Roll Over Right

Start by measuring the distance from the floorpan to the roof. If the headliner is temporarily out of the vehicle, but will be used later, it needs to be compensated for. Also, the bar will most likely be slanted rearward to a slight degree to keep everything behind the B pillar, so don’t forget to include the lay-back angle in the measuring process.

The rollbar is marked at 33.5 inches, the distance from the floor to the roof

and then cut to fit.

Rules require the hoop, braces, and sidebars be welded to 6 by 6-inch plates. The CRX has a dip in the outer extremities of the floorpan behind the seat, so the best way to mount the plate is to bend the last inch or so over, forming a lip, which will seat in the recess and support the plate.

For extra support, make a small triangle out of .125-inch scrap material and weld in a gusset.

Prior to attaching the plate to the floorboard, a felt tip pen should be run around the perimeter, and a sander used to remove paint where welding will occur.

In the CRX, we had to remove a protective plate for the fuel lines, trim it to accommodate the plate, and reinstall.

Weld the plates to the floorpan using a MIG (wire feed) welder. Because you are attaching a thick 1/8-inch plate to a thin floorboard, you’ll find the MIG easier to use.

After trimming the base of the rollbar main hoop to match the plate angle, position the hoop and hold it in place with masking tape.

The front end of the bar will be welded to a 6 by 6 by 1/8-inch steel plate, which must be contoured to fit snugly in the appropriate area. For the CRX, the outermost part of the plate was bent upward at 90 degrees to fit flush against the rocker panel (the closer the bar is anchored to the panel, the better). A "pocket" should be formed on the inner part of the plate.

Prior to welding the plate in place, the surface of the floorboard should be prepared by first heating the sound deadener with a heat gun (or hair dryer, in a pinch), then scraping it off, and sanding the area to remove any paint.

MIG-weld the plate in position.

Determine the proper "fishmouth" cut on the side bar, where it attaches to the main hoop. A cardboard template can be employed to determine the proper fit and easily transfer the trim path to the tube.

This procedure can also be repeated on the other end of the side bar, where it mates to the front plate.

Simply roll an appropriately sized piece of cardboard snugly over the tube, push it past the end to do the trial fitting, then slide it back down the tube and scribe the cutting mark.

All of Morrison’s support bars come from the factory with one end precision-fishmouthed at 90 degrees.

Finish-weld the side bars in place. TIG/heliarc is preferred for a more even penetration and better-looking welds, however, MIG is also acceptable by the rules makers.

When securing the base of the side bar, you should make sure it is positioned as close to the rocker panel as possible.

Just as with the other bars, the plate attachment area needs to be prepared (sand off paint), and plates welded to the floor. The rear bar can be fitted in a similar manner to the side bar using a cardboard template. (Another way to "fishmouth" tubing is with a notcher, which is essentially a fixture that positions the tubing at any desired angle and allows you to cut it with a hole saw.)

Here, Art tapes the support bar in place in preparation for welding at the lower plate.

Next on the agenda is to determine the best location to anchor the rear bars. Note that the primary force exerted on a rollbar in the event of a serious accident (rollover) is downward, so this is an important consideration when determining attachment points. For the CRX, a place directly in front of the bumper mounts was deemed most suitable.

Fit the crossbar last. It’s typically mounted around the mid-point of the main bar and also used to mount the shoulder harness. NHRA rules require the harness to be anchored at a point within 4 inches from the top of the driver’s shoulder. When mounting the seat, also consider that the driver’s head must be within 6 inches of the rollbar (front to rear) and at least 3 inches below the top of the bar.

Fitting the bar is fairly straightforward. One side comes pre-notched. Attach it to the rollbar with tape at the proper height; hold it in the proper position up against the other side of the rollbar and mark the point where it would touch. Then using the cardboard tube method, determine how much of a "fishmouth" is necessary. Slide the mockup over the crossbar, index off the contact point, extend the cardboard outward as required and mark the cut line (the bottom of the arc should correspond with the contact point).

After the crossbar has been fitted, tack-weld one side. Then measure the distance from the top of the crossbar to the rollbar on that side and position it similarly on the other side. Finish-weld and you’re in business. (Important: Do not grind on any welds; it’s against the rules.) At some point in time, should the need arise to have a full cage (capable of running 10.99 or quicker in the quarter-mile or a speed in excess of 135 mph), the Morrison rollbar can be upgraded to the required specs by adding a kit which includes front bars, a windshield "eyebrow" bar, and forward strut tubes.

Toolbox: Optimum: MIG and TIG welders, tubing notcher, radial saw, disc sander (90 degrees), vise, hammer, tape measure, felt-tip pen, ratchet wrench and socket, heat gun, gasket scraper. Minimum: one welder, cutting torch, hack saw, disc sander, vise, hammer, tape measure, felt-tip pen, open-end wrench, hair dryer, scraper.

The finished product.

Rollbars are cool. Not only do they look "racy," but they provide protection in the event of an accident. That’s why they’re the minimum required in competition for coupes and sedans capable of running the quarter-mile between 11.00–11.99 seconds and convertibles clocking 12.00–13.99.

Of course, stuffing a rollbar into the confines of a compact car can be a bit of a challenge—so when it came time to build in some extra protection for his ’88 Honda CRX, Kenny Fong, head honcho over at Darkside Motoring in Chatsworth, California, opted for a kit from noted race-car chassis-builder Art Morrison.

In recent years, an increasing number of import enthusiasts have been having Art Morrison Enterprises design custom rollbars (and cages, which are required for cars running 10.99 or quicker). As a result of this, the Fife, Washington–based firm has amassed a sizeable database for its computer-designed products, and the CRX was in its files. Then it was a matter of transferring the CAD data over to Morrison’s in-house tube-bending operation, and voila—the requisite 1.75 by .134-inch wall main hoop, side bars, and rear supports (along with 6 by 6 by .125-inch-thick steel plates) were packaged up as a kit.

The cost to have a rollbar installed professionally can typically be several times the purchase price of the rollbar kit itself, so knowing how to do it yourself is an appealing proposition for many performance enthusiasts. We took advantage of one of Morrison’s sojourns to SoCal, and he graciously spent a day showing how to install a rollbar the right way. Even though Art’s been doing this type of thing for 25 years and quickly marched through the project, he feels that most any competent home fabricator can do the install in one day. And the techniques shown here will apply to virtually any installation.

Before you start the installation, the interior should be stripped of as much as possible. This includes seats, door panels, carpeting, and the like. The headliner can stay put if it’s going to be kept. Some sound-deadening material will also need to be removed where the reinforcing plates will be welded to the floorboard. Follow along to see how easy is it to install a rollbar.

As a final reminder, NHRA rules require the rollbar to be made of 1.75 x .118-inch mild steel (an absolute). Tubing can come from mills with a tolerance of ±.006 inch and, as such, a standard .120-wall tube can really measure .114-inch in thickness—and not pass tech (inspectors use sonic testing equipment). Morrison makes their bars out of .134-inch wall material so there is never an issue about passing tech. If minimum weight is an absolute, rollbars (and cages) are available in .083-inch wall 4130 chrome-moly tubing. With a purchase price of $185, plus the effort to install it, a rollbar makes a very cost-effective investment in safety. And it just looks mean. Clearly, it’s a project that merits your consideration.
www.artmorrison.com