NHC250 Cummins fuel system

K9keeper

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Hello,
Just curious to know if any of you have ever plumbed in an in-line filter between the PT Pump and injectors? I figured something in the 10-30 micron range. I'm not talking about a spin-on type filter just small and serviceable. I figure it can't hurt to have something just prior to those injector screens.
Thanks
 

simp5782

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Hello,
Just curious to know if any of you have ever plumbed in an in-line filter between the PT Pump and injectors? I figured something in the 10-30 micron range. I'm not talking about a spin-on type filter just small and serviceable. I figure it can't hurt to have something just prior to those injector screens.
Thanks
The big cam pumps have a filter unit that hooks to the back of the IP. It bolts right on the back of the NHC250 pumps in place of the rear cover you can get a 10 micron filter for that. That is plenty.

I run a dual spin head under the cab plus the pump mounted filter 80 micron 20 micron then 10 micron to extend service life of the filters.

Nothing between pump and Injectors that could handle 225psi I would think
 

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K9keeper

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Thanks for the reply. There are mini high pressure inline serviceable filters available in low micron ratings from specialized companies. This particular truck that we're working on has a 2 micron spin-on filter added as a secondary after the stock original cartridge unit. All that along with the magnetic filter built into the PT pump should provide adequate filtration, I just figured it can't hurt to add a "final" filter that could be inspected at service intervals to insure nothing prior in the system is failing. Thanks for sharing your system set-up. Looks good.
 

simp5782

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Thanks for the reply. There are mini high pressure inline serviceable filters available in low micron ratings from specialized companies. This particular truck that we're working on has a 2 micron spin-on filter added as a secondary after the stock original cartridge unit. All that along with the magnetic filter built into the PT pump should provide adequate filtration, I just figured it can't hurt to add a "final" filter that could be inspected at service intervals to insure nothing prior in the system is failing. Thanks for sharing your system set-up. Looks good.
Been running these motors for years if the fuel going into the pump is clean the fuel coming out should be as well. Most horror stories of clogged up screens is due to rust from water in the fuel and then the truck sat.

Youncould look at a filter in the return side going back into the pump this would catch anything the screens did not since 90 percent of the fuel is returned to the tank anyway but a small portion goes back to the pump.

2 micron is way to small for most engines. Mine wouldn't hardly move cause it would be trying to suck a golf ball thru a garden hose to get the fuel it needed.
 

Floridianson

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On the top of the IP is a large plug screw driver thingy and inside is fine mesh filter with if I remember a magnet built in. Other than the addition of the filter base/ spin on filter that can be added to like Wes said is about as much as I would do. Side note the small filter inside the PT has what they call preformed packing for a type of O ring. This preformed packing is not n O ring per say as it is square and need to get it from the Cummins dealer. That is where I got mine and no longer have the part number.

Yea Wes when it gets down to a 2 micron absolute filter like my Cat filter for my Duramax it is a push through filter. I had to add a 10 psi lift pump before the filter.
 
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K9keeper

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This particular rig must have suffered fuel contamination at some point and debris got passed the original stock cartridge. The magnetic screen in the pump
and the screens of the injectors had collected quite a bit of contamination as well. We have drained and flushed the system and added the spin-on filter.
(I can go up to a 10 micron as recommended) Before I fire this engine up, I just want to be able to insure we got it all flushed out. The option of a filter in the return line for this seems adequate.
Thanks to all
 

simp5782

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This particular rig must have suffered fuel contamination at some point and debris got passed the original stock cartridge. The magnetic screen in the pump
and the screens of the injectors had collected quite a bit of contamination as well. We have drained and flushed the system and added the spin-on filter.
(I can go up to a 10 micron as recommended) Before I fire this engine up, I just want to be able to insure we got it all flushed out. The option of a filter in the return line for this seems adequate.
Thanks to all
Remove the shut off valve from above the fuel solenoid rig up a JIC fitting to some hydraulic fittings that you can add to a can that you can put fuel additive in that can be pressurized with shop air.

Remove both return lines and put them into cans with applicable fittings and lines

Keep running fuel cleaner and clean diesel thru the system with shop air pushing it thru till you don't see any contamination
 

Micmada

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On the top of the IP is a large plug screw driver thingy and inside is fine mesh filter with if I remember a magnet built in. Other than the addition of the filter base/ spin on filter that can be added to like Wes said is about as much as I would do. Side note the small filter inside the PT has what they call preformed packing for a type of O ring. This preformed packing is not n O ring per say as it is square and need to get it from the Cummins dealer. That is where I got mine and no longer have the part number.

Yea Wes when it gets down to a 2 micron absolute filter like my Cat filter for my Duramax it is a push through filter. I had to add a 10 psi lift pump before the filter.
Any one know how to loosen that plug. Mine is tight in there and there is no way to loosen it without damaging the screw head that seem of a softer material. Maybe I need to take apart the area and use a plumber pipe wrench.
 

simp5782

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Any one know how to loosen that plug. Mine is tight in there and there is no way to loosen it without damaging the screw head that seem of a softer material. Maybe I need to take apart the area and use a plumber pipe wrench.
Are you rebuilding your pump ? If the pump is not inoperable or has internal damage, the filter doesn't need to be bothered
 

Floridianson

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Well years ago I posted with pics that filter removed. Yea it did not have metal and not clogged enough to cause a running problem but it did have fibrous material I figured came from the fuel filter. Magnet was clean. If something could get by the primary filter then yes the PT filter should catch it. As for removal I used a big washer that fit the slot perfect and a adjustable crescent wrench. The filter they say is cleanable but I also had a new screen filter from Cummins and the preformed packing before I removed the filter.
 
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