Take care of your crank!!!

Sun Jan 04, 2004 11:29 am

There's been talk of engine rebuilds and crank/bearing questions, so I thought I would share a couple of pictures of what can go wrong when things aren't checked over VERY carefully.
(sorry about picture quality!! :oops: )
Image
These bearings are from a 1250 Cockshutt that we parted out, but the principal is the same with a Cub. It would seem that the PO to the fellow we bought this from found that parts were hard to find and did a "rebuild" with low quality parts. Th ebearings he was able to find have to be machine to fit the crank, and have to have the tabs bent out when inserted to the block and caps, etc.
It would seem that he didn't know/ care, and didn't check his clearances!
All of the main bearings spun, and one rod bearing!


This is what happened to the crank.
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I know its not very clear but, at the top left of the journal you can see some silver/gray streaks. That is where the bearing, which didn't have enough clearance, stuck to the journal.

Always check clearances after replacing bearings. Just because the package says the parts are the right size doesn't mean the right parts are in the box (it happens), or that the machining job was done properly. There can always be human error!

Once again, sorry about the fuzzy pictures! :oops: ( I gotta get a digital camera!!)

Sun Jan 04, 2004 6:12 pm

Thanks Partsman. Just installed new mains on my crank .CNH (had it turned .010)installed new.010 over bearings. took the time to install plasticgauge, got the right clearance .002.Take nothing for granted.Will do the same when I install the rods.I blew the rod on a 8hp Briggs a couple years back because I thought there was oil in it :oops: It hangs in my shop.

Sun Jan 04, 2004 11:46 pm

Yup, we get a lot of tractors for parts because of avoidable mistakes, such as forgetting to torque down a rod cap!!!!

Wed Jan 07, 2004 9:22 am

Also, watch for filed rod caps. Another short-cut that hampered my engine rebuild. :evil:
HR

Wed Jan 07, 2004 6:59 pm

HR, by filed rod caps, do you mean that some one filed the cap where it bolts to the rod to take up the slack?! :shock:

Thu Jan 08, 2004 7:48 pm

Yeah, that's exactly what I mean. It's a nifty trick alright, until the next owner goes into the engine rebuild process. That's what I found, along with a beer can shim under a rod bearing!!
:evil: :evil:
HR

Sat Jan 10, 2004 8:01 pm

WOW!!! What some guys will do to say a buck!! :roll: