REBUILDING K-301

[illinilefttackle 399]

Hello Guys- I'm "refreshing" a k-301 that appears to be in good shape-no evidence of oil burning-no noticeable slop in crank & rod clearance- SO-I want to hone it and Lap in the valves -so I can use it in my C-125 while I go thru it completely. I got this engine from TICKSTER-What a Guy!-

I'm a old (literally) car engine rebuilder-can I use my Ridge Reamer to cut out the ridge at the top of the cylinder? Then use a Flex-Hone to hone the walls to get them ready for a new set of rings? I don't plan on touching the crank-unless I see something weird when I pull the Rod cap off. Speaking of rod caps-anything "trick" to tightening the bolts-Threadlocker- to keep it from loosening? I'll check the valve clearance and adjust-so far, does it all sound good?

Anything else that I missed?-Thanks-AL

OOPS-I almost forgot-how do I tell if the piston is STD?

[kpinnc 10,676]

Al, I can't give you any help with which tools you can use. I have never rebuilt a Kohler that didn't require a new bore, and the machine shop always did it afterward for me. In short, I cheated I guess...

I did use high temp thread lock on the rod cap, but mine had nuts instead of bolts. about 10 years now, and it's still running, so I guess it was OK.

Without claiming to speak for all Kohler pistons (I know nothing about the Mahle ones), the few I have seen did have STD, .010, .020, or .030 stamped on the top. You may have to scrape off the carbon to see it, but it'll usually be there.

Good luck with the re-build. You should get another 20 years out of that engine!

Kevin

[TT-(Moderator) 1,127]

I'd say that if a cylinder bore is worn enough to merit using a ridge reamer, then it needs bored. Any time an engine is pulled down for rebuilding it is imperative to measure all wear points to verify they're within the specifications provided in the Kohler manual. Critical clearances such as crankpin diameter can not be gauged by the naked eye, and you certaily can't tell if a cylinder is "out of round" (egg-shaped) just by looking at it. These smaller flathead engines don't have much compression to start with, so anything less than having the valves and seats reground to ensure proper sealing could result in lower performance and hard starting. This would be different if the engine was rarely used, but these tractors get "pounded" on a regular basis, so saving money now will only cost you more later.

Back when you used to be able to buy piston rings and a gasket set for under $20 it wasn't that big of a deal. It will cost closer to $50 for those parts (OEM) today, so you want to make certain you're not throwing that money away.

If the engine you are working on "measures up" (literally) it would be a great candidate for "freshening up". (rings, gaskets, and seals) Points, condenser, spark plug & wire, and possibly even a new governor spring are always on the list too.

Sometimes it's hard to justify spending $300 to $400 on a single-cylinder small engine, but if you look at what an equivalent replacement costs (engine, or complete machine) it won't seem so terrible.

[Confused99 2]

I would think if you have a noticeable ridge, it probably needs bored to atleast the next size. The best way to know if yours is STD is just to measure. I think sometimes also, the oversized pistions have the size stamped on the top if that is still readable.

Jason

[Confused99 2]

ya beat me TT. Good advice.

Jason

[linen beige 14]

TT,

You beat me to it too, pretty much took the words right out of my mouth.

Unless the "ridge" is really just carbon build up, (happens a lot around here, don't know what's in our gas.) if your thumbnail will catch on the ridge, which merits using a reamer, definitely have it bored. New rings in a loose or egg shaped bore are going to speed up the wearing of the block, and you'll have to rebuild it again way too soon.

[T-Mo-(Moderator) 4,337]

Al,

I'm by no means a mechanic and I'm sure you know more about engines than I do. But I concur with TT and the others. And as for costs I rebuilt my K321 for around $250-$260. But I was friends with the machinist so I'm sure he gave me a break. He did use Kohler parts and I think a good chunk of that was the parts.

[illinilefttackle 399]

OK Guys-I'm right in the middle of this thing-Do Kohler cranks have a oil hole drilled into the journal? If so should I be able to stick a small wire in it-how far?

Those of you that have put your hands inside one of these-I have no play in the crank journal -up & down-but there is some side to side (very little) Is this normal?

Crank has no movement sideways-crank journal or rod journals dont have any scuffing. Really looks good to my "old" mechanics eyes.

I honed the cylinder wall-it had very little ridge made from carbon only. Nice cross hatch pattern now. Valves have plenty of meat left on them, good contact pattern, no slop in guides, no sign of oil passing the guides. Will lap them in with compound.

I'm taking out the balance gears-like Brian Miller says. Their shims are worn some.

Thanks for any input-AL :whistle:

[illinilefttackle 399]

:whistle: Aw Fooey! A guy just can't win! I concede.-AL

[KyBlue 652]

Why the long face?? Thought it was lookin good?

[illinilefttackle 399]

:WRS: I was doing my thing-then I put my magifiers on (old you know, can't see)- The exhaust valve is burnt on the edge- Crank has a ding in it that at first looked like an oil hole, but my "better" eyes can see it's not a hole. I have seen this on auto cranks and you can still use them after their ground,becuase it fills up with oil and never touches the rod journal, but none the less, not what I was looking for. The very top of the piston, above the top ring is scored on one side.

The cam looks OK ,but it does have some mild discoloration- on both lobes-the accelaration ramps go from silver to red to blue (just very subtle. almost transparent colors, I've never seem that-really doesn't look like it got hot-no scoring.

I guess I'm going to bite the bullet and send it to the machine shop-I had hoped to use this one "cheap" while I did a major overhaul on my original engine now in my tractor- BUT- I can limp along with that and do a major on this one-it will keep me from any down time( thanks again to TICKSTER}.

