Porsche Engine Building:

The heart of the Porsche is the engine. Upgrades, enhancements, and even engine swaps from later cars are possible. The chassis in the 911 has been relatively unchanged for decades, and allows for engine transplants, and increased power. Now that even the newest air-cooled engine is approaching the ten year mark, many will need overhauls or valve jobs. Also now that these cars are more affordable, some owners have the desire to upgrade when doing overhauls. Since the technology has been decades in the making, the aftermarket has produced some great products to increase reliability and performance.

Porsche parts as we all know have always been expensive, and engine parts are no exception. The labor that is involved is far more than the typical domestic engine due to the complexity, and need for attention to detail of the six cylinder engine. An overhaul for any four cylinder can approach the 20-25k mark; a few years ago it was maybe half that price. The 911 (2.0L-3.6L) and 930 (3.0L-3.6L) engines can be in the 20-30k+ range depending on the year, displacement, work needed and specifications. 996 TT/GT2/GT3 engines can range from 20-50k depending on what is needed for the rebuild or enhancements. Competition engine costs are usually double the street counterpart figures for full overhauls.

Some of the issues we are seeing come from unfamiliarity with the basic design and construction. Do it right the first time, and you won't have to do it again.

356:

The four cylinder Porsche air-cooled power plant, and the ancestor to the 901 six cylinder engine design. These pushrod engines are very durable when assembled properly, and now with some fantastic aftermarket parts they can live even longer. Race engines can be built today within excess of 200hp! Over the past few years parts pricing has gone up dramatically since some manufactures are ceasing to produce critical parts (i.e. main bearings), and labor costs are on the rise.

They owe their roots to the 1930s 35/36hp VW design, but have very limited interchangeability with their VW brethren. These engines need special attention to detail, and should not be assumed to be "the same" as a VW type 1 (beetle) engine.

Most of the issues with 356/912 engines have come from the problem of time (long term storage, use, and "turkey" repairs over the years). Another issue in recent years has been the compatibility with today's gasoline. All of these issues can be rectified with proper service, and proper overhauls. When overhauled properly, these engines can last for over 100k miles on the street. The early A/B engines have some inherent parts that need upgrading with regard to heads, rods, and valve train to be reliable. If the engine is not for a concours car then choosing to build a later 356C/912 engine can be far more rewardable.

911:

The exceptional six cylinder 911 power plant is one for the books. It is simple in design, versatile, and durable. It has been used in virtually every kind of racing either by Porsche or independents because of the power potential. Over the years it has increased from the original 2.0L introduction to 3.8L in production form. The early 2.0L engines remain a formidable force in historic racing, and some street cars have garnered hundreds of thousands of miles without much more than typical servicing. There are some needed updates that make these even better engines but for the most part are bulletproof when cared for. The parts are very similar in all six cylinder engines with the evolution of displacement and the refinement along the way. Beside some of the troublesome items along the way (2.7L head studs, thermal reactors, 3.0L head studs, and some 3.2L with valve guide problems) all these engines are very reliable and enjoyed by many daily drivers.

If these engines need to be taken apart for service, damage, or upgrades it makes sense to "replace since we are in there" considering the amount of time and energy it takes to overhaul a 6 cylinder. These engines also are unique in their design so it really takes a specialist to make sure everything is done properly.

930,965:

Turbocharged six cylinder production cars. This engine design has propelled the Porsche 911 super car for decades against the best of Ferrari, BMW, and Lamborghini. At the core it is a simple 911 engine with forced induction. The engine had been used in Porsche GT racing in the mid 70s, and found its way into production 911s in 1975 for homologation purposes. It was an instant thrill and handful at the same time. Since the power and stress is two fold from the normally aspirated 911 engines, overhauls come more frequent. A couple of issues arise from these engines, but most of them come from the users' perspective; either too much boost from adjustable boost knobs being installed, rigged wastegates, or poor quality fuel. These cars are also at the top as far as expense, and high-end exotics trade owners more often; more hands means varying levels of care or concern. Now that most of these cars are approaching the 20 year mark, age is taking its toll. There are more parts with these engines in the way of plumbing, and parts tend to be more expensive. The early cars suffered from emissions equipment, adding to the potential heat and pre-mature wear. Many of these engines do not get the service that is needed due to the complexity of plumbing and time needed to access spark plugs, and valve adjustments.

