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Ldrivon

Mystery Knocking Sound

What is the Noise?!  

9 members have voted

  1. 1. What is the Noise?!



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post-11244-138698179821_thumb.jpg
:cookoo:
The Mystery Knock...
:smart:
Written By Lance Drivon
With a Bottle of Melrose Merlot 2006
:drool:


:spend:It all started out in that nice May evening in 2010 installing my new plate, gauges and exaust. After installing them all and about to take off on her maiden voyage after startup I draw in a tip off a Snap-On pick that the previous owners mechanic had broke of in the inercooler boot that I wasnt aware of. BANG BANG BANG BANG.....I went cold. The riveting noise of that hollow clock clock clock noise.... SO I take it to a Mechanic who works on Big Rigs and light duty Diesel trucks. They pull the head,drop the pan. Head gets milled and magnufluxed. New genuine cummins parts gets put into engine. They said the engine looked virgin. New Piston. Cleaned cylinder. All back together and ready to seat the rings on the #1. I run it nice for about 2000-3000 miles and then start working her.So within the last few months I notice a noise.

So I had accidently brought her to :nono:1600* 2 times for 4-6 seconds each time but didnt notice any noise after.(:thumb1:I was showing my dad My 96 could kill his 01...and it did.) Not the transfercase rattle:nono: but another noise. So I fix the transfercase rattle and now I can hear it beter..:stuned: Hours with a stephascope under and over the engine. I replace the following just to get rid of the common little things people always neglect to do..

:spend:
New Liftpump...
New Overflow Valve...
New Fuel Filter....
Injectors Pop tested and adjusted by Oregon Fuel Injection...
Adjust Valves...
Pull all return lines and supply lines away from cab...
Adjust valves...just incase the first time was wrong...

The noise is still there. When I brought it back to the Mechanic they said they hear something but its nothing they reconize. I take it the next day to another diesel mechanic and its not there at idle this time. At 65 you can hear it claping away like a hydraulic lifter but softer. Some days its louder. Somedays its hardley noticeable. It has become more noticeable at idle cold sometimes.. Sometimes not.. Your really have to squint and listen to it sometimes and sometimes you can hear it just over the combustion noise of this loud critter and its crazy injection pump.

Things I am thinking starting in order of what I think..

Piston Melted from hot pulls at 1000-1100* and the few short times of 1600*?

#1 wristpin boss in piston cracked and making noise acording to heat or cracked piston?

Exaust valve hitting piston because a thicker head gasget not used when put back on?

P7100 pump #1 plunger getting hit by its cam causing a clap knocking sound. The reason I say this is that the #1 injection line will make your ears bleed and the rest of them sound the same to each other. Your ears will be numb a little and ring after listning to the #1.

rod bearing but unlikely with the noise. Its not getting louder and louder...It comes and goes in volume. Seemes louder when colder <sometimes>.

The truck runs smooth. No white smoke. Starts great in cold mornings. 35 psi boost and I adjusted the afc with a regulated air supply to get the settings close. I am thinking of buying a bore scope and inspect the pistons. I found out From Moparman1973 the injector nozzels are 9/32" so i found a bore scope for $100 with a 5.8 mm head and shaft I can use to inspect them. I have to order it but I need some input on will a injection pump make a noise when the plunger is getting stuck or if a piston is melted or cracked smacking the head or cylinder.

Hope someone has had something like this before and I am starting to warm up the old knuckes for some finger bleeding work here.

Thanks in advance guys!

My wife is convinced I have gone mad but she has a 2001 2500 and she understands whats its like.....VP$$.......:evilgrin:i mean VP44

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A video of this sound would really help but I know the noise probably won't be audible in the video. I will say that mine has something of this nature as well, doing the same as you describe. Mine isnt a knocking but more of a well maybe it is, just seems faint and almost muffled. I took my intake manifold plate thing off and stuck a light in the valve ports and there was a lot of crap in there, varying between each one, a lot. I am thinking the crap around the valves has something to do with it. I have seen 1600 as well.. Truck runs same as yours too so it really is weird. Pretty sure it just has to be something with the valves. Don't want to fork $100 for a head gasket yet.

