Stuart Hilborn: Chemist, Inventor, Hot-Rodder, Racer & Manufacturer
By Ken Berg – The Motorsports Education Foundation
Stuart Hilborn invented the fuel injection system and it became the system of choice in racing, beginning with his hot-rod V8 and then the Meyer & Drake Offys. He is still active and, like the others of his generation, is using the computer to design and manufacture his products. One of them is an
experimental rotary-valve throttle design to be tested on an IRL/Aurora engined car shortly. This provides a nice introduction to the man, leading on to the thought and reality of continuous change and improvement in racing, by racing people having the competitive instincts of the Racer’s Edge.
OVER THE YEARS
Stuart was born in Calgary, Alberta around 1917. The family moved to Pasadena in about 1930 after which they made a number of moves in the Southern California area. In 1935 Stuart graduated from high school and then went on to Los Angeles Junior College. He majored in chemistry but had not yet acquired an interest in cars. In about 1938 he went to work for a large paint company, remaining with them until 1949, while serving three years in U.S. Army Air Force. He formed an idea for delivering fuel to the engine by means of injector nozzles which would spray the fuel, fed by a high pressure pump, at a constant pressure to a point right above the valve. When the valve opened the fuel would be pushed into the engine by its own pressure. Air would be sucked in if naturally aspirated or pushed in if supercharged to complete the mixture for ignition on the power stroke. This simple device revolutionized automotive fuel systems and is now used on virtually all passenger and racing cars. Stuart continued to refine his injector systems at his factory in Aliso Viejo, California into his 80s. There is a continuous history of change and improvement to all the things he has done in his long career. We discussed this theme of the Racer’s Edge in his spacious office above his factory.
A Chronological Timeline – As Told By Ken Berg
In 1939 he went up to Muroc Dry Lake, now Edwards AFB, with friends … just to look. But he got hooked and bought a hopped up Model A roadster in 1940. It was a strong competitor and Stuart was soon turning speeds of over 120 miles-per-hour (mph) on the dried beds of California’s alkali lakes.
In 1941 he bought a small streamliner from Bill Worth and made plans to put the V-8 engine from his roadster into the streamliner. His friend, Eddie Miller was a major figure in racing and helped Stuart modify the engine even more. Eddie designed the 4 carburetor layout–with three Stromberg E’s and one double-throat EE. Miller also hand-ground the camshaft. The heads were milled and filled. A Scintilla-Vertex magneto gave the spark, and twin oil pumps gave 90 pounds-per-square-inch (psi) for heavy-duty racing service.
They got the streamliner timed at over 134 mph at Harper Dry Lake that summer of 1942. Stuart was in the Centuries Club at this time. Most of the boys were enlisting or in defence jobs and had no time for racing so it ended for the duration of the war and he stored both cars while he was in the service. Stuart entered the Air Force, qualified at Las Vegas Air Gunnery School and became a weapons trainer for B-17 and B-29 gunners.
The war ended in May of 1945 and in 1946 Stuart was still awaiting his discharge in Mississippi. He began to think about his race engine and those four carburetors … and he conceived and drafted plans for a fuel injection system which seemed much simpler than even one carburetor which has quite a few finicky little parts and passages to it. But, as he told me many years later, “I can’t really say what first gave me the idea”. He finally got his discharge in March and he went back to the paint company. And started construction of his injectors. Eight of them for his V-8.
Having recognized the need for separate injectors to each cylinder, he then attacked the problems of getting equal flow from all injectors, at all speeds, by ingenious experimentation and burning of the midnight oil. He did a little grinding on the chamfer at the inlet side of the fuel orifice and Bingo! he found he could regulate the flow from each injector by custom shaping the chamfer to get more, or less, flow. Then he began to show the promise of a much improved fuel system. It was far and away better than carburetors had ever delivered. At El Mirage, on Sunday April 28th, 1946 he ran at almost 140 mph in the Streamliner. This was the first post-war Southern California Timing Association (SCTA) meet. He was still racing both the roadster and the streamliner, sometimes with injectors, sometimes with four carbs, and on at least one occasion, with two carbs.
In 1947 they went up to Rosamond for tests with the new injectors. Stuart took the car up to 120 mph and prudently left it at that. The engine was running well and responded well to the fuel injection. The test told him that the injectors would do the job for him.
