Question. Does the engine have to be pulled in order to remove the crankshaft on my D6C Dozer? Serial number 10k7968
I would say most likely, as you would have to remove the flywheel and flywheel housing just to name a couple things. Why are you wanting to remove the crankshaft?
Some bearings are spun. I was hoping to be able to do an inframe rebuild but it’s looking like I’m going to have to pull the engine.
Yes. See KSH's reply above. To do that the right way is going to require removing the engine.
Don't want to wish any bad luck on you but when you say there were spun bearings this may not be an easy fix. Damage to the bore in block would probably mean a line bore job if over sized on OD bearings are available. And even if there is no damage to the block spun bearings tells me there is trash going everywhere engine oil goes. Among other things I picture is an oil cooler core needing replacement, oil pump close inspection and most likely repair or exchange. While you are cleaning the block check for piston cooler nozzles, not 100% sure but think this engine has them and they get oil from the main bearing saddles and may be plugged. And those are the few things I can think of off top of my head and not having looked at a D6C engine in over a dozen years.
Some digging on SIS and it may be possible to line bore block for over size mains: Then again finding a shop to do that might not be as easy as it was back in say the 1970's around here!
Usually the rod bearings will spin before the mains because they get oil last. If you are really lucky, the mains may not have spun-only the rods. Ran low on oil? Then every bearing may be damaged
If a bearing spun until the crank throw discolored into a pretty dark blue with purple accents.........yeah forget it. I wouldn't even try to reuse it.
All true, not sure why I was thinking mains. But like as 56wrench says could be all bearings! I know I would not be comfortable unless I stripped engine to the bare castings and ran a brush though all oil passages. I know what a small piece of cork from the end of an oil filter can do to a 988 87A Cat engine, lucky for me I wasn't the one who changed the filters in that one!