The Nissan Motor Co. pretty much rewrote automotive history in the early 1970s with the introduction of its 240Z. This breakout performance model proved to the masses …
Getting Things Rolling
Datsun finally got things right with the 1963 release of the SPL 310, a 1500cc roadster with a more contemporary shape than its predecessors. Unlike their earlier attempts, the SPL 310 was powered by an 85-horsepower, G-type 1500cc pushrod engine. (While the 1500cc engine was standard, several cars have been converted to the 1600cc R-I 6 engine found in many later sedans and roadsters.) The SPL 310 was introduced with a single SU carburetor, and later models came with a pair of SU carbs.
Compared to Datsun's earlier attempts at a roadster, wheel size was smaller (it decreased from 14 to 13 inches), and the rear gear ratio changed, from 4.62:1 to 3.89:1. The rear fold-down seat was replaced by a bench seat, while an A-arm suspension with coil springs replaced the torsion-bar front suspension. The quicker and more powerful SPL 310 was also a better seller than the earlier attempts, with 3148 units sold through early 1966.
In 1966, the SPL 310 was replaced by the SPL 311. A larger 1600cc engine replaced the earlier 1500cc unit, while twin SU carbs were now standard equipment. Front disc brakes replaced the earlier 10-inch drums, and a package shelf was used instead of the back seat found in the earlier cars. Wheel size was increased from 13x4.5 inches to 14x5 inches, too. Despite the mechanical changes, the bodywork of the two cars was very similar, with most outward differences limited to the grilles and trim. The SPL 311 also featured a slight flare on the front fenders.
Of the 40,000 Datsun roadsters sold between 1961 and 1970, more than half (23,609) of the total were SPL 311s. They were affordable and included many options for which buyers paid extra on MGs and other comparable sports cars of the day. With a few exceptions, the car remained pretty much the same through the end of the model run in 1970.
Midway through the 1967 model year, Datsun introduced the 2000cc SRL 311, which joined the 1600cc SPL 311 on the sales floor. While nearly identical from the outside, the new car featured a host of changes: larger 2000cc, overhead cam engine with 135 horsepower (Solex versions were rated at 150 horsepower); five-speed, all-synchromesh transmission with fifth gear overdrive; better, stronger seats; aluminum brake drums; rear torque link; dual circuit master cylinder, with pressure differential valve; 160 mph speedometer (replacing earlier 120 and 140 mph gauges); and a different front grille with a "D" located in the center. Obviously, the badges now read "2000" instead of" 1600."
It's important to note that the 1967½ 2000 had many items unique to that year; for that reason, it will always be one model favored among collectors. It was produced in limited numbers, as the 1968 model year brought enough changes to place the 19671h 2000 roadster in a league of its own.
Even more collectible are the cars equipped with Solex carburetors. These cars also incorporated a different cam grind, a larger-capacity oil pan, and a 4.11:1 limited-slip differential. From the outside, both the 1600cc and 2000cc models received even larger front fender flares in mid-1967.
Model Changes
Just as Nissan became more interested in exporting cars to the U.S., the Department of Transportation mandated a host of changes in 1968 that affected both the 1600cc and 2000cc roadsters, along with most every other car sold in the U.S. that year.
As mandated by the new DOT rules, a padded "safety" dash with recessed gauges replaced the roasters' earlier flat dash, while push/ pull switches replaced the original toggle switches. Headrests became standard equipment, while shoulder harnesses were added to the safety belts. Datsun started using a padded steering wheel with a larger center section, and the ignition switch was moved from under the dash to a locking steering column.
Windshields were now integrated with bodies and were no longer removable. Starting in 1968, the rear-view mirror was attached to the windshield frame instead of the dash, and like the Corvette, the radio was now mounted vertically in the center console with many of the switches located there instead of along the dash.
Only a few mechanical changes were made for the 1968 model year: all U.S models were fitted with cold-air injection smog pumps, a detuned advance curve in the distributor and smaller carburetor needle seats. The electrical system was also changed, as the fuse panel was relocated from the engine compartment to the glove box. (Now you see why the 1967½ 2000cc models are so desirable?)
More changes were carried out for the 1969 model year, as teardrop side markers were added to the front fenders, and round marker lights were in.stalled on the quarter panels. (For 1970, front and rear side markers were square.) The license plate light was no longer incorporated into the rear bumper; instead, two lights were added, one on each side of the Iicense plate. These later models also featured upgraded electrical systems, with better grounding and headlight relays.
