fuel manifold installation

[Bmarler]

I opened the valve and found those seals. So those hard plastic are made from ptfe. The stem enters from the inside and pushes through the small opening, its seal will press against the wall to seal. The outer section of the opening also has a seal for the bonnet nut, the inner ring of this seal is raised to create a seat for the bonnet nut, probably working as a second line of defense for the inside seal.

To reassemble, should I use plumber grease to cover these seals and the ball?


View attachment 165749View attachment 165750

I like to use a tiny amount of silicone grease to help keep from scarring up the seals when re assembling. Not enough to even see, but enough to feel.

 

[paulga]

The difficulty is, the 1/4 mini ball valve in the middle position has to be installed at last, because ball valves have a stem that needs clearance for install. This mini ball valve is installed on top of a 1/2 to 1/4 reducer. The reducer has a 15/16 hex head, and I would want to tighten on the reducer hex, but the space was too small to fit a 15/16 open end wrench.

The mini ball valve has a 22mm hex head and 22mm wrench fits in ok. I assembled the mini ball valve and the reducer first, then hand tightened it into the manifold, finished by tightening on the ball valve using a 22mm open end wrench. Is this practice correct?

 

[Mac2]

The difficulty is, the 1/4 mini ball valve in the middle position has to be installed at last, because ball valves have a stem that needs clearance for install. This mini ball valve is installed on top of a 1/2 to 1/4 reducer. The reducer has a 15/16 hex head, and I would want to tighten on the reducer hex, but the space was too small to fit a 15/16 open end wrench.

The mini ball valve has a 22mm hex head and 22mm wrench fits in ok. I assembled the mini ball valve and the reducer first, then hand tightened it into the manifold, finished by tightening on the ball valve using a 22mm open end wrench. Is this practice correct?

View attachment 165892

I used marine tex on the threads so they would never leak. This also helps to line up the ball valve handle, knowing it might not be completely tight. Can’t tell what you used.

 

[paulga]

I used marine tex on the threads so they would never leak. This also helps to line up the ball valve handle, knowing it might not be completely tight. Can’t tell what you used.

I used Loctite 567
using marine tex, is hand tighten sufficient?

 

[Bmarler]

Your method is fine. You can assemble in any order you want. Hand tight isn’t tight enough with any sealant. Marine Tex, while it works for others, isn’t something I use for thread seal. I like something I can take apart later if needed.

 

[paulga]

Your method is fine. You can assemble in any order you want. Hand tight isn’t tight enough with any sealant. Marine Tex, while it works for others, isn’t something I use for thread seal. I like something I can take apart later if needed.

if in between the mini ball valve and the manifold is a close nipple that does not have a hex part, should I hand tighten the nipple to the manifold then the ball valve to the nipple, then wrench tighten only on the ball valve?

Is it necessary to first use a strap wrench on the nipple to ensure the nipple is tightened on the manifold end?

 

[Bmarler]

In that instance, I usually prep and insert the nipple into the valve body, snug by hand. Then I prep the other end and assemble into the manifold. Tighten all at the same time.
If there was a reducing bushing in the manifold with bigger threads than the valve and nipple, I’d tighten the bushing first as it can take more torque to set it than the smaller threads in the valve and close nipple.

 

[paulga]

In that instance, I usually prep and insert the nipple into the valve body, snug by hand. Then I prep the other end and assemble into the manifold. Tighten all at the same time.
If there was a reducing bushing in the manifold with bigger threads than the valve and nipple, I’d tighten the bushing first as it can take more torque to set it than the smaller threads in the valve and close nipple.

so the correct installation sequence should be: ball valve in the left port, the reducer in the middle port, ball valve in the right port, then the mini ball valve in the last step

this is the reducer that plumbs the mini ball valve to the manifold

 

[Mac2]

Marine Tex is permanent, but the only solution I know of to seal the threads against diesel when you can’t torque the fitting down. I’ve only had to do this with a manifold due to having to line up the valve handles.

 

[luna]

I never have liked a close nipple as I always wonder how tight they are because you are driving two connections at once. Yes, they work fine, but are disposable as in order to completely remove them you need to drive on the threads.