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During the last 2 seconds was it the knocking that happened just short of every second? I didn't realize the knock was that slow if that indeed was the knock. The problem I see with that is that it eliminates a lot of things on the engine. Each injector fires 6.25 times a second at 750RPM (since you were idling that's what I used). The valves open just as many times as well. Lift pump does as well. The only thing that is that slow that I can think of is the overflow valve popping, but I wouldn't think it would make that much noise being just a ball on top of a spring. I'll keep thinking.

  • Like 1

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Exactly! I changed it but the only thing I can get much noise on is the injecton line on #1. I changed out overflow valve too when I did the inectors with no change is sound. Actually the sound is a little more pronounced now after inectors were cleaned and reset so that's why I was thinking injection pump since I increased the Psi by almost 500 psi. If I can get the noise beter at idle I will crack injector lines again see if I can make noise go away.

--- Update to the previous post...

If this helps at all. This morning on my way to work I regulated the throttle to pin point the noise beter. I hear it beter when I am at cruise speed for 4th and 5th best. Slight throttle and noise slightly a tad louder. Deacceleration by 5 mph its hardly noticeable. If not even there until I press the pedal just enough to maintain speed.If I turn truck off on compression I don't hear it at all. But when I say I don't hear it it could be there still just not so loud.

--- Update to the previous post...

So what noise gets quieter with heat?

--- Update to the previous post...

There is 3 bolts holding shut off solinoid on pump..2 on top one on back. I forgot to post that I am missing that one and i have a leak there for some time it looks like. if that one is missing could it be low enough for oil not to be able to get high enough? I been trying to find what the right size is so I can make it right.

--- Update to the previous post...

What would a single bad delivery valve do if it was bad.

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The problem is that, that knock is so slow it just can't be any of those things. I can think of something that builds over time and then relieves as a knock but I just can't think of what would do something like that. As heat builds things expand so the thing knocking could be loosening up, when it's cold everything is tight so it knocks more.

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So it does it regardless of clutch engagement or whether or not you are moving, correct?That leaves just the engine which I am gonna have to list everything out that moves and think of how to pinpoint it.Pistons/Conrods-Too FastCrankshaft-Too FastCamshaft-Too FastTappets-Too FastPushrods-Too FastRockers-Too FastValves-Too FastOil Pump-Doubt itWater Pump-Possibility but too fastAlternator-Too FastVacuum Pump-PossibilityPower Steering Pump-PossibilityFan-Likely Possibility, is it whacking something?Belt-MaybeA/C Compressor-Too FastP7100:Plungers, Delivery Valves, Cam, Governor, Rack-All Too Fast, and rack won't do that anywaysInjectors-Too FastStarter-Not involved, and flywheel moving too fast (if it was nicking starter gear somehow)Flywheel-Too FastTurbo-Way too FastLift Pump-Possibility, but changed out with no luckThermostat-Highly Doubt itI need to think about it more. I think some things could still cause a slow knock at idle, even if they are moving fast.

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oil pump?front gears?kdp nick a gear?isnt the pressure plate bolted to flywheel?cracked pressure plate or broken spring?cracked flywheel or loose bolts?main bearings?thrust bearing?

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oil pump? front gears? kdp nick a gear? isnt the flex plate bolted to flywheel? cracked flex plate or broken spring? cracked flywheel or loose bolts? main bearings? thrust bearing?

If you are talking about your 12v in your sig it show you have a manual and in that case you would not have a flex plate as that is what connects the crank shaft to the torque converter on automatics. I think you are referring to the clutch pressure plate that mounts to the flywheel and if it has a broken spring/springs in it will cause knocking noises or if the springs fell out and are rattling around in the flywheel housing will cause noises as well as worn input shaft / pressurep plate splines. These noises are usually only noticed at low rpm or while drive line is light to unloaded Did you check for exhaust leaks through out the system or cracked manifold ect? I am partially hearing impaired so I couldn't hear the noise in the videos so I can't help in that department.
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I couldn't resist picking the "What noise" choice as I can't hear it with 75% hearing loss in one ear and 25% loss in the other and to cheap and stuborn to get some aids.:cookoo:

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I couldn't resist picking the "What noise" choice as I can't hear it with 75% hearing loss in one ear and 25% loss in the other and to cheap and stuborn to get some aids.:cookoo:

Don't worry. My dad is promised full hearing loss and a divorce if he doesnt get some. He thinks it shows age..I think he can turn them off anytime so he cant hear my mom..I think he still thinks he has a 360ci V8 in his 01 2500. he just cant get how there is SOO much more power than his old 5.9 W200 1976...he asked me they are both 5.9 right?:duh: Question..Maybe i have created my own wear that is suffering something. Back in December I installed a remote start. I know its a Manual but I have had 4 Mishaps. Ok well only 2...The other 2 was showing off. But One time my wife left it in reverse and it started and the parking brake was on. So it turned over a few times and died. second time I left it in first and it was met with a rack and the parking brake. It was running at like 60 rpm.lurched forward 2 feet and died. the other 2 were intentional to ssee if the truck would start in gear and how dangerous its going to be.(we live on a ranch so it was safely done.) what would this resistance want to start to grenade. what is going to be the weak point if you were just to come to a stop in first and just mash the brakes and make it slow down and die? Just curous. Maybe it will help us find the solution unless no one thinks it would cause BIG problems....??

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what would this resistance want to start to grenade. what is going to be the weak point if you were just to come to a stop in first and just mash the brakes and make it slow down and die? Just curous. Maybe it will help us find the solution unless no one thinks it would cause BIG problems....??

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Unless I have a magical moment..... Scratch that... It's louder every day... Pulling off oil filter tomorrow.. checking for metal.. if No metal I pulling the head off pending an inspection through the injector ports.. very much riveting noise coming from area of motor mount passenger side up on block.. I'm actually hoping its something cheap but hopping I get to pull it.. I haven't yanked an engine since a 454 I blew up in 97. I'm looking forward to have a write up sticky on pulling a 12v. If everything is bad as it seems I'm buying a snap on timming tool for $210 and sending pump in to be tested.

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When you cut the filter open and cut a section of filter media out of it, the way to check for debris is to colapse the accordian media and wrap a rag around it and the put it into a vice and squeeze the oil out which is what the rag is to sop up and then the debris is easier to see when you open the media back up. as it will show up better when the dark oil is gone and it is embedded in the media.

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Found maybe 3-4 tiny pieces of a brittle aluminum or nickel. Tiny like you can see them but just thin and small around.. I will put the filter in a vice later but for now I am laying down sick.

--- Update to the previous post...

As my wife says it "looks like glitter" now my question is if I have a scored cylinder would the rings bring back down aluminum? Im not finding any golden flakes just all silver glitter looking stuff. Im wondering if I should pull the head next or pull the pan.:spend::truck:

--- Update to the previous post...

http-~~-//www.youtube.com/watch?v=FcQtoL90DvU

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Get an oil sample after its warmed up and take it or send it to a lab, if you have a CAT dealer they can do it. It will identify what material it is and possibilities of where it comes from. That way you are not chasing, you can get a more accurate idea where to look.

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I will do that. Seems though. With the sound she is making and the noise gets quieter I'm leaning to a piston. But never the less my first step will be an oil analysis.

--- Update to the previous post...

http-~~-//www.youtube.com/watch?v=7qNTJEQbDhI

--- Update to the previous post...

quieter when she gets up to full operating temp after 15 miles at 60 mph... louder in the first 6-8 miles...

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Narrows it down to piston or bearing/bushing. Hard to see in the videos, But it looked too shiny for either so It could be chrome off cam lobe or follower. Can't remember right off if the lift pump has a lever or roller that rides on the cam if roller it could be chrome from it as well.

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The lift pump has a tappet. Solid rod with mushroom end that rides on cam.When I went to go start her to heat the oil up to take a sample I noticed it did Something it never did before and it seemed to have a slight miss.. not bad so I am thinking that cylinder is starting to loose compression and not firing. After a few seconds she smoothed out besides that noise... Took a sample.. off to the mail tomorrow to cat for the verdict.

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