The Solex version of the 2000 could still be ordered as a dealer-installed option, or the parts could be ordered individually and retrofitted by the owner.
1970 was the last model year these cars were produced. The early success of the 240Z, combined with slowing sales of the roadsters, led to the decision to halt production. In addition to the 23,609 1600cc versions produced, Datsun also built 15,718 2000cc roadsters through the end of the 1970 model year.
Racing History
Bob Sharp and Peter Brock were the two most prominent people racing, both the 1600 and 2000 roadsters. With Nissan taking a keen interest· competition and following the teams' early successes with the 1500, Bob Sharp was well-placed to build on his achievements when the 1600 was introduced in late 1965.
Bob owned one of only two dealerships to be engaged by Nissan to sell factory-approved, non-Nissan competition items for installation on the roadster. In 1967, in his role as Nissan's competition consultant, he was asked to produce a competition prep manual jointly with Nissan. That manual is still considered a must-have for anyone serious about racing a roadster today.
The 1600 was eligible for the SCCA's F Production class, where it raced alongside other popular small-bore sports cars of the day. The team quickly enjoyed further Divisional successes, and in 1967 Bob Sharp was rewarded with his first national SCCA championship.
More importantly for Nissan, Sharp's win marked their first-ever national championship–the first of 10 to be racked up by the 1600 and 2000 roadsters. Since that first win, Nissan has amassed 77 SCCA national championship wins, the most of any auto manufacturer.
Bob Sharp continued to race the 1600 successfully in F Production in 1968 and 1969, at the same time racing the 2000 in C Production class while Nissan's generous sponsorships continued. Sharp captured the Divisional championship in 1968.
In 1969, the team campaigned the factory lightweight 2000, of which fewer than 10 ever left Japan. The Bob Sharp team enjoyed further victories in later years, with their focus moving to the 510 and Z car. Consecutive national championships followed with both models.
While Bob Sharp and his team continued to win victories in their 1600s and 2000s on the East Coast, the Brock Racing Enterprises team, consisting of Peter Brock, John McComb, John Morton and Frank Monise, was winning consistently on the West Coast.
In 1968, the BRE team campaigned the 2000 roadster in SCCA's D Production class, culminating in a divisional title for Frank Monise. Midway through that season, lead driver John Morton took the top position, while a second roadster was driven by John McComb. Morton's was set up with the Solex carbs and cam arrangement to run in C Production class, while McComb's car remained in D Production. Both roadsters achieved similar successes.
The Morton and McComb roadsters incorporated several performance modifications: a front air dam cleverly disguised as brake ducts (these were the first cars in SCCA history to use an air dam); and a spray bar, which lubricated the cam followers (the idea was later incorporated by Nissan into its 510 efforts); and a compression ratio that was increased from 9.5 to 12.8:1 with the addition of Venolia forged domed pistons. Weight-saving items, such as a British aircraft battery and a plastic clutch scatter-shield were also incorporated, while a full roll cage was built into the tub.
Buyers Guide
Besides looking at the overall vehicle in question, it's important to know a little about what separates a good car from a clunker. Keep in mind that the newest roadster is 30 years old.
Always check the vehicle identification number stamped on the frame. It is located on the front left portion of the frame, just below the washer bottle. Usually the imprint is light, and a buildup of dirt, grease or paint can make it hard to read.
Compare the VIN on the car's frame to the title to make sure it is correct. Also check the plate located between the firewall and windshield. This plate has the VIN number as well as the engine number. You can find the engine number stamped on a casting on the passenger side of the engine block near the timing cover.
A Datsun 1600's VIN number will begin SPL-212xxxxxx, while the 2000 will begin with SRL-311xxxxx. If these numbers don't match up, it's quite reasonable to assume that either the engine has been changed out or the frame was swapped. If the swap is done properly, this should not deter you from investing in the car, unless you are specifically looking for an original car.
Cars of this era had little or no undercoating, and therefore tend to rust over time. Common areas of rust-through include the bottom rocker panels, trailing areas of the front fenders and the cold air intake area (below the cowl vent).
Be sure to check the trunk area, as the fuel tank is attached to the trunk floor with straps. With time and wear, these straps can break and pull away pieces of the floor with them. The area above the rear wheel wells, where the quarter panel is seamed together, can rust out as well. For more detailed information on rust identification and repair, see the Nov./Dec. 1999 issue of GRM.
