Parts Catalog Accessories Catalog How To Articles Tech Forums
Call Pelican Parts at 888-280-7799
Shopping Cart Cart | Project List | Order Status | Help



Go Back   PeachParts Mercedes-Benz Forum > Mercedes-Benz Tech Information and Support > Diesel Discussion

Reply
 
LinkBack Thread Tools Display Modes
  #1  
Old 08-05-2022, 02:05 AM
JHZR2's Avatar
Registered User
 
Join Date: Jan 2002
Location: New Jersey
Posts: 4,741
OM60x prechamber leak

I replaced the #5 prechamber because of a stuck heat shield. The car started up easily, but isnít idling as smooth as before despite new rebuilt injectors and new viton return tubing.

While I guess there could still be air in the system, all I did was let it idle for about five minutes, my greater concern is the fact that I immediately observed a leak from the prechamber.

Ive done some searching, and know gxsr has found that some prechamber styles (newer ones?) donít seat and seal the same. The bevel at the bottom is different, and the top lip thst seals is thicker. I guess that could be my issueÖ.

But anything else I should look at? Iím going to pull the injector, ring, and prechamber to have a look.

Itís an obvious puff-pull-puff of air, so itís definitely a leakÖ

__________________
Current Diesels:
1981 240D (73K)
1982 300CD (169k)
1991 350SD (113k)
1991 350SD (206k)
1991 300D (228k)
1993 300SD (291k)
1993 300D 2.5T (338k)
1996 Dodge Ram CTD (442k)
1996 Dodge Ram CTD (265k)

Past Diesels:
1983 300D (228K)
1985 300D (233K)
Reply With Quote
  #2  
Old 08-05-2022, 08:23 AM
JHZR2's Avatar
Registered User
 
Join Date: Jan 2002
Location: New Jersey
Posts: 4,741
FWIW, I measured the top “sealing” surface of the original prechamber vs. my replacement. They are the same thickness. I can see what resembles to me a slight difference in the prechamber beveled edge that sits at the bottom of the hole in the head.



How critical is a pristinely clean (bright) sealing lip in the head (at the bottom of the threaded area)? Does it need to be bright? Would fine scratches affect sealing (mine is not but cleaning in there is hard and aggressive cleaning would be hard to do).

There’s definitely black residues where the leak was escaping up the threads.

I don’t think so, but do these fine gaps “carbon up” and self-seal?

My other last ditch option is to take a prechamber from my other 602 turbo and see if it seals better (since it would be the OE design and not the MB replacement which seems to have differences per gsxr)?
__________________
Current Diesels:
1981 240D (73K)
1982 300CD (169k)
1991 350SD (113k)
1991 350SD (206k)
1991 300D (228k)
1993 300SD (291k)
1993 300D 2.5T (338k)
1996 Dodge Ram CTD (442k)
1996 Dodge Ram CTD (265k)

Past Diesels:
1983 300D (228K)
1985 300D (233K)
Reply With Quote
  #3  
Old 08-05-2022, 08:28 AM
Registered User
 
Join Date: Sep 2007
Location: Calgary Alberta Canada
Posts: 1,749
Can you show us a picture of the sealing surface. Yes it needs to be super clean and flat ditto for the lip on the prechamber. A tool is available to resurface the seal surface in the head if absolutely necessary.
__________________
92 e300d2.5t
01 e320
05 cdi
85 chev c10
Reply With Quote
  #4  
Old 08-05-2022, 08:55 AM
JHZR2's Avatar
Registered User
 
Join Date: Jan 2002
Location: New Jersey
Posts: 4,741
Quote:
Originally Posted by dieselbenz1 View Post
Can you show us a picture of the sealing surface. Yes it needs to be super clean and flat ditto for the lip on the prechamber. A tool is available to resurface the seal surface in the head if absolutely necessary.




Older photo that is cleaner since. But the general perspective.

Prior prechamber sealed just fine but there was a lot of hard carbon underneath.







