Pelican Parts Forums - Time travel

Another article about the best engine Porsche never built, the 2.8 short-stroke.
You may recognize this engine from the cover of the first addition of Wayne's 911 engine build book.

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Slip Sliding Away in a Carrera RS Replica
Article and Photos by Randy Wells

“The combination of sprint cams and slide-valve injection is not really a street-friendly combination,” Jerry Murray explains as I prepare to test drive his blood red 2.8 liter shod early 911. Undeterred, I strap myself into the perfectly positioned race bucket and turn the key. The motor awakens from its afternoon nap accompanied by a raucous swell of air-cooled flat six goodness. I blip the responsive throttle knowing that a lot of revs will be needed to get rolling thanks to the Kevlar clutch and aluminum flywheel out back. As we gently ease into traffic the engine sneezes a bit, almost as though it’s out of tune. “It took us a long time to get the car dialed in for the street,” Jerry remarks as we pick up speed. “I sometimes need to lubricate the throttle bodies before getting started. If I don’t, the slides can stick open.“ This is not exactly a comforting thought as we are already accelerating down the backstretch leaving Laguna Seca Raceway. But resistance is futile, and it’s foot to the floor at the first clear opening. That’s when everything starts happening very quickly.

Forget about being melted into your seatback with the long steady pull from a modern engine. This beast snaps your spine so hard it will pop the buttons off your lederhosen. Even with 8500 rpm available, constant vigilance is required to hit shift points that come up uncomfortably fast with the close-ratio gear set. “I probably inadvertently over-rev this car more than any other I’ve owned,” says Austrian born / LA based Murray. “Thankfully, Supertec built me a bullet-proof motor”. It’s at this point that I’m grateful they also added big AP brakes on all four corners. As I throw out the anchors for a rapidly approaching bend it becomes abundantly clear - the only thing that parallels this car’s acceleration is its ability to stop.

“The Can/Am style calipers with 12” rotors and twin master cylinders were used on 917’s, but eventually made their way to 911 racers seeking an edge.” Jerry’s lips are moving, but the screaming racket coming from the open intake stacks and sport muffler is drowning out everything except the one thought that I might die and go to heaven today. After another attempt at the land speed record it’s hard on the binders again. This slows our pace just enough to start the ride all over again at the next corner. A quick turn of the wheel, roll on the throttle, skate along that thin line between traction and no traction, catch the slide with some opposite lock, then be glad the limited slip differential does its job. Cars that were right beside us are dispatched to the rear view mirror in a heartbeat as the tractor-like pull from this impossibly torquey motor propels us continually forward. I tell myself I could get used to this - all the while fully aware that I’m dangerously close to breaking the speed limit and expanding my carbon footprint beyond what is considered politically correct.

We are rapidly approaching our destination, so I make one more sub-sonic pass to ensure the experience is indelibly imprinted on my brain. When we finally slow down enough to catch our breath, I realize the car’s ride has been firm in the corners and reasonably supple on the straights. On smooth surfaces it’s supremely planted and sticks like glue, but irregularities like cracks, seams and pavement scoring can make this 911 a handful. Jerry’s understated delivery continues, “It definitely reacts to everything on the road, for better or worse, so you need to stay on top of this car.” As we unbuckle, he tells me more about what went into his special 911, “I bought the car about ten years ago as a 1972 RS replica built by Mark Kittinger at Black Forest. It had the upholstery, RS flares and bright red paint job you see today; along with a 2.7 RS spec MFI motor. The first thing we did was take the car to Henry Schmidt at Supertec in Fallbrook, Ca. I bit the bullet and asked Henry to build a motor that was out of the ordinary. We went with a short stroke 2.8L with twin plugs and MFI.”

