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How to properly "ground" CC gas tank?

Paul C
 

Hello all.

Have a 48 CC with a repaired and sealed gas tank ready to go back in.  It is one with the two external metal straps holding it in place.

I've put a new sender in the tank already.   I've painted both the tank and the straps also.  I'm still on the original 6V positive ground system as well if that matters.

I've got the one wire for the post on the sender all set to go.

How to I properly "ground" the tank shell to the body?  Should there be a wire?   Or did the straps originally ground the tank?

I could add a wire from the body to a screw on the sender also if need be... just unsure that is necessary.

I've seen some other older cars that have a rivet in the cardboard/asphalt insulating gasket that sometimes goes between the straps and the tank for grounding, but I don't have any originals to inspect for the Crosley.  Checked the manuals, but I don't see this detailed.

Thanks for you insights.

Paul

crosleyshortsport
 

Paul,  The screws that secure the sending unit to the tank will ground it, as long as you did not use sealant around the screws. If you did and I suggest it, you must run a groundwire from the top of the sending unit to the frame. If you feel comfortable with the gasket you used and the screws holding the sending unit touch the unit securely, you can be sure to get a good ground between the straps and body, so long as you make sure that where the strap and body meet are bare metal and always use a little dielectric grease at every ground piont. As an old Crosley guy taught me many years ago, "If anything electrical on a Crosley is not working, check your grounds, check your grounds, check your grounds"  When I finished up a restoration on a Crosley that had been 95 % completed by a professional, none of the electrical worked. The paint was fabulous everywhere. I pulled every ground point and ground the areas to the metal, applied some dielectric grease and presto !  Everything came to life !

On Sep 13, 2017 5:06 PM, "Paul C" <pcrane@...> wrote:
Hello all.

Have a 48 CC with a repaired and sealed gas tank ready to go back in.  It is one with the two external metal straps holding it in place.

I've put a new sender in the tank already.   I've painted both the tank and the straps also.  I'm still on the original 6V positive ground system as well if that matters.

I've got the one wire for the post on the sender all set to go.

How to I properly "ground" the tank shell to the body?  Should there be a wire?   Or did the straps originally ground the tank?

I could add a wire from the body to a screw on the sender also if need be... just unsure that is necessary.

I've seen some other older cars that have a rivet in the cardboard/asphalt insulating gasket that sometimes goes between the straps and the tank for grounding, but I don't have any originals to inspect for the Crosley.  Checked the manuals, but I don't see this detailed.

Thanks for you insights.

Paul

dale@servicemotors.net
 

Hi paul the straps ground the tank.  You can run another wire as a ground also.

Sent from my iPhone

On Sep 13, 2017, at 2:33 PM, crosleyshortsport <crosleyshortsport@...> wrote:

Paul,  The screws that secure the sending unit to the tank will ground it, as long as you did not use sealant around the screws. If you did and I suggest it, you must run a groundwire from the top of the sending unit to the frame. If you feel comfortable with the gasket you used and the screws holding the sending unit touch the unit securely, you can be sure to get a good ground between the straps and body, so long as you make sure that where the strap and body meet are bare metal and always use a little dielectric grease at every ground piont. As an old Crosley guy taught me many years ago, "If anything electrical on a Crosley is not working, check your grounds, check your grounds, check your grounds"  When I finished up a restoration on a Crosley that had been 95 % completed by a professional, none of the electrical worked. The paint was fabulous everywhere. I pulled every ground point and ground the areas to the metal, applied some dielectric grease and presto !  Everything came to life !

On Sep 13, 2017 5:06 PM, "Paul C" <pcrane@...> wrote:
Hello all.

Have a 48 CC with a repaired and sealed gas tank ready to go back in.  It is one with the two external metal straps holding it in place.

I've put a new sender in the tank already.   I've painted both the tank and the straps also.  I'm still on the original 6V positive ground system as well if that matters.

I've got the one wire for the post on the sender all set to go.

How to I properly "ground" the tank shell to the body?  Should there be a wire?   Or did the straps originally ground the tank?

I could add a wire from the body to a screw on the sender also if need be... just unsure that is necessary.

I've seen some other older cars that have a rivet in the cardboard/asphalt insulating gasket that sometimes goes between the straps and the tank for grounding, but I don't have any originals to inspect for the Crosley.  Checked the manuals, but I don't see this detailed.

Thanks for you insights.

Paul

Butch
 

Hello Paul,

Although, as others have said the straps will ground the tank and sender (as was original on Crosley), they aren't always reliable due to age, dirt and corrosion.

It is MUCH better to add a separate grounding wire, under one of the sender screws to a screw or bolt on the frame. Naturally, you will want to sand/grind the frame down to bright, shiny metal where you attach the wire and don't paint it until AFTER the connection has been made.

My 2 cents, no change required.

Butch

On 9/13/2017 5:06 PM, Paul C wrote:
Hello all.

Have a 48 CC with a repaired and sealed gas tank ready to go back in.  It is one with the two external metal straps holding it in place.

I've put a new sender in the tank already.   I've painted both the tank and the straps also.  I'm still on the original 6V positive ground system as well if that matters.

I've got the one wire for the post on the sender all set to go.

How to I properly "ground" the tank shell to the body?  Should there be a wire?   Or did the straps originally ground the tank?

I could add a wire from the body to a screw on the sender also if need be... just unsure that is necessary.

I've seen some other older cars that have a rivet in the cardboard/asphalt insulating gasket that sometimes goes between the straps and the tank for grounding, but I don't have any originals to inspect for the Crosley.  Checked the manuals, but I don't see this detailed.

Thanks for you insights.

Paul



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Paula W
 

This thread has been very helpful to me. I have a follow-up question on the consequences of an ungrounded tank. I'm still learning the basics of the electrical system and I'm taking to heart "check your grounds".

I have a 1947 sedan. The car has a refurbished tank (professionally cleaned and recoated) and a new sending unit that was installed with the original straps and new webbing. The gauges weren't working well if at all prior to my sending them out for repair. The FUEL needle never moved as long as I've known this car (several decades). At this point I have no idea if my tank is properly grounded or not since I did not see the mechanic's actions closely enough when he was installing the sending unit and tank. It's something I want to check.

My question:
I now have repaired gauges ready to install. Must I ground the tank before installing the repaired gauges and before I drive the car again? I am wondering if a possibly ungrounded tank is dangerous to me or to the gauge - or to anything else. (The car is temporarily sidelined for a non-related issue.)

Thank you for any help on this.
Paula

Paul C
 

Best to ground the tank.   While very  unlikely, there is a chance the tank could build up some level of static electricity over time.

I don't think there would be any "danger" to the gauges.. Simply, if the tank is left un-grounded, there will be no complete circuit from your fuel sender to the gauges.   So, you would only have gauges that didn't work.

Based on the feedback, the original gas tank straps provided the ground.  Over time, these can rust or even be refurbished/painted which can degrade or interrupt the grounding effect.

Looks like the safe bet is to add a wire to one of the sender screws and connect cleanly (bare metal) to the body/frame.  This should ground the sender directly, and the tank itself by the virtue of the screw going into the tank itself.

If you have used a sealer on the screw's thread while going into the tank, that may become an insulator, and in such cases, you may wish to ground the tank directly as well.   In my case, I added a metal hose clamp at the based of the filler neck (below the filler hose) added a wire, and made sure I had good metal to metal contact... Then grounded the wire to the body with a metal screw.

Thanks all for the feedback.

Paul