Buying Advice JD 4120, 4320, 4520, 4720, same engine, same compression, different HP. (boost?)

[charosenz]

I am looking to buy a 2014 or older JD. I have been looking at used 4000 series. What struck me as a bit odd is that it appears as though the 4120, 4320, 4520, and 4720 appear to be the same engine except the HP goes up from 43 to 60. Same bore and stroke. Same compression (+/- .5).

I can only imagine that they increase the boost on the Turbo on the higher number models in this series.

Does anyone actually know the boost pressures, and if so, a link to the data?

Thanks.

Charlie

 

[dusty3030]

I had a 4120. From what I remember there are different injectors as well on the higher hp engines in this series.

 

[LouNY]

More fuel more boost and possibly an intercooler.

 

[charosenz]

I have read the other models have larger injectors, but unless it goes with increased boost, larger injectors ( all else equal) would not increase HP. Just curious how much boost is added on those other models.......

 

[Industrial Toys]

Same with our 6200, 6300 and 6400. All the same Engine and displacement. Just different injector pumps. Kind of a ripoff if you ask me.

 

[jd110]

4120 has 7.5 psi boost, 4320 has 9 psi, 4520 has 13 and 4720 has 14.5.

 

[charosenz]

4120 has 7.5 psi boost, 4320 has 9 psi, 4520 has 13 and 4720 has 14.5.

Super,

Thanks a ton for the reply with details. I suspected as much but seeing the data is proof.

Charlie

 

[dodge man]

There may be some things to support the extra power, bigger radiator, oil cooler etc. Maybe not also.

 

[johncanfield]

I have a 2010 4720, good tractor and plenty of power. It is too small though for a 3 point MX8 shredder, it's happy with the MX6.

 

[Kyle_in_Tex]

You can get on Deere's parts system, log in, and look up stuff like injectors, pistons, etc to check for mechanical differences.

 

[RickB]

No log in required if you don’t want dealer pricing.

 

[oldtimer 66]

The 4X20 series tractors have the front axle, rear spindle, captured in the oil pan. You may want to take a good look at that connection if you are buying a used tractor. The oil pan weights 55 lbs and is a integral part of the front structure of the tractor. On the HP differences there is the boost factor but there are also different injectors, greater lbs. per hr from memory. Like Rick B said look the parts up on the JD web site

 

[Andrew1001]

I have it available, if you still need it text me or Whatsapp me +13473438125

 

[Kyle_in_Tex]

^^^^might be bogus^^^^

to what are you referring?

 

[lostcause]

this phenomenon is the same on the smaller tractors too. i posed the same question too, and i believe that if you look you will find different head / cam / valve part numbers as you go up the line. i was looking at an emissionless 25hp one, wondering what separated it from the 30-40hp ones with the same base engine.

 

[Kyle_in_Tex]

I have a 2010 4720, good tractor and plenty of power. It is too small though for a 3 point MX8 shredder, it's happy with the MX6.

Sage advice there. Hope your tractor is running well.

 

[johncanfield]

Sage advice there. Hope your tractor is running well.

Yessir, it's my faithful ranch hand that's only called in sick one time

 

[jenkinsph]

I have a 4520 cab with the intercooler 2009 60 hp. Keep in mind the hp was raised in 2009 about 7 hp for each model. It has been a good tractor for me.