Check Those Grounds!

[mcgovern61]

In the process of rebuilding/restoring my '82 Standard wire harness, I came across an issue that surprise me. There is only 1 frame ground wire in the wire harness.

Frame ground wire in wire harness:

This wire connects to the frame bolt located under the ignition coils. It is imperative that this eyelet is clean as well as the frame mounting surface.

The main frame ground is pretty easy to see from the battery negative to the frame and it should also be checked and cleaned accordingly.

The last ground kind of caught me off guard! :shock:

While checking the ballast resistor on my old '82 coils (which are not currently being used), I was looking for any leakage between the ballast resistor, the coils and the frame on the coils. I discovered that the ballast resistor is good! :yahoo:

BUT, I also discovered that the frame mount for the coils is also the grounding point for the coils! :shock: It never dawned on me that the coils get their ground directly from the frame via the mounting bolt connections! I hear so many stories of cracked and overheated coils and always wondered what happened? I know that my stator wire connector on the '81 harness melted as a result of corrosion and a bad connection. I can only assume that the coils could be subject to similar "heat" if there is a bad ground connection.

Looking at these coils and mounting brackets, I can see how that could be a real problem! :shock:

 

[backlander]

I just so happen to be working in the same area on my 84, getting everything ready to put it back together Gerry and noticed the same thing, but I have each system torn out as units, like complete wiring harness, etc. The coils and ground problems are due to dissimilar metals being used or mated together, aluminum and steel, setting up corrosion. You get the same thing when mating copper and aluminum, seems like the aluminum always oxidizes and causes the loss of ground. I'm using dialectic grease on the ground bolt area at the coils (G2) and Main ground at battery (G1) to see if that helps.

 

[mcgovern61]

I do have to wonder why Honda chose to use aluminum for the coil bracket and also grounding point. I would have thought a steel bracket would make a better ground with less corrosion (except for rust). I am going to clean these up real good and use dielectric grease also. I see how it has worked wonders at my stator plug!

 

[julimike54]

Don't know why it would not be applicable, in house wiring when aluminum is carrying current inspectors expect to see NOALOX coating the joint. It's to prevent oxidizing of the aluminum
https://www.idealindustries.ca/products/wire_installation/accessories/noalox.php
Might do same as dielectric?

 

[OldWrench]

I do have to wonder why Honda chose to use aluminum for the coil bracket and also grounding point.

Probably trying to keep the weight down, and it is a lot faster to machine aluminum than steel; but that is just a guess.