the staff of Motorsport Marketing
the staff of Motorsport Marketing Writer
12/11/13 11:10 a.m.

Choosing Your X: Like other iconic, long-production-run models such as the Porsche 911, all Fiat and Bertone X1/9s are fundamentally similar. From 1972 to ’88, the chassis geometry, suspension, brakes, steering and body elements were not changed. Bumper treatments were the most obvious differences, undergoing three different designs: one in 1974, one from 1975 to ’78, and one from 1979 to ’88.

The driveline began with a 1.3-liter engine and a four-speed transmission from 1974 to ’78. In 1979, the X1/9 was upgraded to a 1.5-liter engine mated with a five speed. The 1979-’80 models were carbureted and full of emissions equipment that made maintenance, drivability and performance problematic. In late 1980, Fiat began fitting all Fiat X1/9s with fully electronic Bosch L-Jet injection, really paving the way for a modern, emissions-compliant car without the spaghetti of vacuum hoses, air pumps, EGR valves and thermo switches—years before most other automakers.

In my opinion, 1974 or 1987-’88 X1/9s are the best cars to buy because they bookend the series and have distinctive styling cues. When driving a very early car like a 1974, you see just how advanced the engineering was—combined with clean lines and blade-style bumpers—and instantly know why they were such a hit. The later cars have a bit more refinement, with more comfortable seating, power windows, nicely styled factory alloy wheels, and a more powerful fuel-injected engine and five-speed transaxle.

Long Life: The engines are robust units that will last forever if the cooling system and air-fuel ratio are kept up to snuff and basic preventive maintenance is performed. Head gaskets are a frequent problem with the cars due to neglected or damaged cooling systems or out-of-tune carburetors.

Better Bushings: The right-inner bushing on the steering rack is an inexpensive resin bushing that disintegrates over time, causing erratic handling due to excessive toe changes to the right-front wheel over bumps. A worn or sloppy rear control arm ball joint will cause all kinds of excitement on wet roads when rear toe settings on one side or the other suddenly start changing while at speed.

Missing Electrons: The electrical systems are not inherently flawed, but exposed 1/4-inch spade and bullet connectors—industry standard at the time—simply can’t put up with years of wet driving. Fortunately, it’s simple to cut and replace most problematic connectors if needed.

Rust, Italian Style: Four easy-to-see spots that usually tell the structural story about the rest of the car:

1) In the front trunk, check the left and right vertical panels parallel to the struts. This is a three-layer, sheet-metal laminate, and when water gets in, it begins rusting from the inside out. This is not a structurally important area, and it can be repaired, but it’s a harbinger for other issues on the car.

2) In the rear of the car, two cavities between the engine cover and the targa bar—concealed with plastic bezels—should be checked. These have drains, but debris often clogs them and the car will rust here.

3) Look at the rear vertical shock tower panels and ensure they are the same as the front shock tower panels.

4) The rear suspension pickup points should be closely inspected. Any corrosion in these areas is usually terminal.

Scratch and Dent: Superficially, the lower windshield frame, floor pans, rear trunk pockets and forward rocker panel extensions are common areas for cosmetic problems to tackle while you are planning a refinish.

More Power: If a really nimble and really fast X1/9 is what you want, then a driveline swap is the most direct solution. Countless enthusiasts have swapped a multitude of engines into these cars over the years, and it’s not considered sacrilegious to do so. We have performed several swaps using the modern Honda/Acura K20 and K24 series, which provides great return on investment. This swap results in 200 to 300 horsepower and a robust six-speed transaxle; it does not disrupt the vehicle balance.

The X1/9 is an extremely strong chassis and can easily absorb 250 horsepower without body flex or ill effects on handling. Owners who have had a 200-plus-horsepower driveline conversion inevitably say, “This is what this car should have been all along.” With a power-to-weight ratio under 10:1, X1/9s with this treatment can truly approach supercar territory, not only in straight-line speed but in handling, agility and looks, for a fraction of the cost.

Matt and Marnie Brannon

Midwest-Bayless Italian Auto

1333 Kingry Street

Columbus, OH 43211

(800) 241-1446


Shop Smart: When looking for an X1/9, buy the car in the best condition, regardless of year. There are secondary criteria, but generally one could start with a chassis from almost any production year and build up the car as desired. It is far cheaper to buy a car in good condition than to bring back a rusty basket case.

Mushroom Tops: When shopping for a car, check the strut tops for mushrooming. This indicates the strut was bottomed badly and there may be more extensive damage. Inspect the insides of the headlight buckets and nose panel for poor-quality body repair. These are complex assemblies, and if previous damage was badly repaired, it can be expensive to correct.

Interior Space: Early interiors are generally roomier but more Spartan than the later 1.5-liter cars. Larger and taller drivers tend to prefer the 1.3-liter interior for the additional room. As noted, either interior can be fitted to either chassis, and it’s common to find 1.3-liter chassis fitted with the later 1.5-liter driveline.

Belt Check: X1/9s are surprisingly robust cars. If kept serviced, the SOHC engine will endure years of hard use with little fuss. This engine was one of the first production engines to use a cogged-rubber timing belt. The FSM recommends it be changed every 40,000 miles. The 1.3-liter engines are an interference design, so to be more prudent, change the belt every 25,000 miles or every three years. Servicing the belt is a simple job compared to more modern cars.

Transmission Troubles: Transmissions are something of a weak point. The Fiat SOHC was originally a 1115cc/50-horsepower unit fitted to the front end of a 128 sedan, and the transmission was designed for this application.

