Hi i have an older D41A-3, had #1 rod bearing fail (closest to oil pump). Had a full rebuild 10years ago (done maybe 60 hours) . I did find the oil pump had a broken tooth, would this be the cause of the bearing to fail? would 1 broke tooth make enough difference? i would have though the end bearing would fail 1st if starved of oil?
The HEF loves failure analysis. Post of picture of the rod bearings so we can determine why it failed. If the oil pump is the culprit, you are going to see issues with all the bearings. Am curious why the oil pump is missing a tooth.
Hey have attached some pics i only had 1st ones of mains, and the last 1x of rod ( they all look similar to this one) the 1st bearing had completely disappeared so assuming alot of this damage was bits of bearing going through everything? the damaged tooth was just floating in the pump. there was no signs of other damage in pump.
Any chance of some pictures of the oil pump gear and housing?
I see the one failed rod bearing with heavy side wear, well into the copper. I would like to see the back side of that shell . It shows the indications of a bent rod. Why is the rod bent? Incorrect timing, use of starting fluid, incorrect fuel setting?. There is contamination damage on the mains, but that’s not the root cause of failure. I feel like I’m overlooking something. I’ll have to ponder this some more. I would cut open the lube filter, for grins. Are the rods drilled?
Are you referring to this picture? I think those are main beating lowers, as there a seven of them.
But there is no oil groove or hole.
See the other photo of the upper (block side) of the seven main shells. I'm assuming here that the photo KSH posted above was of the cap main shells.
Is the bearing with the heavy wear the rear?
The Op said it was #1. I’m wondering if the #1 rod journal is ground under size with a standard bearing installed. Perhaps a lack of lubrication on that particular journal.
Has that engine ever had anti-freeze in the oil for whatever reason.? Time to take a look on the back of the bearing shells and break out the micrometer for the crank.?
What is the make and model of the engine? Damaged bearings is only one piece of evidence in a failure analysis. One would need to examine all the the components before trying to deduce the root cause of the failure. Some other questions, is this the rebuilt engine we are talking about or the original engine. Sixty hours of operation is nothing in the projected life of any diesel engine. One should probably do some measurements of the components and look into the history of what was done by the rebuilder. Were new rod bolts installed? Was the crank polished or ground? Was the oil pump new or jest reused? Another thought, just because the oil pump is mounted next to the front bearings doesn't mean that the input wasn't plumbed to some other place. Many times the input oil goes to the middle main bearing and then flows to the rest.
I agree. Before you posted I was about to ask on which journal was the oil feed to the crank, expecting the answer to be #4 main journal. TBH the location of the oil pump doesn't make a lot of difference in the grand scheme of thing when the oil goes from the pump outlet to the filter and from the filter to the engine.
Which gear? Drive gear or one of the gears in the pump? If the pump wasn't turning, everything would be cooked, not just one bearing.
Hey thanks for replys Motor is a Komatsu 6d105. After closer look at motor, the oil pump is at front on motor, but oil filter is on the very back end of motor, it looks like oil galley goes to back end 1st (would that explain 1st bearing fail as least oil getting there?) that copper coloured bearing is at the rear. i will attach pic of broken pump engine was rebuilt after seizing (we had 15 years of use before seizing) the shop that rebuilt it is a well know one, although we got quoted approx $10,000 (NZD) then they gave us a bill of $24,900, we fought the price down to i believe around $20k. i wouldn't think they done us dodge and put old parts back in after them but who knows. Just looking at repair bill it Had used crank ground and .050 bearings. new oil pump fitted. no engine start been used. I cut oil filter was just really black but no pieces of debris of any sought. no antifreeze been in oil, hasnt used any fluids since rebuild was running great. (re john c this is all on rebuilt engine, and they charged for new rod bolts) i have attached new pics of sets of mains and conrod bearing front and back
pump and gears
The front rod bearing is the usual damage place that shows up from lack of oil generally on most Komatsu engines that I've put my hands into. Photos of the broken sides of the oil pump gear might tell a story. Was there a suction screen on the uptake for that pump. A broken tooth initially indicates a foreign object got in there to break the tooth. It could also be a bad gear to begin with. Photos of the outer case might reveal scratches and gouges from foreign objects or the broken tooth itself. Was that broken tooth recovered? The way the teeth are engaged doesn't reveal anything about possible back lash between the gears themselves.
Okay. So, did she start knocking? What prompted the disassembly? Or, did I miss that?
You could have used your 2021 thread or is this a different motor thats had the same problem . Last time there was no oil pressure at one point
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I may be missing something, other than a few brain cells, but did you say there was absolutely nothing left of the #1 rod bearing shells? Not even a thin piece of the shell stuck to the rod cap? I have a hard time believing that there would not be at least a few large fakes of it in the oil pan of caught in the suction strainer! At the least I would expect the lower bearing shell to be there in some form. How long did this engine get run while making all kinds of bad noises and missing on that cylinder. And if this is the same engine from 2021 have to I have wonder why an engine would be run only 50 hours in the ten years after a major rebuild, then again that might be a story for another thread!
Some very important pieces to the puzzle that didn't make it over to this thread.
