Riva-Revolution-Final.Pdf

RIGHT: Period photo of the Lamborghini-powered Riva was Riva boats and Lamborghini featured in back of Road & cars are both iconic Italian designs. Track magazine. Though historically the two have been for the most part unrelated, there was one Riva boat that was powered by a pair of Lamborghini V12s. This particu- lar boat was owned by Ferrucio Lambo- rghini, who had ordered it from Riva in 1968, when the Italian supercar company was at the top of its game. The mid-engine Miura supercar had begun production in 1966 and had taken the automotive world by storm and Ferrari was now on notice that it had a serious competitor just down the road. Normally the sleek, wooden Aquarama boat (hull number 278) that Ferruccio Lamborghini ordered from Carlo Riva would have been powered by Above: Ferruccio Lamborghini (on left) and Carlo a pair of simple but powerful Crusader Riva around the time that the Ferruccio ordered the V8 marine engines made by GM. How- boat. ever, as the owner of a car company known for its fast, high performance road cars, Ferruccio requested that Riva install a pair of Lamborghini-en- V8s. for the project. gineered V12 engines in place of the Despite the disappointing per- Though the boat would still use somewhat pedestrian V8s. The pair of formance of his new boat, Ferruccio a pair of Lamborghini sourced V12s, motors were sourced from the Espada, enjoyed it and kept it until his death in the owner wanted the boat to perform a luxury, 2+2 GT car that Lamborghini 1993. At that point, the V12s were re- properly in a marine application. That had begun producing in 1968. moved and replaced with the original meant more torque at lower RPMs. The In order allow them to work in pair of Crusader V8s. The Lamborghini primary method used to achieve this the boat, the V12s had to be modified marine engines were sent to the com- is to increase the displacement of the for marine use. Riva also designed and pany’s museum, while the boat itself engine, which in this case would have a built an exhaust system with open pipes was put into storage, since none of Fer- two-pronged effect on the torque curve at the request of Lamborghini that ruccio’s children had any interest in it. of the engine. First, a larger motor would make the boat sound like no oth- A few years ago, the boat was would produce more torque because er. While a pair of high-revving V12 en- rescued from storage by a Dutch enthu- of the larger displacement. And sec- gines may have been a great idea in the- siast who decided to restore it back to ond, enlarging the engine while keeping ory and one that should have had stellar its original form, complete with a pair the cylinder heads basically the same results, the performance of Ferruccio’s of fantastic Lamborghini V12s. While would lower the engine speed where one of a kind Aquarama was somewhat the boat was being restored in Holland peak torque occured. The latter change disappointing. The primary problem was by Riva World, a world renowned Riva was particularly important in this case, the fact that the 4.0-liter V12s didn’t restoration company, the restorer of since the desired result was additional produce peak torque until 5,000-rpm. Ferruccio’s old boat contacted Caro- torque at a lower RPM than the original Those familiar with boats know that low- bu Engineering about the possibility of high-revving engines. Peak torque would end torque is what is needed to get the building a pair of custom V12s for the also be adjusted by altering the cam- boat quickly up to planning speed, which boat. Carobu’s worldwide reputation as shaft duration. is why Rivas were traditionally powered a builder of high performance vintage The first step in the engine build- by low-revving, but torque American Ferrari V12s made us the logical choice ing process was inputting the basic engine parameters into Carobu’s engine simulation program. The performance specifications of the original 4.0-liter Espada V12 was used as a baseline from which the final engine would be configured. With the baseline engine simulated properly, changes were then made to achieve the desired result. The bore and stroke was changed, cam- shaft timing adjusted and the marine specific exhaust system modeled. In the case of the latter, the exhaust is a simple log manifold that cannot be tuned. The intake flow of the engine was also changed for optimum performance. The results of the computer simulation were then used to design new parts for the engine configuration. Specially made components included a new Razzo Rosso 80mm billet crankshaft, custom connecting rods and Razzo Rosso forged pistons. Because of the longer stroke