Any pump moving fluid can do a lot better job pushing the fluid rather than pulling it.
Same principle as a deep water well pump. The pump is at the bottom of the shaft not at ground level.

 

What Kwik cited is a good example.

The suction of even a "perfect vacuum" will only lift a liquid just so far (it varies according to the specific gravity of the liquid).

Given enough pressure, you can PUSH that same liquid a LONG way into the air.

Pop

 

Flame away if it makes you happy, it won't hurt my feelings.

Yes, you have provided another place for fuel/air to exit, but if there is air in the fuel, there is nothing in your system that guarantees that it won't take the path through the injector instead of out the end of the head.

You're still making assumptions. You're assuming that you have "no air in", not a safe assumption at all. I'm not saying you didn't help the situation, you've certainly done a number of things to limit the amount of air intrusion, but there is still air in the fuel. Even an AirDog or Fass can only remove ninety-something % of the air, nothing is 100%.

You are also assuming that all air in diesel fuel is visible...wrong again! Just because the fuel looks clear doesn't mean it's free of air.

I'm not knocking what you've done, just trying to correct your assumptions about the effectiveness. It is totally unrealistic to think you can remove all air from diesel fuel, all you can do is make mods to try to limit it as much as possible.

 

A few questions come to mind.

One) I would assume that international would have a say on what's done to they're engine and if Int supplies a regulated return system to rid the heads of as much air as possible, then why would Ford remove it? Cost? Jeez for a 6k upgrade whats a few hundred more?

2) the pulsation that Kwik mentions is very real and possibly problematic. the pressure spike is instant and hydraulic pressure spikes can cause fluctuations in flow delivery. Has anyone thought of using a precharged chaber similiar in the plumbing industry. They are called water hammer surge arrestors. They are precharged with 50 or 60psi with a captive air chamber isolated by a muti o-ring piston.

I'm wondering if they would dampen the fuel pressure spike.

 

Here is what I'm taking about - not sure if the orings are #2 fuel rated?

http://www.pppinc.net/whasweaton.htm

 

For Kwick - look at some of the ways that air entrainment can be caused.

http://www.machinerylubrication.com/...oup=Hydraulics

 

Various sources of bubble formation within the hydraulic system include:

1. Suction resistance
2. Pressure drop through an orifice
3. Pressure drops through pipes and hoses
4. Turbulence from valve opening and closing
5. Shock waves due to sudden closing of valves and sudden cessation of pump operation
6. Pressure drop due to sudden opening of a valve
7. External force on piston rod
8. Plunging of fluid at the return to tank
9. Inadequate net positive suction head available (NPSHA) relative to the net positive suction head required (NPSHR) in centrifugal pumps
10. Suction-side recirculation to sub-best efficiency point (BEP) operation of centrifugal pumps
11. Nearly dry operation of a pump due to insufficient fluid volume.

 

My humblest apologies. Not my intent. Just looking for the explanation. Remember, there are some of us still looking at how to tackle this project and we view all of the regulated return system posts with keen interest in order to get it right. I believe you are referring to entrained air. Is that correct? I don't think there is much I can do about that. I just want to eliminate as much air as I can, and use the expertise available here from trial and error.

 

Are you guys aware that there is a HUGE amount of information about this subject at the other forum site? This stuff has been worked on for several years. There are even high quality fuel system kits available that take the guesswork out of the installation.

 

Yes, we are aware of it.
I would have purchased one of those kits if I wanted to spend the $$$$.
I preferred to save my money and spend it on toys.

 

Which one? Are you aware that there are at least 4 other 7.3 forums on the web? you need to be more specific. If you are talking about TDS, yea, I think most of us are aware.
Actually it has been worked out since basically the inception of the engine. Are you aware that the regulated return fuel system emulates an International fuel system that Ford chose not to use?

You mean like Bob Riley's CPR systems or ITP's regulated return system? How about Diesel Innovations regulated return system, were many of us buy parts for our own version? Yeah, I think most of us are aware of those sites. But where's the fun if all the parts come in the same box with instructions? May as well just take it down to the local speed shop and let someone else put it on.

 

clux, I like your thinking.... I believe that the DIY factor and self-wrenching is what makes PMS and FTE most enjoyable. Lots of creative thinking here.

 

I looked at several systems before building my own. In fact, building my own wasn't much cheaper than one, say from ITP. However, the parts I used weren't the cheapest and it could be done for a lot less. The one thing my system has over the ITP system is larger lines - 6AN on mine vs 4AN on the ITP system. Plus, I liked the idea of doing it myself. I'm a big DIY type of guy, and actually preferred to design and assemble the system myself.

 

Ditto JT... i like my -6AN BIG flow SS braided lines instead of the rubber line. Having to get creative with lousy install instructions was a bit more challlenging.
Fun stuff looking around Jeg's and Summit racing for parts to get the job done.
Nut

 

Oh I am dangerous when I start looking at summits web site, and the one time I had a load out to Ohio and had to layover one night I spend like 7 hrs in thier store, kinda like a kid in a huge candy store and managed to get out of there for slightly over $500 so not bad.