Please post some close up (and in-focus) photos of the fracture faces of the oil pump gear and broken tooth from directly in front and looking in the direction of the arrows. The last few posts and the link to the other thread seem to suggest that the full story is yet to be revealed. Was the oil pump suction strainer present & correct when you tore down the engine.? Have all the crank journals been measured to confirm that they are within specification for the undersize to which the rebuilder stated they were ground .? Was the ".050" undersize metric (i.e. 0.5mm/0.020") or Imperial 0.050".? If it is Imperial then the crank must have been pretty well goofed to require that much grinding - unless it was already ground -.025" previously of course. EDIT: Checked out the link to the other thread. From a photo there the regrind was Metric 0.5mm or 0.020". Have all the back sides of the shells been checked to ensure that they correspond to the undersize to which the crankshaft was (allegedly) ground.? Was the crank checked for straightness before being reground.? Was the block ground oversize on the main bearings.? I second KSH's question regarding the remains of #1 rod bearing. There should have been at least SOMETHING left, even if it probably resembled a piece of tinplate welded to the rod.
After that 2021 thread, did you try replacing that one bearing and running it again?
The broken tooth in the oil pump would likely have locked the pump up and spun the drive gear or pump gear on the shaft since it never took out any teeth on the drive gears. Instant no oil pressure.
It would problaby be well worth closely inspecting the shaft and the drive gear on the oil pump for any signs of rotation between the two. Unfortunately there is no photo from the other side of the pump showing exactly how the gear is retained on the shaft. It's interesting to note that according to the OP this was a brand-new oil pump installed at the time of the rebuild. Another question: Does the machine have an oil pressure gauge fitted or even something as basic as a low oil pressure light.? If it has one or the other, are they working.? One would have to assume not.
Shells in the photos show typical excessive contaminants, the pitting a good indication of coolant attacking the babbitt, dirt as to the scuffing wear or just well used up lube qualities of Old Oil.
There'd have to be slippage or a sheared shaft because I don't see that oil pump looking that good if that loose tooth was floating around in there. It'd either be beat into shrapnel or it'd have split the pump in half.
Hence my question had the oil ever been contaminated with coolant. The back side view of all those shells, both mains and rod bearings, suggest that the answer is yes. Glycol will take the LTO off a shell bearing extremely well. A photo of the other side of the pump is required to confirm that, but FWIW I agree with you.
I'd be wondering also about the operator of that machine. That engine must have made some bad noises for more than a few seconds if in fact as claimed there were zero remains of the #1 rod bearing. Not claiming to be an expert on bearing failures but having seen at least a couple engines that were running with broken cranks and a few with seized main or rod bearings that locked right up, plus a few that popped a rod out the side of the block, I don't recall one where there was "nothing" left to one of the bearings. Kind of makes me wonder if someone plane forgot to install the bearing shells on that cylinder at assembly!
It's probably irrelevant to your problem but I find it hard to believe that broken tooth was in the pump when everything was together and the engine running, at least not very long I just don't see any place that it could have been that the pump gears wouldn't have picked it up and destroyed those gears...I'm probably missing something here but tolerances inside an oil pump are pretty close because of the nature of it's function.
we got quoted approx $10,000 (NZD) then they gave us a bill of $24,900, we fought the price down to i believe around $20k. What is it with people these days? That's like 125% above the quoted price! on a $10.00 quote that's manageable..But on a $10,000.00 dollar quote it's bat **** crazy! It seems like everyone I know around me AND me also that seems to be the order of the day now. I realize replacement parts and labor rates are sky high now, but it would seem the people making the quotes could come a bit closer with their estimates. After all, that's what they do everyday.
I agree with everyone who says there should be evidence of that missing bearing shell somewhere. On every lower end failure i’ve ever seen, the oil pan contained pieces and fragments and the oil filter was full of debris. There is definitely something fishy here
I guess I would have to reassemble that pump with the broken tooth in position and turn it over by hand to believe it was in there with engine running. Just maybe it would be possible that there is a passage in the housing that is not shown where there is room for the tooth to slip out and not get caught and have the pump explode. I have seen some strange things with gear pumps over the years. One I wish I had a camera to record was a hydraulic pimp that had bearing failure that allowed the gears to "machine" their way into the housing. They got deep enough that they actually started cutting into the bolts holding the pump together. How someone did not notice the drop-off in pump outlet before that I have no idea. This was way before the internet and even digital phones. Back then it was rare for even the bosses to have cameras to record things. And if they did it would be maybe weeks before the roll of film was finished and sent to the lab to be processed. Only to find out the flash had not worked or someone's finger was in the way!
Ahhhh, I didn't consider the pump gears stripping on the spindle and just stopping, I would have thought the gear teeth would be the weakest part of that equation.
That's where being able to examine those parts in person would be handy as hell. I know many here would be able to spot things that maybe the poster does not see as important. Just a good up close look at the break area of the gear would let one know if this was a cause or effect of the failure. Did that tooth break over a period of time or was it one single stress? Or even a flaw in the metal itself? I still have to go back to what I seem to recall that this engine only had something like 50 hours running from a major rebuild. Sure makes me think that there was a major workmanship problem or seriously bad parts installed.
Going back earlier, or maybe to the other linked thread, IIRC a new oil pump was fitted during the rebuild. Maybe it was nothing more sinister than the fact that the new oil pump was defective.? I still can't understand why the oil pan wasn't full of metal and/or there were not parts of the #1 rod bearing still adhering to the rod.
So Something fishy in Denmark, ohh if Machines could talk
Do you have any update on this issue.? Inquiring minds want to know.
I had a TD 15C put a hole in the block 60Hrs after the dealer mechanic did the engine up, he used the old big end bolts one of which let go, end result a new short block on IH .
Well here is a picture of the engine in a 769C 651 hours after it was put back to work after Cat dealer did a major overhaul: Also put a hole out the right side of the block and into the oil coolers! It had started making bad noises so like any "good operator" he decided to drive it back to the shop! Almost made it! When truck was moved to another quarry it had another 11,278 hours on it so guess the second repair was a little better! Of course not too much of the failed engine was reused!