Engine ground

[Low Tailwheel rider]

Trying to decide where to attach engine ground cable on engine. This is on a Lycoming IO-360, forward governor and horizontal induction. Here are a few pics of various places I'm considering.
(1) Unused threaded holes vicinity the starter
(2) Various studs holding on the manifold/sump
(3) Various studs holding on accessory case

I am reluctant to use any of the various studs, esp with threaded holes available. Should I be...why or why not? Any particular preferred stud?
Far forward threaded holes complicates routing back to my firewall grounding point on the fuselage.
Appreciate all thought and insight, pics are always good!

Thanks so much - Dave

 

[Carl Froehlich]

I ground using a #2 welding cable to the nice ground stud on the starter. That is what is using the power…

Carl

 

[rv8ch]

Here is how I did it - working fine - 500 hrs.

Mickey's RV8 Site | Ground point on firewall

www.rv8.ch

 

[Carl Froehlich]

Remember to ground your pMags to the engine, not the firewall.

Carl

 

[Little Wing]

I grounded at the red arrow on both sides.

 

[lipper03]

Just checking, is grounding pmags to the engine not firewall for a case where the engine ground strap breaks? I'm still doing fwf, and I think I routed both of my pmags to the firewall lug, but I have to double check.

 

[wirejock]

Just checking, is grounding pmags to the engine not firewall for a case where the engine ground strap breaks? I'm still doing fwf, and I think I routed both of my pmags to the firewall lug, but I have to double check.

Yes. Manual mentions it.
Mine is IO-360-M1B rear gov.
I also grounded to the hole Rod (Little Wing) noted with a red arrow above. Easy to insert a 1/4" bolt. I did add a copper tab for smaller grounds like the P-mags. I wanted the big ground nice and tight. Clean the paint off the area to insure a good ground. Your starter will pull a lot of amps.

 

[fl-mike]

Vacuum pump studs are a good place

 

[hgerhardt]

Do not attach the ground cable to a bolt which compresses a gasket, as it will get loose with time. So that means don't use any of the bolts which hold the rear accessory housing. Also, the desire is to have the cable as short as possible to minimize voltage drop, so that means the back of the engine, specifically to the crankcase. Below is a good point to attach to, but scrape the paint off from both sides first, and use star washers to "dig in" to the aluminum casting for maximum electrical contact.