So , The MAN upstairs has all ways provided for me and mine in the past-I'll need a little financial help from him to do this, but I have faith. Thanks-AL :whistle:

[illinilefttackle 399]

I was doing my thing-then I put my magifiers on (old you know, can't see)- The exhaust valve is burnt on the edge- Crank has a ding in it that at first looked like an oil hole, but my "better" eyes can see it's not a hole. I have seen this on auto cranks and you can still use them after their ground,becuase it fills up with oil and never touches the rod journal, but none the less, not what I was looking for. The very top of the piston, above the top ring is scored on one side.

The cam looks OK ,but it does have some mild discoloration- on both lobes-the accelaration ramps go from silver to red to blue (just very subtle. almost transparent colors, I've never seem that-really doesn't look like it got hot-no scoring.

I guess I'm going to bite the bullet and send it to the machine shop-I had hoped to use this one "cheap" while I did a major overhaul on my original engine now in my tractor- BUT- I can limp along with that and do a major on this one-it will keep me from any down time( thanks again to TICKSTER}.

So , The MAN upstairs has all ways provided for me and mine in the past-I'll need a little financial help from him to do this, but I have faith. Thanks-AL

I told you I was a man of faith. Too many things have happened in my life to contradict the presence of the Man Upstairs-God. My last post finished with the fact I needed a lttle financial help to be able to rebuild my engine. I eluded to the fact "the Man Upstairs would have to help.

WELL- Friday I received a check in the mail for just enough to pay for the rebuild-40 cents over- It was from an Unclaimed Funds thing that I had filled out and forgoten about because I never heard back! WOW! This has happened to me before too- You can call in coincidence if you will, but I know where it came from. A little help from above. "Ask and you shall recieve". It's off to the machine shop tomorrow guys-Thanks for listening!-AL :whistle:

[Sparky-(Admin) 19,439]

Thats great news Al. Keep us posted.

Mike.........

[TT-(Moderator) 1,127]

A little help from above. "Ask and you shall recieve". It's off to the machine shop tomorrow guys-Thanks for listening!-AL

Al, you're lucky you're working on a Kohler.... I don't know if HE would have "helped" you if it would have been a Tecumseh.

Regardless - it's wonderful news, and we're here if you need any help from the "mortals". :WRS:

[Rollerman 290]

Al, you're lucky you're working on a Kohler.... I don't know if HE would have "helped" you if it would have been a Tecumseh.

He may have TT..but the exhaust would have smelled like brimstone.

Al glad to hear it's all working out for you.

Make sure to get some pics up of the rebuild process.

[illinilefttackle 399]

:WRS: Well Guys The K-301 is at the machine shop! Dropped it off at their satellite office only about a mile from me-then they haul it to the main office downtown where the machine shop is. They are a division of NAPA auto parts in South Bend. The Ridge Co. I have dealt with them for more years than some of you youngins have been alive, and they are good at what they do!.

The Kohler tried bravely to puff out its chest and look big sitting next to a V-8 and a V-6 sitting on the floor waiting for a ride too. I'll keep you posted on the "surgery" and hope to get pics too, if my daughter will let me use her bazillion dollar camera. I'm going to order the rebuild kit from OHIO as soon as they give me the final sizes of everything-Thanks -AL :whistle:

[T-Mo-(Moderator) 4,337]

Al,

God knew you needed that engine rebuilt and He intervene on your behalf. That's a great story. I do agree with the others also, it may not have been in His will if that was a Tecumseh. :whistle:

[illinilefttackle 399]

:WRS: Hey Guys! The machine shop just called-the block will be 10 under and the crank will be 10 under-I didn't think the engine was in too bad a shape-NOW-to order the parts! I'll keep you posted and post some pics when every thing is done and going together-Thanks-AL :whistle:

[T-Mo-(Moderator) 4,337]

That's good news, Al. You're be back mowing in no time. :whistle:

[linen beige 14]

the block will be 10 under and the crank will be 10 under

Before guys start ribbing you about a cylinder being bored to "undersize", I had a very low mile Ford 289 with one cylinder scored by a folded oil ring spacer. The machinist bored it and installed an undersized sleeve. So it was undersize until he bored the sleeve to match the other cylinders.

So it is possible to have a block bored and come out undersized, just may be a little hard to find a piston though.

[Curmudgeon 28]

Aw Jim, take away all our fun from his innocent typo!!! :whistle:

[wse100 0]

I wonder if tickster has any 12-14 hp kohlers laying around :WRS:

[Rollerman 290]

I wonder if tickster has any 12-14 hp kohlers laying around

No K321's...but two K341's, one K301, & 4/5 K241's.

Oh & if anyone goes fishing I have a good supply of Techumseh Power Products boat anchors. :whistle:

[Rollerman 290]

Oh & Al it's good to hear your getting closer to haveing a healthy C125 again.

Will have to pay you a visit sometime & get some pics of the rebuild.

I'll probably learn something. :D

[illinilefttackle 399]

:WRS: Geez Jim- this typing thing is not exactly my strong suite, after all, when I went thru High School for Pre-Engineering we used "Slide-Rules" instead of calculators- I rebuilt my first engine 47 years ago and have doing it ever since. Drag racing, even built engine-trans assemblies for "Avanti Motors" in South Bend for several years-so my mind knows what I meant but my fingers lose the thought in translation. I,m struggling to choose the right parts package from the guy on ebay in ohio-he has 2 different packages, same parts included in each-14-15 dollars difference. The only difference I see is one piston is "Thermal Coated" and the other isn't-SO- I'm going to call him tomorrow to get the low down.

Thanks-AL :whistle: