Sat Feb 19 2011

Fuel line tubing

Well the tube laying on the floor was too short, so I fabricated a longer one.

I could see that Van's didn't make the holes in the brackets aligned with each other (why the heck not?!?!), so I needed to joggle this aft by 5/16 inch.

In order to determine the location of the hole for the purge line, I started by making a template from a scrap piece of 0.025 alum. I drilled a 1/2 inch hole to match the existing fuel line hole and used a snap bushing to hold it in place.

Then some layout work and a pilot hole where the proposed new hole will be.

Marking through the pilot hole on the bracket. It ended up being quite close to both the floor stiffener and the forward face of the bracket.

Hrm...if it's too close to the forward face of the bracket, the check valve will interfere with the cover plate. Let's see...the check valve is 1 inch diameter, so I need a minumum of 1/2 inch from the cover plate. On second thought make that 5/8 inch.

I created a new offset line 5/8 inch from the front edge and drilled another pilot hole. (new pilot hole not yet drilled in this image). I'm editing this update, I can see that I did something wrong...the 2 inch radius shown represents the distance from the centerline of the main fuel line to the centerline of the check valve. However, I should have drawn that radius from the joggled position of the tube. I can see I started to do that...hence the 9/16 inch offset line, but somewhere along the way I must have gotten distracted. No'll see shortly that I ended up doing a lot more iterations and still havent drilled the hole in the bracket.

Here's the little sharpie circle showing the proposed location of the purge line.

In order to connect the purge line (which is 1/4 inch diameter tubing) to the check valve (3/8 diameter tubing), I need a reducer. However, since the reducers are male on both ends, I need a short little section of tubing to join the reducer to the check valve. It was a little tricky trying to minimize the length as much as possible.

Looks like 2 inches is about the shortest I'm going to be able to make.

Note the AN6 to AN4 reducer fitting in the bottom right hand corner.

Dang...still too long. Maybe I can get a short female to male reducer fitting online.