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Discussion Starter #1
I just picked up an 814 rider with a 38 in snow blower and a 50 in deck. The p/o broke the connecting rod took the motor apart and replaced it the new connecting rod lasted for about 15 min. and then it broke.

Any ideas what would cause this or how to fix it so it will not happen again?
 

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One possibility is the crank journal is worn. The way to find out is to get a micrometer and measure the crankshaft. Too loose is as bad as too tight. Both conditions will cause the connecting rod to seize to the connecting rod journal and break.

The other possibility is that the connecting rod was installed backwards. The connecting rod bearing cap has a oil hole on on side. That is what I call the leading side. Installed correctly the rod dips into the oil in a circular motion and as it enters the pool of oil in the crankcase, it forces oil into the hole and into the bearing journal. If the con rod is installed wrong, oil is never forced into the rod bearing so it runs dry and seizes.
 

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I'd check simple things too like: He did have a dipper on the new rod.

15 minutes sounds like a pretty obvious something is wrong.
 

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I'm with them, crank journal. If it threw a rod in the first place, it's pretty much a given that the journal was chewed up. If he didn't get it reground or replaced, a new rod will fail right away.

Inspect it, mike it (in several axes) and then work out whether you can/should grind it undersize.
 

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And it could have been something as stupid as not lubing the bearings before installing in the engine. That means both the piston pin and also the crankpin bearings.
 

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What was the quality of the rod? Lots of garbage for sale at "discount prices" on the net. Encounterd similar problems years ago on rebuild. From then on only top shelf or i won't waste my time.
 

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Discussion Starter #12
So see if the crank can be fixed and watch how the connecting rod goes in. Any rebuild manuals on 14 hp Kohler and parts list out there?
 

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You may also want to talk to Robin Snyder. He specializes in K series for Gravely. He's super friendly and has access to parts. Spent a good bit of time talking to him at the Mow-In this year. I'll have to dig up his card but I know his info is on the Yahoo! site as he posts over there from time to time.
 

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And it could have been something as stupid as not lubing the bearings before installing in the engine. That means both the piston pin and also the crankpin bearings.
Would the engine run for 15 minutes if he failed to prelube the Con rod? I would think it would last for about 15 seconds or less.
 

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Would the engine run for 15 minutes if he failed to prelube the Con rod? I would think it would last for about 15 seconds or less.
Depends on where the rod was when the engine was filled with oil and a batch of other factors.
 

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Discussion Starter #18
Thanks for the info I tryed to get a hold of Robin earler this week (Friday) but no answer so I will try again later. I will down load the manuals and see how my machanical skills are, I have had work done by shops before and still had to try to fix the machine my self.

I will send pictures of the tractor later to day.
 

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The only difference is you are doing the job to the best of your ability and the crummy shop does the job the the least of their ability.
 

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The only difference is you are doing the job to the best of your ability and the crummy shop does the job the the least of their ability.
That was a major selling point for my skills when employed. Detroit Diesel said 7500 hours and the engines would be in need of an overhaul. We ran them to 14,000 before needing an overhaul on one and 12K+ on a second. Only 10K on the 3rd. When I left their employment, 14K engine had 28K additional hours, 42K on block, crank, and geartrain total. Second one had an additional 24K. Third one failed at 10K with something causing a coolant leak. The shop mechanics never could find the problem and their rebuild failed in less than two weeks. Difference in my rebuilds and theirs is they got paid to fix it, I got paid to make sure it was done correctly and hold up to our operational needs. That always meant setting all measurements to the least tolerances acceptable. Our couplings were rated at .060" TIR and I was unhappy if they weren't under .005". I have reason to believe Robin is also that type person.
 
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