Like many passionate car enthusiasts, my journey into classic car ownership began with a chance encounter and a shared love for automobiles. Eight years ago, a conversation sparked a friendship rooted in German heritage and a mutual appreciation for finely engineered vehicles. This connection led me to a treasure tucked away behind a workshop: a 1951 Mercedes 170s.
This particular Mercedes 170S, while missing its original engine and transmission, was remarkably well-preserved. Aside from a minor area of trunk floor needing attention, the body was solid, holding the promise of its former glory. Being German, with Mercedes-Benz deeply ingrained in my upbringing (thanks to my master mechanic uncle), I knew I had to take on this restoration project.
Time has flown by, and progress has been slower than anticipated, but now the momentum is building again. The first step in breathing new life into this classic Mercedes 170S was tackling the 6V to 12V conversion. Fortunately, the simplicity of the circuits in older vehicles made this a straightforward process. Swapping out the bulbs for 12V replacements is all that’s needed to bring the electrical system up to modern standards.
However, the real challenge, the one that has stalled this project for far too long, has been the engine. The original engine and transmission simply wouldn’t be practical for today’s roads, especially in Texas, where highway speeds demand more robust performance. My vision for this Mercedes 170S is to enjoy it as an occasional daily driver, a stylish and reliable classic for local jaunts. Resale value isn’t a concern; this car is a keeper, a vehicle to cherish and bring back to its vibrant best.
Initially, following the advice of my friend Corky, a seasoned Miata expert, the 1.6-liter engine from an NA Miata seemed like a promising candidate. Its compact size and readily available parts made it appealing. We test-fitted the Miata engine, but a significant hurdle emerged. The exhaust manifold’s driver-side placement clashed directly with the steering column. Even a custom exhaust header wouldn’t provide enough clearance without requiring major modifications to the steering system. Furthermore, the purist voices in the automotive community weren’t shy about expressing their disapproval of a Mazda engine finding its way into a Mercedes-Benz, though ultimately, it’s my vision and my car.
Seeking to keep the powertrain within the Mercedes-Benz family, I explored the M102 four-cylinder engine from the 190E. The M102’s passenger-side exhaust ports would solve the steering column clearance issue. However, these engines are physically quite large for their displacement, and finding one paired with a manual transmission proved to be a difficult task. A fleeting thought crossed my mind: transplanting the DOHC M102.983 from my ’85 190E 2.3-16 into the 170S. In return, the 190E would receive a more potent M104 engine, ideally with EFI and forced induction for a future project. But the M102.983 feels perfectly matched to the 190E, making this swap less appealing.
Remembering a spare 5.0-liter M117 V8 engine awaiting a rebuild, I considered the allure of V8 power in the Mercedes 170S. Unfortunately, the M117’s considerable length and width quickly dashed those hopes. Fitting it would necessitate cutting into the firewall, a modification I was keen to avoid. An MB V8, despite its appeal, was ruled out. The idea of pairing a manual transmission with that V8 was also tempting, but impractical given the fitment constraints.
A more unconventional option surfaced: a 13B rotary engine with its transmission, already in my possession. The rotary’s compact dimensions would make installation relatively straightforward, and getting it running wouldn’t be overly complex. However, the long-term prospect of daily driving a rotary engine in a classic Mercedes gave me pause. While I appreciate the unique character and performance of rotary engines, and the 13B’s distinctive sound is undeniably captivating, I’d prefer to minimize potential reliability concerns in a car intended for regular use. I am not afraid of maintenance, but prefer to engineer solutions rather than potential problems.
This brings me to my current predicament: the search for a suitable four-cylinder engine. The ideal candidate would be compact, easily adaptable, feature passenger-side exhaust ports to avoid steering column interference, and, crucially, offer more than the original engine’s modest 52 horsepower.
The 1.0-liter three-cylinder EcoBoost engine briefly caught my attention. These engines are readily available and affordable. However, adapting a front-wheel-drive engine to a rear-wheel-drive classic Mercedes 170S, along with the complexities of standalone management for its direct injection system, seemed like a potentially overwhelming undertaking.
The journey to revive this Mercedes 170S is ongoing. The engine choice remains the critical decision. Each option considered presents its own set of challenges and compromises. The goal is to find the right balance of performance, reliability, and ease of installation to bring this classic Mercedes back to life and onto the road.
Thanks for following along with this restoration journey! Stay tuned for updates as the engine saga continues and progress is made on this beautiful 1951 Mercedes 170S.
