D 2. The 3/8" plywood firewall doubler is
now glued to the 1/4" plywood firewall front.
Use either Thick CA or epoxy and make sure
that the front of the firewall doubler is
centered on the back of the firewall. Wipe
away all excess glue that squeezes out.
Tick marks for alignment
Determine where the mount should be
installed on the firewall. Use the template in
the left column to make it easy to locate the
mounting holes. Photocopy or cut out the
template and tape it in place on the firewall.
Poke a T-pin t h o u g h the template to
accurately mark the bolt locations on the
firewall. Drill a 1/8" diameter hole at the four
pin holes and install the mount using 4-40
bolts, #4 flat washers and 4-40 blind nuts.
The length of the bolts will be determined by
the thickness of the firewall. A 1/4" firewall
will usually require 7/8" long bolts. Do not
tighten the bolts all the way yet.
D 3. Cut or break the "spreader bar" off each
mount half. Carefully trim any extra plastic off
each mount half left by the spreader bar. The
surfaces where the spreader bars were attached
need to be very smooth to allow the mount
halves to fit together. Also trim the flashing off
any other rough edges. Snap the two mount
halves together as shown in the sketch.
Slide the mount halves apart until the engine
mounting lugs will sit flat on the beams.
Adjust the mount until the firewall centerline
(or offset line) is centered between the "tick"
marks on the mount. Tighten the 4-40 bolts
to hold the m o u n t halves in position.
Determine how far forward the engine should
be positioned on the beams and mark where
to drill the mounting holes. Remove the
engine and drill a 3/32" hole at each mark.
Put a drop of oil in each hole and install the
engine using the #4 x 5/8" screws provided.
If you prefer to use 4-40 machine screws (not
included) to install your engine, just tap the
holes you drilled with a 4-40 tap.
With the engine installed on the mount, mark
the location for the throttle pushrod and fuel
lines. Remove the engine and mount. Drill a
3/16" hole in the firewall for the throttle and
two 7/32" holes for the fuel and vent lines.
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