Gas Struts for the Notchie Decklid

[dguy]

Some time ago I decided to have a go at making my own brackets so that we could replace the decklid springs on our two notchies with gas struts.  My first two attempts didn't hold up well, but presently my 3^rd rendition of the brackets has been in use for over a year and I thought I'd share the design since this version is showing no signs of weakness.

It's pleasantly simple, and positions the strut adjacent & near-parallel to the ribs on the underside of the decklid when the lid is closed.

A single strut could be used to assist a set of weak springs, or add extra lift where scoops, wings, or other body work has been added and the original spings are no longer sufficient.  Dual struts can do the job all on their own, allowing the body of the hinge brackets to be trimmed back should anyone have reason.

It may be possible to use this method "out of the box" with a fastback decklid, however due to differences in the plates which support the inner rear corners of the engine compartment vents some massaging is likely required.  You're on your own for that--I don't have a fastback to play with.         :p

[dguy]

Shopping List: (for a single strut installation)

• 2" corner re-inforcement bracket, available from your local hardware store;
• Gas strut with ball end fittings, 12" from ball center to ball center when extended, 8" or less when collapsed;^*
  
• Nut & bolt, 5/16" dia. x 1/2 - 3/4" long.
• Misc. washers.

Tools Required:

• drill & assorted bits;
• tap which matches the thread of the strut's ball studs;
• brazing torch & rods, or appropriate welding gear for light gauge metal;
• hacksaw or other cut-off tool;
• miscellaneous screwdrivers, sockets, and wrenches which you should have in your tool box already given that you own a Fiero.

^*More on the characteristics of the strut later.

[dguy]

What follows assumes that you're building a bracket to be installed on the left-hand (driver's) side of the car.  The right-hand side bracket is a mirror image of the left; pay attention to the orientation of the components as you go...

It all starts with a simple little 2" corner bracket, available on-the-shelf from (I imagine) pretty much any hardware store.

Remove between 13 and 15 mm from the "top" of the bracket.

[dguy]

Remove & disassemble the bracket on top of the strut tower which supports the inner rear corner of the engine compartment vent...

...and grind flat the flange shown here.

[dguy]

Braze or weld the corner bracket to the Fiero's bracket in the orientation shown.  Rivets or other fasteners may work, but I have no idea how well they'd hold up by comparison.

Clean it up and make it look pretty again, and mount one of the ball studs 1/2" above and 1/2" back from the edges the modified bracket.

[dguy]

Since the corner bracket is now partially or completely covering one of the holes used to attach the small L-bracket you removed earlier, drill out the hole & re-attach the L-bracket.  Since the flange and thread the original bolt used is now gone, replace that one with a nut & bolt.

[dguy]

Drill & tap in to the decklid rib, and mount the second ball stud as shown here.  The hole's center should be in line with the centers of the hinge bolts, and mid-way between the rear-most hinge bolt and the mount for the original decklid spring.  If your victim has a '84 decklid, some trimming of the side lip of the center vent will be necessary.

Ignore the other holes you see in this photo...  those are leftovers from earlier experimentation with strut lengths & positions.

Install the bracket on the strut tower, and attach the strut.  The body of the strut should be attached to the strut tower, the piston to the decklid.  Use washers to shim the ball stud on the decklid such that the head of the strut does not get caught on or rub against the hinge bolt while going through its range of motion.  Depending upon the outer diameter of the washer(s), you may need to grind a flat in to the washer(s), or grind a curve in to the decklid hinge for clearance.

[dguy]

That's it, that's all.       

Now about the struts...

The ones I used are a 90psi strut, measuring 12" from center-to-center of the end fittings when extended, with 4 1/2" of travel.  Twin struts with these specs, with the torsion springs removed, support a luggage rack-equipped decklid nicely.

They have sufficient strength & leverage to hold the lid open against wind gusts, yet they are not so strong as to cause the lid to fly open when initially unlatched.  I haven't had the opportunity to test these struts with a naked decklid, or one adorned with a wing.  The supplier I use for the struts however also has a 120psi model in the same length should the 90s proove too weak.


...and I apologize now, as I do not have an automotive application reference for these struts.  After running all over hell's half acre in a vain attempt to obtain operating specs for the struts used in various vehicles, I discovered that Seagrave would sell these to me over the counter.

[aaron88]

One more thing, for all of you that want to know.  Gas shocks have to be mounted so that the inside rod end is lower than the outside end when in the resting position (trunk closed).  This ensures that the seals don’t dry out.


Aaron

.

[dguy]

Gas shocks have to be mounted so that the inside rod end is lower than the outside end when in the resting position (trunk closed).  This ensures that the seals don’t dry out.

Horizontal should be safe as well, shouldn't it?

[aaron88]

not as safe

[MacPhail]

Is this what the finished product will look like?

http://www.2bluesc.com/pictures/Done/06%20Summer/Brew%20City%20Muscle%20Show%20+%20Random/IMG_1019.JPG

Cheers, Derek

[dguy]

Is this what the finished product will look like?

More or less, yes.

BTW I have a sister thread about this on PFF, which includes a partial list of strut pressures vs. decklid styles as well as manufacturer part numbers.

[MacPhail]

Is this what the finished product will look like?

More or less, yes.

BTW I have a sister thread about this on PFF, which includes a partial list of strut pressures vs. decklid styles as well as manufacturer part numbers.

I think it's going to look fabulous.  Look forward to seeing it.

Cheers, Derek