VRaptor SpeedWorks "You Dream It, We Build It!"

Fuel Tank Cross-Over Kit

October 24, 2012  by Shane

This kit solves a few problems with the installation of the cross-over hose between the fuel tanks.  The FFR provided parts have no real provisions for sealing up the AN fittings to the tank.  The teflon washers provided will not provide a good seal.  Also, for the ’97-’03 tanks, when using the programmable fuel gauge, there is no need for any of the internals of the GTM Driver’s side tank……the jet pump and fuel level sender are not needed.  With this being the case, you need to figure out a way to seal the AN fitting to the tank, as well as figure out how to block off the ports in the tank, as they are no longer used.  The location of the AN fitting drilled into the tank also usually results in interference with the wheel-well aluminum panels, and requires the panels to be trimmed for clearance.  This kit solves these problems by replacing the ‘Vette jet-pump/sender assembly with a replacement plate that has mouting provisions for the FFR provided AN fitting, as well as the proper seals to seal the AN fitting to the plate.  The original OEM tank gasket and bolts are re-used to seal the new plate to the tank.  This kit also provides the seals and washers needed to seal the AN fitting drilled into the GTM passenger side tank.

What you get in the kit is:

1 Aluminum “Adapter Plate”

2 Pressure Sealing Washers (to seal the AN fittings to the outside of the tank)

2 Square-cut O-rings to compensate for variations in thickness of the tank walls and also to provide constant pressure on the AN fitting nut and Pressure Sealing Washer

2 Aluminum Washers to install between the AN fitting nut and the square-cut o-ring.

For installation, you will need to trim the “webbing” out of the ID of the pressure sealing washers (these are the washers you see in the photo that are inside the plastic packaging that are moulded to the steel outer washer).  You can do this with a razor blade or exacto knife……just be sure to not cut into the main part of the rubber seal.  Install the pressure sealing washer onto the AN fitting.  Install the AN fitting with the pressure sealing washer thru the aluminum mounting plate (or thru the hole in the plastic tank for the pass side GTM tank).  On the inside of the tank (or backside of the aluminum plate) install the square cut rubber O-ring, then the aluminum washer and then the nut.  DO NOT OVER-TIGHTEN THE NUT!!  100% of the seal takes place with the pressure sealing washer between the hex flange of the AN fitting and the aluminum plate or plastic tank.  The square cut O-ring inside the tank DOES NOT MAKE A SEAL.  The O-ring is there only to provide a consistent pressure to the outside pressure sealing washer and make up for variations in tank wall thickness at the drilled hole location in the tank.  The nut that secures the AN fitting only needs to be tightened enough to pinch the pressure sealing washer against the tank enough to make contact all the way around and seal.  If you over-tighten the nut, it will squish the O-ring out from behind the aluminum washer, tear it in half and then you will no longer have any tension against the pressure sealing washer.  If you look at the 4th photo down, you can see a good example of a proper installation.  The outer edge of the O-ring is crowned out to be about right at the OD of the aluminum washer.  This amount of tension will provide constant contact for the pressure sealing washer.  Do NOT tighten the nut by holding the nut stationary and turning the AN fitting with a wrench.  This will tear/roll the pressure sealing washer.  Once you reach the proper tension, you will notice that there is still “compliance” in the fitting…..in other words, with the crossover 90 degree fitting installed (be sure to hold the AN fitting in the tank stationary while you tighten the crossover AN hose end) you will be able to rock the fitting around in the tank slightly if you pull or push on the fitting with some force.  This is normal!  As long as the pressure sealing washer is pinched tightly between the AN hex flange and the aluminum plate or tank, it will not leak.