LP relocation FYI

[Sticks]

For those of you who are looking into relocating the OEM LP and want to open up the lines as much as possible...



The fuel filter and the LP ports can be drilled out and tapped for a 1/4 NPT thread. This eliminates the 12 mm conversion or the AN hose restriction.



If there is enough interest, I will post how to disassemble the fuel filter housing (on the newer models with the plastic lid). It is kind of a PITA if you are guessing at it. The fuel pump is easy to take apart to drill and tap.

 

[Ncostello]

Sticks... how do you take the late model filter apart? I've managed to get the drain off and the WIF but am dead in the water with the black heater element. It kinda looks like it would just pull upwards... but with the wiring and all I cant easily move it and dont wanna break it.



How do you keep shavings outta the lift pump on the discharge side?

 

[Sticks]

By drain, you mean the plastic shaft in the center right? Not the actual drain?



The Heater ring has two hooked tabs that sit below the ring. You need to pry the tabs away from the side of the filter, while lifting up on the ring. You may have to walk it back and forth from one tab to the other until they are almost clear of their catches. I took an old retired flat blade screwdriver and bent about 3/4 of the tip over 90*. It is a real tight fit, but yeah, it pulls right out. Once you get the tabs clear, you need to pull evenly on the entire ring. If one side gets ahead of the other, it will lock up on the threads. Assembly is much easier



The pump is easy. Take the three bolts out of the top, remove the cover plate, gasket, vane plate (1" round disk), screen, and vane assembly. As you take them out, set them down in a manner that you can put them back in EXACTLY as they came out. A magnet on the vane assembly will help to pull it up, and keep it all together. I don't know how critical it is to keep it in the same formation, but with a moving part there is always wear so better safe than sorry. When drilling and tapping, just keep a vacuum cleaner going to catch the shavings on the inside of the pump.



The 7/16 bit is only going to shave off about half the thread thickness, the 1/4 NPT finishes them off.



NOTE - Make sure you do a real good rinse of the filter housing and the pump to get all the shavings out. ESPECIALLY the filter outlet to the VP.



Anyone feeling spunky enough to try this on a VP44? It's only a $1200 unit.

 

[Ncostello]

I meant drain as in the plastic water drain on the side... 4 torx screws and its off. I hadn't messed with the center pipe inside. Thanks for the info. I figured some form of shop vac had to be used.



Plus I always put a few drops of 10W-30 on my lift pump rotors when re-assembling them. Till the fuel gets to it I figure it helps lube the vanes and make a better seal to build vacuum.



Someone once posted on here that they somehow broke a banjo bolt out in the middle of no where. Their solution was to buy a 1/4NPT fuel barb fitting and some fuel hose at an auto parts store. They drilled and tapped the VP while on the truck eek: ) and got it going. I believe they had no problems and its still running fine that way. Guess if your desperate you'll try anything to get back on the road. I would drill the VP too if I had to... keywords "had to". I'm too chicken otherwise!

 

[Ncostello]

Sticks... what about that plastic shaft in the center... does that just unscrew? I notice its got a hex head but that may or may not mean anything.



I got a 1/4" NPT fuel hose barb fitting and fitted it up against an old lift pump. How many threads can you cut before bottoming out the tap? It didn't appear too deep to me just by looking and not measuring. I figure I can't vacuum the output side of the lift pump while tapping except from the outside. So perhaps holding it so the output port is facing down would help shavings fall back out after removing the drill bit... then vacuum and perhaps flush somehow from the input side. Just a thought.



I'm gonna try this on my old pump first.

 

[Gary - K7GLD]

"Anyone feeling spunky enough to try this on a VP44? It's only a $1200 unit. "



Might be an exercise in futility, without knowng what other restrictions exist just inside the VP-44...



ON another note, wouldn't it be easier to just re-thread a hose barb to fit the LP and filter? I haven't really looked - maybe hafta check it out... I know I *have* rethreaded metric stuff to the closest domestic size with good results... Sure easier than the disassembly of the LP and fuel filter...

 

[Ncostello]

It would be but the metric threads in the LP and filter are straight (parallel) whereas threaded NPT stuff is tapered... hence the need of the sealing gasket or oring. You probably could get it to seal but you'd gall the threads real good mixing tapered with straight. I dont know if I've ever seen tapered metric dies. Good point however worthy of investigation.



My good buddy (although always very busy) is a self taught master machinist. He just upgraded to an automated Cincinnatti Milicron in his shop. I'll talk with him and see if he'll spin me some hose barb fittings with M12x1. 5 O-Ring ends that'll go right in the metric ports.



EDIT: Metric tapered is available (DIN 3852 specifications) but you'd still have to retap the LP and filter to this. Otherwise if the standard fittings had enough hex head you could install an oring and just die cut metric parallel threads.

 

[Sticks]

Originally posted by Ncostello

Sticks... what about that plastic shaft in the center... does that just unscrew? I notice its got a hex head but that may or may not mean anything.



I got a 1/4" NPT fuel hose barb fitting and fitted it up against an old lift pump. How many threads can you cut before bottoming out the tap? It didn't appear too deep to me just by looking and not measuring. I figure I can't vacuum the output side of the lift pump while tapping except from the outside. So perhaps holding it so the output port is facing down would help shavings fall back out after removing the drill bit... then vacuum and perhaps flush somehow from the input side. Just a thought.



I'm gonna try this on my old pump first.

You don't need to take off the water drain, only the center shaft, and yes it does unscrew. BE CAREFUL it is plastic, and they did use green lock tite on it. I don't know that I would try anymore than 15# torque before I would opt to just flush it out real good when I got done.



The LP can be disassembled enough to gain access to the inside. Once you take out all the vanes, hub, and screen, you will have a clear view of the output on the LP. Just the same, do a real through rise job. Run the tap as far as you can or up to 2/3 of the tap. That should give you at least three full threads to hand tighten a barb fitting. If you have a dead LP, that is a good one to practice on. A little grease on the tap will also help to catch the shavings.

 

[Gary - K7GLD]

HMMMmmm - my youngest son is a machinist up in springfield Oregon - he could machine the whole dern thing...



(edit) Shucks, we could maybe turn this into a money making project...

 

[Ramafid]

I tapped my 1st lift pump for 1/4 npt. It worked pretty well. What I did was ball up a little piece of papaer towel and stick it inside the inlet and outlet lines. This was to prevent any shavings from getting into the pump. I tapped the new threads and then used a shop-vac to suck out all the debris. Worked quite well. The 2nd lift pump I cut the threads of the 1/4 npt to 12 by 1. 5 mm. I like this method better because it is easier. Just shave the threads down with a file and put the die on and you are done. No worries about shavings in the pump.