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  #1  
Old 11-22-2009, 09:19 PM
konstan's Avatar
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What is making that sound (some sort of engine knock)

What do you think might be causing this sound:

http://www.youtube.com/watch?v=s2pEM3fAepw

I adjusted the valves, corrected chain stretch (installed a 4 degree key), played with the rack dampener bolt, and rebuilt injectors with new nozzles. (No, I didn't test or balance them)

This knocking sound just does not go away. It is the same as it was when I first got the car.

The idle is nice and smooth, and I was very impressed when I took it out on the interstate today. it felt powerful and not loud (and I could not hear the bloody knock at 60 mph).

Normal sound?

Should I keep obsessing about it??

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  #2  
Old 11-22-2009, 09:29 PM
compress ignite's Avatar
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Narrow Down the location

by loosening each one of the injectors (Individually) with the engine running...
the one that stops the "Knock" may be your problem area.

OR

Mechanics Stethoscope to be able to locate the noise.
http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=41966

(I don't like the sound of that!)
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What is making that sound (some sort of engine knock)-screenhunter_01-nov.-22-21.28.gif  
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  #3  
Old 11-22-2009, 10:19 PM
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Yep, that's the stethoscope I have... the knock seems to be closer to the front (i.e. 1, 2 or 3). Going to try the removing injector line nut one by one thing and see if I can narrow it down.

What sound do you not like?
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  #4  
Old 11-22-2009, 10:58 PM
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Nature of the beast, I replaced a motor that was knocking like that. Looking back I shouldn't have, I drove with a knock for many many miles. If I were you I'd enjoy your car and not worry. I know the noise is annoying (yeah it is I am a perfectionist) but I think you will be fine if you just let it do it's duty...
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  #5  
Old 11-22-2009, 11:00 PM
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What am I listening for? That engine sounds normal.
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  #6  
Old 11-22-2009, 11:31 PM
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Sounds exactly like my engine....
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  #7  
Old 11-22-2009, 11:33 PM
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my 82 300SD engine has 220k kms on it, barely broken in lol and it has abit a knock sound like that too, my chevy 6.5LTD has a knock like that too when its cold? i think its just diesel thing, tried running some purge through it yet?
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  #8  
Old 11-22-2009, 11:53 PM
Craig
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My best guess is an injector. See if you can identify a specific loacation. Have you ever had the injectors checked/ replaced? How many miles on them?
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  #9  
Old 11-23-2009, 08:25 AM
C Sean Watts's Avatar
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Quote:
Originally Posted by konstan View Post
rebuilt injectors with new nozzles. (No, I didn't test or balance them)
I think you may have answered your own question - to an extent.
Quote:
Originally Posted by konstan View Post
Should I keep obsessing about it??
You're one of us now, you have an antique car with a diesel engine YOU ALREADY ARE OBSESSED
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  #10  
Old 11-23-2009, 11:58 AM
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Quote:
Originally Posted by C Sean Watts View Post
You're one of us now, you have an antique car with a diesel engine YOU ALREADY ARE OBSESSED
Yes, I am!!!

I found this video on youtube http://www.youtube.com/watch?v=tOhLBkBR1k0&feature=related

Title is 'piston slap', this is the closest sound to mine that I was able to find...
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  #11  
Old 11-23-2009, 12:04 PM
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Piston slap articles

http://dspace.mit.edu/bitstream/handle/1721.1/15728/09216886.pdf?sequence=1

interesting stuff...
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  #12  
Old 11-23-2009, 12:17 PM
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Sounds to me like typical "nailing."

http://www.youtube.com/watch?v=dseUEVVGsAw&feature=related

I'd try some Diesel Purge!
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  #13  
Old 11-23-2009, 12:47 PM
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Quote:
Originally Posted by konstan View Post
Yep, that's the stethoscope I have... the knock seems to be closer to the front (i.e. 1, 2 or 3). Going to try the removing injector line nut one by one thing and see if I can narrow it down.
If you can narrow it down to a particular cylinder that way, then you could swap a couple of injectors to see if the behavior "goes with the injector".
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  #14  
Old 11-23-2009, 02:31 PM
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ENGINE KNOCK

I had an old 240D that knocked until i replaced the vacuum pump. Good luck!
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  #15  
Old 11-23-2009, 09:45 PM
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well i thought mine sounded like that but ill let you be the judge.

http://www.youtube.com/watch?v=V_jLKHKxOGc

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