“I got on the throttle early and hard. I could feel the engine was really strong and pulling hard. I stayed on it. If it was going to blow I wanted it to blow now, not next month at our first race. At one-twenty the car was still accelerating so I knew things were close to right. I didn’t want to push it higher because we were all alone out on the lake without the usual ambulance standing by. In case of an emergency, I could be in real trouble. We loaded up and headed for home. Everyone was delighted with the first test.”
The first race of the year and the first competition for the Hilborn injector was to be at Harper Dry Lake.
“I headed out across the lake on a check-out run on the Friday. I slowly increased my speed to about a hundred and twenty-five miles an hour. Everything felt good. Suddenly, I saw flames shooting out from the engine compartment.” He got the fire out but exposure to phosgene fumes from carbon tetrachloride (Pyrene) on the hot engine made him, “unsteady on my feet and could hardly stand up.”
The engine was still plenty hot but the extinguisher was empty so he could only hang on woozily to the car until his crew got out to him. They replaced spark plug wires and got ready to run on the Saturday and Sunday. They ran 134 mph on chewed-up course and felt they had done pretty well on this their first competitive run with the prototype injector set-up.
The next month they decided to run 2-carb manifold in a comparison test with the injectors. The car spun, a wheel collapsed, it flipped, and Stuart wound up in the Victorville Hospital. After the meet he found that he had suffered a damaged vertebrae. He was put in a body cast for a three-month stay at Sawtelle Veterans Hospital.
He was back on track in the Fall and ran the roadster at El Mirage … look at the speeds they were getting in those early days. Initially the cars were assigned a third, timed run if they could make a target speed .
Then a new era began to open up for Stuart and his injectors. The owner of a two-midget team which was worked on by Stuart’s friends sold the team. The new owner, Howard Keck owner of Superior Oil, wanted to run a car at Indy. Stuart and his injectors were headed for the Show! His friends invited Stuart to come with them on the team and maybe, if Stuart continued his development for the big Offy 270, they’d get a chance to try it at the famed Brickyard!
1948 Hot Rod Exposition
But first, there was another Show. In 1948 Stuart had a shop chrome up the prototype V-8 injector set for the Automotive Equipment Display and Hot Rod Exposition. It was to be held on January 23rd – 24th – 25th at the National Guard Armory, Exposition Park in Los Angeles. He got his display set up just in time and immediately began attracting visitors. Seeing his injectors for the first time raised some questions in the minds of some of his visitors. As Stuart said, “one guy kept asking how it could work if it wasn’t timed to the intake stroke?
“Everybody else timed their injectors … Why do they go to all that trouble and expense if it isn’t necessary?”
Stuart told him, “I don’t know, maybe its just follow-the-leader.
Expert: ‘they must gain something or they wouldn’t do it.'”
Stuart: “what do you gain by interrupting the fuel-flow 40 times a second?”
Expert: “I don’t know, but everybody does it. Your system won’t work!”
Stuart: “I’m going to find out!”
Hot Rod Magazine Cover
In April, a smiling, confident Stuart made the cover of HOT ROD Magazine and the lithe and dangerous-looking black Class B streamliner was featured as the Hot Rod of the Month. One hundred and thirty-six mph had been unofficially recorded. “Hilborn hopes to run his car for its ninth successive season and crack the evasive ‘ground-sonic curtain’ speed of 140 mph. Stuart is developing an overhead- valve (OHV) package for the Ford V-8.”
His first race of 1948 was at El Mirage on Saturday, April 24 and was reported by Wally Parks in the May issue of HOT ROD … “Outstanding feature of Saturday’s running was the setting of a new record for Class B Streamliners by Stuart Hilborn’s sleek black #11 which is powered with a ’34 Ford V-8 engine. Under the skillful piloting of Howard Wilson, Hilborn’s car made the two-directional runs at an average speed of 145.64 mph.” Both are in the Low Flyers Club. The speed set a new, absolute two way record for SCTA. It was faster than anyone had run, in any class!
On August 28-29 Stuart ran the streamliner again and got a 146.10. And then ran an exhibition quarter-mile in 14.60 seconds at 123 mph. An acceleration run. A first, one-car, drag race! Wally Parks reported: “With this interesting exhibition, made on a loose and dusty course, S.C.T.A. members are looking forward to the future presentation of some official short distance acceleration trials, plans for which are now in progress.” Apparently, Wally was already thinking up the National Hot Rod Association head-to-head drag races!
