Roosa master pump

[JDJim]

Ok educate me. I have a JDB633-2408 pump. I see new rebuilt pump advertised as JDB633-2719 and 2721....what is the difference? The application is late 4020 and 4000...201000 serial and above. Thanks.

 

[tim s]

The bore where the pump fits into the engine block is larger for one thing..

 

[JDJim]

Well that?s interesting. I have a late 4000 and it has the exact same block as a 4020. It seems to be a later Roosa model number. Not sure how it could be a larger bore where it mounts?

 

[tim s]

It is,,and the block is a different number, but still a 404,,there are several different 404 blocks..

 

[JDJim]

Ok. Thanks Tim. I was looking at having another pump done and started looking for a used pump. Lots of 633 pumps but very few w the 2408 designation. I will have to do some more research.

 

[Dieseltech]

Very late JDB 4020 pumps used rounded heal governor weights and cage, also had eight degrees pump advance range. Early pumps used square heal weights and cage with five degrees pump advance.

 

[D-]

4010/early 4020 have smaller hole than console tractors.

 

[JDJim]

Ok I see. So...the 2408 is earlier pump and the 2719 and 2721 are the later pump? Is the 8 degree advance of use? We are playing with a 4000 in classic stock pulls. Trying to learn. Thanks.

 

[thepumpguysc]

There are a couple of guys on this site {3} that specialize in inj. pump rebuilding..
Me being one.
Feel free to email me for a very reasonable estimate.

 

[Dieseltech]

Re-check the 2408 pump, it should be a four cylinder JDB431AL2408 that fits the JD 202 engine, not a 4020. 2719 is a 4020 PS pump, 2720 fits the early 7700 combine, 2721 is a 4020 synchro tractor with the rounded weights and eight degree advance same as the 2719 and 2720 pumps. Fuel setting are the differences. If you have more questions feel free to E-mail [email protected]

 

[JDJim]

Diesel tech, this is on a 4000, late 71 model. Both mine and my neighbor have exact same pump with 2408 designation. Is it possible this pump was unique to the 4000model?

 

[tim s]

I have made a bushing to use the older pump in a newer block,,but to go the other way you would need to ether bore the block or turn the pump housing down,,ether way is not good...

 

[Scott 730]

(quoted from post at 09:54:45 07/22/18) Re-check the 2408 pump, it should be a four cylinder JDB431AL2408 that fits the JD 202 engine, not a 4020. 2719 is a 4020 PS pump, 2720 fits the early 7700 combine, 2721 is a 4020 synchro tractor with the rounded weights and eight degree advance same as the 2719 and 2720 pumps. Fuel setting are the differences. If you have more questions feel free to E-mail [email protected]

My 1971 4020 PS has pump #2404. Parts catalog PC-1116 says this is correct. Also shows #2402 for Synchro. :?:

 

[Dieseltech]

Looks like a 2402, which is one of the early JDB large pilot pumps. Will check the advance curve spec later..

 

[Dieseltech]

2719 is the CBC replacement Power shift pump, 2721 is the CBC replacement Synchro Range pump. Early 4020 used suffix 1AJ, 3AJ, and 5AJ pumps.

 

[Dieseltech]

JDB 2402 is for Synchro Range, 2403 is for 7700, 2404 is for Power Shift. All have five degree advance.