Removing Injector Crush washers
 

I have a 1977 MB 300D and I took the injectors out for servicing. I can not seem to get the heat shield (crush) washers out of the prechambers. I've done this job at least 3 times on a 79 240D usually without any problem. (I have a great bent pick for getting them out.) After closer inspection it seems to appear that the hole under the injector is all one piece, nothing will budge, have cleaned them up and can't seem to find a seam anywhere. Also, when I thread the injector back in there are no threads showing above the pre chamber. On my 240D I can see a bit of thread and the 300D injectors, when I put them back in seem to seat deeper. Is it possible that there were no crush washers in there? The Prechamber seat (where the injector seats) has a bit of a profile (slightly raised centre)but does not appear to be the same profile as what the top of my crush washers look like .

Basically the new crush washers have a 1/16 to 1/8 raised ring on the outside edge and the existing injector seats do not . However the centre is raised on the existing seat as is the crush washer.

I really can't tell if there were any in there? Any advice?

I am really leaning to the fact that there were none or this engine is different than my 240D and doesn't need any?

Any Help greatly appreciated!!!

Will

1979 240D 340,000 KM 60,000 on WVO Trusty but Rusty!
1977 300D 249,000 KM Awaiting conversion

There may not be one in there, I would put one in, torque down, and see if it leaks.

Take a look at the soot/carbon on the end of the fuel injector. Now take a flash light and point it down the pre-chamber. If internal hole is the same diameter as the soot/carbon mark on the injector, then the crush washer/heat shield is still there. If the hole is bigger then you don't have any heat shields. I wouldn't just put in the heat shield and test it as is, you need to investigate visually a little more.

If indeed there is one in there, it is mostly glued in there by the carbon deposits . Get an aw or an angled tool (I like using a paint can opener), pop it out.

if it's there, IT'S STUBBORN
 

Tried everything to get it out (if it's there) I've had "glued" ones
before but I can't get it to pop and I've gone above and beyond my normal techniques. The coking on the removed injector tip is the same size ring as the hole in my new crush washers.

I seem to remember the hole in the prechamber being bigger than the hole in the middle of the washers but that was on my 79 240D.

I guess they are still in there??? Just reuse the damn things? The one odd thing though is that a thread or two show on the injectors once installed and torqued on the 240D I have, but even just finger tight the injectors show no threads on the 300D with the presumable stuck crush washers...this is why I thought maybe they weren't there (and becasue I can't seem to get them out or even tell that they are there to get out.)

Will

Could the injectors be torqued down without the heat shields? Nah?... I know they get carboned down but a 90 degree pick usually does it.:confused:

I have jammed a wide screw driver into the hole and popped it out that way usually works pretty good. Rick

Spray them down good with PB blaster or what ever your favorite is and let them soak over night.
If you have a slide hammer or some auto parts stores will loan you one for free get one that has a "Seal Hook" small enough to fit through the hole on the heat shield. Hook it in (being careful not to hit the hood with the slide hammer) and see if you can jerk them out.
There is also 2 body styles of injectors; one has a shorter nut than the others this may explain why more threads show on some than others. I guess it is also possible a PO installed 2 heat shields
If the above idea dose not work it might be possible to put some heavy grease (to hold the metal chips) on a tap and thread the heat shield and install a bolt and slide hammer them out.
Lastly machine shops have special expanding pullers used to pull out sleeve bearings that will go into the hole and expand and can be yanked or pulled out.

Shove a rat tail file in the hole in the washer give it a little twist and they pull right out.

Instead of the file how about an Easy-Out.

I don't see why that wouldn't work too. I just always used a rat tail file because it is already long.

an instrument cluster hook has always worked for me

if there is a ring that is raised down there, the washer is still there.
if it is a concave depression then the washer is gone.

I am OK with what ever works.
When I read you post it started me thinking as to what else would work so I thought I would post it. Also I have 2 times had a files fall of the work bench and hit the concrete and break; so I know they can be brittle; and Easy-Outs are pretty tough. Depending on who made the Easy-Outs they could be as short as 1 1/2 inches to 4 inches long.

Well, that didn't work
 

Tried all of my old tricks to get these suckers out of the 300D. Pulled the injectors in my 240D and the heat shields and had a look to compare. Definitely look like the heat shields are still in the 300D but they look a lot different with only really a raised centre.

So I checked them really carefully with a flashlight, mirror and pic to try and find where the H.S. ended and the pre chamber ended.....couldn't really find a lip or seam or anything.

I eventually decided to try using a pic again, one with a hook on the end that you can get some leverage with and of course small enough to fit down the hole of the H.S. well guess what.............it broke, snapped 3/4" of an inch clean off the bloody thing. I lost it, screamed obsentities, threw my tools across the garage. I was afraid to look. It must have went in I thought...how could it have not? it was pretty much down the hole when it broke, it'd be impossible for it to not have fallen in the engine.....I braved it, just to verify what I already knew....or thought I knew. Guess what? It was perched there precariously, I couldn't believe it, it didn't fall int eh engine! Out comes my magnet, a check to make sure the other half is actually magnetic, ok good it is. Carefully, sweating bullets, I managed to remove this blasted piece of metal.

Long story short, if those heat shields are in there, they are there to stay. Going to start her up next week, when I finish with some other things and we'll see how she sounds.

I really wonder though if there is something to these earlier (1977) models, the prechamber/Heat shield just look different. I can not believe that there are two separate pieces of metal there or that if they were separate, they aren't now. There is definitely a raised centre around the hole and it is not concaved but there is no outer raised ring like on the new washers.

I'm stumped.

Leave the injectors out and turn the car over with the starter- with good compression they will loosen quite a bit, if not go airborne. I just had a stubborn heat shield and used a variety of methods to get it out.