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Rear clam hinge lift struts

11K views 43 replies 22 participants last post by  2m6mc2 
#1 ·
Finally, I installed gas lift struts to augment my BOE Fab rear clam hinge, I should have done this years ago when I installed the hinges. I used a strut with just enough force to hold the clam mid-way open, it really makes the hinge feel like a factory piece. Much less force is needed to move the clam; I can open and close it with one hand from either the left or right side of the car; you don't have to open from the rear like you had to do with the stock BOE hinge.

To anchor the chassis side of the struct I fabricated a couple of simple mounts and used an existing hole in the subframe to secure them, I drilled an 8mm hole in the BOE hinge for the clam side mount. The lift struts I added were from Bansbach easylift P/N – D3D3-42-150-385--006-220N 6" (150mm) Stroke 15" (385mm) Extended Length Force: 49.40 lbs (220N) (link below)

https://store.easylift.com/clearanc...EGoNiCMXiaWN2NgCbTwTmFlssvvhCMVqmoCKUpcsacmp0

Remember, it's a Lotus, each one is different, your mileage may vary...
 

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#4 ·
Fantastic!

Two questions. First, why did you only use one strut and not put a strut on both sides? Two, how close are they getting to the exhaust? These struts do not like heat and I'm wondering that track use may get them too warm.

Great Job,
Eldon
 
#5 ·
Eldon, I did use two struts (one on each side), I only posted pictures of one of them, sorry about the confusion. The lift struts are rated to 80°C (176°F) so they're fairly robust, to address the heat I'm using a heat shield on the left side lift strut to shield it from the 180 degree bend in the exhaust, I think the right side is far enough away to stay cool. I'm fabricating the heat shield today so I'll post pictures later. I've removed most of the factory heat shield from around the exhaust and I'm using a custom rear valance panel that allows more airflow; things stay pretty cool back there as it is.
 
#6 ·
Some pictures would be great. On my Exige, I do not have that hole unless you drilled yours out. Also, the Exige clam weights a little more than the Elise clam so I'm wondering how close the strength of the rods are.

Also, where in Iowa do you live? I grew up in Cedar Rapids and went to school at ISU even though I'm a Hawkeye fan!

Later,
Eldon
 
#11 ·
I'm not sure about the weight of the Exige clam, these would still provide quite a boost over not having anything, but they also have plenty of other lift struts with higher force ratings. I"m in central Iowa in the Des Moines metro area, and I'm an ISU grad too!
 
#10 ·
Thanks man, it's great to have time to work on it again. I'm hoping to have it driving again soon as time and budget allow.
 
#15 ·
Bumping this....came up when lookign for pics of the clam hinge. This looks like a great modification!

Any updates as noted or additional pics?
 
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#16 ·
That will definitely be one of my winter projects. :grin2:
 
#22 · (Edited)
Sorry about leaving this post half-finished, I spent some time modifying my original design to improve fitment and clearances. I'll attach more detailed pictures and drawings of what I ended up using, and for all those that have asked, I'll include a link to a video of the struts in action. It won't let me upload all the pictures in one post so I'll add a second post for the remainder of them. I used coupling nuts (M8 1.25 x 25mm) to act as spacers to achieve clearance on the hinge and exhaust.

Video link:
 

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#23 ·
Here are the remainder of the pictures...
 

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#25 ·
I don't want to turn this into a 'Parts for Sale' thread. That being said, I could make the brackets and put together a kit of the parts needed (minus the gas lift struts themselves and the insulation for the left side strut) the kit would cost in the neighborhood of $60.

In addition to supplying the lift struts and insulation for one strut, you'd have to drill a properly placed hole in each of the BOE clam hinge brackets and enlarge an existing hole in the Lotus sub-frame, and possibly modify the factory exhaust insulation if it is still installed.

PM me if you're interested.
 
#26 ·
?? I decided to make this one of my fall projects. I got the struts a couple of days ago and have assembled the parts. The struts are metric and I was able to get all the fasteners at my local ACE Hardware. I got the steel plate for the bracket at LOWEs. Any-who, I cut and drilled a couple of extra sets of brackets (revised) if any one is interested!
 
#27 ·
Hi Jetblast,

I like your idea and appreciate the design and layout work. I would like to do this but:

I'm a bit concerned about the close proximity to the exhaust, as mentioned previously by others.

The strut being gas filled. If this motor mount melts down in a location farther away from the exhaust than the strut I'm concerned that the life of the strut may be very short. Once the gas in the strut is heated very high repeatedly especially in a track driven car it's going to expand perhaps much more than the design intended?
This will cause it to lead past the seals especially as the seals deteriorate over time and in the high heat this may be short.

Admittedly lots of maybes and unknowns here.

I know that the struts that are used to open the camper shell on my truck over the course of a few hot summers will loose most of the opening force.

You've used some shielding:
** Have you put a temperature probe, laser etc.. on it after getting the system hot?
** How effective is the shielding.
1255365
 
#28 · (Edited)
The strut on the drivers looks like its right over the catalytic converter. The normal operating temperature of a cat is 1200 to 1600 degrees F.

That is however the internal temp and interesting but irrelevant here.

The important temp is at outside surface of the O2 sensor area which is 450 to 500 degrees. I don't know how fast the temp let's say at 500 degrees drops with distance.
Anyone have laser temperature gun to check this out?

Jetblast, Do you happen to have one?
 
#29 ·
Mark,
Where is the heat shield for the motor mount? Also, did this car have a rear panel delete? I have the heat shield for the motor mount and the rear panel delete. I have never melted a motor mount. Also, JetBlast has mentioned that he wraps the driver's side in heat shielding to protect the strut. Time will tell how fast it degrades.
Later,
Eldon
 
#30 ·
Hi Eldonz,

The heat shield for the motor mount is missing so I thought this was a somewhat reasonable comparison since the strut used here is much closer than the motor mount. The motor mount is not right over the O2 sensor area which is the highest temp spot and receives only radiant heat whereas the strut gets both radiant and convected heat. Just a very rough and unscientific comparison.

The rear panel delete is great for lowering temps when you are moving. When moving slowly in traffic or sitting at idle there's no air moving through. The heat will be very high and it will have an effect as soon as the air stops moving.

The heat shield used on the struts is definitely a good idea. I'd like to know how effective it is. It would be more effective if it had an air gap between the strut and the shield.

I think the best and easiest way to see what's going on is with a thermostat laser gun or a thermo camera.

Here's a video on exhaust temps. On our cars there's no shield on the cat as there is in this video so look at the very big difference between the shield temp and the cat temp.

 
#31 · (Edited)
A BIG thank you to Jetblast for posting this upgrade. I just finished the installation, opening and closing the clam is now a piece of cake, Boe should make this an option when buying the clam hinge kit. ?
1255554
1255555
1255556
 
#33 ·
I always like to propose a solution, if I can find one, to the issues I point out so I have been looking around for something that would take care of the possible heat issue with the struts.
This is not to say that the heat shield that Jetblast and others are using is insufficient but we just don't know. I'd still like to see a temperature heat gun reading of this.

Here is something that looks very effective for this application. Its effective up to 2000 degrees and the adhesive backing is good up to 300 degrees
www.thermotec.com
adhesive-backed-heat-barrier
#13500

I think I'll use it on the bottom of the plate I'm getting to place under the inter cooler also.
 
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