Fuel System Mods (Part 1)

With most of my Citation off at Eric Langbein Racing for fabrication work, I am left with precious little to work on now in the Maisey Racing garage. So, tonight I took out the HPD fuel system parts and started seriously looking at the modifications needed to fit the new in-tank fuel pump and regulator.

My original plan (at least in concept was to fit the entire pump, regulator, wiring assembly in through the existing opening in the cell for the fuel pickup line. Trail fitting the pump showed that it is sufficiently small in diameter to slide in easily. The fuel regulator block however is another story. it is about 1/4" too large to slide past the nut plate inside the cell opening.

That got me thinking. While I can probably install the regulator by sliding the plate aside and stretching the opening, maybe it would be better - and make future service much easier - to enlarge the opening. Shown here in masking tape is a quick drawing of how I would do this.

Basically my idea is to make the opening oval and create new aluminum backing and top plates (and rubber gasket). This will provide plenty of room to remove and service the parts later on if needed. It will also provide a less cluttered space to mount the wiring connector and outlet elbow fitting. (My tank currently has the vent line installed in the filler neck, and at this point I am inclined to leave it there).

This is a picture of the existing, unmodified opening. It has a 3" OD round nut plate inside the cell and a 3" round cover with a rubber gasket outside. (The original AN6 bulkhead fitting is centered in the outer plate).

Test fitting the HPD supplied pump shows that it will fit fine through the existing opening. But if I need to muscle the fuel regulator block into the same opening, I will have to install the lines above it after I squeeze it through the hole ("ship in a bottle" style). I am thinking that this will not bode well for future service and maintenance.

So at this point my plan is to make two new sandwich plates. I would cut the center out of the inside the tank plate and thread the holes. The top plate would be solid and have two holes for the fuel outlet and the wire bulkhead fitting. I would make a corresponding rubber gasket to go between the top plate and the cell membrane. This would essentially replicate the existing setup but would provide sufficient room to slide the entire assembly in and out of the tank while still attached to the top plate. Making future service (like cleaning the "sock" as easy as removing the eight socket head fastners.

Shown here are a couple of quickly improvised templates drawn on masking tape attached to some surplus aluminum plate I had laying around the shop.

BUT - cutting into the expense fuel cell to enlarge the opening is not for the faint of heart. So before I proceed, I plan to post this part of the Blog on ApexSpeed.com (http://www.apexspeed.com ) the Honda FF Conversion forum (http://hondaff.yuku.com ) asking for input.

So if you have advice or comment please post it on one of these boards or here in the blog. I am looking for input.

Tomorrow night I plan to crank up the bandsaw and make the two plates to at see how they look and fit.

Sean