Crank Replacement without complete teardown

[Erik B]

To fix a problem most likely started by a rebuild screw-up in '69, I need to replace the crank in my '48 B. I'd like to do it through the sides and crankcase cover only, leaving the head etc. in place. The old flywheel is already off, and I got to spend plenty of quality time with my clutch last summer, so I'm not concerned about getting that removed.

Apart from not screwing up camshaft timing, is there any reason I can't R&R the crank through the sides and top, without even draining the oil, assuming I don't dork it up and drop anything?

I have the JD and IT shop manuals.

 

[cole in mo.]

No need to remove the head, just undo the rods and push them forward, undo the mains, and oil lines, and pull it out.

 

[a49deere]

Oil is cheap in the scheme of things. Why skimp, now is a perfect time to clean out sludge and gunk from crankcase. Besides, I bet you"ll end up with oil dipped hands, parts, and pieces. Let alone all the stuff you may drop in will working on it, dirt, small pebbles, ect that may be around covers.

 

[metal4130]

Agreed. Drain the oil you will be amazed at the sludge and gunk in there.

 

[David G]

Good time to flush crankcase.

 

[Erik B]

I would just go ahead and do the oil too, but I opened it up a couple years ago and scoured the crankcase, oil pump, new screen, etc., then have run full synthetic oil ever since, so I know it's spotless in there.

I'll probably end up dropping in stuff and changing the oil anyway, my bigger concern was whether I had to pop the head for some reason, in order to do the crank job (due to cam timing, or who knows what).