john deere 850 overhaul?

[alexv48]

Hey guys, first post on the site and it's a good one! I bought a john deere 850 a month ago to be used as a mower and small food plot tractor. It has 2,8xx hours on it, 3 cylinder Yanmar diesel motor. Seems to be well maintained prior to me. I was doing some discing with it last week and had 2 warning lights come on, "CHG" and "oil" which to my stupid self stood for change oil, I ignored it because the guy i got it from had it changed right before I bought it. Anyway I ran it out of oil. I know how to screw things up! So steam came out of the blow by tube and then came a knocking sound. I shut it off and found it to be empty on oil (go figure!) filled it up and still had the issues. So it started and ran with the new oil but now it does have issues starting, it will start but takes a few more cranks. So what now? I am intermediate when it comes to mechanical skills, but not sure if something like this is over my head. What would an overhaul kit run for this? the only one i found wAS 2,600?? Is there a chance I could just need new rings etc? I know its all my fault and am paying the price.

 

[DLTTrekkers]

Knocking sound.......check bearings and connectingrods........check crank......BIG problems!

 

[Tx Jim]

New rings is more than likely not the problem although if oil consumption is a problem rings are needed.. I'll bet your engine will need new rod/main brgs and maybe the crankshaft turned. You'll be lucky if main brgs didn't spin in the their housings. You might check with Yanmar dealer for parts as 850 has a Yanmar 3T80-J engine

 

[pmsmechanic]

It light be cheaper to make your own kit. Look up the part numbers of what you need online and google them.

 

[sequoyah101]

You've wiped out the bearings.

Look for Yanmar parts or aftermarket. You can't afford to go JD so just drill right on by that. There is an outfit on Ebay or sss that has overhaul kits. Like someone said, those are Yanmar engines. There should be a model number on the block somewhere.

Overhaul isn't hard. Just get a book. You'll need to find a good machine shop to clean up the crank. Probably get by without a head job. If it was running good before running out of oil it should be OK. You may have crapped out the cylinders though. Only inspection will tell.

Boone, Iowa. I have cousins that used to live up by Stratford.

 

[alexv48]

So I still have not dove into this project because its a bit intimidating and I have been busy at work. I do want to add that I did check the oil after the light was on and it was fine at that time. But apparently it went downhill fast! But I have an experienced friend that is ready to help. I see there are lower, mid and higher end (priced) rebuild kits, obviously i wont know until I dive into it on how much I need to replace, but would this kit in this link cover most of what I need? Also, how do I know what size of bearings I have?? Engine Rebuild Overhaul Kit | John Deere | 8650 | 8760 | 762 | 792 | 850 | 855 | 862 | B | 890 | A | 992 | D | 992 | E | 619T | 6101T | Diesel

 

[PHPaul]

That's not even close to the right kit. The 850 uses a Yanmar 3 cylinder diesel. The kit at the link is for a 6 cylinder John Deere diesel.

 

[buickanddeere]

I have to wonder why a yanmar with those few hours was consuming oil ? has it been dusted with air cleaner problems? Or did some goof bust the rings with ether ?

 

[alexv48]

So I dropped the oil pan and took a look around. looked like a small spoonful of metal in the bottom of the pan. The front main bearing was the one doing the knocking. Other main bearings had very little slop to them. Obviously the scoring on the connecting rod is an issue right? Other Connecting rods looked fine (to the human eye) It's impossible to know the condition of the crank without removing it completely right?? I know these photos don't help much but I did what I could. Any advice is very welcomed. how do I make my photos larger!?!?

 

[PHPaul]

You'll need to remove the crank to have it turned anyway, they'll check all the journals for scoring and out-of-round tolerances.

You'll need all new bearing inserts for rods and mains. Connecting rods are likely fine, but it wouldn't hurt to have them checked as well.

T'was me, I'd just pull the engine and tear it all the way down, have everything checked.