MF 150 knocking, Crankshaft bearing?

[fingers958]

I have a 1967 (I believe) MF150 that started knocking. I pulled the pan an see the the crankshaft is rubbing on the dipstick casting hole. Before I tear it down any further, I'm just trying to get suggestions on what/where to go next to fix it. Everything inside looks good. I'm thinking main crank bearing? and is this hard to fix? Tractor runs good, no smoke, no oil leaking from the front, etc...
Pics attached:

Any suggestions on where/how to proceed would be greatly appreciated!
Thanks,
Joe Stoddard

 

[Harry in Ky]

You might want to check crankshaft end play. If that seems excessive, maybe you should take a look at the thrust bearings?

 

[5030]

Could be rod knock or wrist pin slap or even sloppy pistons slapping the cylinder walls. Stuff does wear out.

 

[dodge man]

Maybe I’m looking at the picture wrong but it doesn’t look like it’s rubbing on the hole for the dipstick but the dipstick itself? Either way to really find out you’ll probably have to take it apart and measure things.

 

[Gale Hawkins]

Best of success in finding the source of the noise.

Here is my wrist pin story. While still in high school I put new rings and rod bearings in a Ford 801 and it knocked on startup. The guy at the machine shop that I was using suggested possibility of it being a wrist pin.

The six volt battery was so weak. It would not turn the engine over with the head on but after I took the head off it would turn the engine slowly. So I'll put a hand on each piston and turn the motor with the starter and I could feel were the knock was coming from and pulled that rod and sure enough wrist pen was bad and took it to the machine shop. He put a new wrist pin in it and the tractor ran for many many years.

 

[fingers958]

You might want to check crankshaft end play. If that seems excessive, maybe you should take a look at the thrust bearings?

This makes more sense to me. Any pointers on how to check these? Not very familiar with thrust bearings.