Engine Rebuild and Restoration

Lamborghini V12 Engine Rebuild

In 2002 an oil leak in the transmission case became an issue. The leak could not be repaired for lack of access and this lead to removing the entire engine and transmission. This was a huge undertaking and was done by a local expert in the repair of high end German cars (Poudre Sports Car Enterprises). The repair of the transmission case was probably an $200 job, but the labor to get the engine out (and back in) was very substantial. Thus, while the engine was out, many other aspects were inspected and addressed.

The engine was rebuilt in all respects except the cams, crank, rods, pistons and liners as these inspected and measured and appeared to be fine. Stainless steel values were used and the heads received special care. The Weber carburetors were cleaned and inspected. A new clutch disk was fitted, flywheel resurfaced, throw-out bearing serviced, new gaskets, new motor mounts, new thrust rings/washers, all new rubber seals and hoses, reconditioned value springs, timing reset, new main seal for the output shaft, rebuilt slave cylinder, etc., etc. Many of these issues were far from worn out, it is just that they were easy to replace while the engine was out.

The two radiators were rebuilt and new high performance fans were installed. The exhaust headers were removed and sent to Phoenix to be coated with a space age ceramic compound to prevent rust and retain exhaust heat, keeping the engine bay cool. Of course new plugs, plug wires, condensers, coils, rotors were attended to along with new temperature sending unit, new accelerator cable, and new air and oil filters. The engine and transmission were repainted as original, as well as the 4 cam boxes where were repainted in crinkle black. Many little things were done to enhance the cosmetics and bring everything back to original condition (repainting the air cleaner units). Nearly all parts were supplied by GT Car Parts in Phoenix. The whole process took over a year.

Since then the main oil lines up to the oil cooler mounted in the front spoiler were replaced. Wiring in the front trunk was redone, brake fluid and cooling fluids were flushed and replaced. These cars seem to have their “needs.”

The entire engine and transmission, without the 2 intake manifolds and 6 Weber carbs, but otherwise ready for reinstallation. The transmission extends into the cabin with the engine lying midship. The driveshaft runs from the transmission back through the engine sump to power the rear wheels. The engine and transmission weigh some 800 pounds and the engine/transmission unit is over 6.6 feet in length.

This photo shows the crankshaft bolted inside the long block; note the piston and rod to the left. The crank is made from a Ni-Cr-Mo steel billet and took over 30 hours to machine when made in 1979. The crank sits in 7 main bearings. These engines provide 375 horsepower; peak horsepower occurs at 8,000 rpm, however, the power falls off above 8,500-9,000 rpm.

Looking down on the engine block with pistons and rings installed. Reliefs for the values can been seen on the tops of the pistons. Compression ratio is 10.5 to 1. The heads are held in place by 14 studs. The entire block is sand cast in one piece.

The left photo shows the heads installed and the 4 cams in view. The new clutch disk is shown in the photo to the right and the resurfaced flywheel is shown in the left photo. The driveshaft from the transmission enters the engine sump through the apature just below the clutch disk/flywheel. Each of the 4 high lift cams required about 6 hours of machine time. Each cylinder head is sand cast in aluminum and took 144 hours to manufacture originally.

This photo shows the oil sump that houses the driveshaft. Note the ribbing cast into the engine block and sump. The power output to the half shafts and onto the wheels is shown at the lower right. The large sump adds additional strength to the block. The water pump is just to the right of the timing chains. The block and heads are all aluminum.

Six connecting rods and aluminum pistons are shown in front of the aluminum engine block; note the duplex timing chains to the left in this photo. Note too the pressed in steel cylinder liners in this photo. The block is a one piece sand casting and required 23 hours of machining time to produce. These early engines are quite oversquare at 82 x 62 mm bore and stroke, respectively. The beautiful casting of the block is illustrated in this photo.

The exhaust headers were coated (both inside and outside) with a special ceramic coating, a product of the space program, and appear almost like chrome. This coating has substantial temperature advantages and assures that rust will not be a future problem. These beautiful headers can barely be seen when looking in the engine bay.

Engine is nearly finished and ready to go back in the car. Note the aluminum intake manifolds and Weber carbs are yet to be installed. Here the intricate aluminum casting of the engine block and transmission can be seen. The ceramic coated headers are also easily seen; the starter and solenoid are black to the left just behind the left branch of the headers. This photo pays tribute to Italian craftmanship.

The size of the engine and transmission can be appreciated in this photo. Stephen Shroeder (pictured), owner of Poudre Sports Cars, rebuilt the motor over a year long period and looks pleased to see it almost out of his shop.

The sump is also extensively finned and adds strength to the bottom of the engine. Even the cam covers are made of aluminum and finned to aid in cooling.

Details of the hemispherical combustion chambers and valves. These heads were state-of-the-art in the 1970s.

New clutch disk in place. Note, the drive shaft passes back through the engine sump just below the clutch and flywheel.

The engine is ready to be shoehorned back into the car. Here, a standard engine puller (blue) is mounted on a standard, floor mounted rotary lift (yellow). This setup was necessary to get the high clearance needed. Special metal plates (borrowed from a friend in South Carolina) are bolted to the heads and make precise control of the engine possible.

Tight fit; the engine/transmission is approximately 6.6 ft long and weighs nearly 800 pounds. Note the Porsche engine block in the far corner — looks small by comparison.

This is another photo of the engine.