Racing a Mercedes-Benz 300 SL Gull Wing on Salt

This story is about an exceptional guy with an exceptional passion: Bob Sirna. I have known him for more than 25 years, and I have been privileged to be on his pit crew at the vintage sports car and vintage Indycar races for many years – and at the Bonneville Salt Flats in Utah.

Bob Sirna of Rochester, Michigan, is the only man in the world who races a 1955 Mercedes-Benz Gull Wing coupe at the Bonneville Salt Flats. He has raced it there some 13 times over the years in search of a speed record, but was not successful there until the late summer of 2016.

Infected with “Salt Fever”

Sirna was introduced to the Bonneville Salt Flats many years ago by Gull Wing owners Lynn and Roberta Yakel from Michigan, and became infected with what the racers call Salt Fever. He decided to take his beautifully restored silver Gull Wing off the road and turn it into a Bonneville racer for the F/Grand Touring class. But he wisely kept all of its original production parts so that it can be restored to original condition later on.

Bob Sirna and his 1955 Mercedes-Benz Gull Wing

In search of a speed record

He spent many years trying to extract enough horsepower and durability from the original 3-liter six-cylinder single-overhead-cam engine that powered his Gull Wing coupe, each year encountering one technical problem or another that prevented getting a speed record at Bonneville.

In 2015, Bob decided to change engines to a modern 3-liter double-overhead-cam four-valve Mercedes M104 Series six-cylinder engine built for Bonneville by the American racing company Roush Competition Engines, so that the Gull Wing could take advantage of the engine’s better breathing power and higher revs at Bonneville’s 4,200-foot altitude. I went to Bonneville again to be part of the Sirna record attempt crew, and to photograph and record the effort with the new engine.

After passing the technical inspection, the car was placed in the queue for a record run, and ran flawlessly up to a speed of 188 mph, 16 mph over the existing speed record, before the new engine developed a lubrication problem at high speed and expired.

That was when the real fun began at Bonneville for Bob Sirna and his crew, which was made up of retired racing mechanics, designers, electronics and computer experts, engine builders, and even a medical doctor. We found a garage and auto parts store in the town of Wendover to remove the broken engine and replace it with a second, nearly identical engine.

A tricky challenge: the new engine

The words “nearly identical” became the big problem. Since the late-model inline six-cylinder engine is much taller and wider than the original leaned-over 3-liter Gull Wing engine, the space all around, above and under the new engine was measured in fractions of an inch, so the old engine had to be removed very slowly and carefully and the new engine installed even more slowly and carefully in order to make all the fuel lines, intake system, exhaust system and wiring work.

The removal and installation process took two full days to accomplish, mixed in with a lot of colorful English and a few laughs of simple frustration. If one side of the engine was okay, then the other side wouldn’t work. If the other side was okay, the front of the engine wouldn’t fit behind the radiator.

It had to be installed at a very radical angle front to back in order to mate with the custom-built 5-speed manual transmission and the hydraulic clutch setup. Typically, there would be five grown men moving the engine and all its parts around to get it installed properly, and another man under the car guiding the back of the engine toward the transmission.

Even more challenges: broken clutch

Ah, the clutch. Once the new engine was installed and all the intake, exhaust, cooling and wiring circuits were finished, we discovered that the clutch wasn’t disengaging because of a persistent fluid leak in the circuit. That would make push-starting the race car and shifting through the gears problematic, and it was far too late to take everything apart again, so we went to Bonneville with a broken clutch.

While we waited in the long line of race cars attempting to set records, everything was checked again, and the engine oil was warmed up using a generator mounted on the pickup truck that would push-start the Gull Wing. Finally, it was our turn to run.

After 15 years of trying: certified record!

A hundred yards down course, the Gull Wing fired and Bob shifted through all five gears, pushing the engine to 9,500 rpm in fifth gear. The Gull Wing reached a speed of 189.714 mph. A record was in hand. The car was towed directly to impound, where it stayed overnight.

The second run, the next morning, was even faster than the first, 191.805 mph, for a record average of 190.759 mph, nearly18 mph over the old F/GT record. The silver Gull Wing easily passed post-race technical inspection, and the record was certified, after 15 years of trying.

The World’s Fastest Gull Wing!

A few weeks after the record was official, Bob Sirna was notified by Mercedes-Benz Research & Development’s Powertrain office in Germany that he would be recognized as the owner, builder and driver of The World’s Fastest Gull Wing.

The citation reads “While there have been many noted race drivers throughout the years that have piloted these now vintage and historic Mercedes vehicles to date, we cannot locate anyone who has traversed the surface of this planet any faster than you during your record run. Congratulations on this incredible accomplishment.”

My friend Bob Sirna has spent all of 2017 showing the Bonneville Gull Wing at prestigious gatherings like the Amelia Island Concours d’Elegance in Florida and the Concours d’Elegance of America in Plymouth, Michigan, and will spend the next year taking the car completely apart and restoring it to its original condition. When it’s finished, it will be the only roadgoing Gull Wing in the world with a Bonneville speed record in its history.

The Veteran automotive journalist was part of Bob Sirna’s pit crew at Bonneville. He used to travel with his friend to the Mille Miglia in Italy and the Goodwood Festival of Speed in the UK.