T/A AAR Hood Bow, How did it happen?

[RSI700VIPER]

I recently purchased a T/A Challenger and it has the customary bow in the hood.  I know that some people remove the hood springs to prevent the bow from occurring or getting worse, but I would prefer to keep the springs functional.  Plus, the hood is already bowed but I don't want it to get worse.  I'm curios though how the bow actually formed.  One would assume that there is a constant upward force from the hood springs and with the hood pined down in the front, the twisting action would cause the hood to arch.  But, it seems with the hood in the down position and the hinges fully closed, there is no perceptual upward force trying to lift the hood.  The effort to lift the front of the hood when it's on the car with the springs on feels the same as trying to lift the hood when it's sitting on the ground, so how did the bow originally form?  I would think the bow is more likely to form with the hood left fully opened and left that way for a long time vs. leaving it closed.   Thoughts?       

[torredcuda]

Maybe a combination of both, I`m sure there is some upward tension from the springs and just the weight of the hood when open would both tend to make the fiberglass bow over time. I`ve heard of owners using weight on the bowed part to reverse the effect and use a prop rod when open to push slightly upwards.

[750-h2]

AAR & TA hoods were bowed when they left the factory. Just a poor design. I have a 1970 road test on an AAR where the writer sarcastically states that the hood was so bowed that he could check the oil without opening the hood.

[HEMICUDA]

AAR & TA hoods were bowed when they left the factory. Just a poor design. I have a 1970 road test on an AAR where the writer sarcastically states that the hood was so bowed that he could check the oil without opening the hood.

That would be absolutely correct, they were bowed when new.  Also, there is no spring tension on the hood when it's closed.  The only way I've found to correct the bow is to slice the under structure, flatten it out where it needs to be and re-glass.  Just finished two AAR hoods for customer cars, one was way worse than the other.

[torredcuda]

AAR & TA hoods were bowed when they left the factory. Just a poor design. I have a 1970 road test on an AAR where the writer sarcastically states that the hood was so bowed that he could check the oil without opening the hood.

maybe the molds were not  strong enough, have a friend that used to build boats and said the molds needed a lot of reinforced structure surrounding it or the heat from curing would distort things.

[HEMICUDA]

AAR & TA hoods were bowed when they left the factory. Just a poor design. I have a 1970 road test on an AAR where the writer sarcastically states that the hood was so bowed that he could check the oil without opening the hood.

maybe the molds were not  strong enough, have a friend that used to build boats and said the molds needed a lot of reinforced structure surrounding it or the heat from curing would distort things.

As crude as those hoods are, sure didn't look like they spent a whole lot of time on them.  Seems every single one is different, some not as bad as others.

[headejm]

@RSI700VIPER  Tell us about your new T/A and definitely show us some pictures! 

[IRON MAN]

AAR & TA hoods were bowed when they left the factory. Just a poor design. I have a 1970 road test on an AAR where the writer sarcastically states that the hood was so bowed that he could check the oil without opening the hood.

Sad but true. I have owned a 1969, 1970, 1971, 1972, 1973, etc. Corvettes, all were daily drivers. All had original hoods and not one had a bow in it. As said, e-body fiberglass hoods were designed poorly.   

[Chryco Psycho]

SO here is my $.02
If the springs apply no pressure to the hood when it is down then the hinge should stay down when lowered to the closed position but without the weight of the hood the hinge will not stay down , the hood weight is basically equal to or greater than the spring pressure so even in the lowered psoition the spring is still expanded & applying pressure so the spring has to putting pressure on the hood constantly . 

[Cuda Cody]

Here's what happened to me.

I restored a 1970 Challenger T/A.  I did all the body work with the springs off the hood and everything was dead nuts perfect with the tops of the fender aligning to the top of the T/A fiberglass hood.  When I got the car all done I still did not put the hood springs on, that was until I decided to take the car to a show and wanted the hood to stay open by itself.  Won 1st place at the car show and when I got home I didn't take the springs off.  Kinda forgot about having the hood springs on and it may have been a couple weeks or even a month or so later when I was walking in my garage and looked over at the T/A.  That's when my heart sank.  The hood had bowed up about 1/2" in the middle and looked liked crap.  I was pissed.

The fix?  I took the hood springs back off and put 50 pound bags of cement on the edge of the hood and left it there until the bow was out of it.  It worked!  The hood went back to perfect alignment and has stayed perfect'y aligned for many years now.  I learned that the hood springs is what makes these hoods bend.  I'll never put my hood springs back on. 

[Cuda Cody]

If you want to know for sure if the hood springs add pressure...

Step 1 = open the hood with the springs on.

Step 2 = open the hood with the springs off.

It's that simple.  The hood is WAY heavier with the springs off the hood, I know I've checked it...  Night and day difference.  Even though the hood springs do not left the hood up automatically, they are still taking a lot of weight off the downward pressure of the hood making it nearly neutral to lift up.  It's just like a garage door spring.  The garage door spring makes the door neutral weight allowing a person or even a tiny garage door opener to lift it.  Try lifting a garage door without a spring.    It doesn't work.

Also, that's the reason T/A hoods have smaller hood springs.  The bigger springs apply to much pressure up.  Even the factory knew the springs apply pressure. 

[IRON MAN]

Ring Brother's sells gas strut hood hinges for e-body fiberglass hoods. Will gas strut hood hinges help at all?

[scf100]

What Cody said.....

I just bought a 1969 Shelby Mustang convertible clone.....huge bow in middle of fiberglass hood....

Put towels down on hood.....put a 40 lb bag of potting soil on each side.......let sit in sun all day....
Took hood springs off......result?.......flat fiberglass hood from now on.......

Made a prop rod from a half inch by 3 ft wood dowel, put furniture rubber feet on each end, painted rod silver ( so it could be seen and not accidental bumped)

Done

[Chryco Psycho]

Ring Brother's sells gas strut hood hinges for e-body fiberglass hoods. Will gas strut hood hinges help at all?

No , the gas struts will still put pressure against the hood unless the leverage is such that the strut does not help to lift the hood when closed .
simple solution is 2 rods , I don't have the length handy but a straight rod with 90* bend on each end approx 1" long  , lift the hood & slide the rods into the holes in the hinges & the hood stays up without any prop rod

[Brads70]

Ring Brother's sells gas strut hood hinges for e-body fiberglass hoods. Will gas strut hood hinges help at all?

No , the gas struts will still put pressure against the hood unless the leverage is such that the strut does not help to lift the hood when closed .
simple solution is 2 rods , I don't have the length handy but a straight rod with 90* bend on each end approx 1" long  , lift the hood & slide the rods into the holes in the hinges & the hood stays up without any prop rod