I use these instead, but they add about 3/8" to the length.

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The other attribute of these fittings is that the threads are machined to a tighter tolerance. Your manifold, if designed for fuel may also have these more precise threads. It's called National Pipe Tapered Fuel (NPTF) for a reason, as it is used for fuel systems.

 

[Bmarler]

so the correct installation sequence should be: ball valve in the left port, the reducer in the middle port, ball valve in the right port, then the mini ball valve in the last step

this is the reducer that plumbs the mini ball valve to the manifold


View attachment 165903

That’ll work.

 

[Bmarler]

Marine Tex is permanent, but the only solution I know of to seal the threads against diesel when you can’t torque the fitting down. I’ve only had to do this with a manifold due to having to line up the valve handles.

Here’s another thing you could try: https://getpipe.com/x-pando-pipe-jo...AoZyZEjQDRq4Rt7mbZmhaM8XQDlbs7t4aAjQTEALw_wcB

But it sounds like you’re comfortable with marine Tex. It’s good stuff to have around for all kinds of things. There’s always some marine Tex in my tool box.

 

[paulga]

This is what the set up looks like. Thanks all your input.
There is no leak so far.
The manifold is not horizontal but this could be minor issue.

 

[paulga]

The lower end of the 3/8 hose sees some permeating pretty fast, the higher end of the same hose is dry. I checked the leak is not from the threads, but from the hose-barb connection area.

The lower end hose connects to a 45 degree hose barb. The hose od is 17.5mm, it is within the manufacturer range of the spring clamp. Could the 45d barb fitting has defect?

 

[paulga]

The lower end of the 3/8 hose sees some permeating pretty fast, the higher end of the same hose is dry. I checked the leak is not from the threads, but from the hose-barb connection area.

View attachment 166170
View attachment 166173
The lower end hose connects to a 45 degree hose barb. The hose od is 17.5mm, it is within the manufacturer range of the spring clamp. Could the 45d barb fitting has defect?



View attachment 166172

The spring clamp used is CTC17BAND12

 

[KnotYet]

As a quick and easy test, slide that spring clamp over and use an appropriate hose clamp there.

 

[paulga]

As a quick and easy test, slide that spring clamp over and use an appropriate hose clamp there.

I switched to a screw clamp. Also tightened the fitting further to tilt the barb up a bit, and applied a layer of sealant on the barb before sliding the hose on. Now there is no leak so far.

Last time, after turning on the valve, the fuel primed the filter swiftly. This time however, the prime didn't happen. If the fuel should automatically try to reach to the same level of the tank, it should prime the filter. Is there something blocking the fuel? Maybe the sealant that I applied to the barb somehow got in the way?

 

[KnotYet]

Many pumps must be primed, i.e, most of the air excluded, before they will pump at all.
Something as simple as an air 'lock' or a shift in the boat's trim could affect the gravity feed.
Don't leave the end of that fuel line open unless you are watching it like a hawk.

 

[paulga]

Many pumps must be primed, i.e, most of the air excluded, before they will pump at all.
Something as simple as an air 'lock' or a shift in the boat's trim could affect the gravity feed.
Don't leave the end of that fuel line open unless you are watching it like a hawk.

How to prime this fuel filter manually? Or remove the potential air bubbles so the auto prime will happen?
I tried connecting this hand pump to the open fuel line, it didn't work. It was able to suck some fuel out , but never able to fill that filter up

 

[KnotYet]

Maybe adding fuel into that fuel line would suffice?

 

[paulga]

Maybe adding fuel into that fuel line would suffice?

The fuel does not get in the filter in that way.

The hand pump hose has 10mm id (1st photo) and the fuel hose has 11mm od(2nd photo). With some grease I was able to join the two hoses. The pump sucked easily a lot of fuel out, so the path is not clogged by anything. But the filter could only be filled ~ 1/8 of its capacity in the end. If I turn on the valve now, diesel will pop out of the fuel hose in the 2nd photo, but the level in the filter will not increase.

What is the reason?

 

[KnotYet]

You may have to pre-fill that filter in a bucket to get rid of all the air.
Is that tiny amount of air enough to stall the fuel pump?

