Kohler K241 - Damage and Rebuild opinions wanted

[OutdoorEnvy 1,522]

Hey folks.  recently acquired a C-100 with the K241 and the connecting rod is broke as well as the piston.  The cylinder walls made it out with no scratches!  Also the broke pieces seem to have went straight to the pan as all gear teeth look good.  camshaft lobes are fine as well as valves.  Aside from measuring the cylinder am I in the clear to replace the piston, rings, and connecting rod?(all necessary gaskets too of course) Crankshaft looks good, would just hone it some before attaching the rod.

 

Only other option I would have is to repower with something else...Trying to keep this somewhat cost effective so a machine shop and full rebuild kit is not something I'm wanting to do at this time. 

 

thoughts and opinions welcome...

 

thanks

 

 

[squonk 41,018]

How about some pics of the crank journal and cylinder wall?

[pacer 3,168]

GEEZ!!! that looks like a grenade went off!! In fact, mentioning "grenade" and that much damage are you aware of 'grenade gears?' Dont see anything in the pan that looks like them, but with that much damage and no apparent serious damage to the cyl/crank ..... If you rebuild take them out while youre in there!

 

Yes, get every thing ckd out and if indeed there isnt damage and you can go back with a 'rebuild kit' then that will be relativley easy and not much expense. "Rebuild Kits", there is some disagreement on using the import kits among the guys here. Some want as close as possible to original parts, and others have no problem with the import kits (I personally have used some 5-6 of them and have no complaints) A kit off the bay should be in $150ish, maybe less (been awhile since I've bought one) They can come in different pkg/parts there is one that has EVERYTHING, then others maybe not have valves, etc. Youll just have do some cking....

 

[WHX?? 48,760]

I would rebuild it. 

Also is there any markings on the piston top to indicate if the engine has been bored over? 

bak4kids Engine Rebuild kit fits Kohler 10 hp K241 w/free tune up standard piston and rod | eBay

on flea bay has complete kits for 100 clams & your choice of piston size & rod. I have used his stuff many time over and never a problem.

My machine guy would be about a franklin (cash is king) so I would have less than 300 fer sure in a rebuild.  Personally I would go with a 10 over rod and be done with it. 

Motor would be good for another 50 years if taken care of. 

 

 

Edited August 16, 2021 by WHX??

[OutdoorEnvy 1,522]

51 minutes ago, WHX?? said:

I would rebuild it. 

Also is there any markings on the piston top to indicate if the engine has been bored over? 

bak4kids Engine Rebuild kit fits Kohler 10 hp K241 w/free tune up standard piston and rod | eBay

on flea bay has complete kits for 100 clams & your choice of piston size & rod. I have used his stuff many time over and never a problem.

My machine guy would be about a franklin (cash is king) so I would have less than 300 fer sure in a rebuild.  Personally I would go with a 10 over rod and be done with it. 

Motor would be good for another 50 years if taken care of. 

 

 

 

Are you saying if the cylinder walls looked fine you'd just use the 10 over piston and rings and no machine shop?  That is what I would like to do.  Keeping this in the $150 or so range would be nice. 

1 hour ago, squonk said:

How about some pics of the crank journal and cylinder wall?

 

I'll get more pics either tonight or tomorrow.  Already had to shower and put nice clothes on for the day.  I'll get some top piston pics and cylinder walls.  Any other pics that would help you all in identifying issues I can get?

 

thanks for the help all!  Love this place!

[WHX?? 48,760]

2 minutes ago, OutdoorEnvy said:

Are you saying if the cylinder walls looked fine you'd just use the 10 over piston and rings and no machine shop

Not without measuring the bore & ring end gaps and comparing to specs. If it is already a 10 over bore,  identifiable by markings on piston top or measure, and out of round/taper are well within specs sure why not just a quick ball hone and appropriate sized piston and rings. I know some of the fellas are gonna come down on me for saying that but yes trying to keep the cost down. I have gotten away with it. But most of the fellas are gonna say you got her open why not just do it right and there is plenty of merit to that. 

