K-321 Balance gears

[Cetan08 311]

Yesterday I tore into an old K-321 to rebuild. Had no compression. Top ring was fair. Second ring was sticking at times. Oil ring completely worn out and stuck in the Piston. Cylinder is in great shape and the Piston has .003 stamped on the top so I assume it is standard. Pulled the pan and perfectly clean inside but one of the balance gears is wiped out. By this I mean that all the teeth are gone. It wobbles on the shaft. I have another gear but what would cause this?

Thanks

[ZXT 2,401]

Personally, I’d remove the gears altogether. Looks like you caught it in time. You’re lucky they didn’t decide to exit the block. They don’t help vibration hardly at all, and by removing them you’d be removing the weakest link inside the engine.

Edited October 18, 2019 by ZXT

[richmondred01 2,237]

Pull them out. When they go it’s like a grenade thrown into a tank.

I remove them on all my rebuilds. After 40 years I never had anyone said that the engine vibrated any more or less. 

[The Tuul Crib 7,336]

 I just put up a thread about this the other day. Mine are coming out of my motor as well. Although mine is all intact I will be leaving them out when I put the motor back together. They are calling them grenade gears !

Edited October 18, 2019 by The Tool Crib

[953 nut 55,059]

3 hours ago, Cetan08 said:

It wobbles on the shaft.

You tore that engine down just in time! That gear was about ready to ruin your engine block. Toss out the entire balance gear assembly.

[AMC RULES 37,127]

If the gear was wiped...

how was the pan perfectly clean? 

[81blackhood 168]

Your piston is a replacement.  .003 over standard.    Kohler used to offer these.   Have one in my K301.  

[953 nut 55,059]

15 minutes ago, 81blackhood said:

Your piston is a replacement.  .003 over standard.    Kohler used to offer these.   Have one in my K301.  

Not all engine blocks going down the Kohler assembly line had a perfect cylinder bore the first time. Ones that needed a little attention were bored .003 oversize and given the appropriate piston and rings. Nothing wrong with that.

[richmondred01 2,237]

4 minutes ago, 953 nut said:

Not all engine blocks going down the Kohler assembly line had a perfect cylinder bore the first time. Ones that needed a little attention were bored .003 oversize and given the appropriate piston and rings. Nothing wrong with that.

Yep.

 

[81blackhood 168]

8 minutes ago, 953 nut said:

Not all engine blocks going down the Kohler assembly line had a perfect cylinder bore the first time. Ones that needed a little attention were bored .003 oversize and given the appropriate piston and rings. Nothing wrong with that.

Well I just learned something.  👍

[Cetan08 311]

6 hours ago, AMC RULES said:

If the gear was wiped...

how was the pan perfectly clean? 

Looks like someone has flushed the engine because there wasn't a drop of anything inside just clean metal. No other damage anywhere.

[squonk 41,020]

I bet that cylinder is out of round. I would have a machine shop check it at least. 

[richmondred01 2,237]

While it’s torn down check the crank too. 95% of all my rebuilds the cranks are out of round and typically off by several thousands.

its cheap insurance of 75.00 to get it turned. Then you are done for another 30 years of service. 

Like squonk said the cylinder is likely out of round and needs to be bored. 

Get it done right once. 

[clueless 2,975]

50 minutes ago, squonk said:

I bet that cylinder is out of round. I would have a machine shop check it at least. 

If you don't have the capability to measure the cylinder accurately then have a machine shop do it, money well spent. As far as the gears, take them out, nothing wrong with a little Kohler vibration, it's " Good Vibrations" .