I started a rebuild on my little 850. Back story is it got hot the other day and seemed to have blew the head gasket , so I dove into the motor and found what looked like a bad head gasket, small groove in middle cylinder wall and the connecting rod bearing in pieces all on the middle cylinder. The rest looked fine, my question is what would you guys do just rebuild the one cylinder and head gasket or do the whole thing. I’m trying to do this budget friendly and also it looks like the cylinders have been sleeved but not really sure how you tell this is my first engine rebuild so kinda learning as I go
bmaverick
Elite Member
- Joined
- Sep 17, 2013
- Messages
- 4,634
- Location
- Beloit-WI
- Tractor
- Yanmar YM2610 ■YANMAR GURU■ EXTRAORDINAIRE
Why not ask in the Yanmar forum since your machine is really a YM2500 in JD green paint.
I once had a JD850. The engine blew too, due to a bad diesel mechanic who messed it up. Anyway, I too went looking to rebuild, but after finding a few cracks in the head, then the block, I really needed a repower 3T80J engine. So, went looking for one and found my Yanmar with the same engine, completely restored better than new for the same cost as a replacement engine.
Now, you are sooooo, lucky the 3T80J engine has cylinder sleeves. The 755 & 855 do not. So, the grooved sleeve can be replaced.
Do you need the TM1192 technical service and overhaul manual then? It's on the YTOG for free.
A refurbished head was $1,500 back in 2014. It's now about $2,500 refurbished with all new parts. You could save $1,000 on a used head and do the rebuild yourself, long as you know what to do and have the right access to a machine shop.