Restoring a Porsche – the right way

It’s not easy for anyone interested in a classic Porsche sports car. If I want an unrestored classic with low mileage and a traceable history, the air becomes thinner and the prices higher. What are the alternatives, though? Restoring a Porsche you bought as a cheap’ish base car? Buy an already restored Porsche? Or would you prefer an unrestored vehicle with a patina? For a comprehensive insight into the world of restorations, we have consulted expert advice and compiled a guide for you here.

Which terms are important?

The world of Porsche restorations is not really transparent for the layman at first glance. Often, even simple repainting is referred to as restoration. Others, however, speak of frame-off restorations. And what does Restomod actually mean? These questions give you an idea, that there is a lot to consider when restoring a Porsche or buying an already fully restored example.

Let’s start with the definitions of the terms. Restoration means as much as “restoring the original condition”. It is obvious, that it is only theoretically possible to restore a decades-old car to 100% of its original condition. In the automotive sector, “restore” is therefore usually synonymous with rebuilding a vehicle.

The boundary between restomod and restoration is fluid

Of course, restoring a 30- or 40-year-old Porsche with stone chips, scratches and worn interiors is not possible without using spare parts. Only using original parts for rebuilding the car is a good start. A full rebuild is commonly referred to as a frame-off restoration. In this process, the vehicle is disassembled and reworked down to the last screw. Strictly speaking, however, this term is incorrect for a Porsche 911. From the very beginning, Porsche relied on a self-supporting body, so that the body and chassis cannot be separated. But what about the use of parts from newer models or tuning parts from the accessories?

There is no clear-cut distinction. Is a repaint already a restoration? The same question arises when suspension components and seats are replaced or the engine is modified. For this reason, the boundary between a restomod, i.e. a Porsche that has been restored and modified at the same time, and a classic restoration is fluid. A restomod is indeed a rebuild of the vehicle, but technically not with the factory delivery condition as the goal. If, for example, parts from higher-end models are used or special equipment is retrofitted, the classification is also difficult.

Without specialist expertise, it is hardly possible to distinguish good from less good restorations

Experts recognize the claim and quality of a restoration from many small details. For a layman, this is almost impossible. Therefore, we strongly recommend seeking advice from an expert. This applies both to the purchase of a restored Porsche and to the restoration of one’s own. That’s why we spoke to Niclas Röhrle. Together with his brother Luca, he runs the Röhrle Mobility GmbH. Having marketed numerous restored Porsches, he knows exactly what details you should pay attention to during a restoration. The brother team also offers what is known as restoration management. From procurement to research to project management, including coordination of the work, they offer everything from a single source.

Niclas, first of all, what are the key areas to look out for in a restoration?

First of all, it depends on the basis of the vehicle. Its sheet metal substance is decisive for the effort and thus also the cost of the restoration. If there is rust on the bodywork, or signs of accident damage, e.g. due to subsequent welding, it becomes very challenging. Good coachbuilders – especially those who know what these cars looked like when they were factory new – are not around on every corner. And since there’s still a lot of handwork in air-cooled Porsches, not every car is 100% like the other, either. Plus, cars that are verifiably unwelded and accident-free offer better value retention.

Therefore, weld seams and points should be checked for originality at the neuralgic points. Of course, you have to know exactly what you’re looking for. This is because some of the old bodies are still hand-welded. For this reason, a layman tends to regard certain weld seams or points as having been welded afterwards. In fact, however, bodywork processing was at a different level back in the day. It is obvious, that great importance should be attached to originality in the work carried out. This is the only way to ensure, that the vehicle is as close as possible to its as-delivered condition. The scope of the work is also crucial. A repaint alone is far from being a restoration. Often, vehicles with hatchet paint or even filler show up on the market as supposedly restored.

One major service does not make an engine overhaul!

You should also look closely at the powertrain. Vehicles with newly sealed engines, new ignition distributors and a fresh service are – unfortunately – often offered as generally overhauled. However, there is no talk of an engine overhaul until substantial parts of the engine have been overhauled. These include, for example, piston/cylinder sets, connecting rod bearings or crankshaft bearings. Only then can it be declared a “general overhaul” and offer real added value for the customer. Of course, the customer should not be forced to replace as many parts as possible. Rather, as many original parts as possible should be used. In addition, not all parts are available new anymore.

