1969 Chevy Nova - Lock It Up
Achieving Better Burnouts-And Launches-With A TCI Roll Stop
From the July, 2007 issue of Chevy High Performance
By John Nelson
Photography by John Nelson
It's one of the contradictions of drag racing: Before you can take a breakneck rip down the quarter-mile, you've got to hold perfectly still. We're talking about thatcoiled, ready-to-pounce moment at the starting line, of course, but we're also talking about the moments before staging. The ability to hold still in the water box for a good burnout can make the difference between properly prepped tires and a spinning mess. Fortunately, a simple device, commonly called a line lock, can make for both better burnouts and starts. These thoughts led us out to the garage, eager to see what it takes to install a TCI Roll Stop on a stout street/ strip Nova.
This is what you get with...
This is what you get with TCI's Roll Stop kit: a solenoid unit, a microswitch to activate it, and various brackets and mounting screws. The solenoid is also available by itself. Depending on your application, various brake lines and fittings will need to be purchased separately.
And this is the brake setup...
And this is the brake setup we were faced with. Pete Cervantes' '69 Nova runs a Currie 9-inch rearend with disc brakes. Cervantes installed a Stainless Steel Brake Corporation proportioning valve to control the aftermarket rear binders, but the front brakes still work off the factory block, one line to each wheel.
Remember, the Roll Stop solenoid...
Remember, the Roll Stop solenoid unit must be placed between the prop valve and the brakes themselves. Our first step was to remove the two front brake lines from the prop valve and carefully move them aside (1). We then blocked off the upper outlet on the valve with a pipe plug (2) and installed a short length of brake line into the lower outlet.
We've mentioned that you'll...
We've mentioned that you'll have to purchase a variety of adapters and fittings, depending on your setup. Two bushing adapters to mate the 11/48-inch pipe thread outlets in the solenoid with the brake lines are a necessity. We also grabbed a T-fitting and another adapter to facilitate reconnecting our front brake lines.
The key component of the Roll Stop, like most line locks, is an electronic-solenoid-controlled valve that is plumbed into a vehicle's brake system, normally (though not exclusively) the front. After pressing the pedal, the solenoid is then activated and the valve is closed. Since the brake fluid cannot flow back toward the master cylinder, the brake line, and therefore that pair of brakes, is effectively locked. They stay that way until the solenoid is deactivated, allowing the brakes to release the rotors.
For the vast majority of CHP readers, a Roll Stop would be installed to work with a car's front brakes. With the front binders locked, a driver can stay put in the water box and burnout to his heart's content, or at least until his race rubber is good and sticky. Of course, our front-wheel-drive brethren can also easily make use of a line lock on the rear brakes. Our man at TCI, Stan Poff, tells us that some racers in classes that don't allow a trans brake will use two Roll Stops, one for each axle. The solenoids are wired with rev limiters set just above the driver's launch rpm; launch occurs by releasing the Roll Stop control button rather than by working the brake pedal.
And that, of course, is the other advantage to be had by installing a line lock. Foot braking works well for many racers, but after pressing the pedal and engaging the Roll Stop, a racer doesn't have to worry about keeping a foot on the brakes. The vehicle is held perfectly still at the line as long as the solenoid is engaged. When the button is released, the brakes are instantly released and the car launched. This is especially advantageous in a manual-shift car like our subject for this story, Pete Cervantes' '69 Nova.
At this point, we had our...
At this point, we had our Roll Stop ready to set into place. We used a small amount of Teflon tape on the adapter threads; you want to go sparingly here so none of this material gets into the brake system.
Installing the Roll Stop is a pretty simple affair. First you'll need to find your configuration in the Roll Stop instructions, purchase the necessary extra parts, and then plumb the solenoid into your brake line, between the proportioning valve and the brakes themselves. TCI is working on application-specific install kits, but for now you'll definitely need a pair of inverted flair adapters to join the 11/48-inch roll stop openings to your 11/44- or 31/416-inch brake lines. You may also need some brake-line fittings. In our case, we used the two adapters, a small length of brake line, a steel plug, and a T-fitting. All told, we spend about eight bucks on plumbing goods at our local parts house.
With that accomplished, you're left with only three wires to hook up, then to bleed the brakes, reconnect the battery, and go try 'er out. A number of microswitch mounting options are possible; Cervantes chose the one that works best for him at the starting line, specifically a shifter knob with a built-in microswitch. After identifying our configuration in the directions and purchasing the parts, installation took all of an hour, including the requisite brake bleeding.
Unfortunately, we didn't get to track-test the Roll Stop before press time, but we were able to make a couple of informal observations. First, whereas holding this car in place for a burnout used to be problematic, lighting up the rear Mickeys is no longer an issue. We expect to see benefits just from that. Better yet, Cervantes can now hold his Nova at the line with the Roll Stop, rather than balancing the brake, gas, and clutch while waiting for the green. We'll let you know how it works out at the track; for now, here are the nuts and bolts of this install.
And just like that, we had...
And just like that, we had the unit connected to the stock prop valve and the front brake lines reconnected to the T-fitting on the other side of the Roll Stop. The lower prop valve port is bigger and handles more pressure, since it was meant to work the passenger-side front brake. In our configuration, working through the Roll Stop and with the top port blocked, it provides enough pressure to work both binders. All that remains on this end is to bleed the brakes.
While the Roll Stop kit comes...
While the Roll Stop kit comes with a basic microswitch and bracket, our subject Nova's owner, Pete Cervantes, wanted to be able to work his line lock at the shift lever. We hit up TCI for one of its Competition Thunder Stick knobs, complete with a built-in switch.
Wiring the Roll Stop is about...
Wiring the Roll Stop is about as basic as it gets: There's a hot wire running to the microswitch through a 4-amp fuse, a wire from the microswitch to the solenoid, and a ground on the solenoid. Any added lengths of wire should be at least 22 gauge.
If you'd rather mount your...
If you'd rather mount your Roll Stop control to your steering wheel, TCI can provide a spiral cord with a microswitch for maximum flexibility.
151 Industrial Drive