I'm not sure what update this is...maybe 3 or 4? I finally had a chance to build an engine stand and then tear down the engine to get the crankshaft out. The damage is worse than I anticipated, but should be fixable.
First off, I took some scrap metal and welded up an engine stand (designing and building this stand honestly took longer than taking apart the engine). I wanted to be able to get the sump off without having to re-lift the engine. There are 2 screws in the sump near the oil pickup which are longer than all the others. When I had the engine in the air before setting it down on the stand I went ahead and removed those 2 bolts so I didn't have to build the stand 2 feet off the table.
Now came time to start tearing down the engine. Fortunately, the Japanese really know how to make things simple and efficient. Basically using 12mm, 14mm, and 17mm sockets and wrenches I was able to get the crankshaft out (Probably a few 10mm's thrown in). I was really worried about re-timing the engine when it all goes back together, but they stamped every gear with the correct timing mark.
Just like I saw before, all the connecting rod bearings were spotless. Something else interesting to note is the design of the pistons. Most diesel engines are dished and have a point for compression combustion to start, but I didn't know an off-center dish recessed into the piston was a thing until now. Pretty cool design, which I'm sure is emissions related.
The pistons all came out without issue, and as stated in earlier posts, the bearings (both big and small-end) were in great shape. By this point, after removing the timing gear set, camshaft, and balance shafts, I was wondering if I was ever going to find the source of the metal and babbit in the sump.
The only problem I ran into during disassembly was figuring out a puller long enough to get the timing gear removed from the front of the crankshaft. I ended up using a bearing splitter? around the crankshaft and then threaded 2 screws in to act as jacking screws (sorry, no picture of this), I had some 1/4" steel that I put behind the jacking screws so I didn't damage the engine block. The gear came right off with such little force that I probably could've pulled it off on my own hah!
Oh well, it still did the job.
On to the crankshaft removal and finally finding the source of the engine knock!
After removing the rear main seal holder (rear bearing holder?) and unbolting the 3 main bearing cap bolts I was finally able to remove the crankshaft. I started taking off the main bearing holders one by one and finally got some carnage on #'s 3 and 4.
The first main bearing wasn't horrible, but not what you want to see when looking at main bearings. Some scoring on the front part of the bearing surface and crank.
The second main bearing was spotless, in fact, it was so spotless that I never took a picture of it on its own! Very strange, but guess it had enough oil to not hurt itself. I wish all the others treated themselves the same as #2
Main bearings #3 and #4 are where the carnage starts. #3 was obviously spun on the crank and caused some damage to the bearing surface and crankshaft. It looks to me like the bearing holder is still OK, despite some evidence of heat due to the blueing. In the picture below you can see bearing #2 on the right (no issues at all), and bearing #3 on the left (with the housing showing some heat marks)
Here is #3 by itself:
Now on to bearing #4, which also houses the thrust bearings. This thing was the cause of most of the carnage. The bearing had spun, and also began taking out metal from the bearing housing. This could very well have been from me running the tractor again to get the front end loader off, but I suspect the vast majority of the damage was done during the initial no-oil fault. You can still see some metal debris on the thrust surface that I didn't clean off, as well as the blueing from heat (which I cant ever clean off!)
Above is main bearing #4's holder, below is main bearing #4's crank journal...ouch...
Due to the amount of crankshaft damage, I'm currently in touch with some machine shops in my area that do re-surfacing jobs. I suspect I'll end up running oversized main bearings certainly on #3 and #4, and possibly on #1. I'm also going to replace main bearing #4's holder due to the amount of metal removed from it spinning. #3's holder is dis-colored, but doesn't appear to have lost any metal. #4's is toast.
As I've said through most of my posts, updates will be in-frequent, but I hope some people reading this are getting some enjoyment/knowledge out of it. I'm always happy to answer questions, or at least to tell you I don't know! The engine is probably going to sit until I'm able to get the crankshaft re-surfaced so it will be another month or more before any updates are made.
Thanks so much for reading!