The same applies to the gearbox. Here, too, it is not enough to replace the oil seal; much more is involved. It is an overhaul when all components that are subject to regular wear – e.g. main bearings, fixed/shift gears, and synchromesh – have been checked and replaced if necessary. My most important advice is therefore not to be blinded by the term “restoration”. All work steps must be transparently documented. For a true overview, all work performed must be fully traceable.

What would the ideal Porsche restoration look like for you?

The restoration starts on paper. The first step is to research the delivery condition ex works. Does the restoration object have “matching numbers”? In other words, do the stamped engine and transmission numbers match the chassis? This is because each chassis number contains a unique combination of numbers for the engine and transmission. The color combination must also be researched. Because cars have often been repainted or had their interiors changed in the course of their lives, this is pretty significant. Only with original color combination is called “matching colors”. Special equipment and body style are also important criteria. After all, many Targas were converted to convertibles and vice versa.

All this can be found out via the so-called “birth certificate”. This can be requested from Porsche Deutschland GmbH. In addition to the engine number, transmission number, exterior color, interior equipment, and optional extras, it also contains the number of units produced of the model in the respective year. After determining the delivery condition, the inventory follows. This also determines whether the vehicle should really be completely restored. First, all parts are carefully inspected and, if necessary, overhauled according to factory specifications. As mentioned at the beginning, the premise should always be to reuse as many original parts as possible. Only if this is impossible, we recommend replacement. In close consultation with the customer, we thus choose the individual approach for each restoration step.

In which cases would you advise against completely restoring a Porsche?

The following example: We recently had a 1955 Porsche 356 Pre-A convertible for sale. The car was proven to have original factory paint, just a little patina here and there. If I repaint this car because of a little wear and tear, I am sometimes setting myself up for a very large loss in value. In this particular case, preserving the decades-old paint job was more desirable than a flawless repaint. With the original paint, the car had 90-120% more value than after a repaint. Here we are talking about several hundred thousand euros!

In such a case, a partial restoration is the appropriate way to do it. The bodywork, especially the paintwork, is left as far as possible in its original condition. Then “only” the assemblies that really need it are overhauled. You should also ask yourself whether a vehicle with very low mileage needs a complete engine overhaul or if replacing the most important wearing parts is sufficient. This requires a sense of proportion and experience. That’s why you can’t or shouldn’t do it without expert advice. To put it simple: There is not just one way to restore a Porsche perfectly. Rather, an individual strategy must be chosen, depending on the overall condition and the customer’s wishes.

What exactly is the work performed during such a restoration?

For me, the restoration of a Porsche can be divided into four areas: Body, powertrain, chassis and interior. Only when all four areas have been worked on precisely and carefully is it a complete restoration. This narrow G-body Porsche 911 Targa 2.7 is a perfect example. It is a desirable 1974 Targa, as a very rare chrome model. In its silhouette, it has many similarities to the 911 F-model. The starting point was good, the vehicle accident-free, rust-free and unwelded. So best conditions for a good result.

This 911 was completely disassembled into its individual parts at the beginning of the restoration, down to the last screw. Then the body was completely stripped of paint using glass bead/plastic blasting and the underbody was ice-blasted. This was followed by a careful rebuild of the paint. For optimum corrosion protection, we recommend cathodic dip painting (CDP). This involves chemically stripping the paint from the body and then cathodic dip coating it. The advantages are obvious: every joint and cavity, no matter how small, is protected against corrosion. Presumably, the body will outlast its owner afterwards. Today, the paint shines again in the original brown copper diamond metallic.

Does that still count as restoring a Porsche?

That is, of course, one of the decisive disadvantages of this process. When the vehicles of the 60s and 70s rolled off the production line, it was not yet in use. That’s why we honestly explain the advantages and disadvantages of the process to our customers and comply with their wishes. Ultimately, we are faced with a conflict between originality and corrosion protection. For this reason, it is not uncommon to do without a cathodic dip coating.