At the same meet, Ray Brown ran his Meyer-equipped V-8-60 #36 rear-engined roadster to an unofficial 124.30. Wally Parks ran 153.32 in the #4 Burke-Francisco Class C streamliner. An all-time high. Everybody was pushing the envelope, burning the midnight oil in their garages and doing all the tough things they had to, to be competitive. The competition was red-hot as records were broken at every meet. The Racer’s Edge was driving everybody to new achievements almost every week end. And it looks like they were having a lot of fun. On September 25-26 Stuart ran again at El Mirage and got 136.36. It was hard to keep improving the old V-8 and Stuart had pretty much proven what he wanted to prove.
Encouraged by the racing performance of his injectors, he bought a small lathe and drill press, and, using the same garage of his friend began making injectors. The first job was for the 105 CID Offy midget engines. First test driven by Norm Holtkamp at lap record speeds, they got a flare of flame out of the exhaust from the over-run, with the throttle partly closed, which was new to the injectors which had previously run only at the ‘lakes on high-speed, straight-away runs. High pump speed created a rich condition for the deccelerating engine and the rich mixture ignited and flamed out of the tail pipe. It must have looked quite spectacular! But it was inefficient and Stuart corrected the problem by shutting down the fuel more quickly and positively when the driver lifted off the throttle for the turns.
Then, Meyer & Drake called. They had heard of his success with the Holtkamp midget. News of new power travels at racing speeds among the racing fraternity. They asked him to come over and do a test on their recently installed dyno. At 6000 rpm carburetors gave 99 hp. The tests on the injectors gave 109 hp. Everybody was impressed. Lou Meyer and Dale Drake wanted injectors for their production engines. And they wanted to become dealers. Right now! And so it was arranged.
Stuart left the General Paint company in 1949 to devote himself full time to the manufacturing of his injectors. The first production run was for 10 sets for the M&D 105 CID midget engine. A test was arranged for a race at Culver City. Bill Vukovich was to be the test driver. Vuky liked the injectors but his gear-box failed. Ed Haddad, another midget driver, got interested and began marketing the Hilborn injectors in the midwest, based on his success driving an injected midget. It was good business to have successful drivers promoting the Hilborn fuel injection systems.
Stuart started making patterns for 270 Offy injectors for Indy cars. And got ready for a second year at Indy. This time he was taking his prototype 270 injectors. Jimmy Jackson was to drive again, even though Keck thought a lot of Lee Wallard, who was somewhat more of a charger than Jackson. Jackson qualified with Hilborn injectors in their first appearance at the Speedway. They qualified the car in seventh place at 128.023 mph average for the four qualifying laps. Again, their car was the Deidt, and again they took off the injectors for the race, finishing sixth. The establishment just wasn’t ready to trust the injectors for the four hours at top speed they would have to run to be competitive at the Speedway. But they were getting some attention to their qualifying speed and performance.
By 1950 there were seven injection set ups at Indy. Some teams rented theirs to others for qualifying. A portable test stand went with Stuart, but when all the injector users in the midwest showed up to get their injectors checked, Stuart abandoned the field laboratory and left it to the factory to arrange service for the racers. Keck hired hard-charging engineer, Mauri Rose who liked the injection system. He averaged 132.319 to qualify on the outside of the front row.
“Our chief mechanic told Mauri that as soon as the car was back together and the carburetors installed, they wanted to run some practice laps. Mauri appeared to be shocked. He asked, ‘why do you want to go back to the carburetors? This is the smoothest, strongest, best running engine I have ever driven. … I don’t ever want to drive another car with carburetors.”
Mauri had already won Indy three times in Lou Moore’s cars and was an engineer at the Allison plant. He knew something about racing engines. He finished 3rd in the rain-shortened race. Five other cars raced with the revolutionary Hilborn injectors installed.
Sales of injectors for all three Offy-engine sizes increased. A fourth size was added for the 176 CID centrifugally supercharged Offy. And early in1951 Hilborn produced the first production model injectors for the Ford V-8. Mauri was back with the Keck team. They qualified well and were running strong when a collapsed wire wheel spun him into an infield ditch, Mauri retired as a race driver.
