Another K321 rebuild to do!

[Chad]

Well, add my newest 444's K321 rebuild to the list vicv07 and Eugen! Mowing a few weeks ago, about an hour in started blowing brown smoke and losing power. Shut it down and see smoke coming from head...

Let it cool down, then pulled the head. Knew it wouldn't be good as some nuts were only finger tight and others really tight. Broke a head bolt over exhaust in the process, so that'll be fun to deal with later (I know there's a welding trick that can work, but I have no welder - probably time I got one anyways!)

Obvious head gasket leak, for how long who knows. Head will need to be flattened for sure. STD bore, haven't done any measurements yet but since the rest of the machine is in such good shape I'm just going to rebuild the whole thing.

To be honest, I'm not that upset about it. It will be a fun project, but I won't get to it until this winter probably. Just glad my other 444 is going strong as I sold my Wheel Horse 520H a few weeks ago. Will rebuild that one later too, maybe when kids are older - will be a fun project (fond memories of rebuilding and restoring our 155 when I was a kid with my dad and brothers).

Anyways, I'll post pics of my journey as I go...might be a while though lol.

BTW - really love the cut with the k45 deck, and mowing in any direction! With the chute off hardly any windrows, but a matching lawn sweeper would be cool to have too



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[Eugen]

Well, add my newest 444's K321 rebuild to the list vicv07 and Eugen! Mowing a few weeks ago, about an hour in started blowing brown smoke and losing power. Shut it down and see smoke coming from head...

the k321 rebuild club eh? sorry to hear you this happen though!

Let it cool down, then pulled the head. Knew it wouldn't be good as some nuts were only finger tight and others really tight. Broke a head bolt over exhaust in the process, so that'll be fun to deal with later (I know there's a welding trick that can work, but I have no welder - probably time I got one anyways!)

I've had success with drilling the bolt right down the the middle, with larger and larger drill bits, until only a thin wall is left. There is a tool which you hammer down the middle, or you can just grind a bolt to have square faces and hammer it a bit in the middle of the drilled bolt. The square profile will bite into the bolt and you can use a regular socket to get it out.

Obvious head gasket leak, for how long who knows. Head will need to be flattened for sure. STD bore, haven't done any measurements yet but since the rest of the machine is in such good shape I'm just going to rebuild the whole thing.

My head was severly warped. I did a lot of rubbing on sandpaper on a very flat tile. I was able to grind it flat to spec though.

To be honest, I'm not that upset about it. It will be a fun project, but I won't get to it until this winter probably. Just glad my other 444 is going strong as I sold my Wheel Horse 520H a few weeks ago. Will rebuild that one later too, maybe when kids are older - will be a fun project (fond memories of rebuilding and restoring our 155 when I was a kid with my dad and brothers).

Anyways, I'll post pics of my journey as I go...might be a while though lol.

BTW - really love the cut with the k45 deck, and mowing in any direction! With the chute off hardly any windrows, but a matching lawn sweeper would be cool to have too

Looking forward to it, when you get around to do it, Chad. I'm about to pick mine up from Mike and then have the crankshaft ground, and on to assembly.

[ssmewing]

Many Kohler K-series engines have loose head bolts. The manual states that you torque the nuts, run the engine for I don't remember how long, and then torque them again. This is not optional as your engine is an example of not following the instructions. The second thing that often happens is over-torquing which is often the reason for broken studs or pulled threads. Over torque also pulls the edges of the head down. You always should have a dead flat with sandpaper to flatten the head on Kohlers. I use a piece of 1/4" plate glass and 2 sheets of high-quality sandpaper and stick it to the glass with a thin coat of spray adhesive. The service manual is free from kohlerengines.com and it details this part.

[Chad]

Thanks guys.

Eugen yes I may take that route for the bolt. Thanks for the tip! Looking forward to seeing your progress too, crazy how we're all in the same boat atm. But to be expected with machines this old - a reminder again of just how well built they are (and that they're absolutely worth fixing over anything you can get today).

ssmewing I did grab the manual and have perused it a bit to reacquaint myself with these engines. You are right that this maintenance wasn't done correctly. A perfect example of the importance of a torque wrench.

It's interesting that in the earlier models (pre 1980 or so) the owners manual explains how to remove head to decarbon. They make it seem so simple (which it is) but easy to mess up without the correct tools; definitely requires at least a little mechanical know-how. The manual for my machines doesn't mention this at all - wonder if dealers asked them to stop after owners were messing things up?! Or Case/Kohler got tired of warranty claims?

I'm by no means a mechanic, but will definitely take my time as I go! Been a while since I've wrenched on a 4 stroke; mostly rebuild chainsaws these days

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