I have noticed that most Shelby hoods have a bow to them. I have heard that it was a result of the springs pulling up on the latched hood. Not sure if that is true, but the look is less that desirable.
I am restoring a 69 GT500 with a slight form of this condition. What is the best (or recommended) way to correct this condition so that the hood lies flat with the fenders when the hood is closed? FYI, i have factory original fenders and hood.
Quote from: kasearch@ix.netcom.com on January 11, 2020, 09:01:34 AM
I have noticed that most Shelby hoods have a bow to them. I have heard that it was a result of the springs pulling up on the latched hood. Not sure if that is true, but the look is less that desirable.
I am restoring a 69 GT500 with a slight form of this condition. What is the best (or recommended) way to correct this condition so that the hood lies flat with the fenders when the hood is closed? FYI, i have factory original fenders and hood.
I would recommend to pull your springs and let it set for a while and see what you have. I only use the light tension springs I can put on by hand when I want the hood open. I also use a prop rod. Depending on the bow it could mean cutting the inner structure or to a lesser extent using weights in strategic locations while the hood sits on horses. My hood had a bow in it until I took off the springs a few decades ago. Stored it at a friend's house and didn't take off the "Branda" springs and found a bowq in my hood 3 months later. Freaked me out and took springs off immediately. Here is how it looks today. https://www.flickr.com/photos/shelbymann1970/albums/72157712540880967
I think on forum 1.0 there was a shop that specializes in straightening hoods.
Just don't remember any details.
Quote from: 2112 on January 11, 2020, 12:24:32 PM
I think on forum 1.0 there was a shop that specializes in straightening hoods.
Just don't remember any details.
It is a good thing you don't remember. Unfortunately I do. The shop in question and to the point it's owner because it is a one man shop are a piece of work with many poor result instances. Don't ask me how I know . :o
Gary u need to bring your good looking 70 Shelby to in. saac this year for the 50th 1970 Shelby meet since last year u showed up without your car. We are going to have SPECIAL 50th gifts for all 70 shelbys designed by none other than SPECIALed. There is a letter documenting aosmith workers actually were bending upward the fender aprons to help the hood alignments but had to stop because of cracking spotwelds or damaging apron tops so they were aware of the problem when new. I think they tried to fix the problem by building up the thickness of the 1'' wide black sealant under fenders as some original cars I seen were very thick especially in the middle area where the hood bow is the worst. I don't know why the 69 Shelby engineers didn't simply use a weaker hood spring since the fiberglass hood was lighter than the regular steel mustang hood.
Just for conversations sake imagine, removing your hood from your car, now you will have two hood hinges in the up position with the spring in normal resting position. Now push the hood hinge down (the position it would be in if you had a closed hood) the spring would be stretched, but would stay down on it own, since its designed to rest in this position causing NO LOAD?or Pressure on the hood what so ever! So can you explain to me how the springs put pressure on the hood when its in the closed positions? My thought is that since the hood is fastened at the front by the hood latch and fastened at the rear with the hood hinges, the upward pressure of the air cleaner seal is the only thing pushing up on the hood and with the heat maybe the real issue? plus possibly that pressure of closing the hood too, when the springs are being stretched!
Not much tension on the air cleaner to hood seal since its soft foam . Hood hinge springs are strong just try to change them when hood is up. The long hood has leverage when u close the hood making it easy to stretch the hood spring while closing.
Quote from: Special Ed on January 11, 2020, 01:21:27 PM
Gary u need to bring your good looking 70 Shelby to in. saac this year for the 50th 1970 Shelby meet since last year u showed up without your car. We are going to have SPECIAL 50th gifts for all 70 shelbys designed by none other than SPECIALed. There is a letter documenting aosmith workers actually were bending upward the fender aprons to help the hood alignments but had to stop because of cracking spotwelds or damaging apron tops so they were aware of the problem when new. I think they tried to fix the problem by building up the thickness of the 1'' wide black sealant under fenders as some original cars I seen were very thick especially in the middle area where the hood bow is the worst. I don't know why the 69 Shelby engineers didn't simply use a weaker hood spring since the fiberglass hood was lighter than the regular steel mustang hood.
