prechamber ball fell off - PeachParts Mercedes-Benz Forum

erubin · #1 09-23-2004, 05:45 AM

the number 4 prechamber in my friend's '83 300SD is damaged. the tip of the glow plug broke off and the atomizing ball broke off. I extracted one oblong piece of metal about 4mm in diameter out of the chamber but can't get the larger atomizer ball out even though it is sitting freely on the bottom of the chamber.

1. When the ball breaks off in the chamber does that usually mean the cylinder is damaged or will replacing the precombustion chamber usually suffice as a repair.
2. How do i get the chamber off without the special tools or can the tools be rented from someone? Performance Products Company does not show rental tools on their website.

Thanks,
Elliot

leathermang · #2 09-23-2004, 06:47 AM

Replacing the precombustion chamber would normally fix the situation....
and you need to take it out to check in the combustion chamber for unwanted stuff...
Performance Products , in their paper catalogs , does say they have a tool rental program, so you have that as a back up..... Phil here at Fastlane may have that also... and he really ships fast....so check that if you are not going to make up a tool for this job.
But it would be much faster to find an injector and weld up a rod on it which can be used as a ' slide hammer extractor'....or if you already have a slide hammer just put a nut on the end of a stub which matches your slide hammer's threads....
Do you or your friend have welding capabilities ?

If anyone has a couple of bad injectors ( but with good outside threads ).... and will send them to me I will make up several of these items and we can just ship them around to whomever needs them....

BrierS · #3 09-23-2004, 07:06 AM

leathermang
I like the sound of that idea . . . wish I had some to donate. When I last had my intake off I had intentions of replacing the glow plugs and pulling the injectors. I chickened out and left the new GPs in their boxes after reading a couple of postings on the problems if they don't extract easily. As soon as the '84 arrives in my yard, I'll feel better about tackling the project (I'll be able to drive a MB).

BrierS · #4 09-23-2004, 07:46 AM

Greg,
I just sent an e-mail to the gentleman that sold me the '84 300D Turbo ($9,800 wonder) asking if he had access to any used injectors. Told him if he could come up with some, I would pay his shipping cost to get them to you. I'll keep you posted . . .
Steve

leathermang · #5 09-23-2004, 07:54 AM

Steve, that was very nice of you.... surely there are a 1000 bad injectors sitting in people's tool drawers... if they are anything like me.... I never throw away anything metal... LOL .... ask Randy if you think I am kidding about that.... Randy actually threw away his used 617 Chain !!! Do you know how strong a 617 chain is ? Even a broken one ! LOL

BrierS · #6 09-23-2004, 08:13 AM

Greg,
Threw away a timing chain? Heck, I could have practiced using my crimper . . .

Steve

leathermang · #7 09-23-2004, 08:30 AM

A broken 617 chain could easily be made into one of those crank type engine removing gear angle adjusters...
Can you take measurements of your Crimper ?

BrierS · #8 09-23-2004, 09:02 AM

Sure, I can take measurements. It is the MB timingchain crimper set for single and double chains. Beyond that, tell me what you want for measurements and I'll give it my best shot.

Keep in mind, I am not using it yet and no one has asked to rent it . . . I would be glad to ship it to you . . .

R Leo · #9 09-23-2004, 09:04 AM

Enough already. So I tossed the old chain; live with it.

Not all of us have the luxury of living on 40 acres of entropy workshop that passers by sometimes confuse with shuttle Columbia's debris field.

R Leo · #10 09-23-2004, 09:10 AM

Quote:

Originally Posted by erubin

the number 4 prechamber in my friend's '83 300SD is damaged. the tip of the glow plug broke off and the atomizing ball broke off. I extracted one oblong piece of metal about 4mm in diameter out of the chamber but can't get the larger atomizer ball out even though it is sitting freely on the bottom of the chamber.

1. When the ball breaks off in the chamber does that usually mean the cylinder is damaged or will replacing the precombustion chamber usually suffice as a repair.
2. How do i get the chamber off without the special tools or can the tools be rented from someone? Performance Products Company does not show rental tools on their website.

Thanks,
Elliot

Somewhere in the Forum I read that the tool used to remove/service bicycle bottom bracket bearings (?) has the same threads as the prechamber and that the tool can be modified to accomplish that task. A search on "bicycle" and "prechamber" revealed this thread.

Pete Burton · #11 09-23-2004, 10:25 AM

that's true. A friend game a tool for a shimano bike part, and it threads into a prechamber perfectly. I intend to make a prechamber tool out of it "someday". Greg, if you want it to make a puller for a loaner program you can have it. On my 617 IIRC, the injectors have a coarse thread that screws into the locking nut that hold the prechamber down, but they do not engage the prechamber.

erubin · #12 09-23-2004, 12:13 PM

How do you unscrew the locking nut that holds the prechamber? You need to do this before using the slide hammer i believe.

I have an old injector that i could have a slide hammer welded to. How boig of a slide hammer is needed? But pete burton writes that once the locking nut is off the home made job wont do it. Seems to make sence. any comments?

leathermang · #13 09-23-2004, 12:54 PM

I can't think of a good name for the device... except " slot driver".... you can see the slot it goes into... and you just need some way to put your torque wrence on it at the top.... so a 1/2 inch square drive would be typical of the top.... I say that because you DO want to Torque it to specs when you put it back in.... because you will be using a new crush washer under it.
For some reason the expensive MB version screws into some threads and then you can turn the slot part .... I don't know if that is necessary or not... would help to keep it lined up.... anyone dealt with this slot tool ?
A typical slide hammer has maybe 5 to 12 inches of travel for the weight....depends on the weight you use and your arm strength...LOL
Look at some catalogs first .... you want to be able to put other tips on the slide hammer.... they are very handy... and you might want to build yours so the threads match commonly available tips... don't want to have to hand make everything from now on....

jbaj007 · #14 09-23-2004, 01:03 PM

The injector does not thread into the prechamber. It threads into the collar. Therefore an injector on a slide hammer doesn't work. Threads for the prechamber are 22 X1.0 which is much smaller and much, much finer than the injector threads.

An old large socket with cutouts that leave "ears" (with slightttt undercuts) has been made by some to remove the collar. Some use a large brass punch in the collar notches and tap it counterclockwise to remove the collars. Not elegant, and no torque values can be set when installing them this way, but works in a pinch.

Pete Burton · #15 09-23-2004, 01:15 PM

yeah, I modified a socket to have two "ears" or dogs which engage that collar. "Not elegant" could well describe what I made. What it needs to be better is a simple piece made on a lathe that fits inside that also pilots the ID of the collar. But my lathe has been disconnected for a year since I moved. Gaak, I need a real workshop again!