While it was improved for installation in the X1/9, it still has its weak points. For all X1/9s, third-gear synchros are a weak point, as is reverse—even more so in the five-speed transmission. Expect a crunch on the second-to-third shift; heavily used transmissions may lose third gear entirely. The transmissions are prone to popping out of gear when reversing, and the resulting damage can accumulate to the point of failing entirely. A thorough overhaul by a competent technician is the only fix for any of these issues.

Miffed Master Cylinders: Clutch and brake master cylinders are prone to leaks due to the fact that most replacement units are NOS and the seals are very old. They are both located under the dash and thus require some effort to change. If you’re going to do one, do both and avoid having to repeat the chore.

Tune Me Up: The X1/9 really responds well to tuning. Remember that these are 1970s-era smog motors and thus suffer from conservative camshaft profiles, low compression ratios and severely restricted intake and exhaust tracts. As a result, improvements in breathing and compression make for significant gains. A more aggressive camshaft, along with a dual Weber conversion and a header, will quickly add 20 to 25 percent in horsepower and torque. A lightened flywheel is a very nice complement, as the heavy stocker makes the engine feel lazy. For a healthy engine, no internal modifications are necessary until the builder gets really serious.

Handling Helper: Handling improvements are just as easy. The X1/9 is the best-handling MacPherson strut chassis I have ever driven and rivals almost any current design. This is Mazda Miata and Lotus Elise territory.

Stock U.S.-market cars tend to roll a lot because Fiat never fitted anti-roll bars to the X1/9. The U.S.-market cars were also raised to meet our bumper height requirements, while softer springs were fitted to meet consumer expectations. Improving handling is as easy as lowering and stiffening the suspension. “Sport” springs are available from suppliers and transform the stock car into a sharp and precise-handling thoroughbred.

If one wants to further sharpen the handling, a front anti-roll bar and real race-bred coil-overs are all that is necessary. It is important to ensure that the foundation is in good order. Fresh bushings and upper strut mounts help keep the geometry in line and the behavior predictable.

Steve Hoelscher

Fiat X1/9 Autocross National Champion


• The later models have power windows that tend to become unreliable as they age. Your best bet is to retrofit the manual versions.

• Like just about any classic, the original air-conditioning system in a Fiat X1/9 is not very effective or efficient. You’re better off removing the X’s targa roof and taking advantage of al fresco motoring.

• A Fiat is not a Chevy—be wary of cars that have been buggered up by previous owners.

• Valve clearances on all engines need to be checked every 15,000 miles.

• The 1.5-liter cars use larger and better wheel bearings. Upgrade your early 1.3-liter car when the original bearings need to be replaced.

• The fuel-injected cars are more powerful than the carbureted versions, but parts are becoming scarce for the Bosch fuel-injection system. If you see replacement parts for sale, buy them so you have spares.

• If you’re in California, your best bet is to find a 1974 or 1975 model and upgrade it to later specs. That way you can avoid the biannual smog checks required for cars from 1976 or later.

Chris Obert

Fiat Plus

2131 D Delaware Ave.

Santa Cruz, CA 95060

(831) 423-0218


Bleed the Cooling System: X1/9s have a long pair of coolant tubes running the entire length of the car. These go from the radiator all the way back to the engine in the midship position. It is common for air to get trapped when the cooling system is flushed or drained for engine work.

The factory had a solution to bleed the air out of the system. There is an often overlooked 8mm Allen screw on the top, left-hand side of the radiator. This is recessed in the sheet metal under the front boot. When filling the system, just open this screw a turn or two and fill the system until coolant comes out. Start the engine and bring it to operating temp. Continue to run it until the fan cycles a couple of times; meanwhile, watch the temp gauge to make sure the car does not overheat. It may be necessary to turn off the engine, repeat the bleeding and refill the cooling system a couple of times during this procedure.

Timing Belt Setup: 1300cc SOHC motors have an interference engine arrangement. In other words, if the timing belt breaks, you are likely to bend valves. 1500cc SOHC engines used from 1979 on do not have interference engines and are not subject to this issue.

The timing setup can be tricky if you have not performed it before. The cam timing pointer is on the timing belt backing plate, and there is a mark on the back of the timing gear. Don’t be fooled by any marks on the front of the cam gear and the pointer on the motor mount. These marks are not valid on American-market cars, and if they are used, the car will not start.

The crankshaft pulley has a mark that lines up with the “0” on the timing cover pulley. The tricky part is knowing the distributor should be pointed to the No. 4 cylinder (the transmission end of the block), not No. 1 (the timing belt end of the block).

Speedo Cables: In the late ’70s, Fiat began installing catalytic converters and EGR valves on their automobiles to meet federal emissions regulations. The early converters and EGR valves were federally certified for 25,000 miles. At the time, federal regulations required cars with this certification to have an EGR and/or cat light to illuminate in the dash every 25K miles.  

The light(s) were illuminated via a counter installed in the path of the speedometer cable (a two-piece cable, one to the counter, one to the speedometer). Fiat later had the converter and EGR federal certifications increased to 50K miles. This eliminated the need for the counter and the two-piece cable. All are now one-piece cables. When installing the one-piece cable, simply bypass the counter and attach the cable directly to the speedometer.

Barry Wilson

International Auto Parts

P.O. Box 9036 Route 29 N.

Charlottesville, VA 22906

(800) 788-2095

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