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Engine Harness Ground

Practical Motorsport Wiring - Club Level

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First of all thank you for putting all this information together. I have learned a lot and this course has given me the needed structure to improve my harness construction. My question is related to terminating the common 12v ground to the engine block. In both the Wiring Fundamentals & Club Level Construction courses there wasn't any practical examples of grounding the harness. Correct me if I'm wrong, but I don't recall seeing this information and I have tried to go back through some of the modules to find that.

Could you provide me with some examples of terminating the grounds? It looks like you are using a solid barrel lug? perhaps with a hex crimp? It would be really helpful if you could give me some tool recommendations for terminating a range of ground wire bundles.


1. What tools do you use to terminate engine harness grounds to O ring terminal?

2. What terminals do you use?

3. What is the process to terminate? I am assuming shove all wires into the O ring terminal and crimp, but there might be a better way?


G'day Drew.

You're on the money, it is as simple as connecting all the grounds into a single terminal lug, and crimping. The size of lug you'll need will be determined by the bolt hole its attaching to, and the overall CMA of the wire included in the crimp.

I use a really cheap hydraulic hex crimp tool from aliexpress for this. It is a little fiddly, as the dies don't stay in place particularly well until you have some pressure on the crimp, but its possible to get a great result with a bit of practice.