Van's Air Force
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bolts for engine ground
- Thread starter dspender
- Start date
Bill Boyd
Well Known Member
How many of you ran a dedicated ground from rear battery location to the firewall/panel area vs just a local airframe ground next to the battery tray?
I'm planning a firewall ground of the engine case to the forests of tabs there that have a through-stud holding them together back-to-back, and local ground of battery to battery box behind the baggage bulkhead. A separate ground wire forward seems like needless weight and $. Missing anything?
I'm planning a firewall ground of the engine case to the forests of tabs there that have a through-stud holding them together back-to-back, and local ground of battery to battery box behind the baggage bulkhead. A separate ground wire forward seems like needless weight and $. Missing anything?
I did when I built my -10. I don't like the idea of using the air frame as a ground.
Toilet hold down bolt is brass, fully threaded. Cut off head and you should be good to go.
Even has brass nuts in bag.
I just installed a new toilet last week and was surprised to find that the hold down bolts were only brass plated steel when I cut it down. Surprised me when I hit it with the cut off wheel to trim it down for the cap and sparks burned into my nice new toilet glazing.
cderk
Well Known Member
I did, but only a small one for my avionics. The battery is grounded locally in the back.
cderk
Well Known Member
why not ground your engine to the engine mount? there are actually ears on the engine mount for this purpose.
Did that. When I built mine I ran 0 gauge from the negative terminal to a post in the fire wall that passed through and into the engine compartment. Braided wire from there to the engine mount. Zero grounding issues with that process. Rapid engine starts even in the Michigan winters
Scott Hersha
Well Known Member
Any descent hardware store will have an isle with the Hillman hardware drawers (here in Cincinnati we have Hillman headquarters, and good selections of everything). Anyway - they should have a section with brass hardware with brass bolts, nuts, and washers. I used 5/16? bolts on the firewall, which is connected to an engine ground strap and a few 1/4? tabs on the hot side, and the ?forest of tabs? on the inside as well as a place to connect your ground pole of your battery if it is aft of the firewall. You will need 2 bolts for this installation if you are making your own firewall ground bus. It?s easy to do, and pretty inexpensive.
TomSpencer46
Active Member
ground
I put a forest of tabs on the cockpit side of the firewall and used one of the bolts to connect my engine ground. On the cockpit side I attached a #2 wire to the longeron that runs to the back under the door sill and hooked my battery ground to it in the back. I think that 3/4 by 3/4 angle can carry the load.
I put a forest of tabs on the cockpit side of the firewall and used one of the bolts to connect my engine ground. On the cockpit side I attached a #2 wire to the longeron that runs to the back under the door sill and hooked my battery ground to it in the back. I think that 3/4 by 3/4 angle can carry the load.
snopercod
Well Known Member
I'm just a fiberglass guy but I ran a heavy (2/0) cable from the negative terminal of the battery directly to a starter mounting bolt. I ran the cable right through the firewall and sealed the penetration with red RTV. Yeah, I know 2/0 is probably overkill, but my starter draws 400+ A when cranking (Yes, I have a 500A shunt and actually measured the current draw). Too heavy, you say? If you were to do the math, your would find that the weight of 2/0 copper vs. #2 copper is insignificant for the 4' ground wire length in my plane.
cderk
Well Known Member
Dan - i read the article, which is interesting. My question is, did he really mean you can?t assume that the engine is grounded just by its connection to the engine mount? There is an ear on the engine mount - i ran a strap from the case to the ear - I?m not just relying on the mount itself.
Thanks
Charlie
Not Dan, but my take is that it?s just not the best ground.
I.e. there?s a lot of extra resistance that is undesirable.
