4520 engine serial numbers

[charles titus]

looked at two 4520's both 1970 one engine serial is m25ro 240642r and other is 404tra 257342r now tell me whats the difference

 

[Rusch]

Are they both actually 4520 motors. A Lot of 4520 tractors ended up with 4620 motors. Believe my dad said it was a full injection problem ours has a 4020 pump with no shims in it. If I remember correctly he said it would collapse the steel filter.

 

[charles titus]

both engines have the injection pump at rear of the block by brake pedals the 4620 blocks had injection pumps located on front of block by the fan blade so did the 4320's

 

[D-]

I don't know about the numbers but it seems like a 4520 block did not have 3 rings sealing the sleeves. Probably they corrected that.
I'm thinking '69 4020 blocks also did not have 3 sealing rings either.
Too much thinking!

 

[Tx Jim]

(quoted from post at 17:05:13 08/19/13)
I'm thinking '69 4020 blocks also did not have 3 sealing rings either. Too much thinking!

According to JD parts 2 different 4020 blocks only had 2 o-rings per liner.
AR70645 O-RING KIT 6 (USE WITH R40610 OR R40620) (2 O-RINGS)
AR65507 O-RING KIT 6 (USE WITH R45950, R47170 OR R48440) (3 O-RINGS) (CONTAINED IN RE23165)

Same scenario with 4520
AR65507 O-RING KIT 6 303519 - (SUB FOR AR51956 AND AR53443) (THREE RING BL0CK) (USE WITH R47020 OR R47110)
AR70645 O-RING KIT 6 - 303518 (SUB FOR AR48687) (TWO RING BLOCK) (USE WITH R43310 OR R45980)

 

[Tx Jim]

(quoted from post at 22:58:05 08/15/13) both engines have the injection pump at rear of the block by brake pedals the 4620 blocks had injection pumps located on front of block by the fan blade so did the 4320's

Do blocks have any casting numbers?

 

[D-]

That probably accounts for the different tag numbers on those engines.

 

[charles titus]

I found out today from a good parts man at arends-awe john deere in riggston il. that the engine with m25ro tag is original to that tractor the letter m designates unit 'engine' the number 2 designates series which is 2 the number 5 designates type of air intake system which is turbocharged the letter r designates unit application which is john deere tractor works the letter o designates variation which there aren't any if it were intercooled it would have the letter a instead of the letter o now the other tractors engine tag read 404tra this engine was not original to the tractor off the assembly line must have been replaced a year or two or three later because 4520's didn't come out with intercoolers and this has one and not an add on either because serial tag designates it 404 is cubic inches t designates turbocharged r designates user factory which is john deere tractor works the letter a designates its variation which is intercooled. the latter or the two tags which is the 404tra engine serial number 257342 is newer than the m25ro engine which serial number is 240642 with that being said the tractor with the older engine is about 600 numbers newer than the tractor with newer engine just backwards of what a person would think that's what made me ask the question.