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Gas Struts/Springs For Hood/Bonnet

PostPosted: Sat 19.03.2011, 14:21
by Elanlover
This project started due to my desire to move the subwoofer currently located next to the battery under the tray to the rear back wall of the trunk. In order to do that I needed to replace the torsion spring system that holds the trunk lid up with gas springs. I figured I might as well look at the hood at the same time. After many attempts and going through a dozen size and force spring combinations I have a winner it would seem. I don't recommend doing the trunk springs unless you're prepared for a lot of extra work but the hood/bonnet springs are pretty easy to do.

Details can be found in this thread but the bottom line is that its easy to install, involves no modifications to the body work and opens the hood up much higher that the prop rod does. It involves 2 gas springs, 2 ball socket mounting brackets for the top and 2 custom made brackets for the bottom. The top bracket simply bolts on top of the hinge mounting plate in place now. They need to have the holes drilled out to be a bit larger to accept the screws but other than that they fit perfectly. The bottom mount brackets slide under the current hinge mounting plates. Then you pop in the springs and voila! Installation time should be 30 minutes or less.

Now, if people are interested in a group buy I will gladly organize it. I will not be making up custom brackets myself but would have the company I am dealing with do them and zinc coat them (yellow) to match the hinge hardware in place now (the top brackets already come silver zinc coated). I cannot commit to a firm price as yet but I believe that the cost for 2 springs, 2 top mount brackets and 2 custom brackets would likely total $100 USD or less plus shipping. It could possibly be as low as $70 depending upon how many people are interested. Below are some pics of the springs installed. Feel free to add yourself to the list if you want to commit yourself to this group buy.

Re: Gas Struts For Hood/Bonnet

PostPosted: Sat 19.03.2011, 14:25
by Elanlover
Committed To Buy: (not to exceed $100 USD plus shipping and likely much less)

1.
2.
3.

Re: Gas Struts For Hood/Bonnet

PostPosted: Sat 19.03.2011, 14:52
by Dico
Superb!

1. Dico
2.
3.

Re: Gas Struts For Hood/Bonnet

PostPosted: Sat 19.03.2011, 15:12
by dapinky
If it's good enough for Paul (who as we all know, dislikes group buys), then perhaps my life would be more complete with one as well.

1. Dico
2. Pinky
3.


PS,
Blair, I'm happy to sort out the UK side of things if it makes it easier.

Re: Gas Struts For Hood/Bonnet

PostPosted: Sat 19.03.2011, 16:07
by steve matthews
Does the Hood/Bonnet raise up by itself.
And how much higher does it go up (picture please).
Very interested, nice upgrade. Did you remove old
rod fixings.
Steve

Re: Gas Struts For Hood/Bonnet

PostPosted: Sat 19.03.2011, 16:18
by Elanlover
steve matthews wrote:Does the Hood/Bonnet raise up by itself.
And how much higher does it go up (picture please).
Very interested, nice upgrade. Did you remove old
rod fixings.
Steve


It does not raise up by itself - you will need to lift it by hand and once open the hood/bonnet stays in place. I gave a lot of thought to that and decided againt a spring with enough force to raise the hood on its own. As it stands now, the spring force is 40lbs and to have the hood raise on its own would require about double that. I didn't want to add that much stress to the hinge plates and screws for fear of damage to the bodywork. As for how high it goes, open your hood by hand and hold it up as high as the hinge will let you open it. Its an inch or so lower than that which is a big difference over the hood prop height. I left the prop rod in place because a) I like a backup and b) the fixings on the hood near the badge are a bit complicated and don't seem to lend themselves to a "neat" or clean looking removal.



Dave, thanks for the offer. I'm hoping the company I'm dealing with will simply ship to each individual's address unless people want to save a few bucks/pounds on shipping costs. I don't think people would save much more than 10 pounds or so per order so factor in the potential cost of local distribution and see if its worthwhile. Happy to have them do one UK shipment though if that's what people would like.

Re: Gas Struts For Hood/Bonnet

PostPosted: Mon 21.03.2011, 11:17
by cliff
Excellent!

