Engine/Transmission (1998.5 - 2002) pumps, lines & whatnot

[csutton7]

since my buddy had that problem with the Haisley set up, which to me is the same as the draw straw your results don't surprise me one bit---I really think the draw straw should be run in conjunction with a primary set up--ie another lift pump tied to the draw straw to come on when one wants to insure more pressure or flow to the VP---really that was the intent of the Haisley system for high HP sled pullers and I think it works in that situation to my knowledge---as a daily driver I don't think it's the cure as a single feed, but of course if you've done something wrong during install then further testing may prove me wrong, so I'm curious to see what happens---



--as I explained before I have Ted Jannetty's 1/2" pick up system on my truck that's just being used for decoration now as I saw no improvement with it when I installed it and used it--I just left it in as it was a little work to take the OEM cannister apart and mate it to the Jannetty part---a very nice looking piece I will add and it does use most of the OEM cannister parts although I think you do something to the screen/float but I don't recall exactly what, but its intent was to basically work like the OEM set up but use a bigger pickup line--now it's hard to say if it was a problem with Ted's part or the pumps or my layout in my early quest for pump reliability, so it would be interesting to see if this part will work with all the new found knowledge--problem is it's expensive and I'm not sure he makes them anymore and have no plans to drop my tank and I'm not sure I could abandon it at this point anyway since I'm not sure if I could reuse the old parts and get it to mate all back up---



I remember HVAC made a 1/2" pick up out of copper, but he bent it along the bottom of the tank--kind of like an "L" shape--I don't recall him ever having a problem losing prime---maybe just using a longer pc of hose and letting it run along the bottom would work--worth a try if you want to go for it--or you could make a pc out of copper pipe and see what happens---



chris

 

[csutton7]

ILIANBG has proved me wrong, so hopefully you've done something quirky and you can get it fixed---



ILIANBG--how far did you run your tube--1/4" from the bottom or ??? just curious as when we did my buddy's Haisler we went 3/8" from the bottom----chris

 

[rweis]

When the fuel gauge reads "empty" as I recall there is still about 5 gallons in the tank. What is the volume of 5 gallons? and when you spread it across the square inches of the tank (length * width) how deep (height) is that?



The "low fuel light" comes on at 1/8 tank. That equals "how deep" is the fuel in the tank?



I typically put in about 25 gallons in a 35 gallon tank. How deep is the fuel remaining?



Let's see:

Need the approximate length of the tank, the approximate width of the tank. Need the approximate cubic inches for 10 gallons of fuel (1 us gallon = 231 cubic inches). Divide 2310 cubic inches by the square inches of the tank foot print and you get depth of fuel remaining in inches at the "low fuel" light.



Which should give an idea of how deep the Draw Straw is in the fuel at the "low fuel" light and how critical the length of the Draw Straw cut is.



Anyone have the square inches of the tank footprint?



Might shed some light on the subject.



Bob Weis

 

[csutton7]

I plan to organize the garage tomorrow which should uncover the spare tank, so I'll take some measurements then--chris

 

[rweis]

Trying to back off and think about this more, I have been running just the OE canister since RASP (about 1 year) because I plumbed the RASP to the tank vent line and the VP44 to the vent line seperately.



Ocassionally I out draw the supply (or that is what it seems) with the RV. Then I slow down some (65 > 60 or 55) and continue on. Mind you only DD2's and Smarty.



I think I am going to do the Draw Straw, and leave the RASP return mounted to the tank vent line. The RASP return would be a consideration IF I kept the bottom filter basket. If you keep the filter basket then I think you have to help provide alternate fuel resupply. I feel the RACOR 690 can easily handle filtration duties. I think the bottom basket is D/C's attempt to keep trash out of the fuel system as it and the lp wire mesh are the only fuel filtering before the final ff. I think the bottom basket could be a choke point with only the 4 gaps in the verticle wall structure and that covered with the filter material especially at higher power settings. Like breathing through a wet hankerchief and running a cross country race. I will have to see when I get it apart, but probably not keep the basket filter.



