Hi, I have a 1986 Ford 1710 with the Shubaura H843 engine. The crankshaft has broken near the 3rd (rear most) connecting rod. I have already bought the new crank, bearings, etc. Does anyone know if I can replace the crank without completely disassembling the motor? The crank is removed through the back of the block, so I am wondering if I can just remove the front cover, mark/align all of the cam and timing gears as necessary, unbolt the connecting rods and slide the pistons all the way up, then finagle the crank out of the block. I don't want to rebuild the entire motor since the tractor only has about 500 hours on it and I know the head and rest of the motor is good. Any help would be greatly appreciated. Thanks!!!
David-Davies
Silver Member
Hello scottlep1. Before you push the pistons up, remove the rocker arm, so all the valves are seated, so you don't bend them. Allso use a crane or cherry picker to hold up the crank. Go really slow so you don't play bumper cars with the crank. If you can rap the crank junerals with some thing so you can't hit the junerals. News paper, card board, wraped with duct tape to keep in place. If you as muck as bump a juneral, take it to a machine shop. The slightest ding will take out your bearring. The macheine shop can polish the crank, so you can still use the bearings.
Dave
Dave
RickB
Super Star Member
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Gravity is your friend. If your plan has any chance of success, it will be with the engine removed from the tractor and inverted. Remove the rockers as suggested above.
Thanks for the input. I decided not to be lazy and cheap and do it the right way. I pulled the head off last night. I will pull the pistons and rods all the way out today. That will allow me to remove the broken crank and install the new one the right way and with no chance of screwing anything else up.
wvpolekat
Platinum Member
Just spend the money on the gaskets and do it right. Just because you pull the head off, that doesn't mean you have to do anything to it.
Yep. I was being cheap. The head gasket is $110 and I was trying to cheap out. I already pulled the head and the head and cylinders are fine. I am just going to replace all of the bearing, seals, crank and be done with it. With one a few hundred hours on the engine I don't think it should need rings.
Zebrafive
Super Member
How did the crank break? Is this common?
Not sure how the crank broke. I bought the tractor knowing it needed the crank replaced. I bought it dirt cheap with only 511 hours on it. It is in mint condition so it was worth it to me to buy it with the broken crank and do the repair. Once I get it repaired I will probably have half of what a decent used 1710 is worth into it.
Hooked_on_HP
Veteran Member
Did it spin any bearings when the crank broke. If it did the block will have to be align bored.
Are you sure no valves are bent. When the crank breaks every thing gets out of time and pistons can hit the valves.
Bill
Are you sure no valves are bent. When the crank breaks every thing gets out of time and pistons can hit the valves.
Bill
If you read my replies above, I have disassembled the motor and the rest of the motor is good. No spun bearings, no bent valves. Also, The block would not have to be line bored if it did spin a bearing. This Shubaura H843 engine uses a bearing carrier/support for the main crank bearings, so if the bearing did spin you would just replace the bearing support. Look at the technical drawings on messicks.com and you will see what I am talking about.