Nick at Vision Motorsports strapped down the 3.2L Carrera to the Dynojet 248C in preparation for the baseline dyno runs.
Overview
The 1978-89 911 SC and Carrera have long enjoyed reputations as the most reliable examples of the 911 lineage. More civilized than their predecessors but still part of an era when driving a 911 at full chat took courage, these models can be very enjoyable and dependable for daily driving. They hold a special place in the hearts of many Porsche enthusiasts, as they are the exclamation points on the first 25 years of the 911's heritage.
With the introduction of the 964 series in 1989, and subsequent 993 and 996 models, many Porschephiles felt the raw feel of their beloved 911 was lost, replaced with a more modern suspension design, extra convenience bits and electronic gadgets that made the purists shudder. Sure, the newer models cars are quicker, brake better and corner faster, but they lost much of the character that appealed to so many since the 911's inception in 1965.
The 3.2L engine as fitted in 1984-1989 911 Carrera models. Note the heater tube to the left of the distributor. This will need to be modified or removed in order to gain the extra clearance necessary for the 993 distributor that will be used for twin ignition.
The SC and Carrera were among the world's elite in terms of horsepower and performance during their build years. However, the 15 to 25 years that have elapsed since the SC's introduction in 1978-and the Carrera's demise in 1989-may as well be an eternity with the leaps and bounds in engine technology since then. The SC and Carrera of yesteryear are still forces to be reckoned with for sure, but in stock trim are overmatched by many of today's sport compact and sedan offerings from around the globe. The table on page 79 illustrates the factory-rated horsepower of some of the most powerful and desirable cars in 1988, when a mere 200 bhp appeared to be upper echelon performance. Obviously, times have changed.
The 180-bhp 3.0L SC engine installed in 1978-83 models and the 207-bhp and later 217-bhp 3.2L powerplants for the 1984-89 Carrera are as bulletproof as any 911 engine ever offered by Stuttgart. There are more than a few documented cases of SCs and Carreras with more than 200,000 miles on the odometer without the internals being touched. While these examples should be considered the exception rather than the rule, it is not unreasonable to expect the 3.0L or 3.2L motors to register 150,000 miles before needed a major rebuild. This engine longevity was unheard of during the time period, especially for a high-performance car such as the 911. Unfortunately, as good as these engines are, they do have their share of faults. The 3.0L engines, and to some extent the 3.2Ls, inherited the same cylinder-head stud problems that plagued the earlier 2.7L engines in the mid '70s. The 3.2L engines Achilles' heel appears to be random valve-guide wear, spun rod bearings due to insufficient oiling and rod bolts that can break if the engine is revved upwards of 6800 rpm. All of these issues require at the very least a top-end overhaul to repair.
My 1988 Carrera waiting for surgery. Vision Motorsport's 935 conversion project sits patiently in the background.
The Car
The 1987-89 Carreras-the last of the "impact-bumper" models originally introduced in 1974-preserve the classic shape and lines that many think of when visualizing a 911. I purchased the 1988 Marine Blue coupe in May 2003. Fitted from Porsche with optional front and rear spoilers, this 911 also had the slick-shifting G50 five-speed transaxle and provided an excellent platform for the host of modifications I was planning.
When purchased, the Carrera had 78,000 miles on the clock and the suspension was tired and feeling its age. The original Boge shocks had lost their damping characteristics and were discarded in favor of Bilstein HDs in the front and Sports in the rear. The stock diameter torsion bars were upgraded to 22mm front and 29mm rear "hollow" units.
Since the Carrera is destined for street use with only limited track time, polyurethane and metal were eschewed in favor of new rubber suspension bushings for the front A-arms, and front and rear swaybar mounting brackets. Neatrix bushings were installed for the rear spring plates, which provide better performance than their rubber counterparts without the vibration and noise commonly associated with polyurethane. A beautiful FFensport 6061-T6 aluminum front strut brace keeps the shocktowers from flexing under hard cornering and rounds out the suspension bits.
Underside view before engine removal. Note the restrictive routing of the stock heat exchangers via crossover pipe and into the catalytic convertor. Significant horsepower can be gained for all 2.7/3.0/3.2 motors simply by backdating the exhaust to the 1974 and earlier systems.
A set of original forged 16-in. Fuchs wheels from a 1989 911 Turbo were uncovered, size 7s in front and 9s in rear. Shod with the same 205/55 and 245/45 rubber as the bulbous Turbo, they fill the narrow-body Carrera wheel wells perfectly and contribute to its aggressive stance. Finally, the car was lowered to European ride height, corner balanced and aligned. The net effect is a firm but not harsh suspension that is an ideal compromise for high-performance road use. I won't be setting any track records, but I also won't lose any dental fillings when driving on potholed roads.
The Goal
A year and 8,000 miles after the purchase, the Carrera began to exhibit symptoms of the infamous valve-guide wear that has afflicted countless others. Intermittent smoke while idling and oil consumption that deteriorated from 1,800 miles/qt to 1,100 miles/qt in a relatively short period of time were telltale signs something was wrong internally. Knowing from the experience of others that the valve guides were likely the culprit and thus a valve job was on the horizon, the tear-down writing was on the wall. It was time to start preparing and saving for performance upgrades.
With only 68.6 hp/liter, the U.S.-spec Carrera motors left a lot to be desired compared to other 911 motors that preceded and followed it. The table on page 77 shows selected specs of Porsche's most powerful street engines. Before rigorous emissions standards became an obstacle in the mid '70s, Porsche's high-performance S motors routinely made over 80 hp/liter. From the mid '70s through the '80s, those numbers dropped as low as 60 hp/liter, as Porsche was forced to redesign the exhaust system and introduce CIS fuel injection to help comply with emissions laws at the expense of horsepower. It wasn't until the mid '90s (with the last 3.6L aircooled motors) where the numbers returned to the good-old-days levels.