Value of a knocking C-121 8 Speed

[Fordiesel69 271]

Overall faded and slightly rusted.  Tranny shifts good, engine is a 12hp and has somthing wrong internal making it knock.  It is not the famous rod knock but either a bad piston skirt or wrist pin.  It knocks on decel, not when accelerating. 

 

Anyways I bought it for the 48" deck, and want to just sell it as is.  What is a good price to ask. 

[WH nut 553]

With no deck and a bad motor, maybe 100 bucks

[Fordiesel69 271]

That sucks.........

 

Should I rebuild it?  I hate taking the rubber mounted engines out. 

[rmaynard 16,341]

Cheaper to rebuild than replace. It may be a pain to remove the engine but in the long run, you will be better off.

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[Wheelhorse84 87]

Could it be the balance gears?

[Fordiesel69 271]

I will post a video.  I honestly don;t know, but it sounds like top end, such as wrist pin.

[Fordiesel69 271]

Here is the video.  It is low res as the image quality is not needed to hear the problem.

 

http://youtu.be/aqUJ4h0ogZE

 

Would I be better off investing money into proper repair parts, and be able to get that back on resale?  My time would have to be free, but I don;t want to spend $100 more just to get $150 out of it.

 

As a side note, I will move the engine topic to the engine forums.  I just provided the video so you can adise on if it would be worthy to fix and sell, or just sell as is.

[Fordiesel69 271]

Anyone?????

 

I kinda want to get started on it, if there will be a better success of getting more.  If not I will just throw it on CL and dump it as is.

[WH nut 553]

Sounds like a rod to me

[Wheel-N-It 2,976]

Rebuild it if you want to keep it.

Sell it if you don't want to keep it. Whoever buys it may want to restore the whole tractor, and it will be better for them if they know exactly whats going on with the engine.

Edited April 28, 2013 by Wheel-N-It

[richmondred01 2,307]

I rebuild these kolhers. It's your rod. Don't start it again. It's ready to go on you which will cost you more when the rod goes.

Here's what you are looking at.

Most likey with that knock you will need it bored,crank ground and while its tore down you might as well do the valves.

Machine work:170.00

Parts: 125.

Labor: what ever the going rate is in PA.

[Fordiesel69 271]

If it is the rod, I am hoping it is not on the crank end of it.

 

I am going to at least inspect it I think.  It does not "FEEL" like the rod, like on the other kohlers I have worked on you could feel slop while turning the crank back and forth.  The others knocked when accelerating and not when decelerating.  I also put the crank into a compression stroke and cannot feel slop.  At certain points in the rotation I can feel a slight thud and hear a slap noise.  To me it sounds like somthing going on with the cam or balance gears.  But looking at it will tell the tale. 

[WH nut 553]

Either way the motor is toast until its fixed. Time for some exploritory

[Fordiesel69 271]

Well, WH nut was correct all along!!!!!!  This is the first engine I have worked on that has a 1/4 inch of play in the rod to crankpin clearance.  It was so bad that the engine was no longer in time, and the rod began to rub on the cylinder wall.  If it was ran another 30 sec the rod would have cracked, as it was already starting to.  The thud I felt and heard in the flywheel was the rod rubbing the cylinder.

 

Now how this happened I have no clue.  The cylinder wall and piston are great.  No scoring, or loose wrist pin.  My thoughts are an aftermarket rod was put in, and ran with the crank already out of round.  Cam looks good, balance gears are a little loose, and the side bearings look and feel good.

 

All the engines I have worked on that had bad rods were nothing compared this.  They would hammer when you load them up, and when throttling down would be quite.  This was so loose it did the opposite.

 

Now I just need to find someone on here with a used crank.  This one is too far gone.

[Fordiesel69 271]

Per above, I will get you guys pics of the damage.  It just may take a bit before I get back to it.