Seraphim bought a trailer not long ago. A nice open AL one that he got off of a friend who had it less than a year(2019). Well I got a truck and he has a trailer...... I told him we need to bring my vert or his Boss9 to In SAAC. I think he wants to bring the boss to YOU to complete it to t-bred but that is another story. Has anyone contacted Larry's widow about pictures he has of KK back in the day? Ed, do you see how nice my hood fits? The hood has NO WORK done to it. BTW my friend's 70 GT500 vert has a LOT OF sealer under the fenders and has the worst hood fitment/bow I have ever seen. I found him another hood a decade ago but we never "fit" it to the car yet. Gary
Quote from: Hotrod Hillbilly on January 11, 2020, 02:04:54 PM
Just for conversations sake imagine, removing your hood from your car, now you will have two hood hinges in the up position with the spring in normal resting position. Now push the hood hinge down (the position it would be in if you had a closed hood) the spring would be stretched, but would stay down on it own, since its designed to rest in this position causing NO LOAD?or Pressure on the hood what so ever! So can you explain to me how the springs put pressure on the hood when its in the closed positions? My thought is that since the hood is fastened at the front by the hood latch and fastened at the rear with the hood hinges, the upward pressure of the air cleaner seal is the only thing pushing up on the hood and with the heat maybe the real issue? plus possibly that pressure of closing the hood too, when the springs are being stretched!
Removing the factory springs on my 70 and my 68 I used to have the hood sat differently and FLATTER on both. So I KNOW that in the down position the springs are putting pressure on the hood-even the lighter tension springs sold by Cobranda. Gary
What's a good source for the low tension hood spring for a 69?
Also anyone got pictures of how they use a hood prop?
Thanks
Quote from: SCJSTU on January 12, 2020, 10:57:16 PM
What's a good source for the low tension hood spring for a 69?
Also anyone got pictures of how they use a hood prop?
Thanks
Get them from Branda Performance .They sell a reproduction of the ones used on 67 Shelby all fiberglass hoods. That is the one you ask for.
Thanks Bob
Quote from: SCJSTU on January 12, 2020, 10:57:16 PM
What's a good source for the low tension hood spring for a 69?
Also anyone got pictures of how they use a hood prop?
Thanks
I can take a picture of mine Stu. I used it on both my 68 and 70 Shelbys when I owned both. I'd use it while installing the Branda low tension springs which I could install by hand. I made mine out of an old jack handle that had a cover on one end and I slotted the other end for the latch bar. One day I was driving my vert and kept hearing a clunking noise. It was my springs hanging on my hood hinges. I had disconnected them but not taken them off. There is also a Maverick prop rod some use. I bought mine 30 years ago but back then couldn't figure out how to mount it as it seemed something was in the way. I still have the prop rod "somewhere". Gary
you can see the white prop rod in this pics. I never used the Branda springs on my 68 because the hood fit perfectly without springs.
https://www.flickr.com/photos/shelbymann1970/49379663777/in/dateposted-public/
https://www.flickr.com/photos/shelbymann1970/49379010408/in/dateposted-public/
No springs here either (original hood & fenders)
I use a short piece of chain between the spring mounting points on the hinges, holds the hood open great!
I'm sure there is a cleaner/nicer way to do it but NO SPRINGS!!
Quote from: mikeh on January 14, 2020, 10:48:03 PM
No springs here either (original hood & fenders)
I use a short piece of chain between the spring mounting points on the hinges, holds the hood open great!
I'm sure there is a cleaner/nicer way to do it but NO SPRINGS!!
+1 . Better then prop rod IMO.
Thanks Bob! ;D
Quote from: mikeh on January 14, 2020, 10:48:03 PM
No springs here either (original hood & fenders)
I use a short piece of chain between the spring mounting points on the hinges, holds the hood open great!
I'm sure there is a cleaner/nicer way to do it but NO SPRINGS!!
