CCW-Profile: HK-Engineering

Since 1984, HK-ENGINEERING has been the only company in the world to restore exclusively the valuable Mercedes-Benz 300 SL and make it fit for the next phase of its life. Serving with intelligence, dedication and enthusiasm.

Entrepreneur, director and world-renowned expert in the automotive icon with the trademark star, is Hans Kleissl. Hardly anyone else has such a wealth of knowledge, experience, and passion. Being a classic car enthusiast and collector himself led to his founding of HK-ENGINEERING. „He’s one of us,” is the common opinion among his customers.

HK-ENGINEERING is set in a lovingly restored monastery in the Bavarian village of Polling, with an additional branch in the Berlin Classic Remise. Further partners and representatives are located outside of German borders, listed in detail under the heading „Contact.“

HK-ENGINEERING is well-established. Throughout years of service in Kleissl’s SL workshop, mechanical engineers have made technical contributions to the sustainable conservation of this unique Mercedes model series. As a result, while it previously took at least a year to bring a Gullwing or Roadster back to its original glory, the mechanics in Polling can now finish an entire „resurrection” of a 300 SL in only six to nine months.

HK-ENGINEERING offers its clients restoration of nearly all original parts: from refurbishing old leathers to matching original body paint. Of course, they are also able to restore classic Mercedes-Benz cars from the ground-up.

Since 1995, HK-ENGINEERING has operated its own racing team. To date they’ve built a dozen SLS-type cars. „While others speak of their great technical competence, we prove ours on the track,“ boasts Hans Kleissl.

Aside from the vast technical expertise, Kleissl is deeply involved in the social aspect of the 300 SL series. He has served on the board of directors for the 300 SL club of Germany for more than ten years.

„You need great passion, because everything you do with great pleasure, you do well.“ Juan Manuel Fangio

HK-ENGINEERING has long been known for it´s high standards in rebuilding engines.

There are many different ways of tackling an engine overhaul. You may take anywhere from 40 up to 160 hours. You might stop at 1/20th of a millimetre – but you can also go for the ultimate 1/100th millimetre. The higher the level of precision achieved, the smoother the engine will run – resulting in a higher output of power as well as longevity.

The engine is the heart of the 300 SL. To be able to perform complete engine repairs in-house, HK-ENGINEERING took over the whole machine fleet of an engine repair company in 2011. Five specialists now work on site to restructure every engine perfectly, none of the parts have to be processed off the premises.

Another division of ours, that receives the highest possible amount of attention , is our fuel pump department. Tolerances here are measured to 1/1000th of a millimetre. As we are able to overhaul fuel pumps and injectors ourselves our advantage over our competitors is even more increased. The over linking together of our engine shop and fuel pump department is one of the fundamental ingredients in our restoration success: always pushing one another to achieve the maximum output possible.

Each assembly step is carried out according to guidelines we have developed over the years. Every mechanic is a specialist in his field. An intricate system of quality control ensures perfect execution of all jobs, resulting in the desired fault free completion of each restoration.

Our longtime specializing enables us to offer lots of useful technical innovations. Rear axle conversions of any kind, installation of limited slip differentials, transmission rebuilds and a transmission exchange programme round up the list of our abilities.

For more information, please refer to our price list of 300SL developments and modifications.

Our body shop produces every Mercedes-Benz 300SL body panel, Gullwing as well as Roadster, steel or aluminum, with exceptionell precision. Achieving such high standards in body shop works, the use of plastic fillers or lead can be reduced to an absolute minimum.

The high standard in production is achieved through specially fabricated models and moulds. The use of high-precision frame gauges for Roadster and Coupé models guarantees that even frames with concealed accident damage can be repaired according to factory specifications.