of the new crankshaft, 9mm deck plates were installed and sealed onto the top of each side of the block. Longer pistons sleeves were installed and bored out to 85mm. With so many changes and alterations to the original motor, this project was more like an engine development proj- had to be hand fitted due to the close which is the same setup that was orig- ect than a straightforward engine re- tolerances, and there was also special inally used on the engines in the Espa- TOP: Block with the custom crank and build. Longer head studs were installed machining on some parts so they would da road cars. In order to work with the pistons installed. to accommodate the deck plates and fit properly. more powerful motor however, each a longer timing chain and custom ma- The cylinder heads were care- of the six carbs was re-jetted to deliver BOTTOM: Detail of the crank. The chined timing chain tensioner sprocket fully hand ported and polished in order the proper amount of fuel and air to the bottoms of the pistons and the were installed. During the engine build- to replicate the proper flow characteris- engine. While the original Lamborghini counterweights on the crankshaft ing phase, many of the components tics that were suggested by the engine engines used a primitive points setup in were machined to provide adequate simulation program. Both the intake and the distributors, the new motors rely on clearance. the exhaust camshafts were ground to a Pertronix electronic ignition in order custom profiles to achieve the proper to deliver a reliable spark. power band. Another necessary change Copies of the simple log man- was clearancing the bottoms of the ifolds that the original V12 engines pistons skirts so that there would be utilized for the exhaust system were enough clearance when opposing pis- remade by the very same fabricator in tons in the 60-degree V12 were at the Europe who had built the original mani- TOP: Bare block came from a Lambo- bottom of their stroke. Additionally, the folds. The manifolds were hand delivered rghini Miura. counter weights on the billet crankshaft to Carobu’s shop in the U.S. by Sandro were machined down in order to clear Zani, the restorer of the boat and the MIDDLE: Specially made Razzo Rosso the pistons at BDC (Before Dead Cen- owner of Riva World. pistons were produced for use in the ter). The changes to the original boat application. Fuel delivery for the bespoke 4.0-liter Espada motor resulted in a Lamborghini engines is handled by a healthy displacement of 5.5-liters, while BOTTOM: An 80mm Razzo Rosso relatively conventional sextuplet of 40 the compression ratio was now a more billet crankshaft was designed and DCOE side-draught Weber carburetors, aggressive 10:1. The most important fabricated. Seen from above, one of the two rebuilt Lamborghini Espada engines shows off its six Weber DCOE carburetors and brass log headers. Before installation in the boat, the headers and other components of the motor are painted the signature blue that all Riva engines were originally painted. holes relocated to the thrust flank of the expertly fabricated to allow the pump was thrilling. In the boat, the perfor- cam, a very involved process. An EDM to operate in the correct direction. In mance was startling. The Riva easily (electronic discharge machining) ma- order to allow the engine to be started, got up on plane and sprinted to a top chine was used to drill the holes. the starter ring gear was recut to ac- speed of 53 mph. The throttle response The ignition on the second en- cept the Bendix drive. was crisp and the open mouth Weber gine was also modified. The dual dis- From start to finish, the design carburetors made some serious intake tributors were made to run backwards, and engineering of the two engines roar as the linkages snapped open. which included modifying the counter took nearly 20 months. Once the two The Riva-Lamborghini resto- weights. Like the first V12 that Carobu engines were shipped back to Holland, ration project is almost done. The final engineered, Pertronix electronic igni- Sandro Zani and his crew set to work interior appointments need to be fin- tions were then installed in each of the on installing them in the restored Riva ished before this regal wooden speed- distributors. The spark plugs wiring was Aquarama speedboat. The first engine boat can be delivered to its new owner. reordered as well in order to accom- was installed to check the fit of the cus- This Riva-Lamborghini is a very unique modate the reverse firing order of the tom made oil pan and the intercooled version of the Aquarama series; only engine.

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