I think it was Bob who mentioned using the chains before to me. Great idea. I found though that I could install the light tension springs by hand so I went that route instead of cutting and making a chain setup since I already had the springs. Gary
Quote from: mikeh on January 14, 2020, 10:48:03 PM
No springs here either (original hood & fenders)
I use a short piece of chain between the spring mounting points on the hinges, holds the hood open great!
I'm sure there is a cleaner/nicer way to do it but NO SPRINGS!!
NICE fitting hood. I do NOT use a prop rod at shows. only use it to mount my low tension springs or if I am working on it at home. I generally show my car with the hood closed anyways since the cars should be shown in their natural state. :)
I was fortunate that when I bought my car in 2002 it had been sitting for many years without springs, I sure that made a big difference over one that is already bowed.
Quote from: mikeh on January 15, 2020, 10:50:03 AM
I was fortunate that when I bought my car in 2002 it had been sitting for many years without springs, I sure that made a big difference over one that is already bowed.
I stored my car at a friends house many years ago and had the low tension springs on it. When I visited 4 months later my hood was BOWED. It freaked me out. I removed the springs and my hood settled back straight.
Quote from: shelbymann1970 on January 15, 2020, 09:44:14 AM
Quote from: mikeh on January 14, 2020, 10:48:03 PM
No springs here either (original hood & fenders)
I use a short piece of chain between the spring mounting points on the hinges, holds the hood open great!
I'm sure there is a cleaner/nicer way to do it but NO SPRINGS!!
I think it was Bob who mentioned using the chains before to me. Great idea. I found though that I could install the light tension springs by hand so I went that route instead of cutting and making a chain setup since I already had the springs. Gary
The problem with the light tension springs on 69/70 is that sometimes (not all of the time) you have a light breeze that is just enough to cause the hood to slam down. That is why I prefer the chain over the light tension springs when displaying the car. The light tension springs are OK for short open times but you have to be careful the hood doesn't slam on someones head when displaying a car at a car show. Not good for the person and not good for the hood. this is as it pertains to 69/70 hoods. 67 all fiberglass hoods are lighter and using two of the light tension springs is not typically a problem although it could be under the right conditions. FYI the heavier 67 hoods with the steel innerstructure used 2 of the regular Mustang springs because those hoods were heavier. 66 used a different looking light tension spring but typically light one on one side and a regular Mustang one on the other.
Quote from: mikeh on January 14, 2020, 10:48:03 PM
No springs here either (original hood & fenders)
I use a short piece of chain between the spring mounting points on the hinges, holds the hood open great!
I'm sure there is a cleaner/nicer way to do it but NO SPRINGS!!
Got a picture?
At SAAC 27 was visiting with a long time (retired) Shelby employee...thing his name was referred to as "tweety". He was a painter I think. We were discussing hood bows on a '67 GT500 I was restoring at the time..#0195. Anyway, he said that was always a problem because of the springs and to remove the bow, remove the springs, place a blanket on the hood and then put sand bags from Home Depot on each edge for 3-5 days. That worked! Sold the car later so don't know if it held up but it was ok for at least two months!
Quote from: Bob Gaines on January 15, 2020, 12:48:34 PM
Quote from: shelbymann1970 on January 15, 2020, 09:44:14 AM
Quote from: mikeh on January 14, 2020, 10:48:03 PM
No springs here either (original hood & fenders)
I use a short piece of chain between the spring mounting points on the hinges, holds the hood open great!
I'm sure there is a cleaner/nicer way to do it but NO SPRINGS!!
I think it was Bob who mentioned using the chains before to me. Great idea. I found though that I could install the light tension springs by hand so I went that route instead of cutting and making a chain setup since I already had the springs. Gary
The problem with the light tension springs on 69/70 is that sometimes (not all of the time) you have a light breeze that is just enough to cause the hood to slam down. That is why I prefer the chain over the light tension springs when displaying the car. The light tension springs are OK for short open times but you have to be careful the hood doesn't slam on someones head when displaying a car at a car show. Not good for the person and not good for the hood. this is as it pertains to 69/70 hoods. 67 all fiberglass hoods are lighter and using two of the light tension springs is not typically a problem although it could be under the right conditions. FYI the heavier 67 hoods with the steel innerstructure used 2 of the regular Mustang springs because those hoods were heavier. 66 used a different looking light tension spring but typically light one on one side and a regular Mustang one on the other.