The 1600 is a very strong little engine–more so than it is given credit for. As with all engines, a compression check is a good indicator tor of the overall condition. Variations in compression of more than 15 percent indicate worn valves or rings. If the compression checks out okay, and the engine is not burning oil or knocking, it's probably running fine. Check to make sure the temperature gauge is working and that the engine is not overheating.
If itruns hot, it could indicate that the head has been milled too far and thus increased the compression ratio beyond normal means. Likewise, check the oil pressure gauge. A common complaint is that at idle the gauge reads 0 to 5 psi. Roadster oil pumps are adequate, though, and 10 psi/1000 rpm is adequate for these engines.
For the 2000 engine, the timing chain assembly is the weak link. It uses a conventional design, but instead of having a camshaft to the side, it uses the shaft to run the distributor, oil pump and fuel pump. Another sprocket and chain connect it to the overhead camshaft sprocket; there is an L-bracket that can break off when the upper chain gets too much slack in it. It's best to replace the nine-piece assembly every 80,000 miles or so. Ditto for the rod bearings.
Datsun roadsters incorporate a conventional wishbone front suspension and live axle in the rear supported by semi-elliptical leaf springs. In the front suspension alone, there are 22 grease fittings that need lubrication. Sadly, many roadsters have been neglected in this area, and it's good to check all the front suspension components for missing dust seals and boots. The ones that are still there are often split open and leaking, or the ball joints and upper/lower control arm bushings are dry, causing premature wear. These components can be replaced, but a set of four ball joints runs $500.
Steering boxes typically leak and should be checked for gear oil. It's not unusual to find steering boxes filled with water after the car has been parked outside for a number of years, necessitating expensive repairs or replacement.
If the steering wheel has more than one inch of free play, a locknut adjuster can take up some of the slack. Later models (beginning in mid-1969) came with a recirculating-ball arrangement that replaced the earlier cam-lever design. To check the steering box for proper operation, lift up the grease cap and check for any movement while the wheels are turned.
Another test of the front suspension is to park the front wheels on several sheets of newspaper, then have an assistant tum the wheel lock-to-lock. While the front wheels are being moved through their range of motion, check under the car for any binding or unusual movement. Check the front anti-roll bar for any bends, too, as some people have been known to use them for tow rope attachments.
Roadsters have excellent brakes–when all the components are working properly. Brake fluid has an affinity for water, which can rust out brake lines and fittings; so check these crucial parts on any roadster. Also check calipers and wheel cylinders for leakage. Most roadsters in unrestored condition will need new wheel cylinders, calipers and master cylinders, as well as rubber hoses.
Another area to check out is where the master cylinder attaches to the firewall. The firewall section is only spot-welded and will begin to flex when the brakes are applied. A master cylinder brace can be made or purchased to reinforce the firewall.
Take a few minutes to inspect the top. All roadsters came with a soft top, tonneau and boot cover. If the material is worn out, it can be replaced, but the frames and related parts are getting scarce. On the 1968-'70 cars, the metal front bow will begin to sag, but can be rewelded or replaced.
Hardtops were offered by several companies as a dealer-installed option. Most are fiberglass with a triangle side window, no window, or a porthole window.
Performance Upgrades
As far as performance goes, the 2000 engine has a 40-horsepower advantage over the 1600; the smaller engine, however, seems to be more popular among racing buffs. This is primarily due to the fact that the 1600 is less expensive to build, and a lot of owners "stroke" a 1600 by using the crank, rods and pistons from a 2000. (The bore is the same.) The extra displacement and longer stroke combine for a substantial increase in horsepower, without the frailty of the 2000's timing chain configuration.
Engine swaps are a popular way to get additional power, especially when the cost of rebuilding a 2000 can exceed $3000. Nissan's KA24 (240SX) or any one of the pickup engines (L18, L22) can be fitted under the hood of a roadster, and for those interested in gaining more power than the four-cylinder swaps, the Infinity J30 and VG30 V6 engines are a good way to go.
If you choose to forego the engine swap, getting your 1500, 1600 or 2000 to run properly will provide you with a lot of satisfaction without breaking the bank.
As all three engines came equipped with dual SU or Solex carbs, check that the throttle shafts have no free play in them; matching up the float levels, mixture and idle speeds is the next step. Mikuni and Weber make replacements for the factory carbs that offer the added advantage of separate idle and mixture circuits. If you have the bucks and want the ultimate in tuning, Electromotive offers an electronic fuel injection system that replaces the stock side-draft carbs with individual throttle bodies.