Using carbon / intake cleaner and q tips, nylon brushes, etc. only get so far, it’s hard access. I don’t want to scratch the flat sealing surface.
__________________
Current Diesels:
1981 240D (73K)
1982 300CD (169k)
1991 350SD (113k)
1991 350SD (206k)
1991 300D (228k)
1993 300SD (291k)
1993 300D 2.5T (338k)
1996 Dodge Ram CTD (442k)
1996 Dodge Ram CTD (265k)

Past Diesels:
1983 300D (228K)
1985 300D (233K)
Reply With Quote
  #5  
Old 08-05-2022, 09:06 AM
Registered User
 
Join Date: Sep 2007
Location: Calgary Alberta Canada
Posts: 1,749
I really needs to have a mirror finish to seal. I've never cleaned them on the car only with the head off and yes they can take several hours reach to prep. If you have an ultrasonic cleaner at least you can drop the prechamber in that to speed up the process.
__________________
92 e300d2.5t
01 e320
05 cdi
85 chev c10
Reply With Quote
  #6  
Old 08-05-2022, 09:16 AM
JHZR2's Avatar
Registered User
 
Join Date: Jan 2002
Location: New Jersey
Posts: 4,741
Quote:
Originally Posted by dieselbenz1 View Post
I really needs to have a mirror finish to seal. I've never cleaned them on the car only with the head off and yes they can take several hours reach to prep. If you have an ultrasonic cleaner at least you can drop the prechamber in that to speed up the process.
Interesting. Ok.

Prechamber was brand new….

Head obviously isn’t…

Will work to clean further. Any recommendations on what tools to use to get in there? Emory cloth or similar comes to mind but I don’t think it’s prudent to use abrasives.

Thanks!
__________________
Current Diesels:
1981 240D (73K)
1982 300CD (169k)
1991 350SD (113k)
1991 350SD (206k)
1991 300D (228k)
1993 300SD (291k)
1993 300D 2.5T (338k)
1996 Dodge Ram CTD (442k)
1996 Dodge Ram CTD (265k)

Past Diesels:
1983 300D (228K)
1985 300D (233K)
Reply With Quote
  #7  
Old 08-05-2022, 09:27 AM
Registered User
 
Join Date: Sep 2007
Location: Calgary Alberta Canada
Posts: 1,749
I used plastic trim removal tools and strong chemicals. Some bits of carbon seem to take forever to get off but they do come off.
__________________
92 e300d2.5t
01 e320
05 cdi
85 chev c10
Reply With Quote
  #8  
Old 08-05-2022, 11:17 AM
JHZR2's Avatar
Registered User
 
Join Date: Jan 2002
Location: New Jersey
Posts: 4,741
Quote:
Originally Posted by dieselbenz1 View Post
I used plastic trim removal tools and strong chemicals. Some bits of carbon seem to take forever to get off but they do come off.
Great idea, thanks!
__________________
Current Diesels:
1981 240D (73K)
1982 300CD (169k)
1991 350SD (113k)
1991 350SD (206k)
1991 300D (228k)
1993 300SD (291k)
1993 300D 2.5T (338k)
1996 Dodge Ram CTD (442k)
1996 Dodge Ram CTD (265k)

Past Diesels:
1983 300D (228K)
1985 300D (233K)
Reply With Quote
  #9  
Old 08-05-2022, 07:19 PM
JHZR2's Avatar
Registered User
 
Join Date: Jan 2002
Location: New Jersey
Posts: 4,741
Quote:
Originally Posted by dieselbenz1 View Post
I used plastic trim removal tools and strong chemicals. Some bits of carbon seem to take forever to get off but they do come off.
I used Schaefer’s Neutra, and plastic tools/towels to pick anything I could. It sealed nicely the second time (knocking on wood).

