Different type prechambers - PeachParts Mercedes-Benz Forum

mkrazy1 · #1 11-14-2006, 09:01 AM

Okay, I have been searching and searching, but can't come up with anything on this. I have a 83 240D with a rebuilt engine. The rebuilt only had about 4000 miles on it started knocking. By loosening the injectors I figured out it was cylinder 1 with the problem. I removed the injector and found the injector pintle got smashed by the round post in the prechamber that came loose. I am in the process of making a tool to pull out the prechamber, and in the meantime I ordered a new prechamber. The new prechamber(s) - (they sent a set of 4) are different inside the chamber than the ones currently in the engine, and I am wondering if it matters. The ones in the engine only have about a 1/4 inch round hole into it, and has round pin in the center. The new ones have about a half inch hole where the inject sits, and a bar goes across the center with a swirl cut into it. Does this matter?

leathermang · #2 11-14-2006, 09:08 PM

Your precombustion chamber style must match the piston style you have in your engine... There are at least two styles... but there were some modifications to the holes in the later style which produced a couple more hp...

mkrazy1 · #3 11-15-2006, 05:24 PM

When I pull the existing prechambers from the engine, I'll compare it to the new ones, but I am sure they are the same size and length. I am pretty sure the only difference will be what is actually inside the prechamber and the size of the hole that meets the injector. The existing ones have have a post that sticks up in the middle of the chamber, whereas the new ones have a bar across the center with a swirl machined into it. I just hope that this difference doesn't matter. Maybe the new ones give better performance?

leathermang · #4 11-16-2006, 07:09 AM

Yes, as long as the style tip is the same as your pistons then the latest style you can find to install will have the best performance.
Just use the proper specs in the FSM with regards to the shims to make sure you don't have interference between the piston and precombustion chamber tip...

mkrazy1 · #5 11-16-2006, 09:09 AM

Thanks,
If I get a chance, I'll take a picture of the new verses old rechamber and post them, so you can see the difference.

Rusty Cullens · #6 11-16-2006, 10:57 AM

You may have been sold the wrong prechamber.
The proper number depends on your engine number.

If the last last 8 digits of you engine number are earlier than :
10 121328 or 12 035839 the part number is 615 010 01 52

If the last 8 digits are later than :
10 121329 or 12 035840 the part number is 616 010 01 52

Look at your invioce and see what you got. Then check your engine number.

KCM · #7 11-16-2006, 11:11 AM

Replaced a prechamber in a 300CD a couple years ago. The hole for the injector to spray into was larger than the old chamber (don't know about the ball inside). The part number was the same so chaulked it up to an update in the part, maybe for the turbo engine. Didn't notice any difference in how the engine ran.

Rusty Cullens · #8 11-16-2006, 12:03 PM

There have been no updates on the prechambers. The part numbers have remained the same forever. Whenever Benz physically changes a part, they change the part number as well.

mkrazy1 · #9 11-30-2006, 10:14 AM

Okay, I am finally getting back to getting this running again. I had to order the prechamber seals from the local dealer. I brought one of the old ones with me since there are different sizes. They ordered the standard 2mm for me. Do they compress? Should I worry that maybe I should have gotten the 2.3mm? The new ones are the same thickness as the used ones.

Rusty, the engine number I have is 616 10 312539, and the prechamber part number was 616 010 01 52, so it looks like I have the right prechambers.

I went to install them but can't find what the torque should be on the lock rings. Anyone know?

I have attached pictures of the old and new prechambers. At first I was kind of worried that maybe the piston would be damaged, but after I thought about it, I figured the pieces had to be pretty small to get through the holes in the prechamber.

Tymbrymi · #10 11-30-2006, 02:25 PM

You've got the exact same prechamber problem I had....

DO NOT DO WHAT I DID!!!!!

(pull prechamber with GP in... GP tip fell into cylinder and destroyed the piston)

One curiosity that I had, and will be interested to find out if it happens to you, is that I put in a fresh Bosch rebuilt injecter, and within 5 miles the injector pintle was blown again. The GP tip also destroyed the piston during this time frame (5-10 miles on the road). I can't imagine what would cause the pintle to blow like that in less than 10 miles unless the injection pump was REALLY screwed up. I sure hope none of my complications happen to you!!

Good luck!!

mkrazy1 · #11 12-05-2006, 05:26 PM

John,

Thanks for your update! I put mine back together over the weekend. After putting the lock rings on, and torqueing to 78 ft lbs (figured that was as good a guess as any), I then turned the engine over manually at the crank a few good turns to make sure I didn't feel or hear anything binding. I then put the injectors and lines back in. I have driven it about 50 miles so far and it runs good.

When all this happened, I had brought the injectors to a place to have them checked, and to rebuild the bad one. They basically said they all were out of spec, so I had them all replaced. I looked at them, but I can't tell what brand they are. They are made in Germany and had a symbol on them that looked like UH. I am not sure if they were the ones I brought to them, or different ones, but they looked new. I was hoping it would have a noticable improvement in power, but it doesn't. It is better but there are a few hills around here on the interstate that I can barely keep it at 65, if that.

I just wish I knew what caused the prechamber to self destruct.

funola · #12 06-30-2007, 10:29 AM

Hey thanks for the nice pics of the prechambers. Where is the "ball" in the pics? I do not see any. Do you have a pic of the tool to pull the prechamber? I've heard it is a kind of slap hammer. How is it secured to the prechamber? I am guessing it hooks onto the big hole on the side of the prechamber. Do you have a pic of the tool? Do you also have a pic of the prechamber collar tool? And finally what was the size of the seal ring for your car? I am trying to gather parts for my 83 300D in case I have to pull the prechambers and want to be prepared.

Quote:

Originally Posted by mkrazy1

Okay, I am finally getting back to getting this running again. I had to order the prechamber seals from the local dealer. I brought one of the old ones with me since there are different sizes. They ordered the standard 2mm for me. Do they compress? Should I worry that maybe I should have gotten the 2.3mm? The new ones are the same thickness as the used ones.

Rusty, the engine number I have is 616 10 312539, and the prechamber part number was 616 010 01 52, so it looks like I have the right prechambers.

I went to install them but can't find what the torque should be on the lock rings. Anyone know?

I have attached pictures of the old and new prechambers. At first I was kind of worried that maybe the piston would be damaged, but after I thought about it, I figured the pieces had to be pretty small to get through the holes in the prechamber.

mkrazy1 · #13 05-19-2008, 09:03 AM

I was going through old posts and realized I never posted pictures of the tool I used to remove the prechambers. I found the bicycle gear removal tool at the local bicyle shop, first picture, then used the one part of it on a slap hammer. I drilled a hole in the end of the slap hammer and tapped it to hold the piece on the slap hammer. To remove the ring holding the pre-chamber in, I just took an old socket and ground it down leaving two tabs to lock into the ring.