____________________

Mike
You can buy a kit or just get the Aeroquip Weber carb adapters 12mmORB to -6 JIC and replace the lines with -6 hose and that wil give you 3/8 all the way.

 

____________________________

Kevin

There is a real mickey mouse quick disconect on the top of the tank for the fuel lines and after removing mine and looking at it I have a hard time beliving it would seal air tight. As far as the claims vendors make well..... I can say with out question since I installed the FASS I have gained a consistant 50k (30miles) per tank so its doing something different than my stock system with the pusher. Will every one see the same results? I doubt it. Many members have fought hard starting issues only to find tank conections and or pinhole leaks in lines, so its a fairly common. Also the return line dumps into the pickup ( I think this was to ensure a supply of fuel at the pickup in a low tank level) so your inlet is picking up fuel that is perhaps frothed up from the prievious loop? I think there are many issuses with this system and design. I think there is also a lot to the pulsations from the VP also, however thats probably more of a issue to the LP than the VP. Many VPs fail yet the LP is good? Could there be seperate reasons for VP/LP failures? Would be nice if someone could lay this to rest.

 

I don't understand the stars either...

Anyhoo, true pressure is a result of flow, however when you are feeding a pump with a fluid, you have instantanious and static flow. The instantanious flow of the suction event for each of the plungers is the problem (as I see it) where you have a sudden drop in pressure. If you drop the pressure below the vapour point, then the entraned air becomes a bubble. Then when the pressure goes up again, the bubble collapses and causes a jetting effect on the surface it was adhered to (cavitation). Cavitation is more than just having bubbles, it causes severe wear to polished surfaces that could lead to further deterioration and failure.

The pulsation issue has merrit also on the LP pumps as the most guys can't get their gauges to live without some sort of pulsation dampening such as a piece of grease gun/hydraulic hose or an orifice/valve. The aftermarket systems which use rubber hosing, I feel, is helping to reduce some of the pulsations in the system simply through elastic dampening by the tubing. I would almost bet that by adding the rubber tubing systems out there to the OEM LP would double its life.

Thoughts?

 

S T E A L E R....works for me...I dont know why that words such a big deal.

Good thought on the flexible fuel line Dog....will certainly dampen more pulsations than the hard steel line

 

The erosion of surfaces caused by air bubbles has a name- impingement. I've seen it wear clear though 1/4" wall pipes on boilers.

 

yup HUGE problem on boiler tubes.

 

Infidel, you are one too!!!! Cool. What station?

As for high pressure impingment of steam on tubes, our unit operates at 2,850 Psi, and a tube leak aimed at another tube will cut clear through a .350" wall stainless steel tube in less than a day


Kevin

 

Yes the term impingement has been used, but for the rotating guys on pumps and viscous fluids are still emotionally attached to Cavitation. Many papers written on it for the API etc. The term cavitation seems to be more for the event of the bubble collapsing and the jetting that occurs there after as the fluid returns to the space after a pressure change, or vibration event. This cavitation is also prevalent in jacket water systems where cylinder liners erode, IE the PowerStroke. There are many theories on how contaminants contribute to it as well as the Ph of the fluid, viscosity, temperature etc.

I don't like way the hoop stress of the tubing dampens the pulsations, however it seems to be working.

I would like to take pulsation measurements on that system to see for sure what the levels are. It would take some work and a few leans on contacts to get the transducers and a good FFT analyser, but it could be done. Heck they make an accelerometer (vibration) the size of a pencil eraser, I know we could get good pulsation data on that system with the right instrumentation.

 

I've tried to solve the pulsation problem by using 10mm id rubber lines from the fuel tank forward. My holley blue has survived for more than 75 k miles now so I think it leads a happy life
When you look at the rotary vane pump in the VP44 you'll see that it's not generating an even flow but does gulp in fuel and then stops the flow (seen from the outside) so the ability to feed the peak demand in the short time through the stock fittings seems crucial to me.(Hence the pressure requirement- pressure we can measure means flow through a restriction) I'm interested in your setup of the accumulator.
I did also find that my quick connect fittings would let air into my fuel system. (Not enough to cause hard starting but enough to make some bubbles visible in a piece of clear hose. (Remedied that with the rubber line)
IMHO the problem with pumps going tu after adding a box is also caused by plunger travel exceeding the smooth part of the bore under pressure. Before the box the plunger would move a certain amount and then the pressure would be relieved. With the wire pierced the plunger will have to supply pressure longer. (The seized rotors are something different)

Just some ponderings
AlpineRAM

 

Not a power plant Kevin, but a agriculural research station. We use a boiler to extract oils from plant materials. Consider myself more as a researcher. Welcome your scientific based input here.
There are quite a few operators on the TDR website, everything from hydro to nuclear.

 

Now lets enter the Rasp system. With a mechanical pump would'nt it feed the vp44 a steady flow of fuel & increase that flow with higher rpms? Thus eliminating the cavitation, the pulseing that kills the stock lift pump.

 

600 Mw, it takes that amount just to start up the plant I work at.
Two nuke units rated 2400 mw each plus depending on river temp.
Maybe we should start a seperate power plant thread eh?

And yes, I do have a FASS and will never go back to that little goofy lift pump. The last one I changed out (number 4) was along side the road at 09:00 in the morning with the temperature about 29 degrees. Doesn't seem like a lot of research went into that fuel system design.

https://www.dieseltruckresource.com/...cat/525/page/2

 

Are you referring to a Cummins ISC powered unit? ISC and ISL use the Cummins CAPS injection pump. The early CAPS units had far more failures than any VP44 pump. Manufacturing tolerance errors was the culprit. CAPS are designed to suck fuel from a tank. The lift pump normally operates 90 seconds and cuts out.
You would cringe at the fuel flow on some buses. Tank to primary such as Davco FuelPro, lift pump, secondary filter, injection pump.

We are having fuel deliver issues on the HPCR ISC and ISL engines. Haven't really identified the true cause, but flow, not pressure appears to be the issue.

Lots of talk about pressure and flow. Normally they are an inverse relationship in a closed finite system. The fuel system is not closed, but the pressure drop between idle and WOT does follow a finite model. Hmm pressure drop, expansion valve.

 

How about a process problems/maintenance thread??

 

The Weber carb fittings are almost as restrictive as a banjo bolt.

I have had custom made fittings that replace the banjo bolts for awhile now.
I read over on tdr where someone was saying some folks are marking up their stuff 300%...LOL sure.

I am going to have pictures up on my site this coming week of a weber beside the custom metric fittings I designed. I started with bigger banjo bolts but did not like the way the fuel had so many bottlenecks, then went to the weber, its not a lot better.

I had a Holley Blue on my 01 that ran for over 50K after 2 stock pumps failed. But how come I had two Holley blacks fail and a PE pump? Last I heard the Blue was still going. I have had a Blue on my 04 for 30K now...no problemo. I think 600MW touched on it. Its the same reason some fuel pressure gauges fail, resonance/pulsations/restrictions. I also think that theres some manufacturing flaws with some of these pumps. Perhaps a quality control issue.

Have a good match in fuel volume and moderate pressure with smooth flow and you will have a better chance of saving your pump.
Another interesting thing, I saw slightly higher pressures [1.5 psi] with the same Holley pump when I matched the inner diameter of the hose [3/8"] and the fittings then I did with going up to 1/2" hose and bottle necking to the metric adapter. I also have more consistent pressure with less rise and drop throughout the throttle range.

Scotty