To be able to delivery top quality for the vehicle finish as well, HK-ENGINEERING set up its own saddlery department in 2012. Our main ambition is to turn every 300SL that enters our shop, into a reliable, fault free vehicle, rewarding it´s owner with the purest pleasure of driving possible. Find out more or take a look at their listings on


Highlights of the inventory

300 SL Coupé – 1955

Beautiful and fully restored 1955 Mercedes-Benz 300 SL Coupe in original delivery color silver gray combined with blue plaid fabric seats and the very rare original Rudge centre lock rims ex factory. According to the present data card, the delivery to the Mercedes-Benz agency in New York took place on March 31, 1955. As additional special equipment were instruments in English script, sealed beam headlight, rear axle ratio 1: 3,25 (for the maximum speed up to 260 km / h), disc wheels with Rudge hubs, windscreen washer and 1kg paint DB 180 Nitro ordered. The car was in the early 60s in the possession of the young millionaire and owner of the Emeryson Racing Team, Hugh Powell.



Later he sold it to racing driver and owner of a Mercedes-Benz agency, Tony Settember. Between 2006 and 2008, a major restoration took place in the USA, which did not require any sheet metal work due to the excellent substance. Since 2015, the car is now in the possession of a German collector. In 2018, he commissioned one of the most renowned appraisers to provide expertise. The result top grade and a value of € 1,600,000. Of course, we will hand over the vehicle with a new TÜV and HK-ENGINEERING delivery inspection. Matching Numbers. Find out more


300 SL Roadster – 1962

Unique opportunity for collectors! We are proud to offer one of only 209 Mercedes-Benz 300 SL Roadsters with coveted disc brakes and lighter aluminum engine ex factory. According to the available built sheet, the car was delivered to the USA on September 6th, 1962. The register shows two owners in Florida, before the Roadster was imported to Germany in the early 80s and completely restored in 1988. Even today there is an extensive photo documentation of the restoration.



The SL was last family-owned for more than 30 years, rarely moved, and still regularly maintained. Particularly noteworthy is that both the chassis, body and engine number as well as gearbox, front axle and steering box have the coveted matching numbers. Great chance to buy one of the finest Mercedes-Benz 300 SL on market. Find out more


300 SL Coupé – 1956

This fully restored 1956 Mercedes-Benz 300 SL Coupé in rare anthracite gray metallic paint combined with beige leather interior was first delivered via Mercedes-Benz Paris, France on 13th November 1956 and later handed over to it’s first owner. The special equipment ex works included a special upholstery, sealed-beam headlamps with separate parking lights, tires with white wall, Radio Becker Le Mans with Reims adapter, automatic antenna and a windscreen washer system.



Later, the coupe was owned by a Belgian and then for 29 years in the Netherlands. In 2012, a comprehensive restoration with work on body, frame, paint, interior, and engine has been carried out. In the course of this work, the bumpers were also removed to make the SL appear even sportier. Of course, these are available and can be reinstalled on request at any time. We are handing over this coveted matching numbers 300 SL Coupé Ready for approval and with new HK-ENGINEERING delivery inspection. Find out more.


300 SL Roadster – 1961

This is a fantastic 1961 Mercedes-Benz 300 SL Roadster in very rare colour with light blue paintwork combined with dark blue leather interior and black top from second German owner! In total, only 101 roadsters left the factory in the colour light blue 334. According to the present data card, the car was delivered on 16 January 1961 and registered a day later for the first owner, a merchant from Paderborn. After his death, the second owner took over the SL. The roadster has been in its possession for more than 45 years. Thus, this is one of the very few who have been extradited to Germany or have never left the country.



In recent years, our company has carried out an extensive overhaul of the entire technology for more than 75,000 euros. The leather interior is still original and is in excellent condition. The bodywork, the paint and chrome are also in very good condition! Like the entire car, the history and documentation is first class. In addition to numerous invoices and documents collected over the years, the original user manual, sales brochure, cardboard lid letter, as well as the original car jack are still available today. In addition, there is the beautiful and rare hardtop for this vehicle. We deliver this dreamlike classic with new TÜV, H-approval and HK-ENGINEERING delivery inspection. Find out more.


…and there are more outstanding classics!





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