Ok, so things are still up in the air. Since the cam is so scuffed up, is there a possibility that one lifter was hanging up due to contaminants/unknown gunk in it's bore or a weak valve spring? The cam is buried so deep it could make the sound have a deeper noise than in a gas rig. If the injector is operating, you have combustion, lots of force during combustion cycle--that is multiple K psi or whatever it is in these diesels, so if a valve was not able to close properly due to a lifter hangup or weak spring, then combustion takes place, valve slams the rest of the way closed, pushing the lifter down onto the cam. Then you turn off that injector, no more pushing on the valves, no more noise from the cam. Not trying to confuse the issue, but that noise on the video did not seem to be a crank bearing, not ones I have heard anyway. They are usually much deeper than that. But I have heard piston slap that almost sounded like that. I feel for you in this situation. This does not make me want to buy a motor that has ever been used for lots of heavy pulling. Somebody did not take care of this motor-it should not look like this!

 

Hence my question about scuffed skirts.

Mine's got a bit of knock as well, but my Blackstones have looked good over the years. I may have some slapping going on.

But, it's been that way for over a hundred thousand miles, and the samples look good, so I'm not about to "fix" something.

At least not yet........

Pop

 

For the most part, the ridge was just carbon. A few spots shaved a little cast iron off, but nothing major. The piston skirts all look good; nothing at all that concerns me with them. I haven't pulled the wrist pins out and mic'd them yet, I realize the oil film inside can be deceiving, but nothing felt loose to me. Rings I haven't taken a really close look at yet, but nothing was obvious when I popped them out of the bores. I showed the picture of the cam lobes to a local machine shop that does a lot of high performance stuff. The guy said he sees that fairly often, and it's usually nothing to be concerned with. I believe he called it, "tracking."

The lifters all came out of their bores smoothly, with no problems at all. The cam bearings and journals look good to me; all nice and shiny with no foreign object damage that I could see. I agree that this engine should have been in better shape. I think it lacked regular maintenance, but I can't really say for sure.

The #5 main bearing journal on the crank showed to be a few tenths smaller than minimum spec, so I've dropped the block, crank and cam off at the machine shop to see what their opinion is, and how they would suggest I proceed from here. I'm hoping I can get by with having the cylinders honed and crank/cam polished. If I need to have one main journal ground .010" under, well so be it, I guess.

 

Today's engine ****:


The crank is out and on the bench. All the journals were in spec, some just barely, except for #5 main bearing journal. That one is a couple ten-thousandths small. That's the same one that had the bearing clearance out of spec, according to Plastigage.



This was the worst looking rod bearing journal. Has some scoring from foreign matter, but overall it's not terrible.



The camshaft cam out, and all that's left is an empty engine block



Overall, the camshaft doesn't look too bad, but the picture kind of sucks . . .


The block, crankshaft, camshaft and main bearing caps are now at the machine shop for further evaluation, and to formulate a plan of action. Probably won't know anything for a couple days

 

I know it sucks to wait... im still waiting lol...
But a good shop is worth waiting on. They will take the time to do it right.

The hone marks look amazing in the pics i can make out

Well... a lifter slapping would make a whole lot of sense since way back at the start of this thread you were sure the knock was at cam speed.

I would suggest new lifters all the way around to go with the fresh polish on the cam.

If you end up having to go +.010-.020 then were pretty much doing the same build simultaneously Brother Kevin.

If all your valves are ok then that will save you about 300$ for a new set...
If they are ok, i would at least do guides/seals and think about the 85$ for 910 springs.
I get dirty thoughts when i lap in new valves lol

Pistons look great! If you have to go over they should be easy to sell to recoup, or save for future need. Keeping my fingers crossed they just need a couple tenths hone to clean up.
The shop will probably suggest fresh cam bearings, i tend to agree. Its torn down this far...

