Hood Mounting Plates
I do not mold-in mounting plates on my fiberglass hoods. They are, a) difficult to mold into the fiberglass in such a way that they are robust, and b) they are susceptible to damage in shipping. But I supply aluminum mounting plates that are shipped with your hood, if you did not order a "pin-on" (racing-style) hood.
There are several ways you can attach the mounting plates to your Z hood. If you utilize the hardware I supply, this is the way I do it. It's not necessarily "the best way," just "one way." Feel free to modify steps as you see fit.
If you create a novel mounting method or have tips that would be helpful for others, please let me know!
- When drilling fiberglass, use higher rpm and light pressure to avoid chipping the gelcoat finish or cracking the fiberglass due to drill binding.
- Hood mounting begins by drilling four, 3/16" holes in the area where your stock hood has a metal plate spot-welded to the inner reinforcement. There are indentations on the fiberglass that give you a rough idea of where to drill, but you can measure and mark for greater precision.
- Drill all the way through the layer on the other side.
- You can enlarge the inner holes to approximately 3/4" with a step-drill bit so that you can pass a deep-well socket through them. In order to avoid inadvertently enlarging the outer holes, you have to drill at the angle shown. The inner surface isn't perfectly flat, so drill carefully.
- Alternatively, you can also drill a larger 1" hole in-between the two 3/16" holes so that you can use a box-end wrench to position the flange nuts instead of a deep-well socket.
- You can clean up the inner edges of the holes with a rat tail file as shown, or with a Dremel tool, etc.
- Pass an M3x25mm bolt through a split washer and a flat washer, and through the mounting plate.
- Position the mounting plates on the fiberglass hood in the same orientation as the corresponding plates on your stock hood, so that they are canted outward. Thus the surfaces to which the hood hinges attach will be parallel to each other.
- Position the flange nuts inside the fiberglass using either a deep-well socket or a box-end wrench as shown earlier.
- Tighten the bolts snugly, but there's no point in torquing so firmly that you crack the fiberglass. Just compress the split washer.
- Attaching the factory latch to one of my cowl tunnel hoods only requires that you drill the mounting holes (which I do not pre-drill, in case you'd rather use hood pins or other hold-downs). If your hood does not have a tunnel, mounting is done in similar fashion to the mounting plates.
- Mounting the hood to the factory hinges is done just like the factory hood...which is to say, it's a bit tricky to get everything lined up. Plus, you probably want to consider eliminating the torsion bars so as to avoid excessive loading on the fiberglass when you are trying to shut the hood. You don't need the torsion bars to lift the fiberglass hood, since it's usually about half the weight of the factory steel hood. However, the torsion bars do provide some pre-load that contributes to alignment and stability when the hood is closed. So, you'll have to compensate for that when they are eliminated.
- If you are having trouble with alignment, you can slightly oversize the holes in the mounting plates to give you more adjustment. If, however, you get them too big, you'll have to run larger diameter flat washers under the bolt heads.
- Once everything is mounted and lined up, you can plug the inner holes with hole plugs as shown. Since the inner surface is not completely flat and the fiberglass is thicker than the design thickness of most plugs, you can use a dab of RTV silicone and a clamp to hold the plugs in-place overnight until the silicone cures and will hold the plugs.