 

[paulga]

You may have to pre-fill that filter in a bucket to get rid of all the air.
Is that tiny amount of air enough to stall the fuel pump?

Maybe it's not necessary to fully prime it. I'll see. I can change the filter or immerse it in diesel if there is a problem. But intuitively the diesel should first fill the filter up before coming out of it.

 

[fractalphreak]

When we bought NWD, the genset ran off one of the main Racor 500 filters with the engines, and the Webasto had the Racor 120AS on it. However, each 500 filter was dedicated to its tank, and they were outboard of the transmissions/shafts and impossible to reach under way to switch over or change.

When I built the new centrally located fuel manifold, I also envisioned the genset and diesel heater (Webasto AT40) using the same Racor filter (in my case the Racor 120AS) and plumbed the system that way.

After that I could never get the Webasto to prime and stay primed, no matter what I did to prime or purge or seek out ways to better seal the hoses. The generator would run flawlessly, but even without running the gen, the Webasto would lose prime and fail to fire.

After consulting with Sure Marine in Seattle, who had sold the heater to our PO, they recommended giving the Webasto its own filter and keeping the fuel line from the tank to the dosing pump as short as possible. (The Webasto installation instructions specify 1.2 m maximum length from tank to pump.) I did that, and have never had a lick of trouble since. Its overkill, but to keep things simple I put the heater on another 120AS so I only have to stock filters for that and the 500's for the mains.

The fuel system I built took fuel from an outboard tank to the center of the boat, through the manifold board and the racor, then back out almost to where it came from to the dosing pump. My guess is my total run was 2-3 times over the max according to Webasto and included a lot of copper pipe that was sized for main engines.

The Webasto install instructions also emphasize using 2mm id copper pipe and has specific instructions on how to use hose in conjunction with the pipe to avoid trapping air bubbles, as well as mounting the dosing pump horizontal.

I think the issue is the dosing pump is so weak and takes such tiny gulps, that the tiniest bubbles in the system will overcome its ability to pull fuel. I thought I was battling leaks, but in reality I think it was likely bubbles remaining in the system that engine lift pumps don't notice but the dosing pump can't handle.

My experience.

 

[paulga]

When we bought NWD, the genset ran off one of the main Racor 500 filters with the engines, and the Webasto had the Racor 120AS on it. However, each 500 filter was dedicated to its tank, and they were outboard of the transmissions/shafts and impossible to reach under way to switch over or change.

When I built the new centrally located fuel manifold, I also envisioned the genset and diesel heater (Webasto AT40) using the same Racor filter (in my case the Racor 120AS) and plumbed the system that way.

After that I could never get the Webasto to prime and stay primed, no matter what I did to prime or purge or seek out ways to better seal the hoses. The generator would run flawlessly, but even without running the gen, the Webasto would lose prime and fail to fire.

After consulting with Sure Marine in Seattle, who had sold the heater to our PO, they recommended giving the Webasto its own filter and keeping the fuel line from the tank to the dosing pump as short as possible. (The Webasto installation instructions specify 1.2 m maximum length from tank to pump.) I did that, and have never had a lick of trouble since. Its overkill, but to keep things simple I put the heater on another 120AS so I only have to stock filters for that and the 500's for the mains.

The fuel system I built took fuel from an outboard tank to the center of the boat, through the manifold board and the racor, then back out almost to where it came from to the dosing pump. My guess is my total run was 2-3 times over the max according to Webasto and included a lot of copper pipe that was sized for main engines.

The Webasto install instructions also emphasize using 2mm id copper pipe and has specific instructions on how to use hose in conjunction with the pipe to avoid trapping air bubbles, as well as mounting the dosing pump horizontal.

I think the issue is the dosing pump is so weak and takes such tiny gulps, that the tiniest bubbles in the system will overcome its ability to pull fuel. I thought I was battling leaks, but in reality I think it was likely bubbles remaining in the system that engine lift pumps don't notice but the dosing pump can't handle.

My experience.

It was an earlier plan to place the manifold after the gen racor filter on the SB side. Now since I found an available T valve near the portside tank, I have changed plan, see my post #103.