GREAT PLANES RV-4 Instruction Manual page 35

3. Drill a 17/64" [6.7mm] hole on each of the two marks
you have made on the firewall. These holes will
accommodate the fuel line and the pressure line. Note: A
two line fuel system will require the use of a fueling valve.
We mounted ours to the firewall in the cowl opening. If you
prefer to have a third line for the fill line you will have to drill
a third hole in the firewall.
4. Attach the engine mount to the firewall. Insert a
6-32 x 1" [25mm] socket head cap screw and #6 washer into
each corner of the engine mount, screwing the screw into
each of the four blind nuts that were previously installed on
the back side of the firewall but do not overtighten.
Note: The engine installation is a side mount so be sure that
engine mount is installed for a side mount installation.
5. Place the fuselage into a cradle or set it up on the
bench so that you can place the engine onto the engine
mount. Position the engine so that the distance from the
firewall to the front of the thrust washer is 4-1/2" [115mm]
and that the engine mount is centered on the firewall. When
satisfied with the positioning tighten the engine mounting
bolts to the firewall.
6. Mark the location for the holes for mounting the engine to
the engine mount. Hint: The Great Planes Dead Center
(GPMR8130) works fast and easy for marking these holes!
7. On the marks you made on the engine mount, drill a
7/64" [2.8mm] hole into the engine mount. After drilling the
hole, tap each hole with a 6-32 tap. Once tapped, mount the
engine to the engine mount with four 6-32 x 3/4" [19mm]
socket head cap screws and #6 washers.
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™ Tool