Hey all. We purchased a 1256 this spring, mostly for cultivation purposes. It had quite a lot of blowby (front axle getting free rustproofing every time it ran) but worked fine for our purposes until July or so. Always sounded like it had a miss at idle but cleared up with some throttle. Over a 9 hour day it would use about a qt running at ~2k rpm in low 3. Wasn't working it very hard.
In July when I got into the taller corn and was running full throttle in high 2 it blew all the oil through the crankcase vent in 2 hours. Oil pressure light came on, shut down right away, and i had a long walk to fetch oil and think it over. Neighbor with a lifetime of IH experience said he thought it was a cracked ring.
Well its apart and no cracked rings. 2 cylinder sleeves have a ~1in vertical crack coming from the top. Above the highest point of ring travel. Conn rod bearings are pretty worn, copper showing on the top end right where it takes the most load on all 6. Sleeves are worn past the max 4.3219 but not by much. #1 is 7 thousands out of round as well, i imagine thats related to the cracked sleeve. Could that much oil slip by that gap that quick?4.325 or so is the average cylinder diameter. We're in this far so we will be doing an in-frame rebuild and getting the neighbor to bring the sleeve tool over to help me out with that critical part of the build. Hoping he'll hang out for most of it to check my work.
I suppose I'm just looking for your thoughts on what could cause so much blowby if not cracked rings or really excessive cylinder wear. Something past the standard or obvious. I'd just hate to go through with the overhaul and be right where we started because my lack of years and experience caused me to miss something. The rings are definitely worn down as well. Ring end gaps way out of spec. I have pictures of all if you'd like them. I'll attach one with it hooked up in the field. It's a handsome machine.
In July when I got into the taller corn and was running full throttle in high 2 it blew all the oil through the crankcase vent in 2 hours. Oil pressure light came on, shut down right away, and i had a long walk to fetch oil and think it over. Neighbor with a lifetime of IH experience said he thought it was a cracked ring.
Well its apart and no cracked rings. 2 cylinder sleeves have a ~1in vertical crack coming from the top. Above the highest point of ring travel. Conn rod bearings are pretty worn, copper showing on the top end right where it takes the most load on all 6. Sleeves are worn past the max 4.3219 but not by much. #1 is 7 thousands out of round as well, i imagine thats related to the cracked sleeve. Could that much oil slip by that gap that quick?4.325 or so is the average cylinder diameter. We're in this far so we will be doing an in-frame rebuild and getting the neighbor to bring the sleeve tool over to help me out with that critical part of the build. Hoping he'll hang out for most of it to check my work.
I suppose I'm just looking for your thoughts on what could cause so much blowby if not cracked rings or really excessive cylinder wear. Something past the standard or obvious. I'd just hate to go through with the overhaul and be right where we started because my lack of years and experience caused me to miss something. The rings are definitely worn down as well. Ring end gaps way out of spec. I have pictures of all if you'd like them. I'll attach one with it hooked up in the field. It's a handsome machine.
your oil consumption is nothing ! i can blow through a gallon in a day with my cockshutt 1755. 301 walkasha . it was a stuck engine and i cheated and did not tear it down . more proof in the pudding working engines that were stuck there is no guarantee what the end result is.
