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Knock in upper engine 1982 300D

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  #1  
Old 01-26-2010 | 10:52 PM
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Default Knock in upper engine 1982 300D

I am a diesel noob. I work on my own cars but this is my first diesel.

I got this 300D for 360 bucks plus I had to rent a trailer to bring it home. The car starts just fine, runs and drives, I had it out on the interstate -- it has plenty of power and does not smoke.

What it does have is a knock, somewhere in cyl #1, upper part.

I did most of the "easy stuff" like air cleaner mounts, blowby drain tube, moved the injectors around, replaced motor mounts and engine shocks, did the timing chain stretch key, valve adjustment, new spring for the chain tensioner, compression test.

The most recent thing I did was took the vacuum pump off and started it for a few seconds without, the knock is still there.

http://www.youtube.com/watch?v=fXS6iyfgvSw

You can hear the knock over the valve clatter.

Using the stethoscope, the best I can do is "upper part of the engine, cyl #1".

WHats next? Head? What am I looking for if I am taking the head off?
 
  #2  
Old 01-27-2010 | 01:58 PM
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Sounds like a rod or wrist pin. First thing is first though have you made sure the prechamber is in tact. It is very hard to single out the noise at least for me listening to it on the computer. I think you should take the pan off and check the rods.
 

Last edited by Unknownfl09; 01-27-2010 at 02:05 PM.
  #3  
Old 01-27-2010 | 02:27 PM
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Originally Posted by Unknownfl09
First thing is first though have you made sure the prechamber is in tact.
I have not taken the prechamber out (yet), no... I will do that, too.
 
  #4  
Old 01-27-2010 | 02:59 PM
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Once the injector is out, you can then use a screw driver to lightly pry on it to feel if it is broken. Odds are its ok because the sound is to constant from my experience.
 
  #5  
Old 01-27-2010 | 06:08 PM
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Originally Posted by Unknownfl09
Once the injector is out, you can then use a screw driver to lightly pry on it to feel if it is broken. Odds are its ok because the sound is to constant from my experience.
The bang is very very rhythmic, and is exactly every 1 cam turn or 1/2 crank turn.
 
  #6  
Old 01-27-2010 | 11:33 PM
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Default What Lies Beneath...

Today I took the oil pan off. At the bottom of the pan, I almost missed them, there were several small *****, like from a ball bearing. I recovered 9 of them, there werent more than a dozen or so probably.

The ***** are 0.155" in size (about 4mm).

No hint of other debris.

Since the knock was coming from #1, is it save to assume that the rod bearing in #1 needs to be replaced?
 
  #7  
Old 01-27-2010 | 11:59 PM
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Rod bearings are not ball bearings. This is what rod bearings look like http://include.ebaystatic.com/v4js/e...en_US_AUTOS.js
I don't know enough about these engines either to tell you what has ball bearings. Could possible be the turbo but I doubt it has ball bearings either. Maybe the oil pump. Grab the rod ends and shake them to see if there is play up and down. You may have some play side to side which is ok.
 
  #8  
Old 01-28-2010 | 12:41 AM
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Went and looked at vac pump. Its bearings (2 of them) are not missing any *****...

What I could reach with my hands in terms of the #1 rod (the oil pump is in the way) seems pretty tight.
 
  #9  
Old 08-25-2016 | 09:05 PM
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Hey, did you ever resolve your knocking issue?
I have a similar problem and would like to get your advice on where to look next.
 
  #10  
Old 08-26-2016 | 06:27 PM
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Hello, As I understand the conversation, Your pan is off, but your head is not. To my amazement you have found loose ball bearings in the pan. MM, I happen to have the mate to your engine literally hanging in my shop with gravel inside the broken oil pan. No loose ball bearings, just gravel. I have not pulled it apart yet but you have my attention. I speculate that you may have a roller chain tensioner in yours. The word is speculate. Anyone that has done a complete rebuild know?
How was your oil pressure? Engine Knocks can be tough to find. I would bet you have a loose wrist pin issue. However I have rebuilt a lot of engines and one thing that has saved lots of grief is , checking your bearings and clearances now the pan is off.
Plastiguage is cheap, easy to use and will eliminate a combined knock that is both wrist pin and con rod related.
 

Last edited by ForcedInduction; 08-31-2016 at 08:45 PM. Reason: spam



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