re-engine jd4300

[kak]

How difficult would it be to re-engine a JD 4300 cut with a Yanmar 4tnv78? The stock engine is a 3tne84, not rebuildable. (Used 3tne84's are rare.)

[wthompson]

Not sure about what all would match/bolt up from one to the other but i did look on jdparts.com for the engine block and found one for the 4300 here: AM878597 - Tractor-Part. The JD part # is AM878597 for the cylinder block, reuse your crank, pistons etc. With new gaskets and rings etc.?
Also found this one for $850.00 CYLINDER BLOCK FITS: 790 JOHN deere CAST # 3TNE84.

[kak]

Thank you!

[dfkrug]

The stock engine is a 3tne84, not rebuildable.

You said your dealer told you the engine is not rebuildable. Based on what evidence?
You can buy .25mm oversize pistons and bore the block if it is worn out. Did
they take is apart and measure the bores?

If you do try to substitute another Yanmar engine, you need to be sure that it
will drive your hyd pump and bolt up to your bell housing.

[kak]

Thanks for your reply. The jd dealer said the wear was too much on the cylinders to allow for re-sleeving. I think the larger engine will drive the hydraulic pump, but I need to check on the bell housing issue.

[dfkrug]

The jd dealer said the wear was too much on the cylinders to allow
for re-sleeving. I think the larger engine will drive the hydraulic pump, but I need to
check on the bell housing issue.

These engines do not come with sleeves. JD offers only one oversize piston and it is
possible the block is worn too much. Technically, you could add sleeves if the block is
worn too much, but that adds a lot in cost, and you will need to deal with a specialty
maker of sleeves.

Yanmar engines are made for many applications, not just tractors. The JD4300 Yanmars
drive their implement hyd pumps off gears in the front of the engine and have a
front cover to acommodate this drive. That is an important consideration.

[dcheek]

if you won't to sell your old engine let me know