• Vas Comblas

The 1978-’83 Porsche 911 SC, Once Destined for Obsolescence, Is Still in Demand

Updated: Jun 3

Shared by Vas Comblas.



Some things from the 1970s and ’80s haven’t aged well. CB radio slang, for instance. Every episode of Joanie Loves Chachi (recorded on VHS). Or Flock of Seagulls haircuts. But the 1978-’83 Porsche 911 SC? Given that values have doubled, even nearly tripled in the last decade, it’s safe to say that this formerly rank-and-file version of the 911, once overshadowed by its older and newer siblings, is defying age like Wilfred Brimley in Cocoon.


The same can’t be said for some write-ups about the car when it was new, declaring the 911 SC dead on arrival. Take these excerpts from a review in the August 1980 issue of Car and Driver:


"Porsche says there will be a 911 as long as there is demand for one, but it’s difficult to see the car or the demand lasting more than another couple years. At the most," the late Mike Knepper wrote in the article’s "Counterpoint" sidebar. "It has outlived its usefulness and as attrition takes the die-hard traditionalists, the 911 will outlive its demand."


The late David E. Davis also played the age card—on a car that has since become Porsche’s most long-lived model: "This Porsche feels old, somehow. It feels as if it’s finally coming to the end of its allotted lifespan… From now on, the Porsche of my dreams has a V-8 engine in the front."


But Davis’ dreamy front-engine V-8 Porsche, the 928 (of course), was more like a bugle sounding out reveille to the 911’s army, who rallied around the rear-engine, air-cooled warhorse. For Porsche, meanwhile, it was a nightmare watching sales of its state-of-the-art grand tourer wither on the vine as the creaky old 911 flourished. To put it in perspective, Porsche built 57,998 928s over about 18 years of production and 57,890 911 SCs in just six years.


For a time, 911 SCs were among the more affordable impact-bumper "G-series" 911s because they were so plentiful, but their values have continued to climb. While popular price guides show a range of $30,000-$50,000—which seems typical—911 SCs have changed hands for $60,000-$100,000, and above, in the past year.


The SC moniker was a further simplification of Porsche’s 911 designations, likely because the car was presumed to be on its way out to pasture. In 1978, buyers only had to choose between the naturally aspirated 911 SC (coupe or Targa) and the 911 Turbo. The Turbo was offered in the U.S. only until 1979 and wouldn’t rejoin the 911 lineup until 1986. A 911 SC cabriolet was offered for 1983, the model’s final year.


The news, for SC buyers back then, was the SC’s 3-liter engine. The magnesium case used previously in the 2.7-liter flat six was out, in favor of a cast-aluminum unit on loan from the 911 Turbo. This change came after some 2.7-liter engines suffered from head studs pulling out of the magnesium cases, particularly in extreme temperatures and on U.S. cars equipped with exhaust-system thermal reactors (an emissions-control device). The 3-liter’s horsepower rating remained constant at 180 hp in U.S. 911s, but cars destined for other continents packed 188 hp in 1980 and 204 hp from 1981-’83.


The SC also sported wide rear haunches from the previous high-performance Carrera model, as well as that car’s beefier anti-sway bars, plus power-assisted disc brakes. Standard wheels were 15-inch cast "cookie cutters," but forged 15- and 16-inch Fuchs wheels were optional and a popular upgrade over the years.


Not all SCs are plentiful. In 1980, a limited-production Weissach Edition coupe was built. Just 400 were made, offered in black or platinum metallic, with 15-inch Fuchs wheels painted platinum, as well as a flexible front spoiler on the air dam and a rear whale-tail spoiler. Inside, the cars had identical beige "Doric Gray" upholstery, with burgundy piping on the seats and burgundy carpets.


The SC was viewed by many when new as the 911’s last roundup, but instead it ushered in the even-more-popular 3.2-liter Carrera, the almost-all-new 964 series, and the last-of-the-line, air-cooled 993-series 911. The SC remains a solid choice for aspiring 911 owners, however, because it was well-built, relatively simple and, if maintained properly, can deliver miles and miles of fun, rewarding driving.


To verify that we checked in with Chris Powell, owner of Porsche specialty shop Chris’s German Auto Service in Redmond, Washington. Chris is on the Porsche Club of America National Technical Committee and is the club’s technical expert for 1974-’89 911s. After earning a degree in chemistry, Chris took a job at a Porsche dealership service department, then built engines for a racing team running Porsches in the IMSA GTP series before stepping out on his own in 1984—where he’s been ever since. He still owns the 356 he bought back in 1975 and a 1973 911S that he used as a track car.


"The nice thing about a 911 is that you can drive it every day, drive it to the track, spend the day driving at the track and then drive it home—all on a regular basis, and it will handle all of that," Chris said. "It’s made to do that."


