grounds and noise suppression

[mbouse]

well, like most of us, i am not the original owner of my Spider; and like many of us, a previous owner has applied at least one new/additional coat of paint on the car before i rescued the vehicle.

However, i thought that my '80 was nearly completely stock when i adopted it. but, buying a parts car a couple weeks ago that is only 4 months older in build date... has me wondering a couple of things.

1. the parts car has two grounding straps on the hood, to the radiator support. WAS THIS A FACTORY INSTALLATION?
2. there is a condensor screwed into the radiator support and connected to the wiring for the rad fan. WAS THIS A FACTORY INSTALLATION?

i've not seen either of these two items before. as far as the hood grounding straps... what purpose would they really serve?

[pope]

Mike, I'd like to see photos of this if you dont mind

[mbouse]

hey pope, stop on by on 11/14/2009, and join the pick-a-part party, and see for yourself.

many parts yet spoken for.

[manoa matt]

Mike,

You mean YOU don't know what is stock? Just kidding. Looking at the construction, attachement, and type of the wiring will tell you wether its factory or not.

My guess is the PO had cooling troubles and suspected the fan switch. Since the fan switch sits in the rad the PO probably thought that the switch grounded through the rad body.

[mbouse]

HA. i guess i do need to post pictures, cuz these dang things look mighty particular. the straps are bare braided wire about 3/16" wide and about 8" long (working from memory here) and the condensor plugs into a plastic connector that appears specially built for this installation.

my bet is that the original radio regurgitated noise when the fan kicked on, and the car kept coming back to the dealer until he installed something in frustration. at least that explains the condensor... but the grounding straps for the hood still have me totally frustrated for a reasonable explanation.

as requested... pictures soon.

stock? yeah, that is why i peer into EVERY engine bay at FFO and regional events. I look to see what equipment is or is not on their cars compared to mine. More than just what mods they made, but what Fiat original equipment appears where. it is a never ending study, since Luigi made rolling modifications to factory design on a regular and repeated basis.

[racydave]

I have the straps on mine. Best guess is that the hinges are using metals different than the hood and body. They may have expected electralasis and corrosion. Seems like I had the capacitor too, but I took the Fiat across town for storage

[majicwrench]

Strap grounding hood is to help the radio reception.
Keith

[mdrburchette]

Could the grounding straps on the hood be there to aid the hood prop when the hood is open? My hood prop is starting to separate from the radiator support and it's a scary sight to have the hood open when there's a gust of wind.

[mbouse]

it was dark when i got home yesterday, so no pictures yet.

please explain how grounding the hood (no source of electrical interference) would aid in radio reception. i know you're guessing... so am I. that is what makes these straps so hard to understand.

Denise, this is a two litre, which has a completely different hood prop than your car. the prop is an actual loop of round stock about 42-48" in total (pre-bent) length. secured across the rad support by at least four brackets, and centered across the hood bracket with a bolt. if the wind were strong enough to circumvent this hood support, it'd snap those ground straps in two easy.

[engineerted]

It could be that PO had used some solid spark plug wires and need to surpress the EMI caused by them. Pick a part party? what year car? Mike.

Ted

[mbouse]

1980... no head, no manifolds. mfg: 06/79

stop on down! Pope is coming, hitch a ride. 11/14/2009, starting with coffee at 9 am.

thinking of pizza delivery and ice ca-cold beers.... but you know those teenagers... they dunn get up before 11, so lunch can't begin sooner.

[manoa matt]

Yep those 2L hoods are notorious for eating up the spark plug boot right as it plugs into the cap. When it does a spark arcs to the hood.

I see Ted's point about the wires. I'm running solid core copper wires too, but I don't have any problems with radio static.

(Of course my radio was stolen out of the car last week, so I don't have to worry about that anymore) It was the cheapest CD player Walmart had. $50 It didn't even have a name, might as well said "made in china" on the faceplate.

[mbouse]

i took another look. all aftermarket stuff and not worth the time to upload pictures.

whew.... i feel better.

Pick-a-part party is 11/14/2009. any and all are welcome. Ted is bringing Pope, or is it Pope bringing Ted? i canno remember. Boyz are comin' from CHI-FLU too. and, a brave troubadour is on his way from Charlevoix.

[majicwrench]

Not guessing at all, the hood is grounded to help the radio reception. I work at a radio station. Any large surface on the car is part of the antenae. If you have the antenae in the back, you get better reception when you are heading towards the radio tower, because of the mass of metal (the hood included) pointing that direction. Turn around, go other way, reception not as good, cause most of the ground side of the antenae is now pointing away from tower.
You will notice on most modern vehicles they have a ground strap on the hood. To help the radio reception.
I have some factory GM and Ford Radio tech info that includes the above.
Keith

[mbouse]

cool. wadda wonderful set of explanations. thanks especially to Keith, who did a fantastic job of explaining how an antenna works. i do recall a time in my past when radio reception was a high priority.

my how we've changed... i only listen to iPOD or CD's, and am gonna have the hole in my fender (antenna mount) welded shut when i have the car painted. i wish they made a car dash unit that ignores the AM/FM inputs. i find the DJ chatter and the commercials (even on "commercial free" satellite) annoying to ad nauseum. remember when FM broadcast a whole side of an LP at a time?

never thought of the rubbing of the dizzy wires on the hood either. though, i have experienced that myself. even with the insulation intact on the hood, i bet there could be a fair degree of static buildup once those rubber boots were chaffed. really good guess Matt.

i am convinced that these straps and condensor were added post dealership, and now am certain they were for radio reception and/or noise suppression. Great discussion folks!