The end of the Draw Straw needs to be prepared to draw fuel from any direction. I think that you can get too close to the bottom. 1/4" is probably as close as you would want to get to the bottom. Chris' measurements of the tank he has will influence this to see how deep the fuel remaining is based on number of gallons remaining. Probably a sump something or baffles so fuel can not just run hog wild from end to end while stopping etc. A 2" deep round can that will go through the canister opening with holes drilled right at the bottom to verticle wall all around the perimeter. Something to slow the fuel slosh down so the Draw Straw CAN pickup the fuel in a reasonably controlled environment and not as the fuel races by. It is not there to provide fuel for minutes of engine operation, just to slow the dynamics of the fuel slosh, like the sump Chris is going to try. Maybe a longer rectangular baffle (3" wide, 8" long, 2" deep set perpendicular (across) the tank slosh direction, a bread pan?) just so it goes through the canister opening and will take the roundness of the canister bottom.



IF I do a baffle I am going to screw the baffle right into the tank floor with nylon screws and nylon nuts on the outside bottom of the tank and see how the fuel seepage turns out to be. Does anyone know how nylon acts with diesel over time? This might wait until I put in the Draw Straw and try it first, but I would not be surprised if it were not necessary OR to not go below 1/4 tank (same thing, but the 10 gallons at the low fuel light plus another 3. 5 gallons).



IF you went the 1/4 tank refill route (to avoid puting holes in the tank) roughly 21 usable gallons would give me @ 16. 5 mpg empty a 346 mile range or @ 10. 0 mpg towing a 210 mile range. The sump would only provide and additional 56 miles empty (3. 5 gallons * 16. 5) or 35 miles towing (3. 5 gallons * 10. 0). May not be worth puting in a sump to get the last bit of extendable fuel.



More thoughts,



Bob Weis

 

[ILIANBG]

Chris, I have mine pretty much to the bottom of the tank, I just cut it at angle, like 45" or more. I haven't had an issue with pressure. I had to change the float, my fuel gauge on the dash was showing empty all the time. The float was almost completely deteriorated. I had a new one on had, so I istalled it. I do not trust the new one. The readings are not really correct- I would drive 300 mi. and barely shows (looks I have 3/4 tank of fuel). I want to find a better alternative for the float.

But the Draw Straw solved my problems with fuel pressure. My screens in the tank pick up were completely clogged. I could not even clean it, so I cut those out.

 

[AdamH]

Hey guys,

Yesterday on the way home I intended to fill up with fuel to see how that would affect the problem. I called my wife as I was pulling in to the station. She told me it sounded like to her that I needed to pull the tank down again so why was I filling it back up with fuel, just to have to empty it, which is a pain. Hmmmm, out of the mouth of babes... So I didn't, I pulled back out, set the Edge on five, smoked the tires pulling out, and the ricer behind me, pressure never fell below 4 psig. Hmmmmm. I hit the brakes pretty good, came to a stop, pressure never moved from the 12 psig cruise. I performed this same program all the way home. Was not able to repeat apparent fuel starvation.

Now I'm really #@$%! .



I don't have a draw straw, I am using the stock tank module, 5/16" hose pickup and all, with the nylon screen material removed, which on mine, was on the bottom, not the sides. (I'm sure this is contributing to my pull-down at WOT). I think maybe the module did not go all the way to the bottom, maybe I forced some trash between the two cylinders when I was cleaning it and the spring was not strong enough to make it drop all the way down.



When I originally began work on the truck I ran it till the Low Fuel light came on. When I dropped the tank it had about 4 gal. in it which gave me about a 1. 5 to 2 in. coverage across the bottom.



The next thing I need to do is replace all the banjo fittings and install a draw straw.



Bob, I believe some of the OE fuel lines are nylon. I want to learn more about this system of keeping psi constant at pump.



I have a spare OE fuel tank. I'm going to cut a 5" hole in the bottom and fabricate a sump using a trap door system, then run the new draw straw and fuel return down into it. I'll let you know how it goes.