The stock distributor works fine, but after 30- plus years, it's a good idea to have the bushings, cam and advance weights and springs replaced. On the 1968-'70 models (both 1600 and 2000), Nissan, in conforming to DOT mandates, added a cold-air injection pump, de-tuned advance curve and fit smaller needles and seats in the carbs. If your local air quality laws permit, backdating your engine to pre-1968 settings will provide a considerable performance increase, especially at the low end.
No matter what the vintage, all roadster engines have mechanical valve adjusters: the 1600 uses a conventional pushrod configuration, while the 2000 has the adjustment on the cam followers. Maintaining proper clearances will extend valve train life, as well as ensure good performance.
Exhaust systems can benefit from the addition of a good header and two-inch exhaust pipe to the back. When choosing a header, check to make sure the flange mates up well to the intake manifold, as both manifolds share the same gasket and fasteners. The 1600 came with a 1.5-inch exhaust from the factory, making the system a good upgrade.
Regarding the rest of the drivetrain the stock clutch is usually plenty stout unless engine is being swapped out for something exotic. The 2000 clutch pack is a heavier-duty unit and is a good upgrade for the 1600. The five-speed is the favorite, and some were made by Borg-Warner. All have aluminum cases and feature close gear ratios, with fifth being overdriven at .089:1.
The Solex-equipped 2000s came equipped with a 4.11:1 limited slip differential, and the non-Solex cars came with a 3.70:1 open rear differential. The 4.11 :1 rears are the favorite among racers, especially when combined with the five-speed.
For autocrossing and road racing, many enthusiasts upgrade the front suspension by installing competition front springs and high-performance shocks. In a budget-oriented move, some owners have removed the lowest coil of each spring. Another trick for racers is to change the camber from zero to one- or two-degrees negative. Changing the caster to a two-degree negative setting will help bring the steering wheel back to a neutral position.
While many roadster owners have added rear anti-roll bars to stiffen the back of the car, the stock leaf springs should be sufficient. With the Iive axle on the roadster, it's pretty stiff already. A bigger front anti-roll bar would be more effective, anyway.
Regarding wheels and tires, it's important to keep in mind that the roadster fender wells are pretty accommodating, but any aftermarket wheels must be at or near zero offset. On the front calipers, there is an exposed brake line that runs inboard from the caliper. Any wheel that has any negative offset will cause the brake line to rub the tire. Stock wheels are 14x6 inches, and they will accommodate a 185/60-14 tire quite nicely. A 205/50-15 works well for maximum width.
For those interested in road racing and autocrossing, Nissan Motorsports still offers lots of competition-ready hard parts for these cars, from connecting rods and camshafts to baffled oil pans and suspension packages. They also offer parts like ultra-close transmission ratios, forged pistons and the infamous side-draft carb kit found on the 150-horsepower 2000cc roadster.
Safety
The first issue on the safety list is good brakes. The 1966-'70 roadsters came with 11-inch rotors up front, and getting everything to work properly is a must. Again, the sheet metal area where the master cylinder mounts to the firewall is weak and prone to cracking, but this can be remedied by bracing the master cylinder to the steering column or by rewelding the bracket to the firewall.
Roadsters have the threaded bosses already in place to accommodate the installation of a factory roll bar. However, the factory roll bar only attaches to the sheet metal thread bosses, so a better upgrade would be the addition of a roll bar that is welded or bolted to the tub of the car or the frame. A rollover is never a good thing.
While the factory seats are sufficient, Mazda Miata seats are an inexpensive way to upgrade the seating. They will need to be raised up an inch or so off the floor in order to slide up and back. The factory seat belts are minimal at best, so for racing and safety in general, a proper five-point harness should be added.
Parts, Restoration and Enioying the Ride
Roadster parts can be hard to come by, but there are a number of vendors dedicated to keeping these cars alive. A good place to start is your local Nissan dealership, which still carries a surprising amount of NOS (new old stock) parts. However, even NOS parts can suffer from Father Time, especially rubber pieces. Fortunately, there are vendors still committed to providing NOS and used parts as well as solid technical advice from which even the novice can benefit.
For those who are looking for a great driving experience in a classic sports car without spending $25,000, the Datsun roadster is an excellent choice. In an age when most of the current offerings from car makers resemble everything else on the road, the Datsun still turns heads. These cars have character and the old-world charm of yesteryear. While they definitely require more driver input than today's cars, the challenge makes them even more fun to drive. Whether your choice is a 1500, 1600 or 2000, street or track, these cars are guaranteed to keep a smile on your face.
