Brief Description: Install Battery and Starter Contactors
I already mocked up where I wanted to mount the battery and starter contactors. I double checked the location and marked the 4 holes using the contactor mounting flange as a guide. Two of the holes would go through the F-601D-R-1 stiffener to add strength and ther other two holes would just go through the stainless steel firewall. I would have to fabricate a reinforcing plate later and rivet it to th firewall. The bolts called for are AN4-4A so I would have to drill the holes to slightly over 1/4". I started with a #30 at slow speed and gradually increased to 1/4". I wanted a tight fit for the bolts so the K1000-4 platenuts would stay centered when I drilled the rivet holes for the platenuts. With the holes drilled, I deburred them and secure the 4 K1000-4 platenuts with shortened AN4 bolts. I drilled the 8 #40 holes,removed the platenuts and deburred the holes. Next, I measured and fabricated the reinforcing plate from .032 aluminum. I drilled the rivet holes and then held the plate to the inside of the firewall and match drilled the holes through the firewall. With it clecoed in place I match drilled the 2 bolt holes and the 4 platenut rivet holes. I dimpled and machine countersunk the firewall and reinforcing plate. I cleaned and primed the reinforcing plate, let it dry and riveted it to the firewall with AN426AD3-3.5 rivets. I riveted the 4 K1000-4 platenuts to the firewall with AN426AD3-4 and 4.5 rivets. Last, I bolted the Lamar X61-0028 master and X61-0030 starter contactors to the firewall with AN4-4A bolts and AN960-416 washers as called for in DWG 31A.