1. Dico
2. Pinky
3. Cliff
4.

Re: Gas Struts For Hood/Bonnet

PostPosted: Mon 21.03.2011, 23:33
by Doug
Elanlover wrote:I gave a lot of thought to that and decided againt a spring with enough force to raise the hood on its own. As it stands now, the spring force is 40lbs and to have the hood raise on its own would require about double that. I didn't want to add that much stress to the hinge plates and screws for fear of damage to the bodywork.

I agree with that thinking; don't want to crack the GRP over time!

Nice, Blair, but what's with the dirty car in the picture? Shouldn't she be cleaned and polished up for the winter?
I'm still first on the list to buy if you ever have to sell her!.....

:mrgreen:

Re: Gas Struts For Hood/Bonnet

PostPosted: Tue 22.03.2011, 00:51
by Elanlover
Doug wrote: Shouldn't she be cleaned and polished up for the winter?
I'm still first on the list to buy if you ever have to sell her!.....

:mrgreen:



The car didn't see the road last year so its a bit dusty having been in the garage for a year.

Was saving her for you :wink:

Re: Gas Struts/Springs For Hood/Bonnet

PostPosted: Tue 29.03.2011, 08:20
by BFG in the BRG
Great idea

I'm in - you thing Elanlover's car is dusty - you should see mine :roll:

Excellent looking modification!

1. Dico
2. Pinky
3. Cliff
4. BFG in the BRG
5.

Re: Gas Struts/Springs For Hood/Bonnet

PostPosted: Tue 29.03.2011, 20:49
by Doug
You want to unload her now, Blair?! :banana:

Re: Gas Struts/Springs For Hood/Bonnet

PostPosted: Tue 29.03.2011, 21:41
by Elanlover
Ok, I've got a bit more information. The new estimate for the springs, 2 standard brackets and 2 custom brackets is now down to $75 plus shipping and any local taxes you will have to pay upon arrival. It may still yet be a few bucks less but not likely too much less. Shipping to the UK could be approximately $40 each or $65 for the lot meaning that about $25 per shipment could be saved by sending them to one person who would distribute locally.

Manufacturing time would be about 3 weeks for the brackets to be on the safe side. I will be away for 2 weeks as of this Saturday the 2nd. I will place the order upon my return allowing anyone else who's interested to sign on.



Doug wrote:You want to unload her now, Blair?! :banana:


Not until I get my new 2015 Elan. :-D

Re: Gas Struts/Springs For Hood/Bonnet

PostPosted: Tue 29.03.2011, 21:43
by Elanlover
Committed To Buy: (not to exceed $75 USD plus shipping and taxes)

1. Dico
2. Pinky
3. Cliff
4. BFG in the BRG
5. Elanlover (brackets only as I have the springs installed)
6.
7.

Re: Gas Struts/Springs For Hood/Bonnet

PostPosted: Tue 29.03.2011, 22:51
by whippit
Committed To Buy: (not to exceed $75 USD plus shipping and taxes)

1. Dico
2. Pinky
3. Cliff
4. BFG in the BRG
5. Elanlover (brackets only as I have the springs installed)
6. whippit
7.

Re: Gas Struts For Hood/Bonnet

PostPosted: Wed 30.03.2011, 23:26
by esprit888
I'm on the fence only due to concerns about the stress placed on the hood/Bonnet connections as you pull the hood closed against the 40 lbs. Lotus couldnt get this right on the rear hatch of the Esprit as most i have seen have stress cracks on the rear buttress which is from closing the hatch, not the pressure applied to keep it open. Scared......... :smt100

Doug wrote:
Elanlover wrote:I gave a lot of thought to that and decided againt a spring with enough force to raise the hood on its own. As it stands now, the spring force is 40lbs and to have the hood raise on its own would require about double that. I didn't want to add that much stress to the hinge plates and screws for fear of damage to the bodywork.

I agree with that thinking; don't want to crack the GRP over time!

Nice, Blair, but what's with the dirty car in the picture? Shouldn't she be cleaned and polished up for the winter?
I'm still first on the list to buy if you ever have to sell her!.....

