UnPossible

UnPossible

Well Known Member
Hey - I've been searching and it appears that removing the fuel pump to install a cooling shroud on a hung engine is no simple task.

As an alternative, I am wondering if I could;

1) cut the shroud in half
2)remove one of the bolts holding the pump on
3) attach one half of the shroud
4) reinstall the first bolt
5) remove the 2nd bolt
6) install the other half
7) reinstall the 2nd bolt
8) finally - lay up a couple of layers of fiberglass to join the two halves of the shroud back together.

I'll still have the fun of having to use a mirror to safety wire the two bolts together.

Is there any reason why this wouldn't work?

Thanks,
Jason
 
your right

it is a pain to do. I installed one after everything else on my engine was hung as a request from my friend. Seems like it took a good part of my day. But I think you are going to have just as much time in doing it the way you described as taking the pump off and doing it right. Plus, there is quite a bit of vibration back there, the fewer pieces to rattle apart the better. Buy a sacrifical allen wrench that fits the fuel pump bolts. Cut, alter, modify it to make things easier. Seems to me that one of the fuel pump bolts wouldn't come out unless the pump was pretty much out of the accessory housing, and maybe they were both like that. Before reinstalling everything, don't forget to feel up into the accessory housing to make sure the plunger didn't slip down and will be in the way. It may be necessary to rotate the prop a little to take some pressure off the fuel pump arm. I don't know your mechanical background but if you haven't dug this deep into an engine before, you might ask a friend that has for help.

Randy
8A
 
I have done temp. measurements

With just a 1 inch blast tube directed at the fuel pump there is only 2 degrees difference in temp between the sides.

Kent
 
kentb said:
With just a 1 inch blast tube directed at the fuel pump there is only 2 degrees difference in temp between the sides.
Click to expand...

Ahhhh! Good stuff! Kent, please tell us more about "between the sides". Where exactly were the temperature measurements taken, and how?
 
Pump shroud

I believe you can effectively cool the fuel pump down a few degrees and I think installing the shroud is a worthwhile PITA.
Especially if you plan on using mogas some day....
What you can do to ease the pain is cut the ears off and use a large hose clamp to keep it in place. A couple of vertically oriented aluminum tubes pop riveted to the inside
(from the outside) will keep the distance from the pump. It's not as elegant but much less trouble than removing those Fuel pump bolts.
Do as you wish.
 
kentb said:
With just a 1 inch blast tube directed at the fuel pump there is only 2 degrees difference in temp between the sides.

Kent
Click to expand...

DanH said:
Ahhhh! Good stuff! Kent, please tell us more about "between the sides". Where exactly were the temperature measurements taken, and how?
Click to expand...

Yes! I am certainly not doubting your calculations, but it seems to me it should be cooler than that side to side. Did you do a test with and without a blast tube?
 
My test.

My blast tube is about 2 inches away from the pump on the back/right side of it. This would be the 7 o'clock position as the pilot sets. My engine monitor can handle a 6 cylinder engine, so I bought two extra wires for the CHT ports and had a guy here at work braze the wires together to form a simple temp probe. These I have used to take many measurements under the cowl.
When I looked at the fuel pump temp I was considering weather to place a shroud around it or not.
I taped the probes, one under the blast tube and the other about 180 degrees from it. The probes were attached to just under the horizontal seam between the upper half and the lower part. I don't have the temp data with me here at work, but I recall that the difference was only a couple of degrees, so I didn't pursue the addition of the shroud. It seems to me that the metal must conduct heat around the pump very effectively.

Kent
 
N427EF said:
What harm exactly are you talking about?
I am just curious.
Click to expand...

Heat soaking the fuel pump... say after a flight one hot summer day, you land and taxi up for a fuel stop. You taxi in, shut her down, get out and organized, fill up and are ready to go again. But that shroud around the fuel pump hasn't had any air pushed through it in say 10-15 minutes or longer. You've got this fuel pump wrapped up in a metal shroud up against the back of the engine and it's baking. Not for me. The other thing I don't like is with the fuel pump all wrapped up in a shroud, you can inspect the pump for missing or loose screws or wet fuel areas hinting signs of a possible failure. Just MHO... your mileage may vary. :)

PS: If you've ever installed one of these shrouds, you probably harmed yourself in some way... a cut finger or hand, busted a knuckle, loss of your religion etc...
 
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anyone did splitted cooling shroud?

I would be interested if anyone did a vertically or horizontally splitted cooling shroud to make it more easily removable for fuel pump inspection? Or if anyone did a cooling shroud in glasfibres?
 
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