A simple repaint does not make a restoration, and replacing seals does not make an engine overhaul. That’s why it’s essential to understand exactly what work needs to be done on the potential Porsche of your dreams. If you think about restoring your own Porsche, you should agree the scope of work in detail beforehand.

Niclas Röhrle, Röhrle Mobility GmbH

During the overhaul, the engine received a new set of Mahle pistons and cylinders from its big brother 911 S. Together with new connecting rod and crankshaft bearings and an overhauled K-Jetronic injection system, the engine as a whole also meets the 911 S’s specification. This means a power increase from 165 to 175 hp. In addition, this narrow body G-model received the auxiliary oil cooler at the front of the fender from the 911 S. This gives it significantly better cooling performance. We thus have a slight deviation from the original, but at the same time significantly increased everyday usability. After all, the “small” 911 of 1974 had to contend with thermal problems from time to time. We always follow the technical upgrades during the model cycle by Porsche AG and only use original parts.

So while restoring this Porsche 911 2.7 Targa the restorer also improved it?

That’s one way of putting it. In this case, the aim was not only to get as close as possible to the original, but also to eliminate design weaknesses. Especially since Porsche itself came up with a solution to the problem. This elegant, narrow G-model also has slight deviations in the interior. The Targa had beige artificial leather ex works in 1974. Here, too, we respond to customer wishes. In this case, therefore, a combination of beige genuine leather and seat panels made of Pepita fabric was installed. Nevertheless, we attach great importance to details and recommended a Pepita fabric to the customer, which was also used from the factory in this era.

The restoration here quoted the original and reinterpreted it in selected places. I consider this an appropriate individualization. Ultimately, it also offers a nicer feel than the original. All suspension parts, including rubber mounts and bushings, were renewed, and new shock absorbers were installed. The goal was to achieve the driving experience of a brand-new G model with an equally fresh look and upgraded technology. At the end of the 1,500 hours of work, the result was an almost perfectly restored vehicle, that leaves nothing to be desired in terms of appearance and technology.

Why a good restorer assembles the car twice….

I would like to make one more comment at this point. A good restorer always assembles a vehicle twice. Why? The empty body naturally has a different force distribution on the lifting platform than when it is fully assembled and standing on its own wheels. Therefore, to assess the panel gaps, the front and rear axles as well as the engine and transmission are installed before starting the paint work. The body is then placed on the wheels. All panel gaps can then be checked and adjusted. If you work particularly cleanly, you also install bumpers, headlights and all add-on parts such as door handles and check their fit. Otherwise, you run the risk of having to rework after the paintjob. Some restorers take the easy way out and do not do this work on the Coupe because it has a stiffer body than a convertible/Targa and is not as susceptible to twisting. A good restorer makes no difference here.

Niclas Röhrle, Röhrle Mobility GmbH

So would you prefer a well-restored Porsche over an untouched one?

That depends on the intention of the buyer. If he wants a vehicle that is as suitable as possible for everyday use and requires neither visual nor technical attention, he is exactly right with a vehicle like our 2.7 Targa. Of course, restoring a Porsche to this level costs more than buying an unrestored vehicle with patina. Given the amount of labor involved in rebuilding it, that’s obvious. However, especially with the early G models, it’s hard to get vehicles with good history and low mileage even now. If you do, they are extremely expensive. If I buy a cheaper car with patina instead, I get a pig in a poke to a certain extent. Unlike a restored vehicle, major repairs and investments can lurk in the shadows.

Extensive repairs to the engine or a new paint job can very quickly eat up the price difference between a cheap and a perfectly restored Porsche. That’s why I think a properly restored Porsche is a good and, above all, reassuringly safe investment. You can enjoy such a 911 without any worries. However, this is also where opinions differ. Over the years there have been various trends. Sometimes the focus has been on unrestored vehicles, then again on restored ones. What we find, however, is that collectors always prefer a very well preserved vehicle to a fully restored one. First-time buyers, on the other hand, often prefer fully restored vehicles. I would advise against buying a base vehicle for restoration on your own. Without expertise, this often goes wrong. But we are happy to support in that case as a part of our restoration management.

Niclas, thank you very much for the profound insight into the world of restoring a Porsche!

Röhrle Mobility Website