1988 Porsche Carrera Project Car: Part 1 Engine Teardown

The Criteria
The venerable aircooled 911 engine is highly tuneable. It would have been child's play to simply increase the displacement and compression, remove the stock Motronic fuel injection and exhaust system in favor of stand-alone engine management and headers and call it a day. But 80 hp/liter would be disappointing as the magic 100 hp/liter can easily be attained with a blank sheet of paper and open wallet. However, the purpose of this engine project is not to build a high-strung competition engine that needs to rev to insane engine speeds and requires race fuel to make the horsepower I am seeking. California residents are subjected to stringent emissions laws and developing horsepower legally becomes an exercise in careful research and planning, and sometimes is better left to those who have a wealth of experience.

The constraints for this engine build are simple: The engine must run on 91 octane and pass California emissions tests every 2 years. The engine must also be tractable in the low- and mid range and not be finicky for everyday use if the need arises. The final requirement was that the original two-piece engine case, crankshaft and connecting rods be retained to save costs. While 3.6L engine transplants from later 964s and 993s into earlier chassis are fairly common these days, finding a used 3.6L engine in excellent condition at the right price can be a daunting challenge.

While researching for this project, I found many used 3.6L motors with as many miles on them as my 3.2L. Since the 964 and 993 motors have also had head-stud and valve-guide issues (among others), I didn't want to go through the transplant headaches only to end up with the same problem I was attempting to rectify! The 3.6L motors are also not a direct fit into the earlier models and require additional conversion pieces, adding further to the bottom line. Being generally conservative in nature, I wanted the peace of mind of a brand-new engine with all of the best updates available. Moreover, I wanted an engine I could foresee reaching the 150,000-mile mark. The 3.6L transplant remains a viable option for many people, but just didn't fit my criteria for this Carrera.

The Players
The name Andial certainly shouldn't require any introduction in this magazine. Many Porsches prepared by Andial over the years have graced the pages of european car. From restoring 917-30s and servicing 959s, to building the all-conquering 962 engines of the IMSA GTP/Group C era, Andial has literally seen and done it all. It was while employed by Andial that I first met Dwain Dement and Steve Becker. Dwain worked as a service technician on the road-car side of Andial's business and Steve was shop foreman on the racing side. Both are excellent mechanics and have a wealth of information with respect to 911 engine building.

Dwain Dement left Andial in the early 1990s and after managing a small independent Porsche and BMW repair shop for a time, decided to open Vision Motorsports in 1995. Initially operating from a tiny 1,775-sq-ft facility with just one hoist, Vision quickly expanded to a 5,000-sq-ft home with three hoists in 1998. Dwain has built a reputation for his 911 Turbo engine-building prowess. Today, Vision Motorsports is one of Southern California's largest independent Porsche service and racing specialists. Its 12,000-sq-ft shop in Laguna Hills, Calif., can provide the finest in general maintenance, performance parts, engine building, suspension tuning, corner balancing and alignments, race-car prep, fabrication and track support.

After toiling 15 years at Andial and Porsche Motorsport North America's racing department in Santa Ana, Calif., Steve Becker took over the daily operation of his Dad's machine shop, also located in Laguna Hills. While he is no longer actively involved in the day-to-day Porsche industry, he continues to build 911- based engines on occasion for local shops and enthusiasts while still finding the time to fabricate sport parts for 911s that are then private labeled by various Porsche tuners. Steve has built the finest Porsche race engines for the highest levels of competition. My high-performance street motor will be in good hands with these guys at the helm.

Since I wanted to have an active role in the build-up of my engine, it would have to be disassembled and rebuilt after hours. Dwain was gracious enough to offer the full use of his facilities. Since I have a regular 40-hour work week like many grassroots enthusiasts, evenings and weekends are my only opportunities to participate. The Vision guys are quite often working late on special projects but weekends are usually devoted to the track. Steve kindly offered to assist and suggested that bringing the motor over a few blocks to his shop would better suit my schedule.

After consulting with Dwain, Steve and a few other knowledgeable professionals, the consensus was that the best way to try and achieve my goal of 80 hp/liter with the constraints was to increase the displacement from 3.2L to 3.5L, utilizing higher-compression 100mm pistons/cylinders and twin-plug ignition as the building blocks. While the SC's fuel injection and ignition systems are different than the Carrera's, the 3.0L and 3.2L engine cases and internals are kissing cousins, which allows for many of the same performance enhancements to have an equivalent result.

Baseline
Since it was important to see and not just feel the before/after difference between a mildly tuned 3.2L and a high-performance 3.5L, I had Nick run a baseline on Vision's Dynojet 248C chassis dynamometer. The Carrera had previously been chipped with custom software developed by Steve Wong at 911Chips. The exhaust gases were more efficiently shown the exit door with Dansk's stainless-steel pre-muffler and final muffler. While I didn't have a dyno number for the motor in stock configuration, I did expect the 3.2L would make a few more horsepower based on what similarly modified 911s have shown on the dyno.

Two runs were made on the Dynojet and a peak 199.01 SAE-corrected rear-wheel horsepower was measured. With the standard 15% driveline loss many people use to differentiate the factory-quoted flywheel horsepower from rear-wheel horsepower, this equates to approximately 234 flywheel horsepower. More important than the peak horsepower number was the greatly improved throttle response; the run to redline is much quicker and smoother, thanks to Wong's programming skills. The Dansk exhaust looks authoritative with twin 84mm tips out the back and emits a pleasing yet unobtrusive growl at WOT that doesn't overshadow the wonderful fan whine the 911 engine is known and loved for. The Dansk pre-muffler and final muffler are excellent bolt-on upgrades for the SC and Carrera owner who doesn't want or need to go into the engine's internals.