I'll save everyone the long versions... Engine rebuild in progress (this is on my own CRD #2 - I really must be a sick man) and it had been tapping before I bought it. Multiple injectors swapped and questionable mechanical knowledge abounding by the techs hired by the prior owner, all with no real results.

Someone stated that they had borescoped the engine and saw "something" in the cylinder, so I decided to pull it down to the block and have a GOOD look. Found nothing. The cylinders all seemed in good shape, I would have been happier if there was more (or any) crosshatching in the cylinders that I could see, but I'm also willing to admit that I may not know what I'm talking about or looking for in that respect.

I did find 4 broken rockers - lifters had failed, but no damage to the valves and it has fresh rockers now.
Copper-Coated the head gasket, (it looks awesome) and put that back in, ARP studs, stage 2 EGR cap (which leaks a bit - another problem) and fresh coolant. Intake elbow, and got everything back to a starting position.

This is the result:

https://dl.dropboxusercontent.com/u/5447172/CRD-new-tapping.mp4

The ONLY code that I have is for Cylinder #3 misfire. (The EGR and FCV also code, but I don't care about those)
I swapped the injector with another, no change - still #3 misfire code. The video was taken after swapping the injector.

Tomorrow, I plan to bypass the fuel system and run an IV bottle of fresh diesel right into the back of the pump to absolutely eliminate any potential air in fuel questions, but this CRD shouldn't have that anyway, it has a Mr Gasket pump back by the tank.

So... Thoughts? What have I missed?

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Bad noises = REALLY bad things.

I hesitate to say it, Geordi, but are you sure you didn't knock one of the rockers off? It seems like valve noise but without a stethoscope I could not be sure. The other possibility is a bad harness/connection to the injector; if you are getting a code on that, the lack of injection could cause similar noises. Changing the injector eliminates the possibility of it being shmutz getting into the fuel line and clogging things up, but if there is an electrical fault in the feed from the injection controller to the injector that would not be affected by changing the injector. First I would clean all the connections, and try it. If you still have the problem, I would check continuity from the #3 injector plug all the way back.

Best of luck
LMW

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Sounds like top end noise to me. I agree with Larry's observation above.

Open her up again, take your time and be more careful.

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I did double check the rockers, all looked good with the cover just hovering - and I have been using pins and rotating the cams out of the lobe-down position so that the pressure is off as the cover settles into place.

Bad harness is something I'm considering too, but unplugging each injector results in the exact same change in the noise, so I think at least some voltage is making it to the injectors. I also received misfire codes for all the cylinders as my reward for unplugging each of them, so the computer does seem to know that it is there or not.

The consistency of the noise and the volume is the only thing that is concerning me - air in the fuel would (I would think) result in a more uneven tapping result, and the ones with broken rockers have had a much more uneven or lumpy sounding idle. This doesn't really fit either scenario.

A wiped cam lobe maybe?

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They all felt good when I was inspecting the parts after cleaning and before putting it all back together, but I admit I didn't have a micrometer to use on them. I didn't see or feel any streaking or pitting that I might expect from poor condition. The outside of this engine is 7 flavors of filthy but the inside looked about like I expected everything to.

I will be irritated if one of the rockers I put in has collapsed. These aren't new, but they were all in pristine shape from a CRD with 80k on it. I also have most of another set from another 80k CRD available, but that is the engine that ate 3 valves so I would avoid trying those.

yes rockers , cam lobe noise , must remove valve cover and double check them asap.

I would check the oil pressure and go from there.

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Question - "it had been tapping before I bought it" so is the tapping now the same?

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"when you rule out the impossible, whatever is left, no matter how improbable, must contain the answer." The questionis, how improbable is the injector harness, givenyour remove and replace?
If that rules out the injectors, then you have some sort of mechanical issue. One possibility is a bad valve spring.

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Case 580B
Mitsubishi MT180 diesel
Kubota BX25 diesel

Could it be a bad wrist pin causing piston slap???

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You can pull #3 injector and bring that cylinder to just a few degrees past TDC. Once the crank is pulling downward on the piston, you can push a long, thin screwdriver down onto the piston and listen for a "thud" or "clunk". If there is wrist pin slop in that cylinder, you'll know by the noise it makes. It should be silent when pushing down on a good rod/piston assembly.

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2006 Liberty CRD....The Moose Hit

This would be heard when rotating the engine by hand, yes?

Unfortunately, if that is the case, then I am still looking for the source. I had rotated the engine quite a few times when the head was off and everything seemed great, I didn't hear or see anything shifting. The pistons all seemed solid.

I just swapped out injector #4 since I have several spares at the moment and that was the only one that matched the engine sticker anyway. No real change in the sound, but in letting it idle for a few minutes and blipping the throttle a little, it DID start to finally change a bit.

The tapping lessened like it was finally purging the air out, but when that was happening, it started picking up a squeak? I didn't get a video of it and that went away and it went back to the tapping... At least that suggests that this is not mechanical, b/c in my experience mechanical issues don't go away. I don't know what that squeaking could be though, but it could be just about anything b/c this has sat for so long.

Lots of smelly smoke out the back though, which is making me think that maybe just maybe this is a bad fuel issue. Now I'm off to the gas station to get a big jug of fresh diesel and we will try that next. Let it idle a couple more minutes until I know that the good fuel is right into the pump and see what that does.

This is certainly a head scratcher.

Fresh fuel directly into the pump had no effect. Interestingly, the pump back by the tank seems to have failed or has a popped fuse because nothing was coming from the filter while the engine was on.

I'm just letting it cool right now and then the top comes off again. Blarg. If I find nothing however... I don't know what next.

Another is a sticky valve. Either might affect combustion pressure and give a fault on ignition.
So would a bad rocker. If you pull the injectors, it would be worth checking the wrist pins just to rule that out. If these were mechanical injectors, I would check the spray pattern...... But.

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Grid power- the one true essential

2005 Liberty CRD- ARP studs, Fumoto, Hayden FC, inline Tstat, ETechno 7v GP, Platinum P1, in-tank lift pump.
1983 Volvo D24T
1981 Volvo D24
Dodge Cummins TD
Case 580B
Mitsubishi MT180 diesel
Kubota BX25 diesel

I've seen a couple ways that I can possibly check the wrist pins, but if I have to pull the valve cover, I will be able to check all of them anyway but it seems that the way to check is fairly subtle on any results. I didn't notice any noises when I had it apart before but I think now I know more what to look for... Tell me if you think this is what I should be looking for:

Get the cylinders to half way and then rock the crank back and forth and look / listen / feel for any clicking or slop between the crank and the piston crown.

At least I have another cylinder head to try if I find anything questionable there on the top - even though the valves all looked great when I cleaned it before. If there IS something with the pistons, that will be annoying because that means I need to figure out a way to drop the oil pan.

Valve cover is back off - I even managed to remove it without touching a single rocker - they were ALL exactly where they should have been, I didn't knock off a single one.

Unfortunately... Nothing obvious presented itself either. I haven't tested the wrist pins yet b/c it was just too hot outside and I had to stop for a while. I looked closely at the valve stems as well, and all seem to be at the same height too. Bugger.

hey Geordi , do you have a spare camshaft , possibly rocker got jamed sideways i think cam lobe is flat by now.

sorry I didn't realize you removed valve cover, did you drain oil and cut oil filter to see if any metal present, that wining noise bothers me.

is head gasket size ok , very important so piston won't contact cylinder head?