If you’re interested in buying one of these once-unsung 911s, here are a few things to keep in mind.


The 3-liter six used in the 911 SC borrowed its aluminum engine case from the 911 Turbo as an upgrade over the earlier 2.7-liter engine’s magnesium case. The SC’s engine also used an 11-blade fan for better cooling. The 3-liter has a reputation for reliability as long as it’s properly maintained and exercised regularly.

Engine The 3-liter, air-cooled, horizontally opposed six powering the SCs has a proven reputation for reliability.


"If it’s driven normally and serviced, 125,000 miles before a rebuild isn’t unreasonable," Chris said. "I saw an engine go to 160,000 miles—it was a Porsche Club member who took really good care of his car. He got nervous because it had so many miles on it, but he took it apart and there was really nothing wrong with it."


The 3-liter’s die-cast aluminum case, combined with the use of Dilavar (a steel alloy) head studs and an 11-blade fan for better cooling, addressed the problems experienced with the magnesium-cased 2.7. The studs in these engines aren’t impervious to time and metal fatigue, however. Heat, corrosion, and age can cause the studs to crack or break, resulting in leaks at the bases of the cylinders—it’s particularly true for the studs nearest the exhaust. There are aftermarket solutions, including replacement studs and threaded block inserts, but removing the old studs can turn into a project if they break off or have broken off in the block. The 3-liter also used more durable bronze valve guides which didn’t fail prematurely, but they do wear out and it’s a common maintenance/repair item. Excessive engine smoke or more oil consumption than normal can mean the guides are due for replacement.


With a typical used 911, "you might be looking at a valve job in the 70,000-80,000-mile range," Chris said.


Cam chain tensioners in these (and earlier engines) are a common wear item and something that shouldn’t be ignored. The 1980 and up engines used a more durable tensioner—still spring-loaded—that will work in the earlier engines. An even better upgrade is to the hydraulic tensioners used in the later 3.2-liter engine, which were fed by engine oil. Speaking of oil, leaks are par for the course on Porsche air-cooled engines. The flexible sections of line leading to the oil cooler are common leakers, as are the tubes that return oil from the top end of the engine. There are aftermarket replacements/solutions for these and it’s not highly technical work, but it can be time consuming. Another issue that’s been widely covered is the blown-up air box which occurs if the engine backfires. An easy measure to ensure that an expensive air box isn’t ruined is to install an aftermarket pressure-relief valve or pop-off valve. It’s just a spring-loaded flapper that you install by cutting a hole in the air box and epoxying the valve in place.


The 911 SC’s Bosch K-Jetronic fuel injection, commonly referred to as CIS for Continuous Injection System, is a good analog design that effectively bridged the gap between carburetion and electronic fuel injection. Chris said that 911 SCs that are used and maintained will have very few fuel-related issues.


"A car that’s driven regularly and serviced is usually fine, because the components last a long time," he said. "It’s the cars that sit—rust, corrosion, or contamination from the fuel going bad sets in—those are the ones that cause trouble."


Two key components of the system are the warm-up regulator, which regulates pressure and fuel flow during and after the warm-up cycle, and the fuel distributor, which meters out fuel to the injectors. Neither are available new, but both can be rebuilt or purchased rebuilt. From 1980-’83 911 SCs incorporated an O2 sensor as well, to more accurately manage the fuel mixture (and help keep the exhaust catalysts from being contaminated). Repairing and setting up a K-Jetronic system is best left to someone who’s been around the system and has the right tools.


"In order to work on a CIS system, you should have a CO [carbon monoxide] meter that sniffs the exhaust—that’s how you set it. People try to set it by ear, and they can be way, way off. If you get it set just right, these cars run really nice. But [an exhaust gas analyzer] is essential and those are disappearing in shops—they cost around $3,500. You need a high-pressure fuel gauge, too, so you can measure that fuel pressure."


Chris also noted that some 1978-’79 3-liter SC engines suffered from valve spring failures.


"It’s a dual spring and the outer spring would break—the inner spring prevented a catastrophic failure, but it did cause power loss because the valve would float," he said. "It was somewhat common to see on 1978s and maybe 1979s."


The 915 five-speed manual is a reliable gearbox, though its shift action can take some getting used to.

Transaxle Early on, there were two transmissions available in the SC: the 915 five-speed-manual gearbox and the semi-automatic Sportomatic. Sportomatic 911 SCs are unusual today as they were offered only for 1978-’79 and manual conversions were popular over the years. The Sportomatic was a manual gearbox with an automatic clutch and a torque converter. It stopped and started like a car with an automatic transmission, but the driver changed gears manually. Moving the lever activated a switch that in turn activated a vacuum motor that worked the clutch (instead of the driver’s left leg). It’s an interesting novelty and can be fun to own, but parts and repair specialists have grown harder to come by.