 

If it's a std. (factory bore) it immediately  would go to a shop for more accurate measuring and advice on what oversize to run. 

 

On the big rod end of the crank it also needs to be measured for out of roundness to determine what's the best way to go. More than likely the damage was done by low or no oil and that means a 10 over rod and crank grinding no question about it. 

2 hours ago, OutdoorEnvy said:

Crankshaft looks good, would just hone

Not gonna work as there is no such thing ... big ends are polished which does not do anything for out of roundness, scratches or gouges.  Has to go to a shop for grinding. Manual specs are less forgiving here and it's rare to have a disaster like this and not get away with goin a 10 or even a 20 under rod. 

I know not what you want to hear but that crank to rod clearance is the most critical and things need to be plasti gaged. 

[squonk 41,018]

Simple. If you don't have a cylinder bore gauge and micrometers. Take the block and crank to a machine shop and have them check them. A few dollars of insurance. And Dial /Digital calipers are not accurate enough to do this.

Edited August 16, 2021 by squonk

[8ntruck 6,991]

Might consider Magnaflux or dye checking the crank and timing gears for cracks, too.

[WHX?? 48,760]

5 minutes ago, squonk said:

Dial /Digital calipers are not accurate enough to do this.

True ...every time I try to measure with telescope gauges  I get different answers. Usually get close enough to figure out what oversize to go with tho.  Some shops may even do it for low/no cost they do the work. That may be the biggest problem is finding a shop in your area that will take the time to mess with it. I finally lucked out and found a shop they does high end race motors but the guy enjoys doing my small bores for a hobby and less stress!   Over 2 hr round trip to see him but well worth it. 

 

Pics of that crank Outdoor.... 

[OutdoorEnvy 1,522]

When I get pics of the crank what all would you like to see?  Right now it's still mounted with the engine as I just left the pan on the frame and pulled it that way to see inside.  The crank journal does have remnants left on it from the rod.  i'm guessing it's aluminum by looking at it.  But what angles and pics of what should I take? 

 

Seems my hopes of a quick measure of the cylinder and getting a rod and piston/ring set to match it are quickly fading...

[squonk 41,018]

You need to get that aluminum off the crank and have it checked. If you don't, you're just pissin into a fan.

[pacer 3,168]

If you got residue on the journal then it would be very unlikely that isnt damaged, possibly badly. After all, something made it self destruct and the rod running loosely from a worn journal would certainly cause it to finally hammer itself to detonate  -- and all that time it would be swiftly putting more wear on the journal. You just might get by with the cylinder, but as the guys have said, it all needs to be confirmed with proper measurements

[OutdoorEnvy 1,522]

Alright more pics...it ain't good either.  So it's had a rebuild already.  which confirms why there was little carbon buildup on the head.  Piston is .020 over already.  It also has a small chip in the wall you can see on the last pic pretty well.  So is it safe to say this block is done?

 

 

 

 

 

 

 

Edited August 16, 2021 by OutdoorEnvy

[squonk 41,018]

Crank can possibly be ground to .020" under and use a .020" undersize rod. Cylinder can be sleeved. @richmondred01 @oldredrider

 

This is why you take it all apart and inspect things before you order parts and assume anything.

Edited August 16, 2021 by squonk

[WHX?? 48,760]

Crap I was hoping the piston was std. Or even just 10 over. I doubt goin to 30 is gonna take that gouge out. The crank definitely has to get ground and the only hope for saving it is to find out if it's been ground before and and can get it to 20 under. Might as well pull the crank it's not gonna go anywhere in that condition.

By chance can you piece the rod together enough to get some numbers off it? That might help. Or try getting the rod remants off for a rough measure. 

I know nothing about sleeving Squonky but guessing cost might get too prohibitiv for Outdoor? Being 241 heavy I wouldn't consider it. Be interesting what master builder Richmond or Old Red  has to say about it. 

PO definitely ran the poor thing short on oil. My stepson ran a 301 short on oil once and ended up with the same mess you have less the cylinder marks. 10 over & 10 under & $300 she now purrs like a kitten. I'm just not seeing that in your future.... 