The engine is the soul of any car and this one is unquestionably a work of art: NOS 3.0L RSR case, 66mm crank, Carrillo rods, 95mm 9.8:1 Cosworth pistons, race springs, 964 oil pump, 40/38 mm ports, RSR sprint cams, 935 twin fuel pumps, twin plug ignition with twin 935 8 pin Bosch CD boxes, and those wild sliders which are replicas of the ones used on 910 Porsches campaigned in the early 60s. Jerry explains the reasoning behind this unusual choice of induction, “Slide valve injection is not usually seen on a street car because it’s difficult to modulate the throttle and it’s prone to binding up from road grit. I never would have thought of this myself, but I turned Henry loose to create a special motor and he came up with some really neat stuff.” Certainly, this motor looks as good as it sounds - with handmade aluminum intakes topped by wire mesh screens and twin plug wires & 935 fuel lines delicately wrapping around the fiberglass shrouded engine. To finish it off, a dual outlet sport muffler exits under the rear overriders.

In addition to the motor, Henry at Supertec spent quite a bit of time considering the transmission, suspension and braking aspects of the car. A late 915 gearbox was chosen for its greater strength and was equipped with an aluminum flywheel, limited slip and hill climb gear set with a tall 5th gear for freeway cruising. “That top gear is the only aspect of this setup that is really not suitable for the track”, says Jerry. “The reduction in RPM between 4th and 5th takes me out of the power band. But for the street, I can’t recall when I needed to keep the revs up during that transition.” The suspension was totally redone front to rear featuring 935 coil over struts, Eibach 250 lb springs in front, 380 lb in rear, Sachs shocks all around (shortened in front to receive mono balls), ERP spring plates, and highly adjustable Charlie sway bars. “The shocks were heavily reworked by the race team we got them from, so I have no idea how they are valved. All I know is that they work exceedingly well, but are not suited for those with loose fillings,” Jerry says. In addition, roller bearing spring retainers were implemented, as were turbo tie rods. Brakes are the aforementioned A.P. four piston calipers with 917 style rotors, twin master cylinders and a balance bar. Considering all the racing components on this 911, you would think it spends all its time at the track. But its primarily use is for driving to and from car events. Still, the rock chips on the front bumper confirm that this is no garage queen – even if it has been shown at the Quail Concours in Monterey, California.

Murray has a long history of owning and restoring distinctive cars since the 1960’s. His 246 Dino is a Copa Bella winner, and he recently sold one of his American hot rods to the Petersen Museum. But ultimately his heart belongs to the Porsche marque, which has been a part of the family for decades. Jerry’s brother and son own early 911s, and his Uncle Wilhelm was a German tool and die maker who worked as a jobber for Porsche in Austria. Like many automotive engineers and craftsman during WWII, Wilhelm was consigned to work on some of Porsche’s “other” efforts. Consequently, he was detained in Austria by allied forces when the war ended. Much like Ferdinand Porsche, Wilhelm was cleared of any wrongdoing and was eventually released. But it was some time before he could begin working again, since the allied command were still housed in Porsche’s Stuttgart facility. Jerry (short for Gerhardt) remembers his birthplace and bloodlines well, “Years later when I would travel to Europe to visit relatives, I would scour family barns and work sheds looking for parts. I never found anything Porsche related, but the family is always on the lookout for me.” Jerry gleefully recalls another of his early hot rod roots; “I was always into anything mechanical. When I was growing up, one of my chores was to mow the lawn. I remember my delight in replacing the old mower’s muffler with a piece of strait pipe, thinking it would go faster. It just made more noise and angered my dad, but it was worth it.”

Many years later, when the decision was made to have an early 911-based hotrod built, he wanted to take a different approach. Creating a cool sounding RS clone would not be enough – the ideal would be to use original factory or vintage racing parts when possible and blend those with a few more modern ones to create a unique experience. Jerry reveals his reasoning, “It’s all about driving the cars, and making modifications to enhance your enjoyment. It’s the same now as when these cars were new. Enthusiasts and racers were always experimenting, trying something different. It doesn’t matter to me if all the parts weren’t factory options, as long as the majority of them are period-correct.” The building of this car continues to be an ongoing process rather than an end point. Jerry and Henry would start work on the ‘72 911, then find a new component and adjust their direction accordingly. It wasn't until the motor finally took shape that they decided the old suspension and brakes were not going to handle the horsepower. Additional hood lighting is just another example of a treatment that illustrates the underlying principle behind this car’s distinguished build.