Adam

 

[csutton7]

take pic's of what you do Adam---will be interesting to see---chris

 

[AdamH]

I'll do it Chris, but be warned, my planning and design is much better than my fabrication skills. I tend to make stuff bullet proof and ugly.
Adam

 

[rweis]

Ugly works . I tend to do things the "Bob Weis Way". Over designed, over built, "do it right once" and NEVER look back. NOT all things work that way, as this truck has taken on a "life of it's own". I have gone back a couple of times to redo, but not too many.



Say 4 gallons = 1. 5", then 2 1/2 gallons = 1", let's round that off to 3 gal =1"



1/8 tank (where the "low fuel light comes on")= 10 gallons (in my tank) = 3" - 4". That's quite deep I would think if the Draw Straw were at the bottom. 1/4 tank let's say = 12 - 13 gallons = 4" - 5". I have a hard time believing that that depth of fluid could become uncovered.



This assumes Adam's eyeballs are reasonably calibrated and a cross check of gallons per inch of depth with a second source would probably help. Chris has an extra tank and might be able to eyeball corsscheck.



There seems to be an unassurred feeling if the "canister" is all the way to the bottom of the tank. I am sure there is some manufacturing tolerance, but we ought to be able to come up with a way to tell it is on the bottom and then measure it to a common point.



Once I get my canister out, since I am going to do the Draw Straw, I will take that "fuel feed / return" out and take a measurer and put the canister back in place like final assembly and measure to the bottom of the tank, and to the furtherest down in the canister with the bottom screen and all the internal screens etc removed. We'll get a couple of different users doing this and get an average length so we know what that should be.



We are getting pretty close to being able to mod this canister and know the results. When I do my Draw Straw I am not going to feed it to the center like the pics that came with it. I am going to feed it straight down, straight down and drill the Draw Straw hole between the canister side wall and however large the hole is to pass the Draw Straw through in the horizontal bulkhead in the bottom of the canister. IF I have to convert the Draw Straw to a metal pickup in the future I want it to be straight down. I think I will even set the canister height and lock it in and wire the Draw Straw TO the canister side wall in several places to insure it does not move in any direction.



Cut a 45* angle on the bottom of the Draw Straw toward the midle of the canister (make sure you have the final clockwise or counter-clockwise rotation done first) of the Draw Straw that is wired to the canister body every so often all the way down the canister to the verticle bottom of the canister, and SHOULD be done.



The constant pressure concept:



2 RASP brass VP44 bypass valve IN PARALLEL spliting the RASP bypass volume back to the tank and I think much much less spring movement (psi variance). Idle = you shim it psi (Shims are readialy available and inexpensive (a couple of $3 or $4)



OR





An adjustable needle valve IN PARALLEL with 1 RASP brass VP44 bypass splitting the volume (probably not as evenly as the parallel identical springs of 2 RASP brass bypasses). Idle = you set it psi by the needle valve



I have to experiment: I have new springs comming so I know what the average RASP guy has (I have "modified (trimmed)" my spring). I have the shims in hand. I have a brass bypass to replace the one you are going to take from the lp one way check valve that becomes the parallel bypass for the tank return. I have a total set of springs for the replacement bypass for the lp, some almost nonexistant resistance (which is what we want for the backflow valve for the lp).



OR



2 brass bypass and a needle valve? ALL in parallel (square tubing with 3 fittings on one side into the bypass valves and needle valve, 1 fitting on the other side from the VP44 bypass line)



Is going to take some time to experiment, but we will be able to get really close to 13. 5 +- some but not much, with hardware store stuff.