BTW Outdoor on a good note excellent pics. 

Edited August 17, 2021 by WHX??

[squonk 41,018]

Richmond's states in another thread that a sleeve job from his machine shop runs around $150

[Howie 886]

I don't know if it is an illusion or not but that almost looks like it is below 

the ring travel. If and a big IF it is below the ring travel I am not sure that

I would hone cylinder is size is ok and run it.

[OutdoorEnvy 1,522]

19 minutes ago, Howie said:

I don't know if it is an illusion or not but that almost looks like it is below 

the ring travel. If and a big IF it is below the ring travel I am not sure that

I would hone cylinder is size is ok and run it.

 

It's funny you mentioned that.  When I first pulled the head the piston was top dead center.  I pushed it down to about where I thought it's travel was near the end and it felt smooth the whole way.  No play or anything unusual at all.  I didn't want to accidentally push it out the bottom.  That's also why my initial claim of the cylinder walls looked fine. I had the head off my k301 a couple months back and cycled it a few times and used that depth as a rough estimate when I stopped on this one.  I could certainly measure the chips depth if anyone would have the correct depth reference for this engine.    

[Howie 886]

You can look at the cylinder and usually tell where the ring stops in the cylinder

especially when the crosshatch is worn more.

[kpinnc 11,896]

Does you block have K241 or K301 on the PTO side? Many 10hp engines used castings for 12hp.

 

If yours has K301 on it, the cylinder walls are thicker. If so, you have more options.

 

A used crank for a 12hp that is in spec is likely as cheap as having one reground. 10 and 12 hp cranks are NOT the same.

 

If you have to buy a rod and piston, might as well go bigger to 12 STD.

Edited August 17, 2021 by kpinnc

[OutdoorEnvy 1,522]

4 minutes ago, Howie said:

You can look at the cylinder and usually tell where the ring stops in the cylinder

especially when the crosshatch is worn more.

 

I just went and checked and it is below the ring line!  It's close but it has cross hatching around it and I can see the line where the cross hatching ends.  It shows up best in this pic.  That line above the nick is where the piston ring line ends and the cross hatching begins.

 

 

[OutdoorEnvy 1,522]

@squonkThe number on the connecting rod is 47 059 06

 

 A quick search and it shows to be a .010 rod

Edited August 17, 2021 by OutdoorEnvy

[953 nut 55,051]

How much oil was in the engine? How many hours was the engine run following the rebuild? With everything else being well oiled and that much aluminum build-up on the crank it looks like it wasn't getting enough oil to the crank.                  Wonder if the oil hole on the crank was placed away from  the cam?

           With the block already being +20 needing to be sleeved and the crank being questionable I would start looking for a replacement engine, You will end up being north of $ 450 to fix this one. 

[squonk 41,018]

9 hours ago, OutdoorEnvy said:

 

I just went and checked and it is below the ring line!  It's close but it has cross hatching around it and I can see the line where the cross hatching ends.  It shows up best in this pic.  That line above the nick is where the piston ring line ends and the cross hatching begins.

 

 

Even IF you could run it with that gouge, you still need to check that cylinder for out of round and taper. Who knows how many hours are on it since it was rebuilt once

[WHX?? 48,760]

Good eye Howie your suggestion is valid. 

20 minutes ago, 953 nut said:

north of $ 450 to fix this one. 

I initially thought that too Richard but now not sure.  Good catch on the rod cap being on wrong too...how  many times have we seen that? 

 Maybe  20 under grind on the crank or a donor crank a new 20 piston & rings if the bore runout measures ok? Just thinkin out loud here 

Measure the bore and see what shakes. If you can Outdoor check ring end gaps at various points in the bore. use the piston to square it up with the bore.  That will give one an idea. 

Guessing you have a manual with all the specs? 

 

Also pull the cam and check it for issues. Usually but not always when a rod goes it hits the cam and snaps it, or worse goes the other way and puts an extra breather hole in the block! 

The Raider 12

Edited August 17, 2021 by WHX??