K161, what was the deal?

[dodge trucker]

As I remember there were 2 different bore sizes of them. When did they switch and what were they?
Got 2 of them to go thru 1 on an Original and the other in a 71. Starting to scope out parts.

[J-Mech]

Yes, there was an early bore and a later bore size. I don't remember the early one for certain off the top of my head.... I think it was 2-7/8". Later it was 2-15/16". It really doesn't matter, as the early bore sub's to the 2-15/16". You can't get the smaller pistons anymore. All the blocks can be bored to the larger size. Eventually, the K161 was dropped and the K181 replaced it altogether.

Just for reference, a lot of the K161 blocks will accept the K181 crank. (Longer stroke.) But some earlier blocks did not have the relief cut outs in the lower half of the cylinder to accommodate the larger crank weights and longer stroke. Ask me how I found that out, lol. Anyway, you can grind out a relief in the lower half of the cylinder and install the longer stroke crank, no problems. Otherwise, there is no difference in the K161/181 blocks.

[dodge trucker]

ok cuz I have an Original engine that needs rebuilt badly. I have an NOS piston saved on my Feebay watch list for a great price and wanted to know before I hit "SOLD".
so the compression height between a K181 piston and a K161 is the same? (center of pin to top of piston) If that's the case I can order a STD piston for a K181..... he hasn't been playing with this tractor in a wile ("life") but keeps talking about it.... I found him a freshly rebuilt K141 long block that we were gonna put the original engine's sheet metal and carb onto "for now" so he can still ride around and play on it.... until I can get the original engine thru the machine shop (the guy I use is good but is so backed up that it takes a while to get anything done there) I have had a Slant 6 block and crank sitting there for almost 4 months now..... ) and so you know my (one and only) kid that owns this machine, is 27 and married himself now.... still a "kid". He bought it as a basket case in high school, blasted painted and reassembled mostly by himself back then.... the engine runs (albeit weak) so it just went back on at the time......

[J-Mech]

"so the compression height between a K181 piston and a K161 is the same?"

yes

[dodge trucker]

Is there a reverse lookup of sorts for Kohler where I can put in a PN and they tell me what size engine it fits?

[J-Mech]

Is there a reverse lookup of sorts for Kohler where I can put in a PN and they tell me what size engine it fits?

Not that I am aware of.