Bob Weis

 

[csutton7]

ok here's my measurements from the tank--I did it in sections as the thing doesn't have a perfectly flat bottom and is shaped weird--



all measurements are approximates(but very close) and are from the front to the rear:



the front section is 9. 5" x 5" x 6" = 285 cubic inches---this section is NOT the most bottom part --up from most bottom part 3"



next section is 9" x 11" x 7. 5" = 742. 5 cubic inches--this section is NOT the most bottom section either--it's up about 2" from the most bottom part



next section is 11" x 11" x 11" = 1331 cubic inches---this section is NOT the most bottom section and it's up about 1" from the most bottom part which is the next section



module section where float and pick up assembly are is 22" x 11" x 11" = 2662cubic inches and IT IS the most bottom section of the tank



rear tank strap section 14" x 10" x 11" = 1540 cubic inches--this section IS the most bottom section also



rear section is 18" x 14" x 10" = 2520 cubic inches---pretty much the bottom also but angles up about 1" at the end



so the tank is approximately 9,081 cubic inches give or take a little(if my calculations are right)---probably a little less due to curves and oddities--



so the center section being the largest section and let's say it's 5. 5" deep from the middle to the bottom and this would = 17. 5 gallons of fuel then a 1/4 of a tank would be 2. 75" deep would = 8. 75 gallons and an 1/8 of a tank would be 1 3/8" deep and that would be 4 3/8 gallons and then 11/16" deep would equal 2 3/16 gallons and 3/8" deep would be close to 1 gallon left in the tank, which when looking at the tank looks pretty close, but of course due to the odd shape of the tank it's probably a hair more in reality--so by looking at the tank somewhere between a 1/8th and 1/4 tank may be the lowest you would want your fuel to get to and I'd say no less than a 1/4 tank if you're driving in the hills/mountains---I think if and when I redo my sump I'll redo the return to make sure I have fuel dumping into the sump at the very minimum--of course I may get in a hurry and do nothing and then adjust as needed





Adam your system of stout but 2am-ish fits in here----chris

 

[rweis]

Chris - length width height?



Bob Weis

 

[rweis]

THANKS Chris, and Adam has pretty good calibration on his eyeballs, 1. 5" + ~ 4 gal



Quick calc: ~ 250 cu in / gal



as a birthday cake upside down



bottom smallest



22*11*1~1 gal + 14*10*1~. 6 gal + 18*14*1~1gal ~ 2. 5 gal for bottom 1"



next 1" up



bottom 2. 5 gal + that 2. 5 gal again + 11*11 ~. 5 gal so now we are 2" deep in fuel and have ~5. 5 gal



next 1" up



bottom 2. 5 + second layer of that 2. 5 + third layer of that 2. 5 + bottom layer of the . 5 above + second layer of that . 5 again + 9*11 ~ . 4 gal ~ 9 gal in the bottom 3 " of the tank.



Or about where the low fuel light comes on ~ 10 gal / 3 " deep in fuel.



I'll have to recheck my upside down thinking but might be sort of sort of close.



THANKS to Chris and Adam again,



Bob Weis

 

[AdamH]

I know my module was sitting on the bottom of the tank because there are very evident marks on the floor of the tank. As soon as I find out what type of sealant to use on my proposed tank mod I'll start to work on the new sump configuration. I'll make sure to shoot it in Hi-Def so you can see all the gory details. :-laf

Good to know my eyeballs are still properly calibrated. Those screwdrivers really hurt! And Bob, I'm still completely lost as to what the heck the bypass and rasp and springs and shims are.
Adam

 

[csutton7]

now that I have time to think a little I think due to the shape of the tank there's probably more fuel than what I've outlined above as the above calc's are based on a perfect shape and it's by far from perfect---chris

 

[rweis]

I am sure all this is a massive WAG, but more info than we had before.



Adam - The RASP lp solution uses a brass bypass valve to adjust the pressure return to the tank. It is a AN-6 male each end then a take apartable (my own word ) 1" cylinder that has a thing like an bullet shape (rounded triangular shape tip from the side but has some cylindrical body length, but slides up and down in the inside of the cylinder) that seals at the pointy end and has a spring at the butt end. The tenson and the linear characteristics of the spring (coil wire, width of the adjacent coils, number of coils, travel etc) then keep pressure on the bullet end seal or compress some due to the pressure of the return fuel back to the tank against the bullet nose.



