Question for Dieseltech

[1370rod]

PES4A 80D 420LS, PES4A 85D 420LS and PES4A 95D 420LS are pumps that will bolt up and work on 7-870 tractors. Can you tell me what will or what will not occur by using a pump not listed for a given tractor. The 80D is for a 770 and the 85D is for a 870. The fuel can be adjusted to match the HP of a given model, just wondering the reason for using the different pumps like they did, Rod.

 

[Nedd]

Not sure about 770-870 but for 970-1070-1370 Im pretty sure those numbers are the size for the plungers in the injector pump. 10 mm. 9.5 mm. 9.0 mm. 100D is on four wheel drive 4690. 95D is on 1370-1570-2390-2590-4490-2470 etc. 90D is on 1070-1175-1270. Thats what Ive seen on the tractors Ive worked on.

 

[Dieseltech]

As Nedd mentioned, 80 is 8.0MM, 85 is 8.5MM, 90 is 9.0MM, 95 is 9.5MM, and 100 is 10MM plunger size. The larger plungers move more fuel with less rack travel and have a quicker injection rate. Putting a larger plunger pump on a smaller engine MAY result in too quick governor action, and putting a smaller pump MAY make engine slower to respond with a load. The Bosch RSV governor has some adjustments to correct either issue though that can be reset on the test bench using the rack dial gauge versus stand RPM.

 

[1370rod]

Having said that I would assume then using a 8 mm 770 pump on a 870 that calls for a 8.5 mm would be perfectly acceptable with some minor adjustments that might be needed. Another situation might be the swapping of injectors, a 770 uses a different injector than say a 1370 that uses a 9.5 mm pump. If one was to turbo a 770 and install a pump with the 9.5 mm plungers I would also assume installing the 1370 injectors would be a good idea? I imagine the injectors for a 13 have larger holes allowing the slightly larger shot of fuel to enter the combustion camber quicker? Rod.

 

[Dieseltech]

I'll have to look at the pencil injectors spec difference of hole size and needle lift. Sometimes there's not much difference.

 

[RGMartin]

I have a 10mm pump on my turbo 770, it was an ebay purchase many years ago intended for a 850 crawler. No adverse effects to date, running through stock injectors.

 

[1370rod]

Good to know, thanks for info, Rod.