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Need photos of firewall just before engine install

rockwoodrv9

rockwoodrv9

Well Known Member
Patron
I hung my engine and then noticed I didn't have the platenut for the battery ground drilled. I will be taking the engine off again to get that installed but would like to make sure I have everything else done before it goes back on.

Also, is it easier to pit the exhaust or other accessories on before or after mounting?
 
FWIW, I just ran my heavy battery ground cable to the firewall and took a pair of copper bus bars and sandwiched them on the firewall, with one copper bar on the inside and one on the FWF side, bolted together through the firewall, with the battery ground cable hung on the firewall side. Location is not critical this way, and it gives a 100% good battery ground location both FWF and under panel for any use, and grounds the entire airframe for local grounds as well.

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10 rivets on bottom firewall flange

I put in 10 rivets on the bottom firewall flange. I left the center hole open for the U720 attach. Then 5 rivets on either side. These would be hard to buck with the engine mount on the firewall.
 
My ground connection is like Airguy's. A good size copper bolt (3/8 ?) anchors the battery and engine ground cables on the FWF side, and the ground bus on the aft side of the FW. There was no need for a platenut using that approach.
 
Thanks guys. I think I was getting too hung up on putting the ground exactly where it is shown on the plans. Am I correct in assuming that I ground to the airframe and then ground my forest of tabs to that ground?

I will take a couple pictures and post them this evening for a review. Thanks again.
 
rockwoodrv9 said:
Thanks guys. I think I was getting too hung up on putting the ground exactly where it is shown on the plans. Am I correct in assuming that I ground to the airframe and then ground my forest of tabs to that ground?

I will take a couple pictures and post them this evening for a review. Thanks again.
Click to expand...

That's what I did in the interior, yes. I ran one heavy wire from my copper bus under the panel to a subpanel point and put my forest of tabs there.
 
rockwoodrv9 said:
Thanks guys. I think I was getting too hung up on putting the ground exactly where it is shown on the plans. Am I correct in assuming that I ground to the airframe and then ground my forest of tabs to that ground?
I will take a couple pictures and post them this evening for a review. Thanks again.
Click to expand...

In the way mine is installed, all the grounds are located in that one spot. From what I read, Greg's is too. The ground bus ( forest of tabs) you get from B&C has the big copper bolt on one end. That fastens it to the FW, with the engine ground strap and battery negative cable tied to the bolt on the FWF side. I'll see if I can dig up my construction pics...
 
OK, this is my plan. Use the flex strap from the battery to the firewall. Then from there to the forest of tabs. In the pictures, I haven't hooked it up yet - just finger tight so I could size the wires. Let me know if this is correct.
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Other wiring at the solenoid.
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