"They’re not very common at all, super rare," Chris said. "I think I’ve only ever seen one or two SCs with a Sportomatic."


Virtually all 911 SCs were equipped with the 915 five-speed manual, which is a durable, reliable transmission. The throw of the stock shifter is long, by sports car standards, and changing gears requires a deliberate hand, but there are aftermarket options that offer shorter throws. When the 915 gearbox is in good shape it shifts smoothly, but worn synchros or worn shifter bushings, or a worn or misadjusted shift linkage or clutch cable, can make the shifting clunky. Sacked engine and transaxle rubber mounts can also have a detrimental effect on shifting performance.


"It’s a tough gearbox, but it can be a little on the balky side and Porsche made changes along the line to improve that," Chris said. "They’ll never shift as well as the newer cars because the 915 had a different-style synchro. They’re pretty reliable, though. The synchros and sliders need replacing sometimes, but a complete overhaul can bring it back to new."


Another common concern: Clutch discs with rubber centers were used on earlier SCs and the rubber tended to deteriorate or break apart, leading to a clutch failure. A conventional clutch with a spring center is a direct and common swap.


Body Porsche really stepped up its use of galvanized metal in the 1970s, so by the time the SCs were released, rust was less of a problem—but it’s still a problem. We’ve seen SCs in the Northeast rust in all of the typical 911 areas: the front fenders around the headlights, around the windshield and rear window, the rockers, rocker supports, lower doors, and the quarter panels aft of the rear wheels. The floors and the front suspension pan (where the front suspension mounts) are also common rust areas and obviously integral to the 911’s structure. Patch panels and new replacement sheet metal parts are widely available, as are used parts, but even in times of rising 911 values, you seriously have to weigh the cost of extensive rust repair, which a lower-priced car might need, against the cost of buying a rust-free example.


"The galvanized metal slowed the rust problem down quite a lot, but it didn’t eliminate it," Chris said. "Anytime there’s a body repair, that galvanizing loses its integrity and it can’t stop everything—especially when they’re exposed to salt or battery acid when the battery leaks."


Suspension and Brakes The SC used typical 911 underpinnings. In the front were MacPherson struts with lower control arms and torsion bars. In the rear was an independent semi-trailing arm setup with torsion bars. Front and rear anti-sway bars were standard issue, as were vacuum-boosted four-wheel disc brakes and manual rack-and-pinion steering. Suspension and brake upgrade options are immense, but a stock rebuild with new bushings, struts, ball joints, tie-rod ends, brake lines, reconditioned calipers, etc. can restore a well-used 911 to factory-fresh condition. Driving an SC is a hands-on experience, to be certain, but it’s unlike any other car of its era.


"Porsche chassis are pretty stout, and they used the same basic setup all the way through 1989," Chris said. "It’s basically the same as the 911 started with in 1965 but with some improvements in 1969-’70. The rubber bushings in the torsion bars and in the rear torsion tube get old and they’ll sag. That becomes a handling and noise problem. But there are replacement bushings for everything, and you can get it back to better than new or even install harsher-riding race-car stuff. It’s all readily available and it’s all heavy duty."


Pasha upholstery with its checkerboard pattern is funky and unusual on U.S. cars. Optional sport seats had large side bolsters to keep the driver and passenger positioned in the turns.

Interior The SC’s cabin is a nice place to live, especially if you prefer an all-analog, traditional-911 environment: pedals poking out through the floor, iconic five-instrument cluster, supportive standard or extra-cost sport bucket seats, HVAC controls that don’t seem to make a lot of sense at first glance, and maybe even a fully functional factory Blaupunkt stereo. Most creature comforts were à la carte in 1978 and ’79, but in 1980 Porsche jacked the U.S. 911’s base price approximately $7,000-$8,000 (to nearly $28,000) and made several formerly optional items standard: air conditioning, power windows, a center console, and a leather-wrapped wheel, as well as black exterior trim. Upholstery options ranged from mild to funky over the years, including vinyl leatherette, leather, Berber tweed, pin-stripe velour, or checkerboard Pasha and Tartan inserts. Not all of those were commonly seen in the U.S. nor available every year when new, but between European import cars and well-stocked Porsche upholstery suppliers, they’re all up for grabs today. Carpet kits are available for SCs but can cost more than $800. Premade seat covers, door panels, and interior trim bits aren’t hard to find for these cars, either, though prices can also be steep.


As time marches on, the 911 SC, once thought to be the bookend for 911 production, has only grown in popularity and risen in value. Chris says he’s not really surprised by any of it.


"They are good cars, and for the day, they were pretty good performers," he said. "There was a lot of smog control going on in those times, but it was a pretty fast car. Of course, nowadays things have changed so much that they’re not, but they will still give you some thrills."


The 911 above boasts a Momo steering wheel and a speedometer tilted for easier viewing.


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