Once the bullet nose comes off its seat seal it has passages that allow fuel to pass through its inner structure and out the butt end to down the inside of the cylinder where the spring is and out the bottom AN-6 connector. Commonly called a bypass valve. There are shims available to put at the butt end of the bullet to tighten the spring characteristics and make it harder for the fuel to push the bullet nose off its seat seal (higher return psi). There are different springs you can swapout that have different tension characteristics higher or lower that make it easier or harder for the fuel to push the bullet off its seat seal (and therfore pass fuel)(lower psi).



The RASP comes with one of these bypass valves for the VP44 input pressure regulation that is T'ed into the VP44 feed line and the output of the bypass valve is routed back to the tank. This is how the RASP system sets the VP44 input pressure to the VP44.



I have found a source for these bypass valves that has a whole slew of springs of different characteristics as well as shims so we will be able to set the fuel psi that unseats the bullet nose seal (and excess fuel goes back to the tank) pretty accurately eliminating one of the VP44 feed variables and able to set real close to the exact VP44 test stand calibration psi of 13. 5.



Parallel bypass valves makes the movement of the internal brass bypass spring travel less distance in a pair of bypass valves than in a single bypass valve because there are two bypass valves working together in parallel.



Another idea is to put a needle valve in, instead of the second bypass valve, to take some of the fuel going back to the tank and take some of the load off the internal spring so it travels less and might be controlled more precisely giving a narrower psi range. Experimentation will tell if that is true.



BACK to the fuel quantity:



Now that the 1/8 tank low fuel warning light has been reached (~10 gal remaining) and it is about 3" deep in fuel, the difference to 1/4 tank in depth (~ 17 gal) [(another 2. 5 gal section + . 5 gal section + . 4 gal section + 9. 5 * 5 section (. 2 gal) ~ 3. 5 gal per 1" depth] is ~ 2 more inches of fuel depth for a total of ~ 5" of fuel depth. This would imply that the tank is 20" in height to be full and would carry (4*7 +10) 38 gal. We know this is a little off, but not a bad estimate.



I am interested in the sump to see what kind of sealer you come up with and what kind of screw attachment system you come up with and if you baffle it for sloshing and how it will be protected. Maybe an external tank completely seperate from the OE tank as a sump?, but that would make it considerably more complicated and maybe not practical. Should be interesting.

 

[rweis]

Vulcan Draw Straw installed today. Observations, modifications, considerations, trouble spots forth comming.



Edit --------

I wrote up my own description of the install and it was 6 pages long, but I will do the short version here and you can email me if you want the long version.



Physical parts:



1. The tank straps would not come out of their frame mounting easily. The front strap the bolt on by the carrier bearing the design of the metal flange was too big to get out from under the bracket, and the T on the frame would not come out through the slot designed for it. The rear strap had the same T problem the front strap had.

2. I left 10 gallons in the tank for leak checks and it made it 70# heavier (~7#/gallon) than empty.

3. The bed design of the truck puts a bed stiffener right on top of the Draw Straw port within 3/4". Rotate the Draw Straw in the verticle axis to gain a better position to screw the fuel feed line on (My feed is pointed toward the center of the bed, not the frame as OEM)

4. Getting the tank hoses reconnected was difficult because I left them to AFTER I had the tank mounted, NOT RECOMMENDED, makes it REALLY HARD to reconnect the tank end of the hoses.



Installl Considerations:



1. Get a replacement tank gasket

2. IF you take the strainer basket off the bottom of the canister (ie the lower basket (where the fuel level is attached to) to the canister can drop down lower in the tank) you will need to screw / bolt the lower canister basket to the top canister basket so you can set the depth of the fuel level reporting mechanism that is attached to the lower canister basket so you can compensate for the removal of the strainer basket.

3. Now you have the lower canister basket screwed into the top canister basket and you have enlarged the hole for the Draw Straw. Mount the canister back into the tank and slightly screw the lid on so you can take a dowel rod and measure where the tank botom is by puting the rod through the Draw Straw hole and reaching the bottom of the tank. This tells you how long to cut the Draw Straw tube. Measure twice, cut once. I cut my Draw Straw and installed it at this point to make sure it was not too long and that "it" would tell you by not seating into the canister top properly.

