620 all fuel pistons

I have a 620 all fuel tractor I just bought that runs great, but has blow by and I need to probably buy over sized pistons. I cannot find any for sale new or any website for all fuel lower compression pistons. Does anyone know of where to look?
Thanks,
Shawn
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No idea where to look, but will recommend changing the oil & filter and try Rotella 15-40 oil (or equivalent -not sure if there is one). Get it up to full operating temp. a few times then re-evaluate. HTH
 
How do you know what you need before you tear it down? Don't get ahead of yourself.
 
Is the crankcase ventilation pump working? Is this a show tractor, a putting around odd jobs tractor? Or is this tractor the machine that makes your living?
What is the compression pressure? Is burning kerosene important to you? Is it burning oil? Do you have the operator"s and service manuals?
 
My plan is to do a full restoration . They only made 475 of these and I think it is worthy of a complete redo. The engine has been apart from the rtv signs, but I am not sure of the engine history. I am the fourth owner. The third had it for 10 years and did nothing but a little tlc and the second owner had it. 25 years and could not remember what he had done. My guess is it sat for years cause the guy I bought from told me the tires were all flat and he put new tubes in them. It does not smoke at all. What is the crankcase ventilation pump???
Jdtractorman
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It may just be evaporating moisture from the crankcase..
Work it a couple hours, to get it up to temp and dried out..
You can expect some venting from the clutch area as normal..
New rings on your original pistons will most likely be all you may need to do, if you do open it up..+ a valve job..

Ron..
 
Nice tractor!!!! i am looking at one identical to yours condition wise it runs great. what is the value of these tractors????
 
Im with D, dont go buy paint and a new steering wheel before you need it.I have several 620 multi-fuel tractors and they are cool but dont go tearing stuff apart and thinking they'll have it at the Dollar General
 
We're i see blow by is out the vent tube off the valve cover. I think i will do a compression test next to validate the compression on each cylinder next.
Jdtractorman123
 
There's a good chance it has allready had gas pistons installed.
Also a good chance it has broken top piston rings. Those models it is a common problem due to alum. Pistons and high hours they get.

If all of the allfuel parts are keep intact what's wrong with gas pistons and just running gas? One could likely just mill some off the top of the gas piston to lower the compression? You would have to compare to all fuel ones to check on if this is possible.
 
Check with Arias pistons, they made mine for the MH44. They can make a brand new forged piston from a model.
 
Top ring grooves wear plus thin rings plus flexing in worn bores equals broken rings. Seen them run so long the pieces wore their way up to the top of the piston and started beating against it.

Never seen broken rings in the like model A with cast pistons and thick rings.
 

Here is an all fuel 60 power steering, live pto, 801 hitch tractor I picked up for a project as well.
The second is an earlier all fuel, no ps, but with 801 hitch. And third photo was a duplicate
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