These turbocharged variants are excellent powerplants, but require attention to proper care to insure long life. The 3.0L get a big help updating the exhaust, adding an intercooler, and some other tweaking. If a 930 3.0L has not been apart be prepared to replace all the cylinder head studs, they are all made out of the early Dilivar material, not just the bottom as with 911SC engines. The 3.3L engines offer the efficiencies that the 3.0L cars did not using an intercooler, better exhaust (euro cars) and an increase in displacement. Upgrades with exhaust, bigger turbos and bigger intercoolers can be made reliable on today's pump fuel. The later 965 3.3L engines are a breed all their own with a combination of a 930 based engine and some 964 equipment added. The 1994 965 brought the 964 3.6L to turbocharged potential, these respond with some of the same modifications. If money is no object then twin turbos, big displacement 700hp+ monsters can be made out of these engines.

964,993:

3.6L, the "big block" of the 911 engines. In 1989 the 964 was introduced with a 3.6L. The engine had the biggest step in development, with a revised beefy engine case, newly designed camshaft housings, and chain-boxes, and the street car received twin-plug ignition, as well as stepped up compression. The engine made a tremendous amount of power and torque for the size. Composites were used extensively in fasteners, manifolds, and shrouding to make the car as light as possible and ease in recycling.

The 993 continued the 3.6L refinement with a hydraulic valvetrain, and a progression with Varioram intake systems to help keep power and torque up. The idea was less maintenance, and good power to carry the heavy sled the 993 had become from the early 911 days.

All of these engines are great powerplants, and tend to be very reliable. 964s are more expensive to maintain since the motor has more plumbing, power steering, and exhaust shielding to deal with. The 993 alleviated the labor costs associated with a traditional valve adjustment with a new hydraulic valvetrain.

There are just a couple of issues with these engines, but all require a substantial amount of work to rectify. Our tech section has more info on these issues but they commonly include broken distributor belts, cylinder to head sealing in pre-1992 engines, and of course the 993 secondary air injection issues. All 3.6L engines we have seen apart at even low mileages need valve guides. It is a must to remove the undertrays from the 964 and 993 cars to help engine cooling. At some point a teardown is eminent, and retrofitting/overhauling will solve the problem and allow these engines to garner hundreds of thousands of miles. Broken distributor belts are sometimes a possibility with early 964 engines, if it does fail and the engine is stressed further, a piston/cylinder can be burned, and again necessitate a teardown. When checking the distributor belt even recently we find 964s without the updated vent kit. The pre-1992 964 3.6L engines suffered from poor cylinder to head sealing, they can be updated to later specs, but require a top-end overhaul, and replacement of the pistons & cylinders. All 993s suffer from OBD secondary air injection ports becoming clogged, and soft valve guides exacerbate the problem. Most owners find this problem too late and require a top-end overhaul.

These engines are very efficient with free-flowing exhausts, and well thought-out engine management. Due to being the pinnacle of the air-cooled engines they are still demanded by club racers, and guys with the need for speed in their early 911s. Basically the same engine was used in the 3.8L 993 RSR, and 993 GT2 that again lived 24 hour endurance racing, won races, and produced over 700+hp. If money is no object, the sky is the limit as far as potential, and some have even built 4.0L engines.

GT3:

The 996 water cooled engines owe their technology to the 959 and 956/962 Gruppe C cars. Dual overhead cams, water cooling come from the 959 engine that first appeared in a street car in 1986. The competition 956/962/GT1 cars had proven the reliability and performance potential of dual overhead cams, and introduction of water cooling. These engines had won every motorsport event they had entered for years, and were de-tuned out of competition by the sanctioning bodies. The Porsche 993/996 GT1 carried the torch for a few years until the recent 996 GT development. Early 996 GT3 cars had 959 part numbers cast into some of the parts, while others were CNC one-off parts until production could keep up with the demand. These engines were then taken from one-off race engines to production cars (996 GT3/GT2/TT). These are phenomenal power plants, have a tremendous amount of torque and power available. The bulletproof nature of the old 911,964 case allowed it to be adapted to the 996 GT3 as it has been for decades. Remember the 935 turbo race cars, some of which had over 700+hp, and lived in a racing environment for 24 hours. Since the 996 GT3 based engines are basically detuned race variants, they are complex in their parts, and effort to assemble. Overhauls and race car maintenance can be costly due to this. Those that own one of these cars know how fun they can be to drive on and off the track.