 

If one or two cylinders are out of spec, I may consider sleeving just those cylinders. Any more than that and I'll throw the old engine back in and save my money for a while to accumulate parts. If it just needs a little cleanup, I agree on the cam bearings, and freeze plugs too. There wouldn't be any sense not doing that stuff with the engine already torn down to where the only thing still attached are the piston cooling jets, lol.

 

For me, there's know way I'd go this far without a complete valve job. See I still don't see why you had a nock. So pistons with new pins all bearing, valve job then all it takes to reassembly and be on my way. Now I'd clean up the fuel passages and oil to the heads for sure. New injectors, T500 and go for it. This is twice, that's the minimum I'd go for me. I just hope all works out. God bless, Chet

 

At this point, I think the knock was #5 main bearing. I don't know for sure, but based on the bearing clearance, journal diameter, and the taper all being out of spec on that one spot, it seems like the most likely thing. As long as the crank is usable without too much work, I'll have them make sure it's straight before they do any polishing/grinding.

 

Never seen a main bearing knock. I had a crank freeze up in a diesel before but it never knocked. Its usually rod bearing, piston or pin. Lots of other things sound like it but those are the main parts.

 

Yeah, I haven't convinced myself completely that the noise is from the main, but it's possible. The reason I lean toward it is the taper in the clearance would give the oil film an easy path to squeeze out of when the cylinder fires. That may or may not be possible, I just don't know. In any event, everything is getting checked while the engine is torn apart, that's for sure. I may never know for certain what the cause of the knock really was since it may actually be a combination of several things, but it had best not be there when the engine goes back in!

 

Would anyone else agree that first piston photo looks washed like from coolant perhaps? Doesn't look like it's from fuel to me.

 

It was definitely carbon, and there was no evidence of head gasket issues. I'll try to remember to look at it again tomorrow to see is the angle or lighting in the picture made it look different, though. I know several of the injectors were performing pretty poorly.

 

First of all I am sorry to see this motor has given you so much problems and that you have had to tear it down this far. As I have been reading along I was hoping you would have found a telltale sign that "OH this is really messed UP!!" But along the way I haven't seen anything that is really that bad, alot of that's not good kind of things. But nothing jumping out saying here is the problem. I think you have gotten alot of great feed back on this. Honestly at the begining I thought it was a wrist pin..well I was wrong. Now these guys are pointing towards a lifter or cam issue which I think there might be some merit to that. Also since it is at the machine shop have them measure the lifter bores and replace all lifters.

Here is why I say that I had a engine (Gasser) a few years back that was making some ungodly noises and knocking. I tore it apart didn't really find anything major so I put new rings, bearing, hone and valve job. Still had the problem... well long story short I went thru that engine 3 times replaced everything and ended up being a bad lifter bore and cam bearing bore alignment was bad. The cam was walking around, up & down and a lifter won't pump up & was bouncing around in the bore. Th block had settled in such a way that the cam bearing bores were not alined and I think somehow that was the cause of the bad lifter bore. Ended up putting all my new parts in another block and it hasn't given me any problems since. It is a marine engine and I now have about 470hrs on it. Good to Go but at the time it was painful going through it. So check everything!
So good luck
Back to the matter at hand have the machine shop check the cam bore for alignment, have the main caps torqued and the main bearing bore alignment checked and lastly the lifter bores checked. Before you throw any money in this block.

 

I agree with Ed. I would do this anyway if rebuilding any block. The time and cost is nothing compared to the headaches.

 

I'm having them start by checking the crank for straightness. That thought entered my mind after seeing how much taper there was in the #5 main bearing clearance even though the journal was only a couple tenths smaller than spec. If the crank is straight, they're going to proceed to check the block and cam. If everything checks out OK, then things will start getting ground and/or polished, clearanced and reassembled.

I'm pulling, inspecting and lapping the valves maybe today or tomorrow. I'll also be checking to make sure the lifters' diameters are all in spec. Before I pulled the engine, I got the stethoscope out and checked the valvetrain for noise, but didn't find anything knocking or ticking there at all.