Dyno tests resulted in 365 horsepower at just under 10,000 rpm.

Now, here’s how a Formula 1 engine should sound! And it’s not even running at full potential!!

This 3.0-liter Ferrari 180-degree V12 pulled from a vintage racing ’71 Ferrari 312B2 (chassis #005) just received a refreshening at Carobu Engineering in Costa Mesa, California, when it was hooked up to a Superflow Powermark dyno for break-in and testing. Best run was 365 horsepower at just under 10,000 rpm. A competitive Formula 1 engine from the early ‘70s would more likely pull around 450 horsepower at 12,000 rpm, and this platform eventually surpassed 510 horsepower in 1980 before the rules change to 1.5-liter turbo engines.

New cylinder liners came from F1 supplier Capricorn Automotive in England. Note the 4-bolt-per-cylinder head-stud arrangement.

“This engine should be making more horsepower, but here’s what I think happened,” Carobu’s Tate Casey’s explains, noting that this engine family was also used in the Ferrari 312B Sports Prototype Le Mans car. “Those engines were detuned to last 24 hours. I suspect this engine has the endurance camshafts.”

The Ferrari flat-12 is a true milestone engine, helping Ferrari crack the Cosworth DFV stronghold on Formula 1 in that era by winning the World Championship with Nikki Lauda in 1975 (see EngineLabs review of the movie “Rush” that portrays the season after).

Mauro Forghieri, Enzo Ferrari’s chief development engineer, was charged with designing a new powerplant after the team scored only one victory in 1967 and ’68. Ferrari had tried a 1.5-liter flat-12 in 1965 with no success but this one would measure to 2,991cc with a 78.5mm bore and 51.5mm stroke (3.09 x 2.03 inches). Those dimensions later changed to 80.0 x 49.6 mm (3.15 x 1.95 inch) for the the 1980 version. Ferrari had two primary goals in developing this engine: keep the center of gravity low — hence, the 180-degree design — and reduce internal frictional losses. To that end, Ferrari designed the crankcase with only four main bearings to support the 6-throw billet crankshaft. At first, Ferrari tried four roller bearings but ended with traditional shell bearings in the middle two positions.

Induction is via individual slide-valve throttle bodies.

Inside a flat-12 engine

The block actually comprises two large shells that are assembled with a series of fasteners. Instead of usual wet liners, this block was cast with integrated cylinders that required cast-iron dry liners. The magnesium dry-sump casting contained three oil-scavenge pumps — one for each 4-cylinder section. Since the cylinder heads were mounted 180 degrees apart, oil couldn’t flow back to the crankcase. So, scavenge pumps driven by the camshafts were positioned under each cam cover. A single pressure pump was mounted on right-hand cylinder head and fed oil to the front of the block.

Top photo shows the rugged gear drive system for the four camshaft. Below is a view of the billet crankshaft positioned in the four main bearings. Note the two end bearings are roller bearings. Although Ferrari put a “B” on the engine designation, it’s technically not a “boxer” engine because each crank pin supports two pistons. A traditional boxer engine has individual throws for each piston.

The twin-overhead cams were driven by a very busy gear arrangement in the rear of the engine. Accessories such as the water pump and alternator were driven up front. The cylinder heads feature 20-degree valve angles (31mm intake, 27mm exhaust), very shallow combustion chambers and a centrally located spark plug.

This particular engine first came to Carobu about four years ago after a failure during a vintage race. The owner needed it repaired in time for the popular Historic Grand Prix of Monoco, an exclusive vintage race for F1 cars held two weeks before the Monaco Formula 1 race. The teardown revealed broken timing gears but Carobu noticed a number of other irregularities in the engine that reportedly was built by a “German specialist.”

“We repaired or replaced just about everything except the crankcase, heads and crankshaft,” remembers Casey. “There were a lot of challenges with this engine.”

Racing towards Monoco

Carobu worked with suppliers like Crower to remake the titanium rods and JE to machine replacement pistons to clear the valves and maintain an 11.5:1 compression ratio. New cylinder liners came from F1 supplier Capricorn Automotive in England. Kinsler rebuilt the Lucas fuel-injection pump to ensure the required 150-psi fuel-line pressure, but Carabu had the chore of tuning the complicated mechanical system. Induction is through individual slide-valve throttle bodies. Originally the Ferrari race cars had titanium headers, but no word on what the current vintage setup includes.

The flat-12 was also used in a Ferrari sport car for Le Mans racing, and the milder camshafts may be used in this engine.

“You have to load the engine on the dyno and read the fuel mixture,” explains Casey.

At that time, Carobu didn’t have a dyno that could handle the unique dynamics of the engine, so it was sent to Europe for installation in the car and testing and tuning on a chassis dyno. There it made just under 290 horsepower.

The engine was raced for two years before it came back to Costa Mesa for a freshening and a tryout on the Superflow dyno.

“Basically, rings and a valve job,” says Casey. “We Magnafluxed the gears to make sure they’re holding up.”

The engine will return to Europe in time for this year’s edition of the Monoco historic races.

Testing after the first rebuild two years ago took place on a chassis dyno. This Ferrari originally was driven by Clay Regazzoni in 1971 and Jacky Ickx in 1972.