john deere 855 compact

   / john deere 855 compact #1  

mitch_lojek

Member
Joined
May 6, 2004
Messages
38
Location
michigan thumb
Tractor
mf 1010
can someone out there help me with some information. I wanted to install new rings on the tractor, and when I looked inside I noticed that I needed to rebore the cylinders. my question is do I have to remove the engine and put it on a drill press or can I get a magnetized base drill and do it with the engine installed. how hard is it to install one of those engine rebuild kits.
any information would be appreciated.
 
   / john deere 855 compact #2  
It can be done in place with a Van Norman cylinder boring machine. It centers on the existing hole and uses the head bolts to stay in place. It has it's own down feed. Also has a vacuum attachment. Nice unit, easily adjusted for diameter. You don't even have to take the crank out if you know the mains are ok, just turn the counterweights at each bore as you move along and cover it with a rag. Leave yourself .001 to hone and fit the new pistons.
I don't suppose you have a boring machine lying around though?
You do mean bore and not just hone, right?
You can hone right in place too, to break the glaze, just don't run the hone out of the bore at either end. Follow the instructions for hatch pattern. Hand grind a chamfer on the top surface of the top compression ring to miss the ridge (ridge dodger or dyke ring) or you risk breaking them.
I can't see boring on a drill press.
Best of luck,
Martin
 
   / john deere 855 compact
  • Thread Starter
#3  
martin,
thanks for the information but we are only taking off thousands of an inch to install larger pistons. would that require the same operation?
 
   / john deere 855 compact #4  
Well,
people do open up the bores with a hone. Its lots of work and you need to be a master to correct any hole distortion. The normal wear on the bores is to be tapered larger at the deck. The hone will just follow the taper and it is difficult to correct this and end up with a true cylinder.
I hope the pistons aren't yours yet. How do you know what size the bores will clean up at? They do come in standard o/s increments.
You may be better off just to break the glaze and put new rings in and live with a slightly looser piston. Don't forget the chamfer trick I told you about earlier. The new rings wont be worn where they will ride in the lands and will run the risk of smacking the ridge and breaking.
Good luck.
Martin
 
   / john deere 855 compact
  • Thread Starter
#5  
nothing's been bought yet. I'm trying to figure out all possible ways to proceed before purchasing anything. one cylinder is out of spec. really bad and personally I don't think it could be saved. if all else fails might just pull the engine out and take it to JD to see what they have to say.

thanks
 
 
Top