Electrical question,for a cobra

Huckleberry5 · #1 (**permalink**) 05-09-2008, 11:46 PM

can you tie off all wires to cowl bar and use it as a ground, or does it interfere with the body?

Double Venom · #2 (**permalink**) 05-10-2008, 04:20 AM

Huckelberry5,
one of the first things I do is mount the cowl (NOT roll-sorry.) bar in place. I then bolt & weld the bottom of the cowl bar to the frame. ( Fantastic safety factor in case of side impacts.) I then weld three or four 1/4x 20x3/4 long bolts to the- inside of the FRONT LOOP of the cowl bar making sure they wont be in the way of the column, gauges, wiper motor, etc.

I weld the heads of the bolts to the inside of the bar so the stut is pointing toward the rear bar. From this point on it will give you the three or four welding studs you can use for different grounding ranges. This process assures you have all the grounds you need and they work fantastic. Simply crimp a 1/4" (eye) rounded wire end onto the wire and simply bolt on with a 1/4x20 nut. Doing it this way, a braided ground wire from the bell housing to the FRAME, the normal required grounds and you will never have a problem with this fiberglass car for grounds!
DV
Good question!

trularin · #3 (**permalink**) 05-10-2008, 09:14 AM

I bolted a bar just for ground connections to the cowl support.

If you have worries about a ground, run a wire to the block from that bar.

wetdog · #4 (**permalink**) 05-10-2008, 10:22 AM

I did it just like DV says works great , electroic speedos need dedicated grounds , so do msd boxes , and the starter solinoid, thats three already . Also if running batt in trunk neg lead all the way up to the block .Body goes on this week wish me luck. WD

Huckleberry5 · #5 (**permalink**) 05-11-2008, 08:58 PM

Thanks guys

David Kirkham · #6 (**permalink**) 05-11-2008, 09:49 PM

I don't know what kind of car you have, but the original Cobra (and our cars as well) use the cowl hoop as the ground. Both cars hand the wiring harness there as well.

David

Double Venom · #7 (**permalink**) 05-12-2008, 04:16 AM

Quote:

Originally Posted by wetdog

I did it just like DV says works great , electroic speedos need dedicated grounds , so do msd boxes , and the starter solinoid, thats three already . Also if running batt in trunk neg lead all the way up to the block. Body goes on this week wish me luck. WD

Nice to know someone knows to have dedicated grounds for some electronics!
You dont want to just pile on the grounds on one lug. This can cause a feed back to sensitive equipment, even radios.

I am starting a entirely new manual on DVD for the CR's Cobra. when it will be done I don't know but after 25 plus years it's past due. It will cover everything I know and many hints from other builders/home owners. Hopefully it will be absolutely detailed, clear and precise!

David, feel free to jump in anytime-thank you.

Wetdog, paper and pen in hand, give me a call and we will go through the entire mounting of the body- take every "self-tapping screw that came with the kit and throw them away! Couple of 1/4x10x20 taps, a couple of proper drills and a whole box of 10x24 "FLANGE" screws, (AND flange nuts) in various lenghts from 1/4" to 3/4" inch in length! I'm ready when you are!

DV

Maurice Johnson · #8 (**permalink**) 05-12-2008, 05:13 AM

Ahhhhhhhhh!!! - dedicated grounds--music to an electricians ears. My 2 cents added in would be don't be tempted to take ancillary grounds, (switching relays, slave solenoid,etc) to the engine block with its dedicated neg return to battery. Different electrical potentials can all add to galvanic action, often confused with electrolosys, especially on motors with mixed components. Aluminum heads on iron blocks for example. BIG problem out here in the marine world.

Ron61 · #9 (**permalink**) 05-12-2008, 05:44 AM

Just another thing that I did on my car when I had it was go to NAPA and buy two terminal strips, Heavy Duty, with 6 terminals on each. One I ran a ground lead to a separate place on the frame and then strapped all the bottom terminals together. The other strip I did with battery and had a cover for it. Then when I needed a ground or battery lead I could just go to these terminal strips and pick up one. I put them on in 1997 and they are still working according to the guy who now has my car. I also had about five other grounds from the frame to the block and other points.

Ron

Dwight · #10 (**permalink**) 05-12-2008, 06:29 AM

I buy ground terminal strip from the electrical supply house with 18 to 24 points. I clean the paint off a couple of places on the cowl bar, drill and tap for two 8x32 screws to mount the strip with. I run a large ground wire (#8 fine strand) from the battery to the strip. Everything under the dash and hood gets grounded to the strip. I have a 5/16" bolt welded to the frame next the battery with a #2 welding lead (fine strand wire/ high amp cable) ground to it.
Six years and 21,000 miles no issues.

Dwight

Double Venom · #11 (**permalink**) 05-12-2008, 07:48 AM

OK,
Maybe I am reading this wrong but a "bus bar" or grounding strip is convienant and easdy to use but most of them , unless each opposing screw/lug is grouned seperately it is nothing more than stacking one ground onto another-just neater and for the most part will probably work, BUT these are NOT dedicated type grounds seperating one electronic device from another. If you have hi-tech electronic equipemtn, i.e.; MSD, Amp(s), electronic speedo, electronic oil pressure, etc. please make sure they have seperate dedicated grounds.
DV

wetdog · #12 (**permalink**) 05-12-2008, 10:10 PM

I love all the info on this site and its free, girlfriend took keys to go cart having too much fun ...back to building . I think everyone will agree electrical problems can be a pain , especially if intermittent ! this is one area where overkill and quality work pays off . DV real soon we will talk i have a couple more holes to cut but my cobra now has eyes at least. WD

COBRANIP · #13 (**permalink**) 05-13-2008, 12:58 AM

Would someone define "seperate dedicated ground" for those of us that have trouble remembering not to stick a fork into an electrical outlet? Do you mean the ground wire is a seperate one all the way back to the battery? If so how many electrical gagues could you/should you attach?
Thanks.

Ron61 · #14 (**permalink**) 05-13-2008, 01:50 AM

A separate dedicated ground is one that you run a ground lead for some special thing such as the battery, a gage set, etc. The terminal strip I used was just for some relays and such and I ran separate leads to most of them except a few that really didn't need a dedicated ground. My belief is that in these plastic cars, you can't have to many good grounds. I have even ran two separate ground straps from different places to the same place as once the body was on it would be very hard to get to.

Ron