body work

Lightspeed · 07-10-2003, 07:28 PM

i got this fiberglass hood scoop for my car a few years back and me not knowing much about body work just bolted it on, well then recently someone told me the proper way to put it on was to rivit it down and use bondo to feather it out to where it looked like part of the hood, well i did this and now im having problems..the bondo is cracking where the edge of the scoop was and somehow its getting water down in there and making it crack...only certain spots are doing this like at the corners...does anyone have any advice on how i could fix this or am i gonna have to redo the whole thing?

fordkid68 · 07-10-2003, 08:12 PM

well first of all I am no expert but have done A descent amount of body work.

I would sugest doing it over again. but I would use fiberglass filler then smooth it out with bondo or iceing. the firberglass filler hardens more like plastic then bondo. it just doesn't spread veary well. but again I am no expert.

hope that helps.

ford kid

Frankenstang65 · 07-11-2003, 04:47 PM

I'm sorry to say, but you will definitley have to start over. The problem with using any type of filler to smooth the edge of the scoop into the hood is that body filler (fiberglass or otherwise)and metal have different heat dissipating properties. This isn't a problem on a fender or a 1/4 panel...but remember that the engine is right under there and the hood temp is constantly fluctuating. Over time, as the filler shrinks and expands it becomes extremely brittle and will eventually crack. Then, water will drip down into the crack...and oxidation will occur. Rust (even only a tiny bit) will take hold on the metal underneath and will continue to oxidize the metal under the body filler that hasn't cracked yet (remeber that filler and primer are not waterproof). It wont be long before more cracks appear, and the body filler begins to break off in chunks do to lack of adhesion to the rusty metal underneath.

When I bought my car it had a riveted shelby scoop to the steel hood (and it had the exact problem you described). By that point the hood was no longer salvageable (the riviting job and bondo work was horrible), so I just replaced the hood.

IMO, the only acceptable way to add a hood scoop to the car is to just buck up and buy an entire fiberglass unit with scoop molded in. That way you get something functional and long-lasting. I wasn't prepared to spend the money at the time...but I love the look and will eventually get a shelby hood or cowl induction unit.

Hope that helps, good luck

bear · 07-11-2003, 09:16 PM

I friend bought a newer mustang with scoop instaled like yours. We took it off & cut A hole in hood & instaled it from the bottom of hood. We welded all thead to bottom of hood & bolted it on used nonharding paintable seamsealer on top. Dont know why you couldent use rivets. Be sure you check braces under hood you need to keep it farely ridget

07-10-2003, 07:28 PM	#1
Lightspeed Registered Member Join Date: Mar 2002 Posts: 49	body work i got this fiberglass hood scoop for my car a few years back and me not knowing much about body work just bolted it on, well then recently someone told me the proper way to put it on was to rivit it down and use bondo to feather it out to where it looked like part of the hood, well i did this and now im having problems..the bondo is cracking where the edge of the scoop was and somehow its getting water down in there and making it crack...only certain spots are doing this like at the corners...does anyone have any advice on how i could fix this or am i gonna have to redo the whole thing? __________________ 67 coupe, 289 ,c4, bored .40, flat tops, crane powermax cam,edelbrock torker 2 intake, edelbrock perf. 600 cfm carb, accel cleaner, ignitor 2 ignition, hooker comp headers, hooker aerochamber mufflers, H-pipe, b&m 2500 stall, b&m ratchet shifter...and more soon to come....

07-11-2003, 04:47 PM	#3
Frankenstang65 Registered Member Join Date: Sep 2001 Location: Seattle, WA Posts: 79	I'm sorry to say, but you will definitley have to start over. The problem with using any type of filler to smooth the edge of the scoop into the hood is that body filler (fiberglass or otherwise)and metal have different heat dissipating properties. This isn't a problem on a fender or a 1/4 panel...but remember that the engine is right under there and the hood temp is constantly fluctuating. Over time, as the filler shrinks and expands it becomes extremely brittle and will eventually crack. Then, water will drip down into the crack...and oxidation will occur. Rust (even only a tiny bit) will take hold on the metal underneath and will continue to oxidize the metal under the body filler that hasn't cracked yet (remeber that filler and primer are not waterproof). It wont be long before more cracks appear, and the body filler begins to break off in chunks do to lack of adhesion to the rusty metal underneath. When I bought my car it had a riveted shelby scoop to the steel hood (and it had the exact problem you described). By that point the hood was no longer salvageable (the riviting job and bondo work was horrible), so I just replaced the hood. IMO, the only acceptable way to add a hood scoop to the car is to just buck up and buy an entire fiberglass unit with scoop molded in. That way you get something functional and long-lasting. I wasn't prepared to spend the money at the time...but I love the look and will eventually get a shelby hood or cowl induction unit. Hope that helps, good luck __________________ 1965 Coupe: 351W, comp cam, Aluminum Systemax II heads (2.02/1.60), 1.7 Cobra full roller rockers, Edelbrock intake, Holley 650 double pumper, Mallory Unilite, MSD-6AL, MSD Blaster 2 coil, MSD heli-core plug wires, Hedman headers, 2 1/2" exhaust (GT style) w/ 40 series delta flows, 69 C4 w/ shift kit, shelby traction bars, 3.55:1 rear Daily Driver: 1989 GT- 5spd, K&N (no silencer), Shorty Headers, King Cobra Clutch, Flowmaster Force II Cat-back

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07-10-2003, 08:12 PM	#2
fordkid68 Registered Member Join Date: Jan 2002 Location: fremont Posts: 306	well first of all I am no expert but have done A descent amount of body work. I would sugest doing it over again. but I would use fiberglass filler then smooth it out with bondo or iceing. the firberglass filler hardens more like plastic then bondo. it just doesn't spread veary well. but again I am no expert. hope that helps. ford kid

07-11-2003, 09:16 PM	#4
bear Registered Member Join Date: Apr 2003 Location: mesa Posts: 3	I friend bought a newer mustang with scoop instaled like yours. We took it off & cut A hole in hood & instaled it from the bottom of hood. We welded all thead to bottom of hood & bolted it on used nonharding paintable seamsealer on top. Dont know why you couldent use rivets. Be sure you check braces under hood you need to keep it farely ridget