I was thinking of a wire brush and some carb cleaner, but I don't want to mess something up. kinda afraid of letting some steel wires broken off down in the injector pc...
anxiously awaiting a clue.
John

Soot is normal, but loads of soft, fluffy stuff usually isn't. There is always a thin coating of dry soot in the prechambers. Wet, sticky, or oily deposits are not normal.

DO NOT use a wire brush!!!! You will likely damage the pintle (it sticks out of the nozzle) and if a wire breaks off, it can cause all sorts of internal damage to the cylinder.

Low compression, late injection (and valve) timing, and bad nozzles will result in carbon fouling. So will extended low speed, light throttle running. Excessive oil consumption will also cause carbon fouling, oily this time.

Do an "Italian tuneup" next chance you get.

Peter

The Factory service Manual says:
"Using brass brush, remove carbon deposits from end face of nozzle body, chiefly around nozzle orifice."

Danny

how many miles on those injectors? The size of the nozzle exit is if I remember correctly about that of a fine human hair (read: realllllly small) and therefore difficult to clean without very good wire brushes (they show the kit in the FSM).

So if you have lots of miles and want smooth running injectors, just get phil to throw in a set of bosio nozzles for you too. more money, but worth it in the long run.

But not in the prechamber. ;)

mostly i was talking about the seat where the heat shields go... I was going to gently clean the carbon off the injectors, if I don't just replace them. I ahve looked at the ones on ebay, that come with the shields and return hose... but I am going to try the used ones from my parts car first...
thanks though. I have no intention of putting anything inside the prechambers.
although, to describe the look of the carbon on the uvula looking thing (pintle?) inside, it is coated with a hard layer of carbon, it may be wet, but it is not powdery. as soon as I get it running a good lm diesel purge is first, then a solid italian tuneup on I-85.
Thanks for the quote from the fsm, a brass brush sounds like a good idea, should I use gasoline or carb cleaner? or should I just scrape it?
John

Since you've got the injectors out already, you should condsider making a pop tester out of a grease gun. Check out this thread, from about post #18 down for instructions on how to make one out of a grease gun. Its really easy and relatively cheap to do(less than $50). If you buy injectors, you're gambling that they will open at the right pressure and have the proper spray pattern. Don't be discouraged from used ones, though. Even new Bosch injectors right out of the box are bad more often than they should be. Being able to test and adjust your injectors is very satisfying and suprisingly easy.

Yes your right. About the only thing I would do with a prechamber with the head still on is pull them out.
VStech is kind of confusing on what he's describing.
So what is it you want to know about? The seat or the injector?
There is no pintle in the prechamber. The pintle is part of the injector.

Danny

"There is no pintle in the prechamber. The pintle is part of the injector."-Danny

There is what we on this site have been describing as a pintle in the precombustion chamber. It is below the hole for the glow plug and is a rod across the middle of the precombustion chamber with a rounded section in it's middle... the purpose is to help break up the spurt of fuel from the injector... before it reaches the 5-7 radial holes in the bottom of the precombustion chamber....
In the archives you will find descriptions of people taking out the injector and looking down into the precombustion chamber and seeing only a little ball loose in the bottom... that is the center section if the rest of the rod gets burned away... and of course really messes with the tiny holes meant to spread out the fuel in the combustion chamber.
The only way to clean the precombustion chamber properly is to take it out of the head.
Greg

A soak over night in some transmission fluid may help.

sorry again. I was responding to two questions.
 

the first part I was talking about the seat that is below the heat shield.
the second part of the statement was that I would just gently scrape the carbon off the bottom of the injector itself and not really worry about any particular way of cleaning them.

now, when I finally removed all the heat shields, (#3 was a BIG pain if the #@$#) tons of carbon all over the threads and the shield was TOTALLY covered in carbon. I scraped the convex area where the shields sit until they were nice and clean, then sprayed tons of PB blaster in there and vacuumed it all out with a shop vac through the GP holes.

I put used heat shields and injectors from my parts car that was running well when the head gasket blew... anyway I bled out the injector lines tightened everything up, installed pencil glow pluggs rewired for parallel power and presto, the sucker fired right up!

yes my TD is now a running, Driving vehicle!
Yea me.
John

AKA the "diffuser element"
 

http://www.kenrockwell.com/190d/index.htm
"THE ENGINE'S REMARKABLE PROWESS is due, at least in part, to the advanced design of Mercedes-Benz LVP prechambers. ("LVP" is derived from the German words for high performance, low fuel consumption and reduced particulate emissions.) Because combustion begins within these cylinder-head cavities, the powerplant's efficiency is significantly affected by variables in prechamber engineering. The LVP concept places each injector nozzle off-center and incorporates a diffuser element to stimulate mixing of air and fuel, thereby improving combustion"

http://i37.photobucket.com/albums/e9...serelement.gif