K181 8hp B80 rods?

[glgrumpy 35]

Tore down my B-80 engine K181 and crank is shot. Looks like brand new .o30 piston and rod, but now rod is shot too. .010 rod in it. Trying a crank of epay, cross my fingers it is good or turnable. Shop says only can go .010 and rods only for that. I know they make ..020 rods for bigger K's, not for little ones? Others talk of cutting old rod and fitting inserts?? My guy says never heard of that. I won't know what's gonna happen till crank is in, but where can one get modified rods if that is needed? What's that site/name of the famours Puller engine builder I've heard of?

[sorekiwi 761]

http://gardentractorpullingtips.com/a1engine.htm

is Brian Millers website.

Another option might be to have a crankshaft shop weld up your old journal, and then regrind it to std size.

[MarkPalmer 81]

It sounds like you are going about it the best way possible by getting a used crank, and hopefully it can be machined to fit a .010 under rod, which are the smallest undersize I have seen for the K181. In most cases, this ends up working out fine as its not uncommon to see Kohler cranks with 40+ years of use on them not worn significantly at the crankpin, it might just be a bit out of round. I have not heard of anyone trying to bore the crankpin bearing on the rod and fit bearing shells. Welding the crank also isn't the best option, as the Kohler cast iron cranks are hardened and the welding heat weakens the hardening.

-Mark-

[Fordiesel69 259]

How is the crank shot? Out of oil or just worn?

Although not cost effective, it can be done.

If just worn, the rod can be be trimmed and re-bored. Also called line boring.

So if crank was already turned 10, then they can do 20 and just trim the rod and make it 20 under.

Basically they grind the mating surfaces which makes the circle smaller, but also oval in shape. They then need bore it round again. The nice part is you can do this with a worn rod and not worry about it breaking.

[Rooster 191]

It sounds like you are going about it the best way possible by getting a used crank, and hopefully it can be machined to fit a .010 under rod, which are the smallest undersize I have seen for the K181. In most cases, this ends up working out fine as its not uncommon to see Kohler cranks with 40+ years of use on them not worn significantly at the crankpin, it might just be a bit out of round. I have not heard of anyone trying to bore the crankpin bearing on the rod and fit bearing shells. Welding the crank also isn't the best option, as the Kohler cast iron cranks are hardened and the welding heat weakens the hardening.

-Mark-

If they use hard surface welding it will be harded than original.

We have it done on cranks and cam shafts all the time.

[MarkPalmer 81]

It sounds like you are going about it the best way possible by getting a used crank, and hopefully it can be machined to fit a .010 under rod, which are the smallest undersize I have seen for the K181. In most cases, this ends up working out fine as its not uncommon to see Kohler cranks with 40+ years of use on them not worn significantly at the crankpin, it might just be a bit out of round. I have not heard of anyone trying to bore the crankpin bearing on the rod and fit bearing shells. Welding the crank also isn't the best option, as the Kohler cast iron cranks are hardened and the welding heat weakens the hardening.

-Mark-

If they use hard surface welding it will be harded than original.

We have it done on cranks and cam shafts all the time.

I have seen the thermal spray welding process work, and its not supposed to weaken or distort the crank as other forms of journal welding might. I can't see anyone going for that much labor on a K181 crank though as they are still plentiful to find in good enough shape for an easy re-grind for .010 under rod.

-Mark-

[Rooster 191]

True!