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Thread: Manta Mirage rear engine cover

  1. #1
    Administrator Sulley's Avatar
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    Manta Mirage rear engine cover

    I have been looking for ideas on how to support the rear engine cover. I currently have a pneumatic air system but (1) it only opens far enough to put in gas and (2) I would prefer something 'less maintenance'.

    So I have been trying to see about ideas on strut style supports.

    Ok here is where I'm going with this. Look at the attached picture. Is it just me or would it be impossible to close the engine cover on this Manta Mirage? It looks like this would never work to me.
    Attached Thumbnails Attached Thumbnails Rear Hatch Support.jpg  

  2. #2
    Champion Member Blueovalz's Avatar
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    That looks like it would work. The difference in strut length between open and closed appears to be well within the range of the struts shown in the photo. The support plates on the bodywork appear to be a halfway decent way of distributing the forces on the fiberglass at a location on the bodywork, and in such a way, that may prevent it from being warped by the constant pressure of the compressed strut.

    If your looking for a method that does not include gas struts, but instead relies on muscle to lift the panel up, and allows the the panel's own weight to hold it open with some free-folding stops, check out a couple of my YouTube videos (another person was asking me about these, which is why I published the video). This obviously requires the weight of panel to hold itself open, so I've also drilled aligned 1/4" holes in the arms so that a PIP pin can be inserted into both overlapping segments, thus locking them in the open position to prevent the wind or such from pushing the panel closed inadvertently. In fact, I use the PIP pins to attach it to the frame and the body panel as well, so that they can be removed in less than a minute for those times when I'm working on one side of the car or the other (the rear panel only), and I need to get the prop out of my way.



    Last edited by Blueovalz; 12-08-2014 at 05:43 PM.

  3. #3
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    I am looking for pictures and ideas to latch the engine cover down in the front. Also where to buy the latches. The latches mine has are not good. Do you prefer cable release or poppers or hoodpins?

  4. #4
    Champion Member Blueovalz's Avatar
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    Depends on what you want Jerry. If you've got a means of fabricating a latching release rod or handle, I'd recommend Bearclaw latches (I used the heavy or large latches for the rear being it will be bad news if these fail). I used 1/4" aluminum rod as the pull-pin or handle for mine, which lies forward of the rear hatch edge, and under the door (must open the lower door to pull the latch). The internal spring on the latch is not strong enough to push the striker up out of the latch when you pull the release arm, so that will need to be addressed or thought through. I've been able to do a work-around for that issue, but a much better means could be fabricated for popping the panel up once the latch is released (I was tired of nickle and diming the excessive add-on weight). A simpler, and attractive set-up would also be Aerolatch using a similar arrangement to hood pins, but much much more refined look.

    Here is the Bearclaw latch on my project, on the edge of the side-pod cover. but it could also be placed on the firewall panel as well (but that has to be carefully constructed due to angles and hinge geometry. The 1/4" hole on the release lever is what I used (plastic clevis from McMaster Carr) the aluminum rod for, which goes forward into the firewall and under the lower door area.


    This is the striker that is on the rear panel.


    Put together with the panel down and in place. I simply threaded the ends of the aluminum rod to 1/4 x NC and screwed on a cheap 1" diameter handle (another McMaster part) on the pull end, and a plastic clevis on the latch release end. Keeping all the latch releases hidden from obvious sight keeps prying eyes from going any further when I'm not around. Not shown here is the plate and guide-hole that the 1/4" aluminum rod would eventually go through. Works very well!
    Last edited by Blueovalz; 09-17-2015 at 09:47 PM.

  5. #5
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    That looks pretty solid. I guess 2 cables and a handle release. I could run the cables under the panel to hide it.

  6. #6
    Champion Member Blueovalz's Avatar
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    Very solid. Because I didn't follow through with a spring loading mechanism to pop the panel up when the releases are pulled, it's better done with two folks, but one can do it with one (inserting a plastic spacer under one side after you pop it, then walking over and popping the other side, and then lifting). The spring mechanism I was designing would have added yet another pound or two to the car, and I'm sick at the weight gain it has taken on already (guessing 2200 lbs). What did help a lot is that I installed rubber pads (pressure sensitive 1/8" thick rubber foam tape cut into short pieces) from McMaster that has good recovery characteristics. These then require a small amount of compression to get the latch to "latch". Because the square area of padding used is proportional to the amount of pressure needed to compress the pad (i.e to latch the panel), it is very adjustable in how much "push" you want to place on the panel in order to latch it, simply by sizing the pad area appropriately. This method of eliminating rattles and making it a solid latch worked out well.

    Your thoughts of using pull cables will work fine, but you will need to find a means (springs, etc) of forcing the panel to pop up and out of the latches once you pull the releases. The gas shocks on the panel (as it appears you have), may completely resolve that matter. I chose not to use those mainly because of the fear of the high compression pressure eventually warping or damaging the fiberglass, plus the high heat the panel is exposed to in combination with that high "constraining" pressure.

    If you don't address the above issue, the panel will not become unlatched until you "pull up on the panel, and release latch" at the same time. My panel is pretty heavy, and when I looked at springs and other options to ensure a strong enough latching pressure at the latch (and not distributed along the fiberglass panel which is what the shocks do) to also push the panel up and out of the latches, it became pretty complicated because of the needed spring rate versus compressed spring pressure, all being compromised by spring diameter and length. So it was just easier to use my plastic lacquer thinner cap-covers as a spacer to place under the edge of the panel once I unlatched one side, and then go over to the other side, unlatch, and lift. Obviously this works much better with two people.



    I looked as 3/4" springs, 3" long (this provided the final compressed spring pressure strong enough to push the panel up high enough to unlatch (the shorter springs with much higher spring rates provide way too much compressed pressure), but the surrounding cylinder (to keep the longer spring aligned during compression, as well as a piston to do that, was in-feasible in the sense of added complexity, limited space, and added reinforcement needed on the panel flanges.
    Click image for larger version. 

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    Last edited by Blueovalz; 09-18-2015 at 01:41 PM.

  7. #7
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    Great info applicable to any kit car. I would have been learning these things the hard way, adding things till it worked.

    Thank you Terry.

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