:mrgreen:

Re: Gas Struts For Hood/Bonnet

PostPosted: Thu 31.03.2011, 00:05
by Elanlover
esprit888 wrote:I'm on the fence only due to concerns about the stress placed on the hood/Bonnet connections as you pull the hood closed against the 40 lbs. Lotus couldnt get this right on the rear hatch of the Esprit as most i have seen have stress cracks on the rear buttress which is from closing the hatch, not the pressure applied to keep it open. Scared......... :smt100
:mrgreen:


I really don't think its going to be a problem but if course, time will tell. The stress is being absorbed not by the bodywork primarily but by the hingework. At the top mounting point, the bracket is bolted over top of the current hinge plate that afixes to the underside of the hood. So, the pressure is actually across the plate and bolts, not the actual bodywork. The only thing that is really being stressed there is due to pressure on the bolts and embedded nuts to push back towards the windshield when the hood is closed. But, the clamping pressure of the bolts onto the bracket means that only a portion of the pressure is truly on the bolts and I have to believe that they can take the pressure as they are the same setup as the trunk lid bolts and embedded (nuts in the lid) ans they seem to be able to take what must be close to that from the torsion spring when the trunk lid is closed.

The bottom mount bracket is held in place similarly but its underneath the hinge plate not on top of it. There are no embedded nuts here. There is a plate on the underside of the bodywork that the bolts run into so no worries about embedded nuts breaking free with wear. All that "might" happen is that there's pressure pushing the bolts against the hole they run through in the fibreglass body. But, once again, the clamping force (which is higher on the bottom plates) will relieve a good portion of that pressure. I have to believe that the bodywork can withstand at least some pressure but even if not one could insert their own metal sleeve into the hole. Even if after many years a few cracks appeared they'd be hidden under the plates.

I gave a lot of thought to simply punching a hole into the body work somewhere and mounting a bracket. But, in order to ensure no stres cracks would appear I would have needed to mount a plate underneath the bodywork to distribute the pressure. So, instead of modifying the body in any way I worked with a company to get a spring size and force that would allow it to be mounted to the existing metal work and hinge plates.

I understand your concern but I really don't think it will be a problem. Its 40lbs of pressure split between two mounting points so, forgetting angles and geomoetry, let's keep it simple and say its 20lbs at each mounting point (insteads of 18lbs and 22lbs for example). Also, there's two bolts per mounting point so each might absorb half leaving 10lbs per bolt if fully absorbing all the pressure. Now, the clamping pressure of the bolts has to carry at least 5lbs worth (I suspect more especially on the bottom plates). So, the bodywork might be asked to cover 5lbs and possibly less over several square inches. I have to believe it can handle 1 or 2 or 4lbs per square inch..........no???? :?:





Come on....you know you want some :-D

Re: Gas Struts/Springs For Hood/Bonnet

PostPosted: Thu 31.03.2011, 01:28
by esprit888
Committed To Buy: (not to exceed $75 USD plus shipping and taxes)

1. Dico
2. Pinky
3. Cliff
4. BFG in the BRG
5. Elanlover (brackets only as I have the springs installed)
6. whippit
7.esprit888 (What the hell, hood needs painting anyway :lol:)

PS: Dusty car to be expected in such a cold snowy city, but the wire off the boost transducer :smt103

Re: Gas Struts/Springs For Hood/Bonnet

PostPosted: Thu 31.03.2011, 19:33
by Jerome MARCHAND
Committed To Buy: (not to exceed $75 USD plus shipping and taxes)

1. Dico
2. Pinky
3. Cliff
4. BFG in the BRG
5. Elanlover (brackets only as I have the springs installed)
6. whippit
7.esprit888 (What the hell, hood needs painting anyway :lol:)
8.jerome marchand

Re: Gas Struts/Springs For Hood/Bonnet

PostPosted: Mon 11.04.2011, 10:24
by ratman
Committed To Buy: (not to exceed $75 USD plus shipping and taxes)

1. Dico
2. Pinky
3. Cliff
4. BFG in the BRG
5. Elanlover (brackets only as I have the springs installed)
6. whippit
7.esprit888 (What the hell, hood needs painting anyway :lol:)
8.jerome marchand
9.Ratman

Re: Gas Struts/Springs For Hood/Bonnet

PostPosted: Tue 12.04.2011, 07:42
by BFG in the BRG
Committed To Buy: (not to exceed $75 USD plus shipping and taxes)

1. Dico
2. Pinky
3. Cliff
4. Elanlover (brackets only as I have the springs installed)
5. whippit
6.esprit888 (What the hell, hood needs painting anyway )
7.jerome marchand
8.Ratman

Sorry to wimp out - change of heart :oops: