Looking at the CNCFab distribution block for their 4-line feed, what if they incorporated a quarter-turn valve to temporarily redirect flow from one of the feeds to each head out to a bleed nipple? That way, bleeding air out of the fuel galleries in the heads would be a simple matter of attaching a hose to the bleed nipple out to an overflow receptacle, turn the valve to redirect flow, then run the fuel pump a few times without starting the engine. Once fuel coming out of the bleed nipple is running bubble-free, turn the valve back to return flow to the normal configuration.

What does the braintrust on here think?

 

Or just keep the stock fuel bowl add an FRx and flip the vellow drain valve?

 

How does that force fuel flow through the heads? Keep in mind that the caffeine is still in my stomach and not fully absorbed yet.

 

Isn’t the CNC 4 line feed a dead head system? You’d need bleeders at the heads to accomplish your idea.

Could you just crack the fittings one at a time and cycle fuel pump until air is “mostly” out like you would with bleeding brakes?

 

Yes it is. Which is why if you have a valve at the distribution block to temporarily reverse the flow of one of the hoses for each of the heads out to a bleeder nipple, then the other hose with normal fuel flow can flush air out of the heads. Actually now that you mention it, simply cracking the fittings isn't a bad way to go either. Simply retighten as soon as fuel squirts.

Okay nothing to see here. Move along.

 

They did a real nice job of building something that I fabbed up in my spare time for a fraction of the cost and now Riffraff uses my basic idea as the basis for the FRX. Clay asked me if he minded that he used my idea for the design theory before he even brought it to market. I'm still running that same system today on my truck.
Feed the rear ports of each cylinder head from the filter housing. Have the return come out of the front ports of each head and then to a tee where there is a small orifice that bleeds any air bubbles back to the fuel return that is teed into the main fuel return from the fuel pressure regulator return. I built it using NPT fittings, barbed fittings, a spool of fuel injection rated hose, split loom to protect the hose and a day's work. During operation it's job is to actively purge any air bubbles from the fuel stream as you are driving along. Air flows through a small hole a lot faster than a fluid will and the fuel pump has no problem keeping up with the small bit of extra fuel volume that the air bleed orifice now brings to the system.

 

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Oh maybe I get it now.

A 3-way valve on one of the fittings at the distribution block. Flipping the valve causes fuel to flow through the other line, through the head, then backwards through valved line purging the air. One for each head.

Seems like a workable idea, but likely overkill since how often do you actually need to bleed the air?

 

Would you even need any valves on the distribution block? Why couldn't you just start at the point farther from it and work your way around?

 

I like to over complicate things <MN accent>doncha knooow</MN accent>.

 

The answer is never.

The stock filter is excellent at removing air before the heads/injectors.

Even IF a gulp of air gets past the filter, it does no harm. It MAY create more noise until it’s either passed through the injectors (without hurting anything) or the air bubbles rise to the top of the filter while the truck rests.

I don’t know what the failure rate is with the SS hard lines and rigid fittings for fuel, but these have a limited service life as HPO crossover (an even dumber idea...). There is a reason Ford put vibraloc fittings on the stock hard lines.

The way we plumb the Vegistroke systems allows us to:

- feed the heads the way the factory does

- feed the heads from the other end than the factory does

- feed all (4) ports like a 4-line feed kit

- open one end of each head to ‘purge’ similar to the FRx design

All of these options can be done ‘on the fly’ and the results can be monitored in real time. There are a couple 1000 of these systems on the road and I’ve installed a several dozen myself - including some home brew versions that offer even more flexibility than the Vegistroke kit.

I can tell you without any shadow of a doubt that none of this makes any measurable difference in performance or any other parameter whatsoever. The only thing you can quantify is the increased chances of failure from deviating from stock. We decrease our chances of failure to basically ZERO with the Vegistroke system by using PTFE-lined SS fuel lines with JIC ends.



My old man (a PE) always said K.I.S.S.

 

I’m a PPE, i.e. **** Poor Engineer.

 

We know. And we love you anyway!!!!

I was a field inspector most of my life and worked with Engineers constantly. I infamously put ‘recommend engineering evaluation’ on my reports. The engineers would ask me how to solve the problem and when I gave them a suggestion, they’d ask why I didn’t just say that in the first place! I always told them it was because they had to prove that idea would work and I wasn’t qualified to do that...

 

That’s why I switched to the dark side that is Project/Program Management. The engineers really loved me after that.

 

Betchya say Ope.