Thanks Bob .I never ran into that problem luckily and take note so it doesn't happen in the future. I show my car with the hood closed or when the springs are on it is less than half open and if someone want to see the engine better i'll open it up farther. I like the natural look at car shows with the hoods down on cars. Gary
I used the chains on my 67 and works very well. U must remember u have them on before trying to close the hood.
Pics of my chains. I put piece of heater hose on to keep them from beating everything up so bad.
Like I said, probably a better way to do it but this works great.
fwiw Mike
Good stuff fellas......
BTW.......my 69 hood was badly bowed with stock springs........removed springs........put towels on both sides of hood
Put 2 -40 lb bags of potting soil on top.........left car outside in 95 degree heat all day and now hood is perfectly flat
Do you leave the chain hanging on the hinge while driving?
(Second picture prompted the question)
Quote from: Hotrod Hillbilly on January 11, 2020, 02:04:54 PM
Just for conversations sake imagine, removing your hood from your car, now you will have two hood hinges in the up position with the spring in normal resting position. Now push the hood hinge down (the position it would be in if you had a closed hood) the spring would be stretched, but would stay down on it own, since its designed to rest in this position causing NO LOAD?or Pressure on the hood what so ever! So can you explain to me how the springs put pressure on the hood when its in the closed positions? My thought is that since the hood is fastened at the front by the hood latch and fastened at the rear with the hood hinges, the upward pressure of the air cleaner seal is the only thing pushing up on the hood and with the heat maybe the real issue? plus possibly that pressure of closing the hood too, when the springs are being stretched!
Interesting. I always thought this might be the case since the hood doesn't fly open when you release the latch. It does pop so maybe there is some load or pressure?
Quote from: SCJSTU on January 12, 2020, 10:57:16 PM
What's a good source for the low tension hood spring for a 69?
Also anyone got pictures of how they use a hood prop?
Thanks
I made a nice safe prop rod from PVC pipe.
Quote from: mikeh on January 14, 2020, 10:48:03 PM
No springs here either (original hood & fenders)
I use a short piece of chain between the spring mounting points on the hinges, holds the hood open great!
I'm sure there is a cleaner/nicer way to do it but NO SPRINGS!!
This works well too.
Quote from: 2112 on January 16, 2020, 11:21:53 PM
Do you leave the chain hanging on the hinge while driving?
(Second picture prompted the question)
Yes, I leave chains hanging, the heater hoses help keep them from scraping everything up.
The chains were originally going to be temporary until I came up with something nicer (plastic coated cables maybe?), but we all know how that goes!
Interesting. I always thought this might be the case since the hood doesn't fly open when you release the latch. It does pop so maybe there is some load or pressure?
Take the weight of the hood. The springs all the way in the close position may not open the hood all the way but what cars do? They are still putting pressure on the hood at the back so the weight beyond the hinges is fighting the short area where the springs have pressure which leads to hoods bowing. How do I know this is true? Well on my old black 68 Shelby my hood had a slight bow until I removed my springs. Ditto for my 70 over the last 35 years. Try it out sometime and see. Gary
Quote from: shelbymann1970 on January 17, 2020, 07:17:15 AM
Interesting. I always thought this might be the case since the hood doesn't fly open when you release the latch. It does pop so maybe there is some load or pressure?
Take the weight of the hood. The springs all the way in the close position may not open the hood all the way but what cars do? They are still putting pressure on the hood at the back so the weight beyond the hinges is fighting the short area where the springs have pressure which leads to hoods bowing. How do I know this is true? Well on my old black 68 Shelby my hood had a slight bow until I removed my springs. Ditto for my 70 over the last 35 years. Try it out sometime and see. Gary
Hotrod Hillbilly claims there is no pressure on the back of the hood when the hinges are closed and in the rest position. Kind of like something going over center. I can imagine the hood hinges designed to operate that way but I don't have any cars with the hood off for a real world test. Can anyone confirm this?
