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  #1  
Old 09-24-2012, 08:53 PM
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Flyguytki Flyguytki is offline
 
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Default Red Cube mouting possible issue

So I mounted the cube today, it is located just after the mechanical fuel pump before it gets to the silverhawk fuel injection servo. I was pleased with the way it turned out until a buddy of mine pointed out that fuel lines are mounted to the motor and the cube is mounted to the motor mount. Is this correct that the cube/fittings will be prone to cracking due to engine vibrations on the mounts when it it is fixed solid to a non moving piece?







-david
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  #2  
Old 09-24-2012, 09:06 PM
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Yep he's correct, especially with the short looking hose you have from the pump.

It's also generally recommended the the xdcr be located between the servo and the distribution manifold.
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  #3  
Old 09-24-2012, 09:11 PM
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Flyguytki Flyguytki is offline
 
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I tried to find a way to put it between those 2 however with the setup I have there just is no room to get it in there with the mounting requirements. I spoke with the EI Guys today and he said there should be no problem putting it where I did. I guess I will ahve to come up with a new mounting solution. Back to the drawing board.

-david
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  #4  
Old 09-24-2012, 09:12 PM
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Ironflight Ironflight is offline
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I am going to concur with Walt - those lines just look way to short to me, and they are oriented such that when the engine moves, the end fittings will be pulled on with every cycle - that is a great way to have a fuel leak/fire. I'll be honest - that installation looks scary to me.

Paul
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  #5  
Old 09-24-2012, 09:19 PM
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N941WR N941WR is offline
 
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One other thing, you do not want your fuel lines to go up hill and then back down hill, allowing a place for water and "gunk" to collect.

This may be more important in a carbureted engine but it is still a good practice.
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  #6  
Old 09-24-2012, 10:50 PM
JakeLewis22 JakeLewis22 is offline
 
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Here are a few pictures of how I mounted my fuel flow sensor between the servo and the spider at the right front corner of the sump. I was concerned about mounting it to the engine but so far it's been working flawlessly. I cut up some fire sleeve to insulate the cube and used red RTV to glue the pieces together. The piece of fire sleeve on top insulates the cube from the mounting bracket. The mounting bolts were tightened just enough until the fire sleeve started to crush and then I safety wire the two bolt heads together to keep them from backing out (along with self locking nut plates). In case you can't tell in the last photo, I put two loops of safety wire between the top fire sleeve and the mounting bracket before I tightened the bolts. I then pulled the loops tight to hold the fire sleeve to the cube.







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  #7  
Old 09-24-2012, 11:37 PM
dhmoose dhmoose is offline
 
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Default Hose sealant?

David, are you using RTV as a sealant for your hose/AN fitting connections? I see some on the hose side of your connections and I didn't think this is a place where any sealant is used. Just curious as I'm working on my FWF.
-David H


Quote:
Originally Posted by Flyguytki View Post
So I mounted the cube today, it is located just after the mechanical fuel pump before it gets to the silverhawk fuel injection servo. I was pleased with the way it turned out until a buddy of mine pointed out that fuel lines are mounted to the motor and the cube is mounted to the motor mount. Is this correct that the cube/fittings will be prone to cracking due to engine vibrations on the mounts when it it is fixed solid to a non moving piece?







-david
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  #8  
Old 09-25-2012, 05:42 AM
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Flyguytki Flyguytki is offline
 
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Quote:
Originally Posted by dhmoose View Post
David, are you using RTV as a sealant for your hose/AN fitting connections? I see some on the hose side of your connections and I didn't think this is a place where any sealant is used. Just curious as I'm working on my FWF.
-David H


David, The Red RTV was used to seal underneath the firesleeve before the hose clamp went on. It is not being used as a thread sealant.

-david
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  #9  
Old 09-25-2012, 07:06 AM
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I would not recommend mounting to the engine... It will work for a while, but the vibration will reduce its service life. I suspect the best place is still in between the gascolator on the firewall and the engine driven pump. You'll get a momentary reading of higher flow when using the boost pump with the cube in that location, but it doesn't seem to affect the accuracy of the fuel totalizing due to the short duty cycle of the boost pump.
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  #10  
Old 09-25-2012, 07:45 AM
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Quote:
Originally Posted by Snowflake View Post
I would not recommend mounting to the engine... It will work for a while, but the vibration will reduce its service life. I suspect the best place is still in between the gascolator on the firewall and the engine driven pump. You'll get a momentary reading of higher flow when using the boost pump with the cube in that location, but it doesn't seem to affect the accuracy of the fuel totalizing due to the short duty cycle of the boost pump.
This was correct in years back Rob, but I talked directly with the engineering folks that make the red cube when we were mounting ours on Tsam last year, and the design has changed - vibration due to engine mounting is no longer an issue according to them.

Paul
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