Porsche Engines; Basics in the differences.

So I always love the old bragging rights of “My Engine is bigger than Your Engine”…. “oh yeah?????, well MINE is bigger than YOURS!!!”…

I think it’s a human trait to always compare and contrast just about everything we can.  So it brought up the question is how big is big, when it comes to Porsche engines.  If you looked at a Porsche 2.0 L engine and saw sitting next to it, a Porsche 4.0L engine, you might be able to tell which engine is larger than the other.   It would however, be especially hard to know, if the 4.0L engine is twice the size, a 1/3, or 3 times larger.


These are clear images of a VW Bug engine right out of the car.

Fresh out of Volkswagen bug, we’re replacing the clutch plate among other things.


Porsche 356/912

The first thing is understanding how a Porsche engines is a far cry from its cousin, a Volkswagen engine.  If you are after some iron clad researching, try getting access to real sized, equal liter Beetle and Porsche motors and then try to pick them apart component by component. 

The black and white image shows the Volkswagen Super Beetle.  Notice  how the alternator fan housing is located over the engine generator.   On a Porsche engine, this arrangement is very different.   However, just like the Beetle engine, a Porsche 356/912, four cylinders lay flat.  However, the pistons and cylinders are different, with much different parts and output differently.

On the Beetle, the exhaust system, including the muffler, looks similar to a Porsche 356/901 series, but piped much differently.  For both the Porsche and VW the engines are similarly mounted in the chassis using a few bolts and motor mounts.  The difference is, because of the rounded shape of the beetle, there is plenty of room to have the VW engine seemingly sitting up higher at the rear of the VW beetle (like a Porsche), with the transmission attached towards the front.  Unlike the Porsche, the alternator fan faces the front of the car while on the Porsche, you can see the alternator fan facing the rear of the car.   When making further comparisons between a 356 and Beetle, note how locations of the wiring harness and how different its organized to provide spark to each of the cylinders.   Note too how wires starting from the ignition connect to the battery and from battery to alternator / generator differ from both cars.

The Porsche 356/912 engine is different from a Volkswagen engine.  However certain similarities with bits of modification, a VW motor can be converted to look like a Porsche 356/912 motor.  As shown on this one image, components bolted on 1915cc VW engine uses dual Zenith 32NDIX carburetors, and cleverly attaches a a small Porsche 12v generator.

It isn’t very hard to have the Super Beetle engine look like factory Porsche engine, especially if having the motor topped off with the Porsche oil filler and filter. This Beetle engine “to look like” a Porsche 356 will produce 125hp which ironically beats the stock 90 hp Porsche motor.  This Beetle motor gives this engine added torque as well.

This is an actual, museum quality example of a factory Porsche 356 /912 engine. Immediately, when comparing it to the VW engine, side by side, without the components, you see that it is not significantly different.  Thus, in principal, they appear similar, it is however different enough to not be VW.   Note the higher level of organization, design, and the way the engine is layed out.    Note also everything appears less weak than a Beetle motor.    It is no secret that with enough fabrication, a clever mechanic can almost make the two visually identical, but not indistinguishable.  Size wise these motors are equal. The Porsche 2.0L engine will interchange the Porsche 356, Porsche 912 and easily fit into a VW as well.  So loved is this motor setup,  It is also not uncommon to find a 911 outfitted with this 4 cylinder workhorse. Needless to say, this motor is quick enough for all of today’s street driving.

Mechanics have been tricking out these engines for years.  They have been maximizing flat spots, increasing torque, and topping out horsepower.  They have done everything from changing air filter housings, spark plugs, plug wires, adjust fuel system, and modify exhaust in hopes to vastly improve performance.  In some cases, extreme measures will modify the engines in such ways, such as to double distributor caps and them going into double starters.  This particular modification is known as “Going Twin Plug” because for each of the 4 cylinders, a second spark plug is installed.  The modification will force each cylinder to more efficient burn.  Added benefits including increases fuel economy, decrease in smog, and way more effective power.  Limited room inside a “funny shaped cylinders” while trying equalize how each of the pistons will behave is key to benefit twin plug.   Certain design considerations such as pinpointing “Rod Angle” sets that second spark plug in a perfect, most effective angle.  Testing performance is also needed to best capitalize on dynometric results which show significant power and torque increases over stock. It is important to note that these modifications don’t change the size of the engine.

It is also important to know the the quality of your components will very much affect how the engine might operate. The recommendations is making sure you option for OEM parts, not facsimiles.. especially when it comes to Bosch electronics.