I wasn't going to take a chance so I removed the springs on my 500. I have springs on my 350 but leave the hood open. Is that better or worse?
I wonder if it's hood dependent too? Hard to believe all hoods are built exactly alike and some are 'weaker' than others?
Quote from: Rodster-500 on January 17, 2020, 09:29:31 AM
Quote from: shelbymann1970 on January 17, 2020, 07:17:15 AM
Interesting. I always thought this might be the case since the hood doesn't fly open when you release the latch. It does pop so maybe there is some load or pressure?
Take the weight of the hood. The springs all the way in the close position may not open the hood all the way but what cars do? They are still putting pressure on the hood at the back so the weight beyond the hinges is fighting the short area where the springs have pressure which leads to hoods bowing. How do I know this is true? Well on my old black 68 Shelby my hood had a slight bow until I removed my springs. Ditto for my 70 over the last 35 years. Try it out sometime and see. Gary
Hotrod Hillbilly claims there is no pressure on the back of the hood when the hinges are closed and in the rest position. Kind of like something going over center. I can imagine the hood hinges designed to operate that way but I don't have any cars with the hood off for a real world test. Can anyone confirm this?
I wasn't going to take a chance so I removed the springs on my 500. I have springs on my 350 but leave the hood open. Is that better or worse?
I wonder if it's hood dependent too? Hard to believe all hoods are built exactly alike and some are 'weaker' than others?
It's the nature of the materials used. The resin is flexable much like wood would be and can be bent.
The original hinge design is for steel hoods.
This is really an issue of mixing mediums. A fiberglass hood is really a "race car derivative". That has a few implications.
One is the issue of longevity. The other is lack of intended precision.
While Smith is somewhat of a cutting edge manufacturer with molded fiberglass reinforced resins, the point in time had approached solving issues with precision fiberglass "stampings" but not necessarily rigidity. Certainly not for a product that would have intentions to last over 50 years?
I'm not sure how you would reinforce the fiberglass to resist these "warpings" but the fact that you can bend it back to where it was supposed to be is a pretty good indication of the flexible nature of the material. It's too flexible.
The use in the Shelby hoods is probably crossing the line into how to use stressed fiberglass panels in a structural application. Something that I never heard of when back in school.
I suppose the text was still waiting to be developed at that point?
Although Smith had built many fiberglass Corvette hoods by then, the hood hinge approach by GM is different.
As I remember the 68s and 69s, the Shelby hoods new that I saw all fit very well.
The '67s apparently were just made twisted to begin with? I think that bending them with these methods like "sand bags" is close to the solution "restorers" are using to get some sort of fit on the front that doesn't make the car look like it was hit hard on the drivers side
Quote from: mikeh on January 17, 2020, 07:00:02 AM
Quote from: 2112 on January 16, 2020, 11:21:53 PM
Do you leave the chain hanging on the hinge while driving?
(Second picture prompted the question)
Yes, I leave chains hanging, the heater hoses help keep them from scraping everything up.
The chains were originally going to be temporary until I came up with something nicer (plastic coated cables maybe?), but we all know how that goes!
I think it is a great solution.
Especially after seeing your hood.
Thanks 2112.
And R.I.P. Neil Peart
I removed the springs on both sides and now the hood is straight with closing! NOW WHAT. Should I use low tension springs or as they are for now?
Thx
Paul
Quote from: 1969shelbygt350 on October 23, 2022, 05:23:51 PM
I removed the springs on both sides and now the hood is straight with closing! NOW WHAT. Should I use low tension springs or as they are for now?
Thx
Paul
The low tension springs may not hold the hood up . It will on some but others not. If it did I would be careful leaving it open unattended. A slight breeze may cause it to come crashing down on someone's head. I used to re attach the factory springs when having my hood open. I got so I could do ether side in leas then a minute . I repurposed a spare tire long hold down hook and used it to lever the springs on and off using my shoulder to hold the hood while doing it.
This is a picture after I removed springs and hood latch closed