Rewiring car

[Bill Baer]

Lou is right on target with the connectors and the relays but I don't consider the Chassis a good ground. Also I have seen several cases of grounding to the block and through the motor plate cause electrical problems (trans brake solenoid, ignition miss, gauges etc)
I would suggest that you ground the battery to the starter ( I drill and tap a hole in mine) and run a #8 or larger wire from there to a ground buss ( a piece of 1/4" thick brass or un-anodized aluminum) and ground everything important to it. This may seem like over kill but bad grounds can be the toughest things to locate/identify so why guess.

Just my 2 cents worth

[Ron Finney]

There is nothing wrong with the chassis ground if done properly. Sorry to disagree Bill, but grounding to the starter still connects the ground to the block, motor plate etc. Usually most ground issues are too small wire or bad connections, not cleaning the chassis, rollbar, block etc. wherever the ground is attaching. Any bad connection creates resistance which provides for a voltage drop. That is the voltage that is creating the oddities in other systems. In an electrical circuit the load should consume all of the voltage, not the wiring, connections, etc. I have seen many people run a big power wire and then a small ground. THEY MUST BE THE SAME SIZE! Now lets blow your mind for a minute, if you study electricity, (electron theory shows that the voltage leaves the battery through the negative terminal and returns through the positive!). Hard to convince people of that but it does kinda explain why most problems are on the ground side of the circuit. Definitely having redundant grounds is not a bad thing, just make sure they are big enough.

The relay advice is excellent. A relay is, is a remote electrical switch. It allows you to use a small current and to control a much larger one. Relays are used to keep from running big wires for every component into the dash or switch. Without a relay, all switches would have to be large enough to handle all of the current the load uses. If we did this, the wiring harness would be huge and we wouldn't have much room. You can use a smaller wire on the control side of the relay because it doesn't take much current to energize the relay and therefore a smaller current switch. Also, by not having to run the high current wires as far, you have less voltage drop in the wires and more available current to the component you are operating. Makes things much nicer.

Good Luck!

Ron

33 S/C

[JS Robinson]

Yes it is. But, Hey that's why there is always more then one place to get things. Everything was the same price also.

[Chris Williams]

Originally Posted by Bill Baer

I don't consider the Chassis a good ground. Also I have seen several cases of grounding to the block and through the motor plate cause electrical problems (trans brake solenoid, ignition miss, gauges etc)

But grounding to the block or the motor plate aren't a chassis ground... They are connected to the chassis (via the motor plate) and many folks anodize or powdercoat the plate, and that's a recipe for a bad ground. A chassis ground (to the, um... chassis) is fine, it's a big solid welded together wire -- of a pretty good gauge.

Electrical connectivity is pretty simple -- just make sure you make metal to metal contact, through a conductor that's larger than you need. No paint, powercoat, anodizing, gaps, etc.

I run a separate ground wire to the dash, but that's because of ignition noise and sensitive equipment -- a bad mix. And I have several spots on the chassis carefully prepped for grounds (sanded clean, solid connectors, etc.). S'all good.

[Ron Finney]

Chris is correct, however who installs an engine without grounding it to the chassis?

[Chris Williams]

Originally Posted by Ron Finney

Chris is correct, however who installs an engine without grounding it to the chassis?

People who assume the motor plate handles that responsibility. Then they powdercoat the motor plate. Oops.

[JS Robinson]

Thank you for all the great tips. One more question. Where is the best place to get weather pack connectors?

[Chris Williams]

Originally Posted by JS Robinson

Thank you for all the great tips. One more question. Where is the best place to get weather pack connectors?

I got all mine from Jegs. Just search for "weatherpack".

[Lou SG2340]

Originally Posted by JS Robinson

Thank you for all the great tips. One more question. Where is the best place to get weather pack connectors?

Summit has them also. Buy a complete kit, its cheaper

[mannymen]

Who sells a kit? I didn't see a kit on summits website