Porsche 911

The earliest and smallest engine for any of the Porsche 911 was the 2.0L engine. It was installed in the Porsche 911 between 1966 and 1969. The engine weighs in at 242.1 lbs and being 1991 cubic centimeters of core metal, it would look as if it handsomely and gingerly slides into an engine bay. Like the same engine used in the VW, its cylinders lay flat and the alternator and fan housing sits centered above the engine. Easily located six single-choke downdraft Solex 40 PI carburetors would allow mechanical adjustments with the hood up. Note location of air filter housing over

The next size up was a the 2.2L. Being just about 200 cubic centimeters larger, or about the size of having 31 sugar cubes piled next to your Starbucks latte, it pumped out a little more horsepower and torque to be a market contender.

You could stare at both the 2.0 and 2.2 engine and pretty all day long and never see those extra 31 cubic inches. The only way to tell is finding the engine stamped with “engine numbers” casted on the motor.

For example if you have a 1969 911T, you should see numbers starting with 619 0001 through 619 8184. These numbers also have a breakdown between Manual Transmission, Sportomatic Transmission, USA version Sportomatic transmission, and USA Sportomatic. In 1970 the 911T will have numbers starting with 610 0001 through 610 8374. These too will have number breakdowns depending on your transmission. What is most interesting is the you’ll find in the larger of the numbers you will see that the bore / stroke sizes increase. For the 1969 911T bore/stroke is 66/80. In 1970 the 911T has a bore and stroke of 66/84. Just to make a comparison of the 911SC produced in 1973, bore and stroke increased to 70.4/90.

In 1973 the Porsche 911RS had the 2.4, which again.. didn’t really look that much larger. Adding an addition metal equivalent of 31 more sugar cubes differences can only be barely visible if next to a 2.0L. Dead give away always should be that fiberglass shroud color. It is important to always match the correct shroud color with the engine size.

Porsche 911 2.4 engines on…

Yellow was the ‘T’ color code

Green was for the ‘E’ engines

Red was for the ‘S’ engine, as always from ’67.

Then 1968 – 1973 911T had Black

As the engine bay starts to fill up to its brim and yet now almost a good quart of extra steel fattening up bore and stroke sizes, the 2.7 sized engine gets a hefty feel. Wider becomes the flat pistons from each other, and deeper the engine falls into the engine bay, its impressive size shows of girth. Gone are the carburetors and in comes CIS with fuel injection. Wire harnesses are organized to power each spark plug individually. At 210 horsepower, the increase would occur due to stripping the car away of its weight by going to aluminum doors and bonnet skins. This engine could propel a car to 150 mph and do it all day long. Its reaching a destiny of perfection in balance and speed. Ride comfort would also maximize as the engine sounded smooth. This was the same engine used on the factory converted Porsche 935 series. To make sure this car keeps all its horsepower to the road, the car was outfitted with the infamous “ducktail” spoiler.

The 3.o L engine was also quite remarkable. It was one of the earlier engines to employ an air conditioner. Back in those days, foreign cars shipped into the United States would be tagged with a huge expensive “luxury tax”. To get around that, new owners would then ship the cars without the air conditioner installed and then have them installed once it would come into the dealership. The 3.0L engine was also optioned to obtain a turbo setup allowing a 1.4 x turbo multiplier. Essentially the engine would result in obtaining some decent outputs. The 1976 version of this engine would be injected with K-Jetronics and have 2994cc. The 3.0 could also clock out above 150mph. Size wise, you will see these motors larger than the 2.2L version.

The Porsche 3.2L Engine is the last of 911 engines. They did make a 3.3 and of course motors pretty much became larger than that. The difference however is that you would also need a larger car to handle both the engine and transmission. In regards to the 911 3.2L also know as Porsche’s “bulletproof” motor really said something about power and beauty. The simplicity (and the complexity) is still there, as with its performance.

Happy motoring!


5 responses to “Porsche Engines; Basics in the differences.

  1. The black and white photograph of the Beetle engine is not a Super Beetle engine; in fact, this is the prototype engine designed for the prototype Volkswagen: VW30. This is not how the production engine of the Beetle or Super Beetle was finally laid out, and is not a proper example for comparison to the 356 or any other Porsche. Also, note that the first production line of 356 Porsches were stocked with Volkswagen 1600cc engine, chassis and suspension components – after the first year of production, Porsche had financial means of altering these parts to make the first ‘real’ Porsche, independant of Volkswagen design and parts supply.

  2. hola soy Armando Rodriguez poseo una combi modelo 1975 en buen estado fisico y mecanico solo que quiero hacer una conversion de motor el que tiene (1600) por un porsche es posible quien me puede orientar ayudar y o hacerlo vivo en mexico d.f arodrig9@hotmail.com la finalidad es que la camioneta perdure mas generaciones de muestros padres.

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