K301 Connecting Rod

[samiam44]

Matt,

This is the text from a Kohler factory piston kit on the internet.

"There are 2 basic designs, the Old Style piston and the New Style (Mahle) piston. If you have the Old Style piston and you are Not replacing the rod you have to stay with the Old Style piston design.
If you want to upgrade to the better New Style (Mahle) piston you can but you have to also replace the rod with the New Style rod.
The Mahle style piston skirt profile was modified to provide a better fit within the cylinder bore. The ring channels were redesigned and the wrist pin was strengthened. A different connecting rod is required because of the extensive design changes.
Beware of shops selling the aftermarket "rebuild kits" more then likely these are imports. These parts in many cases will not inter-change with genuine Kohler parts, example aftermarket rings will not fit in genuine Kohler pistons. They are also selling the old style piston design, further they are also claiming "It's what the rebuilders use". In my 30 plus years in the power equipment industry I have never heard of the term "rebuilders" in the small engine business unless they may be referring to backyard mechanics that are using aftermarket internal engine parts. You may be saving in price but not Quality."


I think this is the problem you are having...

[mattoney]

Alright guys, big update. After I woke up from Thanksgiving (aka "food coma"), I got pretty busy with work, but I did have some time to do some detective work.

Samiam44, I found the same article you quoted from, on http://www.kohler-engine-parts.opeen...ts/piston-kits. According to the piston design, the kit I have (which I'm pretty sure was manufactured by Stens) includes the old style piston. I have had Kohler places ask me if I'm using the old style piston, and this is the connecting rod they've come back with. But the connecting rod and piston seem to work well together. It's the piston vs the block that is the problem.

So I took some pictures, and I took some measurements for y'all to see. A picture is worth a thousand words, and I tend to be rather wordy, so maybe this will shut me up!

First picture is of the difference in size. I put the old rod on the left, new rod on the right, and measured the width of the rod in the area where it was hitting using calipers available at work. I measured the new rod at 0.200" wider than the old in this area.

https://lh5.googleusercontent.com/-P...20modified.JPG

The second picture is a zoomed in view of where the rod was hitting the bottom of the cylinder wall. There was a bit of flashing left from when it was cast, and you can see two lines; one where it hit the cylinder wall when I turned the engine it's proper rotation, and the other where I turned it backwards to see if it would hit that way too.

https://lh3.googleusercontent.com/-5...0/100_1590.JPG

At the suggestion of the last Kohler dealership I talked to, they recommended polishing this area down to remove that excess material, and see if it will fit then. I have polished it down very carefully, making sure not to take off much material, or let the rod get too hot in the process. Here's the finished product.

https://lh3.googleusercontent.com/-M...0/100_1591.JPG

I'm pretty excited to put this thing back in and see if I have enough clearance, but it'll be a week or two before I get the chance to do so. It doesn't seem like it'll take much to clearance the rod, so I'm hoping what little I did will make the engine and its owner happy.

I apologize if I am not posting my pictures correctly. I know some forums get pretty upset about this. If I am doing it incorrectly, please let me know and I'll e happy to fix. I haven't yet found the rules for posting links to pictures hosted elsewhere.

Thanks for all your help, and I'll keep you updated.

[ACecil]

Anytime! Thanks for the update.

[Methos]

Originally Posted by ACecil

Anytime! Thanks for the update.

Oh yeah!

Not a rule but a guide to help you post pics.

http://www.onlycubcadets.net/forum/s...ead.php?t=1024

[mattoney]

Originally Posted by Methos

Oh yeah!

Not a rule but a guide to help you post pics.

http://www.onlycubcadets.net/forum/s...ead.php?t=1024

I found this guideline for posting pictures in your message. What about a url link to a picture hosted elsewhere?

I've been to forums before where they are so strict, making one rule violation you may not even be aware of will get you banned. The last thing I want to do is make anyone mad, and it's almost made me afraid to use forums. So that's why I ask. Thanks for the help!

[samiam44]

What you did looks good! You could smooth that all the way up to the little end too. Big end down to the cap bolt holes.

You want to remove the flashing from the parting line. Filing the rough and then sanding. Drum sander etc. It's always better to have a fine finish than a rough as that's what starts a crack.

The new factory rod looks much beefier than the replacement. Note more contact area for side-thrust, the radii on the inside of the I-beam section blending into the big end is much bigger. Ditto for the small end. Bet that's where the old ones break.

Actual I-beam cross-section looks to be about the same(thickness of the flanges).

How much clearance did you end up?

[Methos]

Originally Posted by mattoney

I found this guideline for posting pictures in your message. What about a url link to a picture hosted elsewhere?

I've been to forums before where they are so strict, making one rule violation you may not even be aware of will get you banned. The last thing I want to do is make anyone mad, and it's almost made me afraid to use forums. So that's why I ask. Thanks for the help!

I just tried your links and got to post the images you posted. Look at the pic I attached and click on the icon inside of that awesome block/circle I made. (Pun intended on my photo editing skills!) Once you click that copy and paste the URL of the image you want to link to. Let me know if you have any questions.

I'd be worried about then being but we'll let you blame the if you seem so don't we're here for you! Ok I'll stop with the emotes for now!

[CADplans]

"Look at the pic I attached and click on the icon inside of that awesome block/circle I made."



Duke,
I ain't seeing what you made, sorry, just trying to improve my photo skills.

[Methos]

Originally Posted by CADplans

"Look at the pic I attached and click on the icon inside of that awesome block/circle I made."



Duke,
I ain't seeing what you made, sorry, just trying to improve my photo skills.

I guess it helps if I upload the image! I'll blame it on the that I don't drink!

[CADplans]

Just trying this out!!