J D Tractor 720

Hi! Can anyone tell me what the piston skirt clearence is on a 720 diesel John Deere tractor?This is a new bore & hone job @.090 oversize. Thanks Mike

Hi Mike; The skirt clearance can vary from one manufacture to another because of differences in metals such as cast iron or aluminum. The differences in alloys used by one brand or another. You should determine the brand and use their specs. very often the box the piston came in has it on the box or on a sheet inside the box. If you do not have this information and can give me the manufacture and part number I will try to get you that information. Ed Kinch

All i got was a cast alum piston. I was hoping maybe someone had a JD shop manuel that had the piston spec in it. I am guessing somewhere around .006-.008 but i don't know if that will be enough. thanks mike

Hi Mike; I will check today to see if I can find that spec. at my machine shop.I will get back to you. Ed Kinch

Hi Again Mike; I found in an old motors manual that the spec. for a 720 diesel, with 6.125 or 61/8 bore to be .010 skirt clearance. I thought that to be a lot so I called a John Deere mechanic friend of mine and without my telling him what I had found he gave me that same spec. and he said not go with less.On a gas engine it is .008. Probably because of the difference in the piston construction. At .030 the spec. would remain the same. Hope this helps. Ed Kinch

thanks Ed , now I can finish this job up thanks alot .MIke