For 1952 Frank Kurtis was to build them the first Kurtis KK500A with 36 degree lay-over Offy engine. Howard Keck didn’t need any advertising so they called it the “Fuel Injection Special”. It was driven by Bill Vukovich who finished seventeenth. Howard Keck wanted a Ferrari, so Stuart gives ‘the Old Man’ at Marinello an injection system, but Enzo short changed them on the car anyway. But Stuart met Jules Goux who helped him to buy a Bugatti for Howard’s brother-in-law.
At Indy Bobby Ball qualified the Ferrari but drove the Ansted Offy powered car in the race. Alberto Ascari drove the Ferrari. A wire wheel collapsed, and they were banned from the Speedway. Many of the cars have Hilborn Injectors.
In 1953 it was the same deal. Ferrari won’t perform so the car was junked. Vuky won for them in the new Kurtis. He led for195 of the 200 laps! This is the first win with Hilborn fuel injection at the Speedway. Stuart got married in Detroit. Keck wanted a new, streamlined car targeted for the 1955 race but delays and problems cropped up. They couldn’t buy the Novi engine they were expecting from Andy Granatelli. Stuart had been working with Herb Porter and a supercharged Offy 183 for the past few years with his injection system but this didn’t seem the way to go for the new car. Leo Goossen was contacted to design another supercharged V-8 Offy but that never came to be, either. The new, streamlined car was ready, but no parts ready at M&D.
So, Vuky was to run the old car, in 1954 with a new 270 and he won again, for the second year in a row! But, then, Howard Keck quit racing and Lindsey Hopkins took over and hired the team. His car is pretty much like their old KK500A.
But in 1955 Bill Vukovich crashed and died on lap 57 at the Indianapolis Motor Speedway and Stuart’s friends quit racing.
1956 to about 1958 Stuart helped out on the team of long-time mechanic friend. One of their cars was a supercharged Maserati with carburetors, to which they adapted a Hilborn set-up but apparently did not qualify for the Show. In 1959 Bobby Grim drove a Kurtis KK500G for the team, and in about 1960 Ebb Rose bought the team. In 1961 Ebb Rose was driving for the Meyer Speedway Racing Team and Racing Associates have two cars in the Show for Herb Porter. In 1962 Ebb Rose qualified in a Philips car of which Herb Porter is part owner. Around this time Ford was trying their version of the Hilborn injector.
Rodger Ward brings his Ford, now with DOHC, home in second. Jimmy retired early. In 1965, Clark wins Indy in his Ford-Lotus. Louis and Sonny Meyer join the Ford team.
Fords win at Indy. Dale and John Drake set out to battle the Fords with the Drake-Offy. Gordon Van Lieuw, Dick Jones and Champion and Dale Drake were experimenting with positive displacement blowers, like the GM Diesel superchargers. In 1965 Bob DeBischop of AiResearch contacted Herb Porter to run some experimental turbochargers. Herb asks Stuart to provide the injection system and they test engines with Dick Jones on the Champion dyno in 1966 and show 100 horsepower more than the positive displacement blowers. And that was the end of the positive displacement blowers, and on to turbochargers! It would be twelve years later that Formula One would begin to use turbochargers.
In about 1967 Ford turbocharged their 168 engine, with Bendix fuel systems and Schwitzer blowers.
Then in 1978 Stuart builds an injection system for the Cosworth and utilizing a rotary valve in place of butterfly valves in the injector. By 1992 the Ford system is basically the same that Hilborn built for Ford/Cosworth.
Continuous development of injectors, pumps and other components keeps Stuart busy. This year they are working on the rotary valve for the Aurora engine in the Indy Racing League. Wherever there are racing engines, or any other kinds of engines, we are indebted to Hilborn’s injectors. They are a part of the continuous development of racing technology, which parallels and informs and draws from all parts of industry and technology to continually sharpen the Racer’s Edge.
Stuart Hilborn has probably fulfilled his ambitions and has certainly left his mark indelibly on automotive technology. A modest man, keenly aware of his accomplishments, he was very courteous and helpful to me while preparing this material.
We lost Stuart in 2013, but his memory and legend lives on. Thank you Stuart, and all like you who make the changes that benefit our lives, directly and indirectly… making products we use every day … providing an example of the Racer’s Edge and showing how it makes an old Model A competitive, or can make something we use every day efficient and affordable.