This wasn’t fully done but it was when I remembered to snap a photo…





Yes, that is a scratch. Guess what idiot forgot to pull the glow plug when slide hammering out the prechamber after midnight, totally disgusted that it was leaking.
__________________
Current Diesels:
1981 240D (73K)
1982 300CD (169k)
1991 350SD (113k)
1991 350SD (206k)
1991 300D (228k)
1993 300SD (291k)
1993 300D 2.5T (338k)
1996 Dodge Ram CTD (442k)
1996 Dodge Ram CTD (265k)

Past Diesels:
1983 300D (228K)
1985 300D (233K)
Reply With Quote
  #10  
Old 08-05-2022, 08:17 PM
Registered User
 
Join Date: Sep 2007
Location: Calgary Alberta Canada
Posts: 1,749
Congrats.
__________________
92 e300d2.5t
01 e320
05 cdi
85 chev c10
Reply With Quote
  #11  
Old 08-06-2022, 09:06 PM
Diesel911's Avatar
Registered User
 
Join Date: Sep 2007
Location: Long Beach,CA
Posts: 44,508
Quote:
Originally Posted by JHZR2 View Post
I used Schaefer’s Neutra, and plastic tools/towels to pick anything I could. It sealed nicely the second time (knocking on wood).

This wasn’t fully done but it was when I remembered to snap a photo…





Yes, that is a scratch. Guess what idiot forgot to pull the glow plug when slide hammering out the prechamber after midnight, totally disgusted that it was leaking.
I forgot and did it to one of mine. I share your pain on that.

In any event I thought that the aluminum crush type seal ring was supposed to seal under the lip of the Prechamber. I could be wrong about that.

There is a cutter to resurface the sealing area in the cylinder head. But you need more than the cutter because you need to know the dimensions of how much was cut out to deterring if the nose of the pre-chamber is too close to the piston.
__________________
84 300D, 82 Volvo 244Gl Diesel

Last edited by Diesel911; 08-06-2022 at 09:19 PM.
Reply With Quote
  #12  
Old 08-06-2022, 09:19 PM
Diesel911's Avatar
Registered User
 
Join Date: Sep 2007
Location: Long Beach,CA
Posts: 44,508
Using the cutter.

see posts 5 and 7 and someone posted a .pdf further along in the thread.

Prechamber Tool

I don't know why I bought it, but I paid over $300 for the cutter. I had some intentions of getting what is needed to take the measurements and maybe at some point renting it out, but it would require at least a $300 deposit and if any parts on it got damaged, even if the replacement parts cost a lot, I have no idea where I would get replacement parts for it.

I know people don't like this sort of suggestion.
Personally, if I did not have access to the cutter, I would get a thin sheet of copper and carefully cut out a sealing washer with a pen knife and make sure the retainer nut is torqued down to spec.

The most likely source of the copper sheets or foil is large craft shops. People put the sheets over a pattern and press into the pattern and end up with an embed image.

https://basiccopper.com/thicknessguide.html

This will give you some idea of the thinness of the sheets.
https://www.youtube.com/watch?v=C1_TR9Xtmn8
__________________
84 300D, 82 Volvo 244Gl Diesel

Last edited by Diesel911; 08-06-2022 at 09:36 PM.
Reply With Quote
  #13  
Old 08-08-2022, 10:57 AM
JHZR2's Avatar
Registered User
 
Join Date: Jan 2002
Location: New Jersey
Posts: 4,741
Well I put around 1500 miles on the car this weekend. No signs of leaks, runs very nicely on the highway… it loves to cruise at 75. Didn’t consume any oil on the trip…

__________________
Current Diesels:
1981 240D (73K)
1982 300CD (169k)
1991 350SD (113k)
1991 350SD (206k)
1991 300D (228k)
1993 300SD (291k)
1993 300D 2.5T (338k)
1996 Dodge Ram CTD (442k)
1996 Dodge Ram CTD (265k)

Past Diesels:
1983 300D (228K)
1985 300D (233K)
Reply With Quote
Reply

Bookmarks

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On
Trackbacks are On
Pingbacks are On
Refbacks are On




All times are GMT -4. The time now is 06:06 AM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2022, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2018 Pelican Parts, LLC - Posts may be archived for display on the Peach Parts or Pelican Parts Website -    DMCA Registered Agent Contact Page