K301 Crankshaft Bearings

[ol'George]

Originally Posted by athomas

I'm a little confused are we talking about the connecting rod journal or the fit for the ball bearings ? big difference as what the alternatives could be, if the rod journal is out of spec then have the crank cut 010 and go with a 010 over rod if the bearing journals for the roller bearings are 002 undersize ( don't know why a shop would mess with those ) then some of the loctite 638 bearing retaining compound which is an oil resistant product can take from .005 up to .009 out of a loose fit .maybe it's just me but I've seen many things called various names ,re reading the post I guess when it says main bearings you are talking about the roller bearings out on the end of the crank !!

In post #1, last sentence, he clarifies 2 Main ball bearings not the rod.
And post #6 mentions the 3 various loctite applicable

[athomas]

That's what happens when ya don't finish reading to the end of the sentence ! my mistake ! I would use the loctite retaining compound, I've used it many times on a lot bigger machinery without issues , I'm sure a good used crank is out there to be had at a reasonable $ also

[ol'George]

After reading your reply, I reread mine and it looks like I was pointing out your mistake, my bad, I didn't mean that, I just meant to clarify things.
Anyway, I'm in full agreement with trying loctite if it is not sloppy "loose"
---- just a not snug fit.
And as you mention, that crank is not difficult to find on the 'net.
Without being there to see/feel the fit, ones description of tight or loose is impossible to accuratly describe. even a mike/telescoping gauge gives different readings to different people.

[athomas]

not a problem !

[West Valley G]

Well, the fact that Thomas said he was confused made me think again
about the machine shop. I said to myself, I wonder if they are confused as
well? Our original conversation I was told it was the main bearings(plural) that were going to be messed up. Called yesterday and said " They don't make
such a thing as ball bearings that are undersized. He said no we need bearing
inserts for the rod. WHAT? After letting him know that the rod is the bearing
that attaches to the crank. He told me he led me down the wrong road.
Which in turn means I led you guys down the wrong road. Thank you all for
letting me know how things get all messed up communication wise.
I see a couple good things that came from this mess.
1) I learned a whole bunch of stuff I did not know. Thank you all
2) I still have a good crank, although now it needs ground to .010,
for the connecting rod that is.
Had to laugh at your thought on the Mars missions George. I thought to
myself . "But I expect the Gubment to screw it up, not the local
guys" It did cheer me up.
I hope this post isn't confusing.

Ken

[ol'George]

Too funny, I had a good laugh.
Sometimes I'm so confused I don't know if I'm winding my arse of 'cratchin' me watch.
So now the comfusing machnist needs a .010 oversize rod so he can grind the crank the proper undersize.
FWIW: there is a well respected fellow on Epay that sells parts as well as kits for kohlers.
https://www.ebay.com/usr/bakt4kids

[finsruskw]

Have used his kits several times w/ zero issues.
They include all you will need except the valve guides which are only $10.ea last kit I got.
Your, umm, machinist would/should know if they are needed or not.
Good luck!

[West Valley G]

Yes that is correct. Take the .002 undersize crank and grind it .010
under and buy another rod to fit that. No problem, clear as mud on this
end . Have been buying parts from the guy that you linked. Been just
fine so far.

Ken

[ol'George]

Now as usual, I'll throw some mud in the clear water.
A rod can be "reconditioned" sometimes.
You mill off a bit off the rod and/or cap mating surfaces, reducing the bore size, then it is honed to the correct size, in this case .002 under stock size.
The machine used is a Sunnen connecting rod reconditioning/honing machine.
They were extensively used when we did a lot of engine rebuilding back in the day.
They are some on Ebay now if one is curious for a look-see.
Also more mud:
The pulling guys are putting inserts like in today's vehicle engines in connecting rods instead of direct rod to crank surfaces.
What I don't remember is if they are modifying stock rods or are aftermarket specialty rods.
Edit: if your going with a new .010 undersize rod, purchase it first and give it to the "machinst" so he can fit the crank to it correctly, and look up the clearance and give it to him just incase he don't have the specks.(I'm too lazy to look for you)
at this point you don't need any more aggravation Ha,LOL!

[athomas]

Originally Posted by ol'George

Too funny, I had a good laugh.
Sometimes I'm so confused I don't know if I'm winding my arse of 'cratchin' me watch.
So now the comfusing machnist needs a .010 oversize rod so he can grind the crank the proper undersize.
FWIW: there is a well respected fellow on Epay that sells parts as well as kits for kohlers.
https://www.ebay.com/usr/bakt4kids

Use that seller for all my rebuilds ! good stuff ,never had an issue !