4. Decide if you are going to have the feed line come off the frame side or the bed side and chamfer the bottom of the Draw Straw to face where ever you want it to face to be sure it has access to fluid.

5. My canister was already marked for the tightness of the lock ring. Be gentle, just keep working the lock ring on until the marks line up (or nearly so). I then tilted my tank on its side (both sides) (remember I left 10 gallons in it) and left it to see if it would leak.



Now testing to see any differences:



Normally I get some minor VP44 feed psi fluxuations during my drive to work. This am not even a single flutter. Totally stable. I need to test with the rv attached and will report that back later.



Bob Weis

 

[Gary - K7GLD]

The RASP lp solution uses a brass bypass valve to adjust the pressure return to the tank. It is a AN-6 male each end then a take apartable (my own word ) 1" cylinder that has a thing like an bullet shape (rounded triangular shape tip from the side but has some cylindrical body length, but slides up and down in the inside of the cylinder) that seals at the pointy end and has a spring at the butt end. The tenson and the linear characteristics of the spring (coil wire, width of the adjacent coils, number of coils, travel etc) then keep pressure on the bullet end seal or compress some due to the pressure of the return fuel back to the tank against the bullet nose.

Sorta like THIS:



#ad




And assembled:



#ad




The above is a simple homebrew "Flopper" bypass valve I'll use on my Walbro to allow fuel flow around it in case it fails - below is the actual regulator, currently set for 18 PSI, to be installed right at the VP-44 fuel inlet port:



#ad

 

[rweis]

The bypass valve I found at Kinsler Fuel Injection. They have a wide assortment of springs and different thicknesses of shims so you can set just about whatever psi you want. One of the key advantages is it is AN-6 full flow. The RASP bypass valves are a little longer, but I have not been able to find springs and shims particular to that valve. I hope that the Kinsler springs and shims will fit the RASP valve. The Kinsler springs are shorter, but I think I can work with (shorten) the RASP spring to get it to do what we want. Or if you do not already have RASP valves just use the Kinsler valves.



The full flow design is in the nose valve. The nose bullet has 6 (I think) holes drilled in the shoulder slope from the slope to the inside hollow chamber where the top end of the spring rides. The cylinder body of the nose bullet fits with very little clearance so it travels smoothly longitudinally within the brass body. When the pressure moves the bullet nose compressed down, the step where the holes are drilled now becomes accessable to the fuel, the fuel moves to the inner surface of the bullet nose where the spring rides and provides mechanical resistance, then the fuel travels down the inside through the spring shim package and that is why the shims are so thin in cross sectional area to not impede the fluid flow and out through the bottom cap.



Bob Weis

 

[Gary - K7GLD]

Other than installation using an absolute GUSHING fuel supply (vast overkill!), I wouldn't expect the need for huge regulators or return lines in a well designed setup - a simple 3/8 should be more than adequate.



In my case, once baseline runs with the Walbro have been made, rather than running the Walbro wide open at the full volume it is capable of - which in MANY cases has produced lots of fuel foaming and air in the lines, I intend to use a PWM to reduce power to the Walbro to a level that slightly exceeds and maintains the regulator set 18 PSI right at the VP-44 under heaviest possible load.



Presumably, this will provide several advantages, no more fuel flow than the VP-44 actually NEEDS under the highest usual demand with least fuel agitation, reduced load/demand and longer, more reliable lifespan from the Walbro - and finally, minimum power draw to operate the Walbro.



Obviously, this relates to my own use of the Walbro - but some of the same principles should apply equally to other high-flow fuel systems using other pumps. It just doesn't make sense to me to design a fuel supply system capable of 100 GPG (or more... ) under relatively high PSI, to a VP-44 that has been shown to be capable of passing only 45 GPH under heaviest demand, THEN having to provide large regulators and lines to shunt the unnecessary overkill back to the fuel tank. That just creates the potential for fuel aeration and heating that is counter-productive to a well functioning system - and MIGHT create more issues than it cures...



At least that's my view at the moment...