JD 4020 Gaulded piston

Dougin texas · Apr 14, 2014

I recently pulled the head off my JD 4020 expecting to find a bad head gasket, instead found 2 gaulded pistons, Pulled main and rod bearings all look good. Any idea what would have caused this?

tim s · Apr 14, 2014

A lot of times it"s because of a bad injector, shooting a bad spray pattern,,and some times it just "happens"...Darn it..be sure to replace your wrist pin bushings and have your rods re-sized..

Dougin texas · Apr 14, 2014

I am planning on replacing all injectors.
I have ordered an inframe OH kit, do you think I should do anything with oil pump? Always had good oil pressure.

tim s · Apr 14, 2014

You should be fine on the oil pump..

D- · Apr 14, 2014

If it's that "four cornered" scoring that supposedly is from mismatched pistons/sleeves. We had to overhaul several new '72 4020s and that's when Deere started matching pistons to sleeves.
Still I have seen those score a year later and those that weren't overhauled score several years later. The odd thing is I have never seen anyones aftermarket sets have that type scoring.
If you have scoring on the sides that is probably from overheating.
You should remove the bottom of the pump and let the gear come out to check housing and gear wear. Many times if they are OK you might have to replace the drive gear. Also look at the cam gear that drives the oil pump. It will probably have steps worn on the teeth and maybe even have sharp teeth.

ET · Apr 15, 2014

Not allowing the motor to warm up and hitting it with a heavy load can cause that type of scoring. Improper use of a dynometer on a new engine will do it.

JD 4020 Gaulded piston

Dougin texas

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tim s

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Dougin texas

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tim s

Well-known Member

D-

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ET

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